Arslan Ashraf Muhammad, Xu Yi Ning, Wang Xuming, Liu Bo Ya, Li Lei, Kang Huixing, Gong Xiao Ying
Key Laboratory for Humid Subtropical Eco-geographical Processes of Ministry of Education, School of Geographical Sciences, Fujian Normal University, Fuzhou 350117, China.
Key Laboratory for Humid Subtropical Eco-geographical Processes of Ministry of Education, School of Geographical Sciences, Fujian Normal University, Fuzhou 350117, China; Key Laboratory for Subtropical Mountain Ecology (Ministry of Science and Technology and Fujian Province Funded), Fujian Normal University, Fuzhou 350117, China; Fujian Provincial Key Laboratory for Plant Eco-physiology, Fuzhou 350117, China.
Plant Physiol Biochem. 2024 Dec;217:109304. doi: 10.1016/j.plaphy.2024.109304. Epub 2024 Nov 16.
The photosynthetic efficiency of C plants could be impaired in environments with low light and high vapour pressure deficit (VPD). However, the interactive effect of low light and high VPD on C photosynthetic efficiency remains unexplored. We grew three C species, Setaria viridis L., Sorghum sudanense (Piper) Stapf., and Zea mays L., under controlled high and low irradiance and VPD conditions in growth chambers. Gas exchange and chlorophyll fluorescence parameters were measured to estimate apparent maximum quantum yield (QY), and C discrimination of leaf dry mass (Δ) was measured to estimate bundle-sheath leakiness (BS-leakiness). Averaged over VPD levels, net CO assimilation rate at saturating light (A) decreased in S. viridis and S. sudanense but not Z. mays under low irradiance. High VPD decreased A of S. viridis but increased A of Z. mays. QY was not significantly affected by low light, high VPD or their interaction, which was associated with the unchanged photochemical efficiency of photosystem II. Low light did not significantly influence BS-leakiness, while high VPD only increased BS-leakiness of Z. mays by 0.08 compared with low VPD at low irradiance. The insignificant interaction of low light and high VPD on QY and BS-leakiness indicates that these C species could maintain photosynthetic efficiency under these unfavourable conditions.
在低光照和高蒸汽压亏缺（VPD）的环境中，C4植物的光合效率可能会受到损害。然而，低光照和高VPD对C4光合效率的交互作用仍未得到探索。我们在生长室中，在可控的高、低辐照度和VPD条件下，种植了三种C4植物，即绿色狗尾草、苏丹草和玉米。测量了气体交换和叶绿素荧光参数，以估算表观最大量子产量（QY），并测量了叶片干重的C4歧视（Δ），以估算维管束鞘泄漏率（BS泄漏率）。在VPD水平上进行平均，在低辐照度下，绿色狗尾草和苏丹草的饱和光下净CO2同化率（A）下降，但玉米没有下降。高VPD降低了绿色狗尾草的A，但增加了玉米的A。QY不受低光照、高VPD或它们的相互作用的显著影响，这与光系统II的光化学效率不变有关。低光照对BS泄漏率没有显著影响，而高VPD仅使低辐照度下玉米的BS泄漏率比低VPD时增加了0.08。低光照和高VPD对QY和BS泄漏率的相互作用不显著，表明这些C4植物在这些不利条件下能够维持光合效率。
