Evaluation of Salinity Tolerance of Some Selected Almond Genotypes Budded on GF₆₇₇ Rootstock

ABSTRACT

In order to evaluate the tolerance of some almond genotypes to salinity, a factorial experiment was carried out based on completely randomized design (CRD), with two factors: genotypes in 11 levels (Tuono, Nonparaeil, Mamaie, Shokoufeh, Sahand, ‘Ferragnès,’ 1–16, 1–25, A₂₀₀, 13–40 budded on GF₆₇₇ rootstock, and GF₆₇₇ (without budding)) and irrigation water salinity in five levels (0, 1.2, 2.4, 3.6, and 4.8 g/l of natural salt (equal electrical conductivity 0.5, 2.5, 4.9, 7.3, and 9.8 dS/m, respectively) and with 4 replication for each treatment in research greenhouse of Seed and Plant Institute in years 2013 and 2014. The results showed that with increasing salinity concentration, growth indicators include the branch height, branch diameter, number of total leaves, percentage of green leaves, leaf density on the main branch, leaf area and leaf area ratio, relative humidity content, chlorophyll index, chlorophylls a, b, total, scion fresh and dry weight, root fresh and dry weight have been reduced in the all genotypes studied, but percentage of necrotic leaves, percentage of downfall leaves, root fresh and dry weight ratio to scion fresh and dry weight, relative ionic percentage, and cell membrane injury percentage of leaves were increased. The results of chlorophyll fluorescence showed that salinity stress affected on the young trees by increasing the amount of minimum fluorescence (F_O) and decreasing the maximum fluorescence (F_m) and reduced variable fluorescence (F_v) in the plants and reduced variable fluorescence ratio to maximum fluorescence of 0.83 in the control plants to 0.72 in Sahand cultivar and GF₆₇₇ rootstock. The result showed that type of scion was affected in obstruction of Na⁺ absorption by the roots and their transported to leaves, as well as was affected in increasing uptake of K⁺ by the roots and their transported to leaves. In this research, GF₆₇₇ is well tolerated to water salinity to 4.9 dS/m but with higher range of salinity showed stress effects. The result showed that type of genotypes budded on GF₆₇₇ rootstock was very effective in tolerant to salinity. Overall, ‘Ferragnès’ was recognized as the most tolerant cultivar to salinity stress. This cultivar could tolerate salinity 3.6 g/l (Ec: 7.3 dS/m). Also, Sahand was recognized as the most sensitive cultivar to salinity stress.

KEYWORDS:

• Almond
• GF₆₇₇
• salinity stress
• growth indices
• chlorophyll fluorescence
• nutrition elements

Introduction

Almond [Prunus dulcis (Mill.) D.A.Webb syn. Prunus amygdalus (L.) Batsch] is one of the most important crops consumed as dry fruit and mainly adaptable to arid and semiarid regions mostly suffering from salinity stress (Bernestin, 1980; Bordi., 2013). In many parts of the world and Iran, salinity is increasing in regions with more evaporation than annual precipitation (Levitt, 1980; Munns and Tester, 2008). Based on the available reports, roughly 12.50% of land areas in Iran are saline, which overwhelmingly contain sodium, while more than 800 million hectares of land area on the earth (6% of overall global land area) are affected by salinity (Munns and Tester, 2008). Therefore, the combination of rootstock and scion as one of the influencing factors in sensitivity or tolerance to salinity of planted fruit trees including almond should be considered (Moreno and Cambra, 1994).

Temperate fruit trees are generally rated as sensitive trees to soluble salts in soils particularly sensitive to chloride and irrigation with saline water may significantly reduce their yields (Bordi., 2013; Grattan, 2002; Rahemi et al., 2008; Zrig et al., 2015). Also, most of the stone fruit trees including almond are sensitive to salt stress and their productivity is gradually reduced at salt concentrations above 1.50 dS/m and down to 50% of normal yield at the salt concentration of 4 dS/m (Maas and Hoffman, 1977; Ottman and Byrne, 1988; Hassan and El- Azayem, 1990).

GF₆₇₇ rootstock, an inter-specific hybrid (Almond × Peach), is propagated asexually as a clone (Moreno and Cambra, 1994). It has been reported that GF₆₇₇ is tolerant to salinity, while Nemagard (P. persica х P. davidiana) rootstock is susceptible to salinity (Montaium et al., 1994). Increasing salinity leads to decrease in values of important traits in almond tree such as longitudinal growth, leaf area, and root development (Flowers, 1999; Bordi., 2013; Zrig et al., 2015). However, Noitsakis et al. (1997) concluded that almond cultivars showed different responses to salinity.

It has been reported that salinity stress is one of the most important environmental factors limiting photosynthesis. Symptoms of salinity stress are expressed at both stomatal and non-stomatal levels. At stomatal level, the plant reduces its stomatas of the leaves by aperture to prevent injuries (Maxwell and Johnson, 2000; Ranjbarfordoei et al., 2006). As a result, net photosynthesis is unavoidably reduced due to a decrease in CO₂ availability, which potentially damages the photosynthetic apparatus (Lawlor and Cornic, 2002). Most of the decreases in photon flux energy used for photochemistry can be explained as an increase in non-photochemical dissipation of excitation energy (Lawlor and Cornic, 2002). Chlorophyll fluorescence (CF) has been used to study plant responses to different kinds of stress (Baker and Rosenqvist, 2004). Chlorophyll (Chl) fluorescence yield (Chl FY) such as minimal Chl FY (F0) and variable Chl FY (F_v) can be used for evidencing stress and damage of the photosynthetic apparatus, and characterizing the environment where plants grow (Deell and Toivonen, 2003; Herda et al., 1999; Kodad et al., 2010). F_v/F_m ratio has been used in many studies related to stress in plants. In most of plants, when ratio F_v/F_m around 0.83 measured in this mean that stress has not been introduced to the plant. Values lower than this will be seen when the plant has been exposed to stress, indicating in particular the phenomenon of photo inhibition.

Under salinity stress, the loss of water availability, toxicity of Na⁺, and ion imbalance cause growth limitation, so plants adopt divert mechanisms to tolerate salinity. It is repeatedly reported that K⁺ deficiency and Na⁺ toxicity are major restrictions of crop production worldwide (Mahajan and Tuteja, 2005; Szczerba et al., 2009). K⁺ can counteract Na⁺ stresses; thus, the potential of plants to tolerate salinity is strongly dependent on their potassium nutrition (Alemán et al., 2011; Nieves-Cordones et al., 2016a).

Despite the presence of information about effect of salinity on morphological and physiological characteristics of almond cultivars, the combination of rootstock and scion tolerate for this plant has not been introduced. Therefore, the aim of the present study was evaluating the effect of salinity stress on morphological and physiological characteristics as well as concentration of nutrition elements in the roots and leaves some of selected almond genotypes budded on GF₆₇₇ rootstock and introducing the most tolerant ones.

Material and method

Plant material and natural salt treatments

In order to evaluate the tolerance of some almond genotypes to salinity, a factorial experiment was carried out based on completely randomized design (CRD), with two factors, genotypes and irrigation water salinity, and with 4 replications for each treatment in research greenhouse of Seed and Plant Institute in years 2013 and 2014. In total, this experiment was carried out with 220 pots. Genotypes were Tuono, Nonparaeil, Mamaie, Shokoufeh, Sahand, ‘Ferragnès,’ 1–16, 1–25, A₂₀₀, 13–40 budded on GF₆₇₇ rootstock, and GF₆₇₇ (without budding), and levels of irrigation water salinity were 0, 1.2, 2.4, 3.6, and 4.8 g/l of natural salt equal electrical conductivity 0.5, 2.5, 4.9, 7.3, and 9.8 dS/m, respectively. To conduct this research, GF₆₇₇ rootstocks that have been produced by tissue culture were replanted into pots filled with 25 kg soil series of fine loamy mixed in early March (Table 1). After rootstocks sufficient growth (6 months after growth), genotypes were grafted on GF₆₇₇ rootstocks by shield budding in middle May; and after scions sufficient growth (10 weeks after budding), salinity treatments were started in late July and continued for 12 weeks. For salinity treatments, natural salt lakes in Qom province were used whose composition is given in Table 2. Also, in order to avoid sudden shock and plasmolysis, salt was gradually added and was reached to final concentration within a week (2 stages of irrigation). Field capacity (FC) of soil in pots was determined before transferring plants to units Pressure plate (Model F1, USA). Irrigation for pots was performed due to change in their weight and leaching requirement. Accordingly, control and 2.1 g/l treatments were applied for 20 times, 4.2 g/l for 19 times, and 3.6 and 4.8 g/l for 17 times. Electric conductivity and pH rate were regularly measured in drainage water to maintain the electric conductivity of both input and soil solutions in a stable range. Finally, at the end of the experiment, soil samples for each treatment were analyzed (Table 3).

Table 1. Physical and chemical characteristics of soil mixture.

Title	Unit	Value	Title	Unit	Value
Depth	(cm)	0–30	Text	–	Loam
S.P	(%)	39	Ca	(ppm)	1230
EC	(dS/m)	1.28	Mg	(ppm)	316.2
pH	-	7.5	T.N.V	(%)	13.8
N	(%)	0.15	Cu	(ppm)	2.12
O.C	(%)	1.49	Zn	(ppm)	4.86
Pavr.	(ppm)	104.9	Fe	(ppm)	27.34
Sand	(%)	46	Kavr.	(ppm)	690
Silt	(%)	34	Mn	(ppm)	16.26
Clay	(%)	20	Na	(ppm)	93.15

Table 2. Water qualitative characteristics used.

Samples with salt different levels	Salinity dS/m	(pH)	Na^+ (mg/l)	Cl^− (mg/l)	Mg^++ (mg/l)	Ca^++ (mg/l)	Hco3^− (mg/l)
0 (g/l)	0.5	7.3	22.1	35.5	17.1	62	98
1.2 (g/l)	2.5	7.4	389	664	20.5	70	126
2.4 (g/l)	4.9	7.6	809	1386	23.01	79	137
3.6 (g/l)	7.3	7.7	1231	2113	23.6	88	149
4.8 (g/l)	9.8	7.8	1653	2836	25.7	99	159

Table 3. EC and pH of soil mixture used in pots then perform salinity stress.

