Adequate internal water status of NaCl-salinized rice shoots enhanced selective calcium and potassium absorption

Figures & data

Table 1 Composition of the treatment solutions

Treatment designation	Treatments and osmotic potential
	Composition (mol m^−3)	Osmotic potential (MPa)
CO	Control	−0.039
Na40	+40 Na (NaCl)	−0.212
Na80	+80 Na (NaCl)	−0.393
Na120	+120 Na (NaCl)	−0.583
Na40–Ca	+Na40 + 10 Ca (CaCl2)	−0.241
Na80–Ca	+Na80 + 10 Ca (CaCl2)	−0.407
Na120–Ca	+Na120 + 10 Ca (CaCl2)	−0.574
Na40–H2O	+Na40 + water spray	−0.212
Na80–H2O	+Na80 + water spray	−0.393
Na120–H2O	+Na120 + water spray	−0.583
The pH of the culture solution was adjusted to 5.5 by the addition of a 1:1 H2SO4 solution.

Figure 1  Proportion of Na or K content and calcium content of rice plants grown at various salt concentrations (40, 80, 120 mol m−3), and the addition of calcium (10 mol m−3) into NaCl-salinized nutrient solution or mist-water spray onto shoots in the salt treatments. a, shoots; b, roots. The proportion of Na and K is denoted by □ bars and

bars, respectively. The Ca content is denoted by ▴ marks.

Table 2 Growth, water status and cumulative transpiration in rice 8 days after the beginning of the treatment

Treatment	CT (g plant^−1)	Shoot					Root
		DW (g shoot^−1)	WS	Content (cmol kg^−1)			DW (g shoot^−1)	WS	Content (cmol kg^−1)
				Na	K	Ca			Na	K	Ca
Control	330.4f	1.43d	4.91h	1.0a	94.0c	2.03b	0.381f	10.29ab	3.3a	84.3f	1.57bc
Na40	278.4e	1.47d	4.08de	31.3b	62.8ab	1.42a	0.335de	10.18ab	52.5c	63.0d	1.00a
Na80	181.7bc	1.03ab	3.90c	58.8d	59.6a	1.23a	0.255bc	10.01ab	73.7e	46.5bc	1.60bc
Na120	137.0a	0.96a	3.35a	94.4f	56.6a	1.23a	0.210a	10.54b	93.7g	41.0a	1.61bc
Na40–H2O	270.9e	1.48d	4.60g	27.6b	69.4b	2.63c	0.322d	10.01ab	52.8c	59.8d	0.96a
Na80–H2O	222.7d	1.27c	4.17e	45.4c	62.4ab	2.13b	0.267c	9.59a	72.3e	48.5bc	1.79bc
Na120–H2O	157.7ab	0.98ab	3.98cd	74.5e	56.7a	2.19b	0.224ab	9.66a	98.8h	43.6ab	1.34ab
Na40–Ca	283.8e	1.47d	4.35f	26.4b	69.0b	5.02f	0.361ef	9.90ab	43.2b	74.4e	1.90c
Na80–Ca	195.6cd	1.12b	3.99cd	44.4c	63.4ab	4.15d	0.281c	10.24ab	63.9d	61.7d	2.74d
Na120–Ca	130.7a	0.90a	3.55b	77.6e	62.6ab	4.59e	0.220a	10.31ab	86.4f	51.1c	1.92c
Different letters indicate a significant difference at P < 0.05 using Duncan's new multiple range test. CT, cumulative transpiration in rice 8 days after the beginning of the treatment; DW, dry weight; WS, water status (water content/dry weight).

Table 3 Transpiration stream concentration factor (TSCF-Na or TSCF-Ca) and K or Ca versus Na selectivity (SK,Na or SCa,Na) in rice 8 days after the beginning of the treatment

Treatment	Shoot				Root
	TSCF-Na	TSCF-Ca	SK,Na	SCa,Na	SK,Na	SCa,Na
Control	1.08c	0.44e	–	–	–	–
Na40	0.41ab	0.37cd	40.18	0.91	24.02	0.38
Na80	0.41ab	0.35c	40.58	0.83	25.24	0.43
Na120	0.54b	0.43de	35.94	0.78	26.23	0.34
Na40–H2O	0.37ab	0.71g	50.25	1.90	22.66	0.36
Na80–H2O	0.32a	0.61f	55.00	1.88	26.86	0.99
Na120–H2O	0.39ab	0.68g	45.64	1.76	26.44	0.81
Na40–Ca	0.34a	0.26ab	52.20	0.76	34.44	0.18
Na80–Ca	0.31a	0.24a	57.21	0.75	38.65	0.34
Na120–Ca	0.44ab	0.31bc	48.35	0.71	35.48	0.27
Different letters indicate a significant difference at P < 0.05 using Duncan's new multiple range test. TSCF-Na, TSCF-Ca, SK,Na and SCa,Na were derived using the equation:
where []i and []0 indicate the ion content and the concentration in the external solution, respectively.