Effectiveness of Amaranthus retroflexus L. aqueous extract in preventing iron chlorosis of pear trees (Pyrus communis L.)

Figures & data

Table 1. Soil extractable iron (Fe) concentration in deionized water; aqueous extract of Amaranthus retroflexus L. and diethylenetriamine-pentaacetic-acid (DTPA) used as Fe eluents

Eluents	Soil extractable Fe concentration (mg kg^−1)
Deionized water	0.002c
Aqueous extract of A. retroflexus	0.242b
DTPA	67.6a
Significance	***
***effect of eluents significant at P ≤ 0.001. In the same column, means followed by the same letter are not statistically different (P ≤ 0.05, LSD Test).

Table 2. Effect of treatment on shoot length (2007) and leaf chlorophyll (Chl) (controlled environment, 2008)

	Shoot length (cm shoot^−1)			Leaf Chl (SPAD)
Treatment	June	July	August	June	July	August
Control	48.9c	86.1b	96.1b	13.5d	17.2c	27.0b
Fe-chelate	57.3abc	99.3ab	102.7ab	25.1a	32.2a	38.8a
FeSO4	51.4bc	81.2b	84.3b	16.8cd	22.1b	33.8ab
A. retroflexus + FeSO4	60.9ab	100.5ab	103.5ab	20.1abc	22.8b	38.2a
A. retroflexus HR	63.0a	113.9a	117.7a	22.2ab	21.9b	38.1a
A. retroflexus LR	49.1c	90.4b	94.9b	19.8bc	17.3c	33.7ab
Significance	**	**	***	***	***	**
** and *** effect of treatment significant at P ≤ 0.01 and P ≤ 0.001, respectively. In the same column, means followed by the same letter are not statistically different (P ≤ 0.05, LSD Test). Fe, iron; FeSO4, iron sulphate; A. retroflexus, Amaranthus retroflexus L.; A. retroflexus HR, aqueous solution at 30 g (dry weight, dw) L^−1; A. retroflexus LR, aqueous solution at 15 g (dw) L^−1.

Table 3. Effect of treatment on leaf mineral concentration at the end of the experiment (controlled environment)

	Macronutrients (g kg^−1)					Micronutrients (mg kg^−1)
Treatment	N	P	K	Ca	Mg	Fe	Mn	Cu	Zn
Control	10.7bc	1.6	6.1b	13.5	3.7	54.0	26.5ab	6.6	52.7
Fe-chelate	9.9c	1.1	6.3b	12.2	3.8	68.7	9.6c	4.9	36.5
FeSO4	11.5bc	1.2	5.5b	15.1	4.7	56.0	29.7ab	5.4	34.0
A. retroflexus + FeSO4	13.0ab	1.5	8.2ab	16.8	3.8	58.4	32.6a	7.7	68.0
A. retroflexus HR	13.7a	1.7	10.5a	15.0	3.2	39.7	21.5b	8.0	47.1
A. retroflexus LR	11.9ab	1.7	7.4ab	13.3	4.1	53.8	29.2ab	7.3	50.4
Significance	*	ns	*	ns	ns	ns	**	ns	ns
ns, * and ** effect of treatment not significant or significant at P ≤ 0.05 and P ≤ 0.01, respectively. In the same column, means followed by the same letter are not statistically different (P ≤ 0.05, LSD Test). N, nitrogen; P, phosphorus; K, potassium; Ca, calcium; Mg, magnesium; Fe, iron; Mn, manganese; Cu, copper; Zn, zinc; FeSO4, iron sulphate; A. retroflexus, Amaranthus retroflexus L.; A. retroflexus HR, aqueous solution at 30 g (dry weight, dw) L^−1; A. retroflexus LR, aqueous solution at 15 g (dw) L^−1.

Table 4. Effect of treatment on root (coarse + fine) and total tree dry weight at the end of the experiment (controlled environment)

Treatment	Root dry weight (g plant^−1)	Tree dry weight (g plant^−1)
Control	103	339b
Fe-chelate	118	396a
FeSO4	97	331b
A. retroflexus + FeSO4	125	392a
A. retroflexus HR	106	359a
A. retroflexus LR	110	342b
Significance	ns	*
ns and *effect of treatment not significant or significant at P ≤ 0.05, respectively. In the same column, means followed by the same letter are not statistically different (P ≤ 0.05, LSD Test). Fe, iron; FeSO4, iron sulphate; A. retroflexus, Amaranthus retroflexus L.; A. retroflexus HR, aqueous solution at 30 g (dry weight, dw) L^−1; A. retroflexus LR, aqueous solution at 15 g (dw) L^−1.