Samples soil with salt different levels	Salinity dS/m	(pH)
0 (g/l)	7.4	1.2
1.2 (g/l)	7.55	3.2
2.4 (g/l)	7.65	5.7
3.6 (g/l)	7.8	8.3
4.8 (g/l)	7.9	10.9

Growth characters

Growth characters including main-shoot length, trunk diameter, and number of leaves were measured just before start of treatments (Table 4), and also after salinity treatments at the end of the experiment. Leaf density on the main branch was calculated via number of leaves on shoot (number of leaf in cm²). Percentage of necrotic leaves (leaves with necrotic 1–50% and 51–100%) and downfall and green leaves were calculated at the end of the experiment (Papadakis et al., 2007). Fresh and dry weights for leaves, main-shoot, and roots were measured immediately after removing, using a digital scale. Dry weight of the samples was measured after separation into an oven in 75°C for 48 h. Leaf area was calculated using leaf area measurement device (Model Li-Cor, USA, and Li-1300) and then their dry weight was measured after separation into an oven in 75°C for 48 h.

Table 4. Growth status of studied genotypes in start of salinity treatment.

Genotypes	Scion diameter (mm)	Diameter control rootstocks in soil surface	Height of control rootstocks	Number of leaves	Scion height (cm)	Number of ramification
1–25	5.09	–	–	44.08	32.70	1
A200	5.40	–	–	70.53	36.11	1
Mamaie	5.04	–	–	69.62	31.12	5.54
NonPareil	5.63	–	–	57.4	43.91	1.27
‘Ferragnès’	5.50	–	–	78.69	43.10	1.15
Tuono	5.78	–	–	75.33	52.36	1
1–16	5.48	–	–	90.31	40.69	1
Shokoufeh	5.46	–	–	88.24	43.20	5.36
13–40	4.81	–	–	52.55	35.13	4.82
Sahand	4.99	–	–	75.53	44.44	3.08
GF677	–	10.26	87.41	59.93	–	4.13

The differences that between genotypes have seen in start of salinity treatments, they are due to differences in their growth rate so that their growth is carried out in research a greenhouse with controlled conditions.

Physiological characters

For determination of leaf chlorophyll, 0.20 g leaf was extracted with ethanol 80% and then content of chlorophyll a and chlorophyll b, total chlorophyll were calculated with the method as described by Arnon (1949). Leaf greenness (chlorophyll index) was evaluated on the same leaves used for gas exchange and fluorescence using a SPAD, Minolta, 502 made by Japan after 12 weeks of salinity treatments.

For determination of water content relative of leaves, Fresh weight (Fw) was recorded and then samples were put into distilled and kept at 4°C for 24 hours in the dark. After the emission of extra humidity, samples were weighed again to obtain the Total weight (Tw). Subsequently, samples were kept in the oven at 105°C for 24 hours and Dry weight (Dw) was recorded. Finally, relative water content was calculated via formulae (Yamasaki and Dillenburg 1999)

For determination of relative ionic content, the amount of 0.5 g of each sample was put in tubes with 25 ml of distilled water at 25°C for 24 hours on a shakier with speed 120 in/min. Electrical conductivity (EC) of the medium was then read using a conductivity meter (conduct meter; Radiometer, Copenhagen). Following the initial reading (Lt), samples were autoclaved for 20 minutes to kill leaf tissues and then kept at 25°C for 2 hours on shakier with speed 120 in/min and a final reading (Lo) was obtained. Finally, relative ionic percentage was calculated via formulae:

Relative ionic percentage = (Lt/Lo) × 100 as in Lutts et al (1995).

After calculation relative ionic, percentage cell membrane injury in samples’ treatment with natural salt ratio samples control was performed as follows:

where T and C refer to the EC values of stress treated and control tubes and 1 and 2 refer to the initial and final EC, respectively (Lutts et al., 1995).

Chlorophyll fluorescence parameters

Chlorophyll fluorescence of leaves was measured using a portable fluorometer PAM-2000 (H. Walz, Effeltrich, Germany). Before measuring chlorophyll fluorescence parameters, leaves were put in dark-adapted state (DAS) for 30 min using light exclusion clips (Maxwell and Johnson, 2000). Maximum quantum efficiency of photosystem II (F_v/F_m) was determined as F_v/F_m = (F_m – F_o)/F_m, where F_m and F_o were maximum and minimum fluorescence of dark-adapted leaves, respectively.

Concentration of Na⁺ and K⁺

For determination of concentration of Na⁺ and K⁺ in leaves and roots, in initially, samples oven-dried at 75°C for 48 h, and then milled to a fine powder to pass through a 30-mesh screen. A known value of 0.5 g of each sample was dry-ached for 6 h at 550°C, dissolved in 3 mL 6 mol/l HCl, and diluted to 50 ml with deionized water. Subsequently, concentration of Na⁺ and K⁺ was determined using atomic absorption spectroscopy (Papadakis et al., 2007).

Statistical analysis

This experiment was carried out based on CRD, with two factors: genotypes in 11 levels and irrigation water salinity in 5 levels and with 4 replications for each treatment in research greenhouse of Seed and Plant Institute in years 2013 and 2014. Totally, this experiment was carried out with 220 pots. Finally, data were analyzed using analysis of variance (ANOVA) using SAS, and the means were separated by Duncan’s multiple range test at 1% level.

Results and discussion

Based on the results of this study (Table 5), as the salt concentration increases, the final diameter and its growth were decreased during the application of salinity stress in irrigation water in all genotypes. The lowest branch diameter and the least increase in diameter of main branch were observed in 4.8 g/l treatment. The decrease in diameter of the main branch in the genotypes showed a significant difference. The lowest increase in the diameter of the main branch was observed in GF₆₇₇ rootstock and Sahand cultivar treated with 4.8 g/l.

Table 5. Effect of interaction between salinity and genotype on some of growth characteristics.

Genotype	Salinity (g/l)	Amount increase in scion diameter (mm)	Final diameter of scion (mm)	Amount increase in scion height (cm)	Final height of scion (cm)	No. of produced leaves	No. of final leaves	Density of leaf on shoot (cm^2)
	0	3.51 j-m	9.40 d-h	28.14 e-j	65.72 l-r	45.00 i-n	91.00 m-p	1.39 m-q
	1.2	3.97 e-h	7.25 k-n	42.14 b-d	61.72 m-s	78.67 e-g	105.33k-n	1.70 h-l
1–25	2.4	3.06 m-p	8.62 h-l	30.42 c-h	66.20 l-r	40.00 j-o	87.67 m-p	1.33 n-r
	3.6	2.37 p-s	7.35 k-n	26.70 f-j	54.37 n-t	45.67 i-n	89.67 m-p	1.67 h-m
	4.8	1.94 q-t	6.70 l-o	25.80 g-l	51.73 p-t	32.67 k-p	75.67 o-r	1.43 l-p
	0	2.41 p-s	7.30 k-n	25.48 g-l	56.15 m-s	100.00 c-e	165.33 b-d	2.95 ab
	1.2	2.64 o-r	7.07 k-o	32.53 b-g	47.67 r-t	118.00 a-c	162.00 b-e	3.40 a
Mamaie	2.4	2.29 q-t	7.87 j-n	16.50 m-r	49.20 r-t	61.33 g-k	137.33 d-h	2.79 bc
	3.6	2.21 q-t	6.57 no	26.30 f-j	49.27 r-t	57.00 g-l	103.33 l-o	2.10 d-i
	4.8	2.03 q-t	6.5 o	11.00 q-s	40.20 t	53.33 h-m	102.33 m-o	1.92 e-j
	0	2.28 q-t	7.30 k-n	36.48 b-g	58.58 k-q	94.00 c-f	131.33 g-k	2.25 c-h
	1.2	2.86 m-p	8.10 j-n	20.20 j-o	61.47 h-n	48.33 h-m	100.00 m-p	1.65 i-n
13–40	2.4	1.96 q-t	7.18 k-n	11.20 p-s	45.20 st	51.00 g-m	109.00 i-m	2.42 b-e
	3.6	2.02 q-t	6.93 l-o	28.65 e-j	50.60 q-t	49.33 g-m	85.00 n-q	1.68 h-m
	4.8	1.83 r-t	6.70 m-o	15.19 n-r	47.00 r-t	23.00 m-p	73.33 p-r	1.22 p-s
	0	3.96 e-h	8.75 g-j	40.40 b-e	84.60 b-e	143.00 a	220.00 a	2.60 b-d
	1.2	3.26 l-o	8.20 j-n	34.11 b-h	77.90 b-h	108.67 bc	201.67 a	2.59 b-d
1–16	2.4	2.67 p-s	7.50 j-n	29.05 d-i	63.23 f-j	107.00 cd	201.00 a	2.91 ab
	3.6	2.12 q-t	7.33 k-n	10.43 q-s	54.57 n-t	37.00 k-o	138.00 d-h	2.18 d-i
	4.8	1.67 s-u	7.10 k-o	17.52l-r	40.47 t	54.67 g-l	112.67 f-j	2.29 c-g
	0	4.11 b-e	9.95 c-f	38.45 b-g	94.20 b	73.33 e-i	151.00 b-f	1.59 j-n
	1.2	3.61 g-j	9.22 d-h	39.34 b-f	92.13 b-d	49.67 g-l	136.67 d-h	1.48 k-o
Tuono	2.4	3.22 l-o	8.65 h-l	42.10 b-d	78.50 b-h	62.67 h-k	108.67 i-m	1.37 m-q
	3.6	2.62 p-s	8.13 j-n	21.09 i-o	76.30 b-h	29.00 l-p	106.00j-n	1.40 l-p
	4.8	2.08 q-t	7.57 k-n	14.31 o-s	75.97 b-h	15.67 n-P	104.67 k-n	1.27 o-s
	0	3.83 e-h	9.25 d-h	44.82 b	94.60 b	116.67 a-c	216.00 a	2.28 c-g
	1.2	2.80 n-q	7.50 k-n	35.95 b-g	71.53 e-j	73.00 e-i	150.00 b-f	2.11 d-i
‘Ferragnès’	2.4	3.00 m-p	7.82 j-n	43.39 bc	80.15 b-g	72.67 e-i	141.00 d-h	1.83 f-j
	3.6	2.37 q-t	7.55 k-n	31.90 b-h	82.03 b-f	60.67 gk	146.00 c-g	1.78 g-l
	4.8	2.23 q-t	6.80 m-o	34.07 b-g	73.03 d-i	78.00 e-h	134.00 e-i	1.84 f-k
	0	4.91 a	10.43 b-d	40.10 b-e	65.60 e-j	77.33 e-h	160.00 b-f	2.43 b-e
	1.2	4.22 b-d	10.38 b-e	59.17 a	81.37 b-g	135.00 ab	176.00 b	2.16 d-i
A200	2.4	3.26 g-j	8.63 h-l	38.43 b-g	73.50 c-i	79.33 e-g	142.00 c-g	1.97 e-i
	3.6	2.61 p-s	8.15 j-m	33.90 b-g	79.30 b-h	96.00 c-f	162.00 b-e	2.16 d-h
	4.8	1.93 q-t	7.25 k-n	18.77 k-p	63.50 f-k	41.33 j-o	141.67 d-h	2.20 d-h
	0	4.63 a-c	9.85 b-f	42.73 bc	94.47 b	51.33 g-m	114.33 h-l	1.21 p-s
	1.2	4.05 b-f	9.75 c-g	27.80 e-j	78.73 b-h	39.00 j-o	101.33 m-p	1.29 o-s
Nonpareil	2.4	3.89 e-h	8.85 f-k	32.80 b-h	70.80 e-j	41.00 j-o	90.00 m-p	1.29 o-s
	3.6	3.46 h-k	8.48 g-l	18.73 k-p	49.90 q-t	28.00 l-p	96.33 m-p	2.04 d-i
	4.8	2.82 n-r	8.1 i-m	21.28 i-n	59.02 j-q	35.67 k-o	80.00 n-q	1.27 o-s
	0	3.55 h-l	9.00 f-j	31.23 c-i	73.40 c-i	79.00 e-g	153.00 b-f	2.08 d-i
	1.2	4.45 b-d	9.65 d-g	24.00 h-m	65.27 e-j	57.00 g-l	154.33 b-f	2.36 c-f
Shokoufeh	2.4	3.12 l-p	7.85 j-n	43.56 bc	65.83 e-j	113.00 bc	170.33bc	2.59 b-d
	3.6	3.07 l-p	8.22 i-m	16.97 m-r	61.83 g-m	45.33 i-n	130.33 g-l	2.11 d-i
	4.8	2.38 q-t	7.25 k-n	28.64 e-j	69.13 e-k	61.33 g-k	160.33 b-f	2.23 d-h
	0	4.15 b-e	8.60 h-l	33.60 b-h	60.00 i-o	63.00 g-k	135.00 e-i	2.25 c-g
	1.2	3.95 c-g	8.95 f-j	25.69g-l	74.80 c-i	68.33 f-j	141.33 d-h	1.89 e-i
Sahand	2.4	3.05 l-p	7.70 j-n	27.23 e-j	56.57 l-r	45.00 i-n	98.67 m-p	1.73 g-k
	3.6	2.23 q-t	7.55 j-n	10.99 p-s	52.60 o-t	29.33 l-p	88.33 m-p	1.48 k-o
	4.8	1.14 s-u	6.50 o	17.00 m-r	54.75 n-t	24.67 m-p	109.00 i-m	0.75 st
	0	3.67 e-h	12.48 a	16.20 m-r	116.53 a	26.67 m-o	94.00 m-p	0.82 r-t
	1.2	2.83 m-q	11.59 ab	19.93 j-p	112.63 a	29.67 l-o	97.67 m-p	0.87 q-t
Gf677	2.4	2.43 q-t	10.98 a-c	16.53 m-r	117.97 a	16.33 n-p	80.67 n-q	0.68 t
	3.6	1.05 tu	10.38 b-d	7.23 rs	92.53 bc	12.67 op	59.33 qr	0.38u
	4.8	0.31 u	9.90 c-f	6.02 s	93.32 bc	6.67 p	51.00 r	0.08 v

