Fig 1.
Changes in chlorophyll content of flag leaf and the second leaf of sequential and non-sequential senescence wheat cultivars under natural and drought conditions.
(A) Xinong 88, sequential senescence wheat cultivar. (B) NR9405, sequential senescence wheat cultivar. (C) Wenmai 19, non-sequential senescence wheat cultivar. (D) Lankaoaizao 8, non-sequential senescence wheat cultivar. Solid and dash lines represent natural and drought conditions. Each bar represents the mean ± SD of three replications. Asterisks indicate statistically significant difference between flag leaf and the second leaf in the same conditions (*P ≤ 0.05, ** P ≤ 0.01).
Fig 2.
Changes in net photosynthetic rate of flag leaf and the second leaf of sequential and non-sequential senescence wheat cultivars under natural and drought conditions.
(A) Flag leaf, (B) The second leaf. Solid and dash lines represent natural and drought conditions. Each bar represents the mean ± SD of nine replications. Asterisks indicate statistically significant difference between sequential and non-sequential senescence wheat cultivars in the same conditions (*P ≤ 0.05, ** P ≤ 0.01).
Fig 3.
Changes in soluble sugar content of the leaf, leaf sheath, and internode of sequential and non-sequential senescence wheat cultivars under natural and drought conditions.
(A) Flag leaf, (B) The second leaf, (C) Flag leaf sheath, (D) The second leaf sheath, (E) Peduncle, (F) Penultimate internode. Solid and dash lines represent natural and drought conditions. Each bar represents the mean ± SD of three replications. Asterisks indicate statistically significant difference between sequential and non-sequential senescence wheat cultivars in the same conditions (*P ≤ 0.05, ** P ≤ 0.01).
Fig 4.
Changes in leaf sucrose content, SS and SPS activities of sequential and non-sequential senescence wheat cultivars under natural and drought conditions.
(A), (C) and (E) Flag leaf. (B), (D) and (F) The second leaf. Solid and dash lines represent natural and drought conditions. Each bar represents the mean ± SD of three replications. Asterisks indicate statistically significant difference between sequential and non-sequential senescence wheat cultivars in the same conditions (*P ≤ 0.05, ** P ≤ 0.01).
Fig 5.
Spike weight, grain weight per spike, 100-grain weight, and grain SS activities (cleavage direction) of sequential and non-sequential senescence wheat cultivars under natural and drought conditions.
(A) The increased weight in spike and grain per spike from 0 to 20 days after anthesis (DAA) and 20 to 40 DAA (maturity), (B) Spike weight, grain weight per spike, and 100-grain weight at maturity, (C) grain SS activities (cleavage direction). Solid and dash lines represent natural and drought conditions. Each bar represents the mean ± SD of three replicates. Different letters indicate significant difference (P ≤ 0.05) between two treatments and among four cultivars. Asterisks indicate significant difference between sequential and non-sequential senescence wheat cultivars in the same conditions (*P ≤ 0.05, ** P ≤ 0.01).