Table 5. Effect of treatment on leaf chlorophyll (Chl) (field conditions) recorded in July 2009 and 2010

	Leaf Chl (SPAD)
Treatment	2009	2010
Control	20.9d	15.5d
Fe-chelate	44.0a	31.6a
A. retroflexus	29.3c	20.7c
A. retroflexus + FeSO4	31.9b	22.8b
Significance	***	***
***effect of treatment significant at P ≤ 0.001. In the same column, means followed by the same letter are not statistically different (P ≤ 0.05, LSD Test). Fe, iron; FeSO4, iron sulphate; A. retroflexus, Amaranthus retroflexus L.

Table 6. Effect of treatment on leaf mineral concentration in 2009 (field conditions)

	Macronutrients (g kg^−1)					Micronutrients (mg kg^−1)
Treatment	N	P	K	Ca	Mg	Fe	Mn	Cu	Zn
Control	18.8	17.2ab	16.9a	13.5	5.2	49.7b	40.2a	101.7	43.7a
Fe-chelate	20.0	15.4ab	10.3c	12.9	4.9	85.5a	32.3b	103.9	33.7b
A. retroflexus	19.7	18.8a	14.3b	14.2	5.3	50.5b	42.3a	94.0	41.9a
A. retroflexus + FeSO4	19.6	13.4b	13.4b	13.7	5.3	47.3b	43.3a	95.0	39.8a
Significance	ns	*	***	ns	ns	**	*	ns	**
ns, *, ** and *** effect of treatment not significant or significant at P ≤ 0.05, P ≤ 0.01 and P ≤ 0.001, respectively. In the same column, means followed by the same letter are not statistically different (P ≤ 0.05, LSD Test). N, nitrogen; P, phosphorus; K, potassium; Ca, calcium; Mg, magnesium; Fe, iron; Mn, manganese; Cu, copper; Zn, zinc; A. retroflexus, Amaranthus retroflexus L.; FeSO4, iron sulphate.

Table 7. Effect of treatment on yield and fruit weight in 2009 and 2010 (field conditions)

	2009		2010
Treatment	Yield (kg tree^−1)	Fruit weight (g fruit^−1)	Yield (kg tree^−1)	Fruit weight (g fruit^−1)
Control	20.4b	220.9a	11.5b	273.1a
Fe-chelate	27.4a	196.9b	17.2a	265.3a
A. retroflexus	24.4ab	194.9b	13.5ab	259.6ab
A. retroflexus + FeSO4	24.8ab	188.8b	13.0ab	244.9b
Significance	*	*	*	**
* and ** effect of treatment significant at P ≤ 0.05 and P ≤ 0.01, respectively. In the same column, means followed by the same letter are not statistically different (P ≤ 0.05, LSD Test). Fe, iron; A. retroflexus, Amaranthus retroflexus L.; FeSO4, iron sulphate.

Table 8. Effect of treatment on fruit firmness, soluble solid content (SSC) and titratable acidity at commercial harvest in 2009 and 2010 (field conditions)

	2009			2010
	Firmness	SSC	Titratable acidity	Firmness	SSC	Titratable acidity
Treatment	(kg)	(°Brix)	(g L^−1 malic acid)	(kg)	(°Brix)	(g L^−1 malic acid)
Control	5.33	12.9b	1.41	5.44	12.8b	1.72
Fe-chelate	5.30	14.2a	1.82	5.46	13.6a	2.28
A. retroflexus	5.18	14.1a	1.45	5.51	13.0ab	1.76
A. retroflexus + FeSO4	4.96	14.4a	1.60	5.60	13.5a	1.94
Significance	ns	*	ns	ns	*	ns
ns and * effect of treatment not significant or significant at P ≤ 0.05, respectively. In the same column, means followed by the same letter are not statistically different (P ≤ 0.05, LSD Test). Fe, iron; A. retroflexus, Amaranthus retroflexus L.; FeSO4, iron sulphate.