Means in each column and for each factor followed by similar letter(s) are not significantly different at the 1% probability level using Duncan’s multiplerRange test.

The results showed that the increase of height and the final height of plants were decreased, in all genotypes as the salinity increased, and the reduction of height in budded genotypes showed significant differences. The rate of increase in the height of the control plants such as the 1–25 genotype, Shokoufeh, and ‘Ferragnès’ cultivars were 28.14, 31.23, and 44.82 cm, respectively, while the rate of increase in the height of main branches in the last three cultivars in the 4.8 g/l treatment were 25.8, 28.64, and 34.07 cm, respectively. These results indicated that the height of 1–25 genotype and Shokoufeh and ‘Ferragnès’ cultivars were respectively decreased 2.34, 2.59, and 10.75 cm, compared to the control plants, which did not show a significant difference, while significant decrease was observed in other genotypes compared to control plants (Table 5). Plant height is heavily dependent on growth environment. Since the growth phenomenon gained vital activities in which condition the plant must be in possession of enough water, reduction in the height occurs in case of failure to provide the required water due to the reduction of cell turgor pressure and length of the cells would be negatively affected (Munns and Tester, 2008). The osmotic effects of salinity stress can be observed immediately after salt application and are believed to continue for the duration of exposure, resulting in inhibited cell expansion and cell division (Munns and Tester 2008).

The results showed that number of produced leaves with increasing salinity concentrations were reduced, but the amount of reduction in the number of leaves produced in different genotypes had significant differences. The maximum number of leaves were observed in control plants of 1–16 genotype (143 leaves), and the lowest amount of it were observed in Tuono and Sahand cultivars and 13–40 genotype under 4.8 g/l treatment (15.67, 23, and 24.67 leaves) respectively.

The reduction in the number of produced leaves did not show any significant difference in Shokoufeh and Nonpareil cultivars and 1–25 genotype in treatment 4.8 g/l compared to the control plants, while in other genotypes, the reduction in the number of produced leaves was significant. The results showed that produced leaves in the GF₆₇₇ rootstock in control plants and treatments 1.2, 2.4, and 3.6 g/l were 26.67, 29.67, and 16/33 respectively, which did not show any significant difference, while the number of leaves produced in 4.8 g/l treatment (6.67) was significantly decreased compared to the control plants (Table 5).

The results of the means comparison showed that leaf density in Mamaie and Sahand cultivars and GF₆₇₇ in 3.6 and 4.6 g/l treatments and in Tuono cultivar and 13–40 genotype in 4.8 g/l treatment were significantly decreased compared to control plants. These results indicated that decrease in the number of leaves produced and the increase in fallen leaves in these genotypes were more rapid than decrease in height of the plants under salinity stress, which resulted in reduced leaf density.

The results showed that with increasing salinity of irrigation water, the percentage of green leaves in all genotypes were decreased. The lowest percentage of green leaves was observed in plants treated with 4.8 g/l. In control plants and also plants treated with 1.2 g/l, all leaves of plants were green and necrotic leaves were not observed. Necrosis and fallen leaves in all genotypes were observed in 3.6 and 4.6 g/l treatments. The lowest percentage of green leaves in 4.8 g/l treatment were found in GF₆₇₇ rootstock, Sahand, Tuono, Mamaie, 13–40 and 1–16 genotypes, Nonpareil and 1–25 genotype, respectively. Percentage of green leaves loss in these plants were significant.

The highest percentage of green leaves in 4.8 g/l treatment were observed in ‘Ferragnès’ (96.10%), A₂₀₀ (94.29%), and Shokoufeh cultivars (92.27%), which no significant decrease in percentage of green leaves in these cultivars were observed (Table 5). These results were consistent with the results of Noitsakis et al. (1997). They investigated the effect of zero, 1.8, and 3.6 g/l of sodium chloride salinity levels on different cultivars of almond and concluded that almond cultivars showed different reactions to salinity levels.

Based on the results of this study, in all genotypes as the salinity increases, the percentage of necrosis leaves were increased and the first symptoms of necrosis were observed in some genotypes in 2.4 g/l treatment. In all genotypes, the highest incidence of necrosis leaves (leaves that showed 1–50% necrosis) was observed at 4.8 g/l treatment, so was the increase in percentage of necrosis leaves in Tuono, Sahand, Mamaie, Nonpareil cultivars, and 1–16, 1–25, and 13–40 genotypes and GF₆₇₇ rootstock were significantly different from control plants, but in ‘Ferragnès’, Shokoufeh, and A₂₀₀ cultivars, were not significantly different (Table 6). As the salt concentration increased and reach to 3.6 g/l, leaves with 51–100% necrosis in plants were observed. In this level of salt concentration, percentage of necrosis leaves in Sahand cultivar, 1–16 genotype, and GF₆₇₇ rootstock was significantly higher than control plants. In 4.8 g/l treatment, percentage of necrosis in Tuono, Sahand, Mamaie cultivars and 1–16, 13–40 and 1–25 genotypes and GF₆₇₇ rootstock was significantly higher than control plants. But in ‘Ferragnès’, Shokoufeh, A₂₀₀ and Nonpareil cultivars weren’t significant compared to control plants (Table 6).

Table 6. Effect of interaction between salinity and genotype on some of growth characteristics.

