Evaluation of physiological traits of summer maize under drought stress

Figures & data

Figure 1. Total transpiration, RWC and growth of maize under different soil water availability. Lowercase letters indicate statistical significance in different soil water availability treatments at P < .05.

Figure 2. Leaf gas exchange and fluorescence under different soil water availability. (a) Net photosynthesis (P_n); (b) stomatal conductance (G_s); (c) transpiration rate (T_r); (d) chlorophyll content (Chl); (e) the maximum quantum yield of PSII photochemistry (Fv/Fm); (f) the effective quantum yield of PSII photochemistry (Ф_PSII). Lowercase letters indicate statistical significance in different soil water availability treatments at P < .05.

Figure 3. The accumulation and content of nutrients under different soil water availability. (a) Carbon (C); (b) nitrogen (N); (c) phosphorus (P); (d) potassium (K). Lowercase letters indicate statistical significance in different soil water availability treatments at P < .05.

Table 1. The b-values in the linear-regression analysis between physiological traits and soil water availability.

Physiological traits	b-values	R^2	p
RWC	.1538	.7139	<.0001
Hi	.9437	.8000	<.0001
Si	.8071	.8548	<.0001
Pn	.5618	.7731	<.0001
Gs	.7142	.7865	<.0001
Tr	.8108	.8156	<.0001
C	.8713	.9557	<.0001
N	.7533	.9224	<.0001
P	.7431	.8808	<.0001
K	.743	.8975	<.0001

Notes: RWC: relative water content; Hi: height increment; Si: stem increment; P_n: net photosynthesis; G_s: stomatal conductance; T_r: transpiration rate; C: carbon accumulation; N: nitrogen accumulation; P: phosphorus accumulation; K: potassium accumulation.

Table 2. RRs of plant growth, gas exchange and nutrient accumulation under different water treatments.

Treatment	RWC		Hi		Si		Pn		Gs		Tr		C		N		P		K
85%	−.020		.044		.147		.085		.019		.003		.077		.086		.198		.206
75%	−.033	a	−.063	a	−.174	a	−.156	a	−.304	*a	−.126	a	−.174	a	−.152	a	−.080	a	−.152	a
65%	−.021	a	−.089	a	−.209	a	−.238	b	−.332	*a	−.299	b	−.263	a	−.262	a	−.114	a	−.145	a
55%	−.030	a	−.467	b	−.363	b	−.333	b	−.438	b	−.479	c	−.531	*b	−.466	b	−.412	b	−.382	b
47%	−.138	b	−.640	c	−.572	b	−.572	c	−.658	c	−.632	d	−.768	*c	−.609	bc	−.511	bc	−.513	bc
40%	−.300	c	−1.516*	d	−1.364	*c	−.803	d	−.944	d	−1.093	e	−.850	c	−.736	c	−.707	c	−.664	c

Notes: The presented values are the means of four replicates for each treatment. Lowercase letters indicate statistical significance within the same column, and asterisks indicate statistical significance within the same line at P < .05.

RWC: relative water content; Hi: height increment; Si: stem increment; P_n: net photosynthesis; G_s: stomatal conductance; T_r: transpiration rate; C: carbon accumulation; N: nitrogen accumulation; P: phosphorus accumulation; K: potassium accumulation.