Genotype	Salinity (g/l)	Green leaves (%)	Necrosis leaves (51–100 percentage) (%)	Necrosis leaves (51–100 percentage) (%)	Downfall leaves (%)	Shoot fresh weight (g)	Shoot dry weight (g)	Root fresh weight (g)	Root dry weight (g)
	0	100 a	0 e	0 e	0 h	19.93 d-h	8.59 h-m	61.17 a-c	20.82 a-c
	1.2	100 a	0 e	0 e	0 h	18.67 e-j	8.26 h-m	50.17 c-h	19.43 a-d
1–25	2.4	100 a	0 e	0 e	0 h	17.22 g-o	8.16 i-n	57.20 a-e	18.06 b-e
	3.6	98.48 a	1.52 e	0 e	0 h	11.06 p-v	5.11 n-r	44.74 d-i	11.52 h-m
	4.8	88.11b-d	7.07 cd	3.94 cd	1.48 gh	9.18 s-v	4.05 qr	37.03 g-l	11.09 i-m
	0	100 a	0 e	0 e	0 h	12.92 o-u	6.68 l-q	31.78 k-p	8.08 o-r
	1.2	100 a	0 e	0 e	0 h	6.97 t-v	3.87 qr	30.13 l-r	7.92 p-r
Mamaie	2.4	99.83 a	0.16 e	0 e	0 h	10.32 p-v	5.32 m-r	34.90 h	10.57 j-n
	3.6	97.05 a	2.94 c-e	0 e	0 h	9.61 s-v	4.74 n-r	37.70 g-l	10.67 j-n
	4.8	61.22 fg	18.78 b	9.95 ab	10.22 d	6.30 v	3.17 r	27.03 n-r	7.88 p-r
	0	100 a	0 e	0 e	0 h	10.25 p-v	5.20 n-r	24.70 o-s	10.18 k-p
	1.2	100 a	0 e	0 e	0 h	11.98 o-u	6.28 l-q	31.88 k-q	8.96 m-q
13–40	2.4	99.31 a	0.68 e	0 e	0 h	8.35 s-v	4.35 p-r	21.27 q-s	8.29 n-r
	3.6	96.87 a	3.13 c-e	0 e	0 h	7.69 s-v	3.84 qr	21.63 q-s	7.86 p-r
	4.8	66.96 f	19.05 b	4.94 c	10.91 d	6.64 uv	3.28 r	23.88 p-s	6.89 r
	0	100 a	0 e	0 e	0 h	19.85 d-i	8.82 g-l	56.82 a-f	16.23 c-h
	1.2	100 a	0 e	0 e	0 h	18.37 e-k	9.16 f-k	52.71 a-g	16.65 c-g
1–16	2.4	99.65 a	0.348 e	0 e	0 h	16.76g-p	7.75 i-o	50.46 b-h	15.50 d-i
	3.6	85.68 de	5.50 c-e	5.01 c	4.32 ef	13.38 m-s	6.56 j-p	47.28 c-i	14.38 d-j
	4.8	80.40 e	7.03 cd	5.68 c	6.58 e	8.77 s-v	4.11 qr	34.31 j-p	9.13 l-p
	0	100 a	0 e	0 e	0 h	25.70 cd	13.36 ed	28.83 l-r	8.56 n-r
	1.2	100 a	0 e	0 e	0 h	23.90 c-f	12.35 d-f	27.89 m-r	8.10 o-r
Tuono	2.4	100 a	0 e	0 e	0 h	16.34 k-p	8.31 h-m	21.11 rs	6.82 r
	3.6	94.43 ab	4.66 c-e	0.914e	0 h	18.80 e-j	9.68 e-j	34.11 j-p	12.40 f-j
	4.8	55.19 g	28.56 a	12.94 a	3.31 fg	18.23 e-l	9.33 f-k	35.67 h-m	10.50 j-n
	0	100 a	0 e	0 e	0 h	24.56 c-e	12.04 d-g	49.81 c-h	16.87 c-g
	1.2	100 a	0 e	0 e	0 h	20.33 d-h	9.94 e-h	44.18 d-j	12.62 f-j
‘Ferragnès’	2.4	100 a	0 e	0 e	0 h	17.46 f-m	8.64 h-m	44.63 d-j	15.44 d-i
	3.6	98.03a	1.97 de	0 e	0 h	19.53 d-j	9.83 e-j	42.83 e-k	12.11 f-j
	4.8	96.10 a	3.52 c-e	0.36 e	0 h	12.02 n-r	6.01 l-p	30.47 l-q	9.56 l-q
	0	100 a	0 e	0 e	0 h	10.00 p-v	5.04 n-r	38.45 g-m	10.11 l-q
	1.2	100 a	0 e	0 e	0 h	12.82 o-u	5.97 l-p	35.50 h-n	10.41 l-p
A200	2.4	100 a	0 e	0 e	0 h	9.38 s-v	4.84 n-r	25.17 o-s	7.71 p-r
	3.6	97.98 a	2.02 de	0 e	0 h	18.18 e-l	8.39 h-m	38.50 g-m	10.87 k-o
	4.8	94.28 ab	3.51 c-e	1.48 de	1.21 gh	10.73 p-v	5.29 n-r	34.50 i-o	9.16 l-r
	0	100 a	0 e	0 e	0 h	28.21 c	13.88 d	59.50 a-d	16.33 c-h
	1.2	100 a	0 e	0 e	0 h	23.20 c-g	11.93 d-g	56.51 a-e	16.36 c-h
Nonpareil	2.4	100 a	0 e	0 e	0 h	17.94 f-l	8.63 k-p	41.50 e-j	11.33 i-n
	3.6	97.63a	1.91 de	0.46 e	0 h	13.38 n-t	6.92 l-q	39.17 g-l	11.12 i-n
	4.8	96.96 c-e	8.03 c	2.91 c-e	3.19 fg	19.07 e-j	9.48 f-j	43.17 e-j	11.45 h-l
	0	100 a	0 e	0 e	0 h	17.33f-o	8.35 j-p	67.40 a	22.52 ab
	1.2	100 a	0 e	0 e	0 h	18.84 e-j	10.32 d-h	65.67 ab	23.58 a
Shokoufeh	2.4	99.58 a	0.42 e	0 e	0 h	11.40 p-v	5.72 l-q	41.30 f-k	13.35 e-j
	3.6	97.06 a	2.86 de	0.09 e	0 h	13.58 l-q	7.14 k-p	40.67 g-l	12.86 f-k
	4.8	92.27 a-d	4.99 c-e	1.49 de	1.87 gh	13.07 n-t	7.02 l-r	40.00 g-l	12.74 f-l
	0	100 a	0 e	0 e	0 h	11.80 o-u	6.00 m-r	47.00 c-h	13.31 e-j
	1.2	100 a	0 e	0 e	0 h	14.33 k-q	7.35 j-n	46.73 c-h	13.35 e-j
Sahand	2.4	96.50 a	3.50 c-e	0 e	0 h	13.43 m-r	6.78 k-o	36.92 g-l	9.63 l-q
	3.6	63.83 f	2.30 b	9.64 b	6.36 e	10.58 q-v	5.32 n-r	31.90 k-p	8.59 n-r
	4.8	37.30 i	16.97 b	12.81 a	27.79 b	11.90 o-u	5.95 l-p	36.67 g-m	9.87 j-p
	0	100 a	0 e	0 e	0 h	41.66 a	23.87 a	57.24 a-e	17.15 c-f
	1.2	100 a	0 e	0 e	0 h	35.54 b	19.99 c	48.35 c-i	14.17 e-j
Gf677	2.4	92.77 a-d	7.23 cd	0 e	0 h	35.32 b	19.40 c	43.50 e-j	12.87 f-k
	3.6	46.58 h	21.84 b	11.61 ab	19.96 c	35.33 b	21.50 bc	50.97 b-g	18.09 b-e
	4.8	25.87 j	21.05 b	11.63 ab	41.44 a	42.42 a	24.60 a	59.33 a-d	20.19 a-c

Means in each column and for each factor followed by similar letter(s) are not significantly different at the 1% probability level using Duncan’s multiple range test.

The fallen leaves were observed in 3.6 g/l treatment in Sahand cultivar, GF₆₇₇ rootstock, and 1–16 genotype. In 4.8 g/l treatment, fallen leaves were observed in all genotypes except for ‘Ferragnès’ cultivar. At this level of salinity, the percentage of fallen leaves in Shokoufeh, A₂₀₀ and Nonpareil cultivars and 1–25 genotype, were not significant compared to control plants. The highest percentage of fallen leaves were found in GF₆₇₇ rootstock (41.44%), Sahand (27.79%), 1–16 genotype (16.58%), Mamaie (22.2%), and 13–40 genotype (9.91%), (Table 5).

The results showed that fresh and dry weight of roots were decreased as the salinity concentration increased, but its reduction was different depending on the type of genotype grafted on them (Table 6). Fresh and dry weight loss in the rootstocks in which the Shokoufeh cultivar was grafted on them in levels of 2.4, 3.6, and 4.8 g/l, and in the rootstocks in which the Nonpareil and 1–25 genotype were grafted on them, in levels of 3.6 and 4.8 g/l and in the rootstocks in which ‘Ferragnès’cultivar were grafted on them, in 4.8 g/l treatment had a significant reduce compared to the control plants, while the roots fresh and dry weight loss in other budded compounds in all levels of salinity showed significant difference compared to control plants. These results indicated that vegetative characteristics of Shokoufeh, ‘Ferragnès’, Nonpareil cultivars, and 1–25 genotype maintained higher than other genotypes under salt stress, also salt stress had a greater effect on maintaining the vigorous root growth. It has been reported that the almond root development range decreases with increasing salinity, which is due to ion toxicity and drought stress due to increased osmotic potential of soil solution (El-Azab et al., 1998; Noitsakis et al., 1997; Rahemi et al., 2008).

The results showed that shoot fresh and dry weight in all studied genotypes significantly decreased by applying salinity stress and increasing its concentration. Shoot fresh and dry weight in Mamaie, Sahand, Tuono, Nonpareil cultivars, 1–16 and 13–40 genotypes and GF₆₇₇ rootstock in 2.4, 3.6, and 4.8 g/l salinity levels and in Shokoufeh cultivar and 1–25 genotype in 3.6 and 4.6 g/l salinity levels and in ‘Ferragnès’ and A₂₀₀ cultivars only in 4.8 g/l salinity level were decreased significantly compared to control plants. These results were consistent with the results of Noitsakis et al. (1997) and Bordi. (2013). In these studies, effect of salinity levels on almond cultivars concluded that almond cultivars showed different responses to salinity levels.

The root fresh to dry weight and ratio of shoot fresh to dry weight in all studied genotypes were increased with increasing salinity levels. The highest root fresh and dry weight ratio to shoot fresh and dry weight was observed in plants that were irrigated with 9.8 dS/m treatment. In salt stress conditions, the photosynthesis rate in plants was significantly reduced, which results in a decrease in the material composition and growth rate of the aerial parts. On the other hand, the effect of salinity on root growth decrease was usually less than shoot growth. Therefore, root fresh weight to dry weight ratio of shoot fresh and dry weight in ‘Ferragnès’ and Shokoufeh cultivars under salt stress conditions, their growth characteristics maintained better than other genotypes, only in 4.8 g/l salinity level this was increased significantly.

Leaf area and leaf area ratio were affected by genotype interaction and salinity stress. The lowest leaf area and leaf area ratio were observed in plants that were irrigated with 9.8 dS/m treatment. Leaf area reduction and leaf area ratio in the GF₆₇₇ rootstock, 1–16 genotype and Sahand, Nonpareil and Mamaie cultivars in 3.6 and 4.8 g/l treatments, in Tuono cultivar and 1–25 and 13–40 genotypes in 4.8 g/l treatments decreased significantly compared to the control plants, but leaf area reduction and leaf area ratio in Shokoufeh and ‘Ferragnès’ were not significant compared to the control plants (Table 7). These results were consistent with the results of Noitsakis et al. (1997), El-Azab et al. (1998), and Rahemi et al. (2008). It has been reported that the decrease in plant growth due to salinity can be the result of a decrease in the leaf area of the plant, which is due to imbalance in growth and division of the cell. In plants under salt stress the leaves were small and thick, and older leaves become premature aging.

Table 7. Effect of interaction between salinity and genotype on some of growth characteristics.

Genotype	Salinity (g/l)	Leaf fresh weight (g)	Leaf dry weight (g)	Leaf area (cm^2)	Ratio leaf area (cm^2/g)	Scion fresh weight (g)	Scion dry weight (g)	Root dry weight ratio to scion dry weight	Root fresh weight ratio to scion fresh weight
	0	0.35 ab	0.13 b	11.39 d-g	89.93 b-f	62.10 e-i	23.62 f-j	0.91 a-c	1.02 d-g
	1.2	0.37 ab	0.14 b	12.76b-e	91.17 b-f	57.29 f-j	22.43 f-j	0.87 bc	0.88 e-h
1–25	2.4	0.39 ab	0.15 b	12.66 b-e	83.88 g-k	52.56 h-l	21.66 g-k	0.85 bc	1.11 b-e
	3.6	0.29 bc	0.11 bc	9.50 h-k	85.28 f-j	38.50 o-s	15.83 o-s	0.73 d-f	1.16 b-e
	4.8	0.23 c	0.10 c	8.70 l-o	79.48 i-m	26.57 r-u	12.39 q-t	0.96 ab	1.38 b
	0	0.24 c	0.09 c	8.61 m-p	95.70 a-c	66.69 d-h	26.00 e-i	0.31 wx	0.48 q-s
	1.2	0.23 c	0.08 cd	8.58 m-p	102.20 a	42.97 m-q	17.27 m-q	0.34 u-w	0.7 i-l
Mamaie	2.4	0.22 c	0.08 cd	8.09 n-q	97.03 ab	48.08 i-m	18.92 k-o	0.56 i-k	0.73 g-j
	3.6	0.21 c	0.08 cd	7.10 q-t	87.36 d-g	36.71 o-s	14.60 p-t	0.73 d-f	1.02 d-g
	4.8	0.17 d	0.06 d	6.32 t-w	84.54 f-j	23.86 s-u	11.04 st	0.72 d-f	1.14 b-e
	0	0.25 bc	0.10 c	8.69 l-o	85.70 f-j	46.02 k-n	18.41 l-p	0.55 j-l	0.54 p-s
	1.2	0.26 bc	0.10 c	8.88 k-n	86.55 d-h	45.76 k-n	18.41 l-p	0.48 n-p	0.70 i-l
13–40	2.4	0.25 bc	0.10 c	8.68 l-o	88.68 b-f	40.71 n-r	16.30 n-r	0.50 m-o	0.52 q-s
	3.6	0.21 c	0.08 cd	6.73 s-v	82.84 f-j	29.73 q-u	12.03 q-t	0.67 e-g	0.74 g-j
	4.8	0.17 d	0.07 d	5.57 vw	79.24 i-m	18.51 u	8.79 t	0.78 b-d	1.30 b-d
	0	0.32 b	0.13 b	11.56 d-g	87.14 c-g	106.51 a	41.60 ab	0.39 r-t	0.54 p-s
	1.2	0.31 b	0.13 b	10.72 f-i	84.69 f-j	92.90 a-c	38.34 bc	0.43 o-q	0.57 m-p
1–16	2.4	0.31 b	0.12 bc	9.33 i-l	78.93 i-m	75.18 c-g	34.36 c-e	0.45 n-p	0.67 j-m
	3.6	0.23 c	0.09 c	6.88 r-u	77.47j-m	45.31 k-o	20.40 i-m	0.70 d-f	1.04 d-g
	4.8	0.21 c	0.09 c	6.45 t-w	74.31 l-o	34.09 p-t	15.43 p-t	0.59 g-i	0.99 e-h
	0	0.30 bc	0.11 bc	10.11 e-h	92.62 b-f	74.74 c-g	31.05 c-g	0.29 x	0.40 s
	1.2	0.31 b	0.12 bc	10.57 e-h	91.19 b-f	68.46 d-h	28.72 c-h	0.29 x	0.42 rs
Tuono	2.4	0.34 b	0.12 bc	11.76 c-f	94.82 a-e	46.64 j-n	20.26 j-n	0.29 x	0.46 q-s
	3.6	0.35 ab	0.13 b	10.38 e-h	78.96 j-m	53.69 g-k	24.33 f-j	0.52 k-m	0.64 j-m
	4.8	0.29 bc	0.12 bc	9.50 i-l	78.86 i-m	44.70 k-o	21.98 h-k	0.48 m-o	0.85 e-h
	0	0.28 bc	0.11 bc	9.27 i-m	85.82 f-j	101.77 a-c	47.04 a-c	0.35 u-w	0.49 q-s
	1.2	0.27 bc	0.11 bc	9.07 j-m	83.22 h-k	76.10 c-f	31.87 c-f	0.40 q-s	0.59 k-n
‘Ferragnès’	2.4	0.29 bc	0.12 bc	10.20 f-i	85.61 f-j	64.69 e-i	27.43 d-h	0.56 i-k	0.69 i-l
	3.6	0.31 b	0.12 b	9.84 f-i	79.40 i-m	76.55 c-f	32.13 c-f	0.38 s-u	0.56 n-p
	4.8	0.30 bc	0.12 b	9.91 f-i	82.45 h-l	46.78 j-n	21.81 g-k	0.44 o-q	0.65 j-m
	0	0.29 bc	0.11 bc	10.89 e-h	94.99 a-d	64.58 e-i	25.63 e-i	0.40 q-s	0.60 k-n
	1.2	0.31 b	0.12 b	11.23 e-i	91.05 b-f	70.16 d-h	29.11 c-g	0.36 t-v	0.51 q-s
A200	2.4	0.28 bc	0.11 bc	9.27 i-l	83.12 h-k	50.88 i-m	21.54 g-k	0.35 t-v	0.49 q-s
	3.6	0.26 bc	0.10 c	7.91 o-r	77.08 k-n	70.00 d-h	29.26 c-g	0.41 p-s	0.55 o-q
	4.8	0.19 cd	0.09 c	6.88 r-u	73.77 m-o	44.81 k-o	20.53 j-m	0.45 n-p	0.77 f-i
	0	0.45 a	0.18 a	17.11a	95.07 a-d	82.63 b-e	34.44 b-e	0.48 m-p	0.72 h-k
	1.2	0.36 ab	0.15 b	14.26 b	96.44 ab	64.93 d-h	27.55 d-h	0.60 g-i	0.87 e-h
Nonpareil	2.4	0.38 ab	0.15 b	14.00 b	93.33 b-f	48.20 i-m	21.09 h-l	0.54 j-l	0.86 e-h
	3.6	0.35 ab	0.15 b	13.22 b-d	86.98 e-i	44.40 k-o	20.05 j-n	0.58 h-j	0.93 d-g
	4.8	0.40 ab	0.17 ab	14.52 b	86.18 e-i	46.06 k-o	20.45 i-m	0.61 g-i	0.94 d-g
	0	0.19 cd	0.09 c	5.99 u-w	69.12 n-q	75.21 c-g	30.36 c-g	0.74 d-f	0.90 e-h
	1.2	0.17 cd	0.08 cd	5.45 vw	73.28 m-p	73.84 c-h	30.77 c-h	0.77 c-e	0.89 e-h
Shokoufeh	2.4	0.18 cd	0.08 cd	5.60 vw	69.90 n-q	46.55 h-n	20.82 h-m	0.63 g-i	0.88 e-h
	3.6	0.18 cd	0.08 cd	5.48 vw	68.51 o-q	43.68 m-q	20.42 i-m	0.63 g-i	0.93 d-h
	4.8	0.16 cd	0.08 cd	4.98 w	64.26 qr	39.64 n-r	19.77 j-n	0.65 f-h	1.02 d-g
	0	0.30 bc	0.12 bc	10.63 f-i	88.62 b-f	65.42 d-h	27.18 d-h	0.49 m-o	0.72 h-k
	1.2	0.29 bc	0.12 bc	10.53 f-i	89.24 b-f	66.52 d-h	28.15 d-h	0.47 n-p	0.70 i-l
Sahand	2.4	0.28 bc	0.11 bc	10.29 f-i	87.71 b-f	43.86 l-p	19.53 j-n	0.51 l-n	0.88 e-h
	3.6	0.21 c	0.11 bc	7.57 p-s	71.23 m-q	28.40 q-u	14.59 p-t	0.64 f-h	1.08 c-f
	4.8	0.14 d	0.06 d	5.70 u-w	71.33 m-q	21.56 tu	11.24 r-t	0.98 a	1.71 a
	0	0.44 a	0.20 a	13.65 b	68.2 n-p	97.12 ab	47.69 a	0.35 u-w	0.58 l-o
	1.2	0.45 a	0.20 a	13.73 b	67.33 o-r	87.04 a-d	42.79 ab	0.33 v-x	0.55 o-r
Gf677	2.4	0.44 a	0.20 a	13.55 bc	66.86 o-r	70.12 d-h	36.29 b-d	0.36 t-v	0.63 j-m
	3.6	0.31 b	0.15 b	11.01 e-h	64.92 qr	50.92 i-m	29.12 c-g	0.62 g-i	1.00 d-g
	4.8	0.21 c	0.12 b	8.08 n-q	59.41 r	43.92 l-p	25.58 e-i	0.80 b-d	1.35 bc

Means in each column and for each factor followed by similar letter(s) are not significantly different at the 1% probability level using Duncan’s multiplerange test.

According to the results (Table 8), the content of relative humidity of leaves was decreased significantly as the salinity increased. The content of relative humidity in the 1–25 control plants was 84.72% while relative humidity content of GF₆₇₇ rootstock leaves which were irrigated with 9.8 dS/m was 63.63%. ‘Ferragnès’ and Shokoufeh cultivars showed the least decrease in the relative humidity of the leaves. The results were consistent with the results of Shibli et al. (2003) and Massai et al. (2006). Salinity, through the gradual accumulation of sodium ions, reduces the relative water content and osmotic potential of the leaf in full turgor state.

Table 8. Effect of interaction between salinity and genotype on some of physiological characteristics.

Genotype	Salinity (g/l)	Relative water content (%)	Chl. index	Relative ionic leakage) (%)	Cell membrane injury (%)	Chlorophyll a (mg/g)	Chlorophyll b (mg/g)	Chlorophyll total (mg/g)
	0	84.72 ab	37.20 k-p	49.73 g-j	–	0.917 a-d	0.615 b-f	1.43 e-i
	1.2	82.86 a-d	36.60 op	52.46 f-j	4.86 n-s	0.928 a-c	0.583 d-h	1.51 c-e
1–25	2.4	80.18 e-h	37.07 k-p	54.57 d-j	5.41 n-s	0.893 a-g	0.607 b-f	1.51 c-e
	3.6	78.82 j-m	36.97 l-p	60.51 c-j	19.02 ij	0.814 c-j	0.457 h-n	1.27 k-m
	4.8	75.85 q-s	36.23 o-r	70.07 a-g	31.39 gh	0.792 e-j	0.453 h-n	1.24 l-n
	0	82.46 a-d	38.20 j-m	49.08 h-j	-	0.904 a-f	0.720 a-c	1.62 a-c
	1.2	82.46 a-d	37.17 k-p	52.98 f-j	7.51 m-q	0.911a-e	0.683 a-d	1.59 a-d
Mamaie	2.4	81.80 c-f	36.13 m-r	57.61 c-j	12.27 k-m	0.904 a-f	0.597 c-g	1.50 c-f
	3.6	77.84 n-q	35.07 q-s	70.4 a-f	33.58 f-h	0.813 c-j	0.507 f-k	1.31 h-l
	4.8	72.51 tu	31.83 u	81.32 ab	42.27 de	0.578 k	0.391 k-p	0.97 o
	0	82.10 c-j	36.70 n-p	48.27 ij	-	0.898 a-f	0.688 a-d	1.58 b-e
	1.2	78.82 j-m	36.80 m-p	52.61f-j	5.43 n-t	0.899 a-f	0.536 d-i	1.42 e-j
13–40	2.4	77.32 o-r	37.50 k-o	59.12 c-j	17.04 jk	0.836 a-j	0.505 f-k	1.34 g-l
	3.6	75.12 rs	34.93 r-t	69.01a-h	35.87 fg	0.776 g-j	0.461 h-n	1.28 j-m
	4.8	71.18 uv	32.03 u	81.69 ab	46.49 cd	0.539 kl	0.374 l-p	0.91 op
	0	81.37 c-f	37.10 k-p	52.02 f-j	-	0.813 c-j	0.533 e-i	1.32 h-l
	1.2	80.61 d-g	36.43 o-q	56.26 c-j	7.36 m-r	0.809 c-j	0.508 f-k	1.32 h-l
1–16	2.4	78.50 k-n	34.57 st	64.78 b-i	19.02 ij	0.771 g-j	0.493 f-l	1.26 k-m
	3.6	69.78 vw	33.67 t	73.96 a-e	36.13 fg	0.740 ij	0.414 j-p	1.16 mn
	4.8	68.52 w	31.27 u	82.90 ab	46.87 cd	0.505 kl	0.327 n-p	0.83 pq
	0	83.75 a-c	48.53 bc	47.65 ij	-	0.955 a	0.778 a	1.73 a
	1.2	82.42 a-d	48.80 bc	50.77 f-j	1.75 r-t	0.874 a-h	0.519 f-k	1.39 e-k
Tuono	2.4	79.71 g-j	48.47 bc	52.09 f-j	7.00 m-s	0.825 b-j	0.466 g-m	1.29 i-m
	3.6	78.60 k-m	44.93 fg	64.46 b-i	29.05 h	0.801 d-j	0.426 i-o	1.23 l-n
	4.8	72.51 tu	40.57 h	74.68 a-d	42.5 de	0.761 h-j	0.350 m-p	1.11 n
	0	81.21 d-g	40.00 hi	47.07 ij	-	0.902 a-f	0.581 d-h	1.48 c-g
	1.2	80.82 d-h	38.93 ij	47.75 ij	1.61 st	0.865 a-h	0.538 e-i	1.40 e-k
‘Ferragnès’	2.4	79.17 h-l	38.43 j-l	50.55 f-j	5.32 n-t	0.854 a-j	0.519 f-k	1.37 e-l
	3.6	79.83 f-i	38.20 j-m	57.45 c-j	16.97 jk	0.910 c-j	0.496 f-l	1.31 h-l
	4.8	78.14 f-i	37.43 k-o	61.10 c-j	23.32 i	0.798 d-j	0.483 g-m	1.28 j-m
	0	84.78 a	48.50 bc	48.11 ij	-	0.929 a-c	0.765 a	1.69 ab
	1.2	82.53 a-d	47.90 cd	49.51 g-j	3.62 o-t	0.923 a-d	0.691 a-d	1.61 abc
A200	2.4	80.85 d-g	46.77 c-e	52.36 f-j	9.32 l-o	0.904 a-f	0.573 d-h	1.47 d-g
	3.6	79.50 h-k	45.53 e-g	60.49 c-j	16.70 jk	0.853 a-j	0.512 f-k	1.36 f-l
	4.8	76.84 p-r	44.43 g	69.72 a-g	28.42 h	0.793 e-j	0.476 g-m	1.27 k-m
	0	81.34 c-f	40.43 h-j	48.49 h-j	-	0.873 a-h	0.565 d-h	1.44 e-g
	1.2	79.74 f-j	38.47 j-l	49.63 g-j	2.16 q-t	0.905 a-f	0.585 d-h	1.49 c-f
Nonpareil	2.4	80.86 d-g	39.00 i-k	53.99 e-j	10.04 l-n	0.874 a-h	0.564 d-h	1.44 e-g
	3.6	78.19 m-p	37.03 k-p	61.24 c-j	22.12 ij	0.805 c-j	0.458 h-n	1.26 k-m
	4.8	75.40 rs	35.73 p-s	65.70 b-i	37.72 ef	0.750 ij	0.400 j-p	1.15 mn
	0	82.91 a-d	52.67 a	48.88 h-j	-	0.944 ab	0.787 a	1.72 ab
	1.2	81.26 d-g	52.33 a	50.42 f-j	0.96 t	0.933 a-c	0.756 a	1.70 ab
Shokoufeh	2.4	80.84 d-g	49.83 a-c	53.59 f-j	3.47 p-t	0.917 a-d	0.673 a-e	1.59 b-d
	3.6	78.23 l-o	48.67 bc	60.16 c-j	13.32 kl	0.837 a-j	0.504 f-l	1.34 g-l
	4.8	75.82 q-s	46.23 ef	65.27 b-i	21.59 ij	0.786 e-j	0.495 f-l	1.28 j-m
	0	82.31 b-e	45.17 fg	47.77 ij	-	0.865 a-h	0.520 f-k	1.34 h-k
	1.2	80.72 d-g	44.20 g	52.76 f-j	8.37 l-p	0.856 a-i	0.518 f-k	1.27 k-m
Sahand	2.4	79.76 g-j	41.33 h	64.61 b-i	22.25 ij	0.824 b-j	0.406 j-p	1.23 l-n
	3.6	73.91 st	37.00 k-p	76.09 a-c	43.69 cd	0.784 f-j	0.372 l-p	1.15 mn
	4.8	64.80 x	34.53 st	85.26 a	59.95 b	0.454 l	0.288 op	0.74 q
	0	79.19 i-l	48.00 cd	42.42 j	-	0.928 a-c	0.781 a	1.71ab
	1.2	80.11 e-h	47.70 cd	48.44 h-j	9.24 l-o	0.921 a-d	0.785 a	1.71 ab
Gf677	2.4	76.80 p-r	46.10 ef	65.02 b-i	29.01 h	0.889 a-g	0.738 ab	1.62 a-c
	3.6	71.21 uv	40.57 h	76.66 a-c	48.42 c	0.731 j	0.391 k-p	1.12 n
	4.8	63.63 x	38.13 j-m	86.43 a	65.16 a	0.433 l	0.282 p	0.72 q

Means in each column and for each factor followed by similar letter(s) are not significantly different at the 1% probability level using Duncan’s multiple range test.

Relative ion leakage percentage in all studied genotypes was increased by increasing salinity concentration. The increase in the relative ion leakage percentage was significant between the studied genotypes. The highest relative ion leakage percentage was observed in GF₆₇₇ rootstock and Sahand cultivar under treatment of 4.8 g/l. After this genotypes, 1–16 and 13–40 genotypes, and Mamaie and Tuono cultivars had the highest relative ion leakage percentage. The increase in relative ion leakage percentage was not significant in ‘Ferragnès’, Shokoufeh, Nonpareil and A₂₀₀ cultivars and 1–25 genotype compared to the control plants (Table 8).

The results showed that the genotypes had a significant difference in cell membrane injury percentage. The highest cell membrane injury percentage was observed in the leaves of the GF₆₇₇ rootstock and Sahand cultivar, and the lowest cell membrane injury percentage was observed in the leaves of Shokoufeh, ‘Ferragnès,’ and A₂₀₀ cultivars, respectively. These results were consistent with the results of other studies. It has been reported that using a relative ionic leak test is one way to find out the extent to which cell membranes are damaged. Recording the relative ion leakage rate allows for tissue damage estimation. This method was used for the first time by Dexter et al. (1930; 1932) to investigate the resistance to cold in plants and, over time, was used to measure cell membrane damage in relation to other environmental stresses, including salinity stress (Chen et al., 1999).

The results showed that chlorophyll index was decreased significantly under salinity stress. The lowest chlorophyll index was observed in the leaves of the plants that were irrigated with 9.8 dS/m treatment. The amount of chlorophyll index decreased significantly among the studied genotypes. The highest reduction in chlorophyll index was observed in Sahand cultivar, GF₆₇₇ rootstock, Mamaie cultivar 1–16 and 13–40 genotypes and Tuono cultivar, respectively.

The results showed that the interaction of genotype and salinity on the amount of chlorophyll a, b and total chlorophyllof the leaves were significant at 1% level (Table 8). Chlorophyll a content was reduced significantly in all of the studied genotypes except ‘Ferragnès’ cultivar in treatment 4.8 g/l compared to control plants while chlorophyll b content at 2.4, 3.6, and 4.8 g/l salinity levels was reduced significantly compared to the control plants. These results indicated that under salinity stress amount of chlorophyll b reduces more than amount of chlorophyll a. These results were consistent with the results of Dejampour et al. (2012). These researchers investigated the effect of sodium chloride salinity stress on the amount of chlorophylls a, b and total chlorophyll in some of the Prunus genus, and they reported that amount of chlorophylls b and total chlorophyll significantly decreased under salt stress. However, reduce in amount of chlorophyll a in these plants was not significant.

The result showed that total chlorophyll content was decreased significantly in ‘Ferragnès’ cultivar only in 4.8 g/l treatment, while total chlorophyll content in other genotypes was decreased significantly in 2.4, 3.6, and 4.8 g/l salinity levels (Table 8). These results were consistent with the results of Noitsakis et al. (1997). Salinity reduces chlorophyll structure, decreases the chlorophyll content and instability of protein-pigment compounds, reduces the plant’s photosynthesis, results in a reduction in the carbon dioxide fixation, and is the main cause of decline in plant growth and yield in plants under salinity stress (Noitsakis et al., 1997).

Based on the results of this study, as the salinity increases, the amount of minimum chlorophyll fluorescence (F_o) was increased significantly. In all genotypes, the highest amount of minimum fluorescence was observed at 4.8 g/l treatment. The highest amount of minimum fluorescence was observed in the leaves of the GF₆₇₇ rootstock and Sahand cultivar, which were treated with 4.8 g/l treatment. (Table 9). Also, maximum chlorophyll fluorescence (F_m) in the studied genotypes was decreased significantly as the salinity increased. The highest amount of maximum fluorescence was observed in control plants. While the lowest amount of maximum fluorescence was observed in Sahand cultivar (489.44), GF₆₇₇ rootstock (545.54), 1–16 genotype (607.00) that treated with 4.8 g/l treatment, respectively (Table 9).

Table 9. Effect of interaction between salinity and genotype on some of physiological parameters.

Genotype	Salainity (g/l)	Fo	Fm	Fv	Fv/Fm
	0	134.33 s	760.00 d-k	625.67 b-i	0.82 ab
	1.2	141.33 p	730.00 j-p	588.67 g-m	0.81 a-c
1–25	2.4	145.00 no	725.33 j-q	580.33 i-m	0.80 a-c
	3.6	145.67 m-o	723.33 j-r	577.67 i-m	0.80 a-c
	4.8	146.00 m-o	690.00 p-s	544.00 l-q	0.79 a-c
	0	141.00 p	735.00 i-p	594.00 f-l	0.81 a-c
	1.2	143.00 op	731.00 j-p	588.00 h-m	0.80 a-c
Mamaie	2.4	147.00 mn	700.00 m-s	553.00 k-p	0.79 a-c
	3.6	150.00 kl	671.67 rs	521.67 n-q	0.78 a-c
	4.8	154.00 hi	450.00 v	296.00 t	0.65 g
	0	144.00 no	790.00 c-h	646.00 b-f	0.82 ab
	1.2	146.00 m-o	798.33 c-f	652.33 b-e	0.82 ab
13–40	2.4	151.00 jk	736.67 h-p	585.67 h-m	0.79 a-c
	3.6	154.00 hi	696.67 n-s	542.67 l-q	0.78 a-c
	4.8	158.33 f	596.67 t	438.33 r	0.73 d-f
	0	136.00 q-s	738.33 h-p	602.33 e-k	0.82 ab
	1.2	137.00 qr	710.00 k-r	573.00 i-n	0.81 a-c
1–16	2.4	141.00 p	650.00 s	509.00 pq	0.78 a-c
	3.6	152.67 h-j	550.00 tu	397.33 rs	0.72 ef
	4.8	159.00 ef	396.67 w	237.67 u	0.59 h
	0	143.67 no	853.00 ab	709.33 a	0.83 a
	1.2	143.67 no	813.67 a-c	670.00 ab	0.82 ab
Tuono	2.4	146.33 m-o	785.00 c-i	638.68 b-h	0.81 a-c
	3.6	152.67 h-j	722.67 j-r	570.00 j-o	0.79 a-c
	4.8	158.33 f	567.67 tu	409.33 rs	0.72 ef
	0	144.67 m-o	788.33 c-k	643.67 b-i	0.82 ab
	1.2	147.00 mn	755.00 e-l	608.00 d-k	0.81 a-c
‘Ferragnès’	2.4	150.00 kl	740.00 g-p	590.00 g-m	0.80 a-c
	3.6	152.33 i-k	706.33 k-r	554.00 i-p	0.78 a-c
	4.8	155.00 gh	693.00 o-s	538.00 m-q	0.77 b-d
	0	138.33 q	753.33 e-m	615.00 c-j	0.82 a
	1.2	146.33 m-o	753.33 f-m	607.00 e-k	0.81 ab
A200	2.4	148.33 lm	745.67 f-o	597.33 e-l	0.80 a-c
	3.6	153.00 h-j	710.00 k-r	557.00 k-p	0.78 a-c
	4.8	158.33 f	675.00 q-s	516.67 o-q	0.77 b-d
	0	138.00 q	807.67 b-d	669.67 a-c	0.83 a
	1.2	135.33 rs	775.00 c-j	639.67 b-h	0.82 ab
Nonpareil	2.4	143.00 op	743.67 g-p	600.67 e-k	0.81 a-c
	3.6	148.00 lm	705.00 l-r	557.00 k-p	0.79 a-c
	4.8	157.00 fg	653.33 s	496.33 q	0.76 c-e
	0	146.33 m-o	858.33 a	712.00 a	0.83 a
	1.2	146.67 mn	860.33 a	713.67 a	0.83 a
Shokoufeh	2.4	152.00 i-k	824.00 a-c	672.00 ab	0.82 ab
	3.6	152.67 h-j	774.00 c-j	621.33 b-j	0.80 a-c
	4.8	162.67 cd	716.67 k-r	554.00 k-p	0.77 b-d
	0	144.33 no	792.33 c-g	648.00 b-f	0.82 ab
	1.2	144.67 no	746.33 f-o	602.00 e-k	0.81 a-c
Sahand	2.4	147.33 mn	690.00 p-s	542.67 l-q	0.79 a-c
	3.6	161.00 de	550.00 u	389.00 rs	0.71 f
	4.8	170.33 b	335.33 x	165.00 v	0.48 i
	0	144.67 m-o	806.33 b-e	661.67 a-d	0.82 ab
	1.2	151.67 i-k	793.00 c-g	641.33 b-h	0.81 a-c
GF677	2.4	158.00 f	748.33 f-n	590.33 g-m	0.79 a-c
	3.6	164.00 c	546.67 u	382.67 s	0.70 f
	4.8	173.33 a	336.67 x	163.33 v	0.47 i

Means in each column and for each factor followed by similar letter(s) are not significantly different at the 1% probability level using Duncan’s multiplerange test.

The results showed that in all studied genotypes variable chlorophyll fluorescence (F_v) to maximum chlorophyll fluorescence ratio (F_v/F_m) was reduced significantly by applying salinity stress and increasing its concentration. There was a significant difference between variable fluorescence to maximum fluorescence ratio (F_v/F_m) in different levels of salinity among tested genotypes. Variable fluorescence to maximum fluorescence ratio (F_v/F_m) was about 0.82–0.83 in the leaves of the control plants, indicating the existence of ideal and non-stressed environmental conditions for the growth of all genotypes throughout the experimental period. In many plant species, when F_v/F_m ratio is about 0.83, it means that stress has not been introduced to the plant and lower levels of F_v/F_m ratio indicate stress condition in plants (Maxwell and Johnson, 2000).

Regarding changes in the variable fluorescence to maximum fluorescence ratio (F_v/F_m), the stress intensity in Sahand cultivar was more severe than other genotypes. Therefore, the susceptibility of this cultivar to salinity stress at 3.6 and 4.8 g/l salinity levels was higher than other genotypes. On the contrary, ‘Ferragnès’ cultivar was damaged less. In other words, variable fluorescence to maximum fluorescence ratio (F_v/F_m) in this cultivar showed the lowest decrease. These results were consistent with the results of Deell and Toivonen (2003), Herda et al. (1999), Kodad et al. (2010), and Starck et al. (2000). It has been reported that salinity stress is one of the most important environmental factors limiting photosynthesis. Symptoms of salinity stress are expressed at both stomatal and non-stomatal levels. At stomatal level, the plant closes its stomata to prevent injuries (Maxwell and Johnson, 2000; Ranjbarfordoei et al., 2006). As a result, net photosynthesis is unavoidably reduced due to a decrease in CO₂ availability, which potentially damages the photosynthetic apparatus (Lawlor and Cornic, 2002). Most of the decrease in photon flux energy used for photochemistry can be explained as an increase in non-photochemical dissipation of excitation energy (Lawlor and Cornic, 2002). This means in each column and for each factor.

Based on the results, the increase in sodium concentration in the leaves of ‘Ferragnès’ and Shokoufeh cultivars was not significant compared to the control plants, while the increase of sodium concentration in the leaves of other genotypes was significant at 3.6 and 4.8 g/l salinity levels compared to the control plants (Table 10). The highest concentration of sodium in 4.8 g/l salinity level was observed in GF₆₇₇ rootstock. Sodium concentration in GF₆₇₇ rootstock leaves was significantly higher than other genotypes in 3.6 and 4.8 g/l salinity levels apart from Tuono, Sahand cultivars and 1–16 and 13–40 genotypes (Table 10). These result showed that scion type affected the obstruction of Na⁺ absorption by the roots and its transport to the leaves.

Table 10. Effect of interaction between salinity and genotype on concentration of Na⁺ and K⁺ in roots and leaves.

Genotype	Salinity (g/l)	K^+ (Leaf) (%)	Na^+ (Leaf) (%)	K^+(Root) (%)	Na^+ (Root) (%)	Genotype	Salinity (g/l)	K^+ (Leaf) (%)	Na^+ (Leaf) (%)	K^+(Root) (%)	Na^+ (Root) (%)
	0	1.49 g-i	0.35 i-m	0.47 d-i	0.31 q		0	0.79 r	0.25 lm	0.35 kl	0.44 m-q
	1.2	1.55 e-i	0.38 h-m	0.50 c-g	0.48 l-q		1.2	0.83 qr	0.27 k-m	0.42 g-k	0.53 k-p
‘Ferragnès’	2.4	1.60 d-i	0.45 g-m	0.55 a-d	0.55 k-o	1–25	2.4	0.99 op	0.56 g-m	0.46 e-i	0.79 f-j
	3.6	1.65 b-g	0.55 g-m	0.48 d-h	0.79 f-j		3.6	1.19k-m	0.69 e-i	0.50 c-g	0.91 b-g
	4.8	1.71 a-e	0.69 e-i	0.42 g-k	0.88 d-h		4.8	1.26 kl	0.93 c-f	0.42 g-k	1.07 b-d
	0	1.70 a-e	0.35 i-m	0.57 a-c	0.32 q		0	0.83 qr	0.29 k-m	0.48 d-h	0.36 o-q
	1.2	1.78 a-c	0.45 g-m	0.59 ab	0.55 k-o		1.2	0.88 p-r	0.41 g-m	0.50 c-g	0.53 k-p
Tuono	2.4	1.83 a	0.62 f-k	0.62 a	0.72 g-k	A200	2.4	0.94 o-r	0.57 g-m	0.53 b-e	0.72 g-k
	3.6	1.66 b-f	1.34 b	0.52 b-f	0.86 d-i		3.6	0.97 o-q	0.65 e-k	0.46 e-i	0.86 d-i
	4.8	1.58 e-i	2.01 a	0.48 d-h	1.02 b-e		4.8	1.06m-o	1.05 c	0.37 j-l	1.12 b
	0	1.76 a-d	0.42 g-m	0.46 e-i	0.36 o-q		0	0.88 p-r	0.31 j-m	0.41 h-k	0.32 pq
	1.2	1.79 ab	0.55 g-m	0.50 c-g	0.60 j-n		1.2	0.97 o-q	0.44 g-m	0.42 g-k	0.55 k-o
1–16	2.4	1.66 b-f	0.76 c-g	0.46 e-i	0.79 f-j	Nonpareil	2.4	1.03 n-p	0.60 f-l	0.52 b-f	0.74 g-k
	3.6	1.60 d-i	1.57 b	0.44 f-j	0.91 b-g		3.6	1.1m-o	0.73 c-h	0.48 d-h	0.82 e-i
	4.8	1.47 h-j	2.05 a	0.33 l	1.07 b-d		4.8	1.17 l-n	0.96 c-e	0.39 i-l	0.93 b-g
	0	1.50 f-i	0.35 i-m	0.48 d-h	0.41 n-q		0	0.82 qr	0.22 m	0.53 b-e	0.31 q
	1.2	1.55 e-i	0.38 h-m	0.50 c-g	0.48 l-q		1.2	1.10m-o	0.25 lm	0.55 a-d	0.55 k-o
Shokoufeh	2.4	1.60 d-i	0.45 g-m	0.55 a-d	0.55 k-o	Mamaie	2.4	1.15 l-n	0.44 g-m	0.50 c-g	0.69 h-l
	3.6	1.66 b-f	0.55 g-m	0.48 d-h	0.79 f-j		3.6	1.06m-o	0.72 d-h	0.42 g-k	0.84 e-i
	4.8	1.70 a-e	0.69 e-i	0.42 g-k	0.88 d-h		4.8	0.97 o-q	1.03 cd	0.35 kl	0.98 b-f
	0	1.71 a-e	0.35 i-m	0.57 a-c	0.32 pq		0	1.05m-o	0.38 h-m	0.35 kl	0.32 pq
	1.2	1.79 ab	0.45 g-m	0.59 ab	0.55 k-o		1.2	1.32 jk	0.49 g-m	0.44 f-j	0.65 i-m
13–40	2.4	1.84 a	0.62 f-k	0.62 a	0.72 g-k	Gf677	2.4	1.62 c-h	0.59 g-l	0.52 b-f	0.84 e-i
	3.6	1.66 b-f	1.35 b	0.52 b-f	0.86 d-i		3.6	1.44 ij	1.43 b	0.46 e-i	1.10 bc
	4.8	1.57 e-i	2.02 a	0.48 d-h	1.03 b-e		4.8	1.05m-o	2.12 a	0.33 l	1.39 a
	0	1.76 a-d	0.41 lm	0.46 e-i	0.36 o-q
	1.2	1.79 ab	0.55 k-m	0.50 c-g	0.60 j-n
Sahand	2.4	1.65 b-g	0.76 g-m	0.46 e-i	0.79 f-j
	3.6	1.60 d-i	1.57 e-i	0.44 f-j	0.91 c-g
	4.8	1.47 h-j	2.05 c-f	0.33 l	1.07 b-d

Means in each column and for each factor followed by similar letter(s) are not significantly different at the 1% probability level using Duncan’s multiple range test.

Root sodium content was affected by the type of scion and salinity concentration. The results showed that as the salt concentration increased, root sodium content was increased significantly. The amount of sodium concentration in the roots of rootstocks in which Shekofeh cultivar were grafted, in 3.6 and 4.8 g/l salinity levels and in roots of rootstocks in which ‘Ferragnès’ and A₂₀₀ cultivars were grafted on them in 2.4, 3.6, and 4.8 g/l salinity levels, was increased significantly compared to control plants. The amount of sodium concentration in the roots of rootstocks in which other genotypes were grafted on them was increased significantly in all salinity levels compared to control plants. Overall, the highest sodium concentration at 3.6 and 4.8 g/l salinity levels was observed in roots of the control rootstocks (not grafted, 1.39%). The concentration of sodium in the roots of the control rootstocks (not grafted) at 3.6 and 4.8 g/l salinity levels was significantly higher than roots of grafted rootstocks (Table 10).

These results indicated that, in 3.6 and 4.8 g/l salinity levels, grafted genotypes (especially ‘Ferragnès’ and Shokoufeh cultivars) were affected significantly by increasing the rootstocks strength, in obstruction of Na⁺ absorption by the roots and its transport to leaves. These results were consistent with results of investigation of morphological traits in studied genotypes. GF₆₇₇ rootstocks (Not grafted), which had the highest sodium accumulation in its leaves, had the highest percentage of leaves necrosis and loss, and at the end of the experiment, these plants did not have any green leaf. In research on various plants under salt stress, it has been shown that the loss of water availability, toxicity of Na⁺, and ion imbalance cause growth limitation so plants adopt divert mechanisms to salinity tolerance. It is repeatedly reported that K⁺ deficiency and Na⁺ toxicity are major restrictors of crop production worldwide (Mahajan and Tuteja, 2005; Szczerba et al., 2009).

Also, the results of the comparison of sodium concentration in roots and leaves showed that in all studied genotypes the sodium percentage of leaves in all salinity levels was higher than sodium concentration in roots. It has been reported that salinity reduces vegetative growth of the plants, and this decrease in the aerial part of the plants is more than the roots, which indicates that the aerial organs are exposed to salinity earlier than the roots (Szczerba et al., 2008, 2009).

With increasing salinity levels (to 4.8 g/l), potassium concentration was increased in leaves of ‘Ferragnès’, Shokoufeh, Nanoparill, A₂₀₀ cultivars and 1–25 genotype, while potassium content in the leaves of Tuono and Mamaie cultivars, 13–40 genotype and GF₆₇₇ rootstock was increased to 2.4 g/l salinity level and then, with increasing more salinity, potassium content in their leaves decreased. The amount of potassium in Sahand cultivar and 1–16 genotype increased only to 1.2 g/l salinity level, and then with increasing more salinity, potassium content in their leaves decreased. Overall, the highest potassium content was observed in 4.8 g/l salinity level and in ‘Ferragnès’ (1.71%) and Shokoufeh (1.70%) cultivars, respectively.

These results indicated that with increasing the amount of potassium ‘Ferragnès’ and Shokoufeh cultivars could reduce the negative and destructive effects of sodium (Table 10).

Investigation of potassium concentration in the roots of GF₆₇₇ rootstock showed that the salinity and type of the genotype were effective on its value. Potassium concentration in the roots of rootstocks in which Sahand, Mamaie cultivars, and 1–16 genotype were grafted on them were increased only to 1.2 g/l salinity level. In the roots of the rootstocks in which ‘Ferragnès’, Shokoufeh, Nonpareil, Tuono, A₂₀₀, 13–40 genotype, were grafted on them, was increased to 2.4 g/l salinity level and in the roots of rootstocks in which the 1–25 genotypes were grafted on them, was increased to 3.6 g/l salinity level. Then in all genotypes with increasing more salinity, potassium concentration was decreased. Overall, the least amount of potassium was observed at 4.8 g/l salinity level and in the roots of the control rootstocks (not grafted; Table 10). These results indicated that the type of the scion is effective in potassium absorption and its transmission to the aerial part. Potassium plays an important role in vital metabolites in salinity stress conditions, so that the K⁺ can counteract Na⁺ stresses, thus the potential of plants to tolerate salinity is strongly dependent on their potassium nutrition (Alemán et al., 2011; Nieves-Cordones et al., 2016a).

Conclusion

Generally, the results of this study showed that by applying salinity stress and increasing its concentration, growth indices including branch height, branch diameter, number of total leaves, number of green leaves, leaf density on the main branch, leaf fresh and dry weight, leaf area and leaf area ratio, leaf relative humidity, shoot fresh and dry weight, root fresh and dry weight, chlorophyll index, chlorophylls a, b, and total chlorophyll in all studied genotypes were decreased, but the percentage of necrotic leaves, percentage of leaf loss, root fresh and dry weight ratio to shoot fresh and dry weight, ion leakage percentage, and cell membrane injury percentage were increased. However, the reduction and increase of measured traits were significantly different among studied genotypes. Also, evaluation of chlorophyll fluorescence variations showed that salinity stress increases the minimum fluorescence (F_o) and decreases the maximum fluorescence (F_m) level in plants due to decreasing fluorescence variable (F_v); therefore, the varied fluorescence ratio to maximum fluorescence is from 0.83 in the control plants leaves to 0.72 in leaves of GF₆₇₇ rootstock and Sahand cultivar. Based on the results mentioned above, reduction (F_v/F_m) was symptoms of the damaging stress in plants. According to data from the results of the method of chlorophyll fluorescence with the results of morphological and physiological traits, it can be concluded that chlorophyll fluorescence technique (F_v/F_m indicators) is a rapid, sensitive, and non-destructive method to check the intensity of stress that induced to plants. Also, the result showed that type of scion and level of salinity was affected on concentration of nutrition elements of leaves and roots. In the total genotypes studied, the highest content of Na⁺ in leaves and roots was observed in 4/8 g/l treatment. The result showed that type of scion was effective in Na⁺ absorption by the roots and its transport to leaves. Also, uptake of K⁺ by the roots and its transport to leaves was affected. In this research, GF₆₇₇ rootstocks (not grafted) are well tolerated to irrigation water salinity up to 2.4 g/l (equal to 4.9 dS/m electrical conductivity), but showed stress effects with higher range of salinity. According to these results, scion type is highly important for the trees tolerant to salinity. Overall, ‘Ferragnès’ cultivar was found to be the most tolerant cultivar to salinity stress (3.6 g/l equal to 7.3 dS/m electrical conductivity) among the evaluated cultivars. In contrast, Sahand was the most sensitive cultivar to salinity stress. This cultivar as well as GF₆₇₇ rootstocks (not grafted) tolerated the irrigation water salinity up to 2.4 g/l.