期刊
FRONTIERS IN PLANT SCIENCE
卷 12, 期 -, 页码 -出版社
FRONTIERS MEDIA SA
DOI: 10.3389/fpls.2021.675546
关键词
crop improvement; drought tolerance; food security; maize; global warming; heat tolerance; water deficit; Zea mays
资金
- FCT (BioISI) [UIDB/04046/2020, UIDP/04046/2020]
- FCT research project INTERPHENO [PTDC/ASP-PLA/28726/2017]
- FCT (Portugal) from the BioSys Ph.D. programme [PD65-2012, SFRH/PD/BD/130973/2017]
This study investigated the responses of maize to high temperature and drought stress, showing that maize genotypes B73 and P0023 adapted to high temperature conditions differently, with P0023 sustaining photosynthetic efficiency by limiting transpiration rate and synchronizing regulation of carbon assimilation metabolism.
Increasing temperatures and extended drought episodes are among the major constraints affecting food production. Maize has a relatively high temperature optimum for photosynthesis compared to C-3 crops, however, the response of this important C-4 crop to the combination of heat and drought stress is poorly understood. Here, we hypothesized that resilience to high temperature combined with water deficit (WD) would require efficient regulation of the photosynthetic traits of maize, including the C-4-CO2 concentrating mechanism (CCM). Two genotypes of maize with contrasting levels of drought and heat tolerance, B73 and P0023, were acclimatized at high temperature (38 degrees C versus 25 degrees C) under well-watered (WW) or WD conditions. The photosynthetic performance was evaluated by gas exchange and chlorophyll a fluorescence, and in vitro activities of key enzymes for carboxylation (phosphoenolpyruvate carboxylase), decarboxylation (NADP-malic enzyme), and carbon fixation (Rubisco). Both genotypes successfully acclimatized to the high temperature, although with different mechanisms: while B73 maintained the photosynthetic rates by increasing stomatal conductance (gs), P0023 maintained gs and showed limited transpiration. When WD was experienced in combination with high temperatures, limited transpiration allowed water-savings and acted as a drought stress avoidance mechanism. The photosynthetic efficiency in P0023 was sustained by higher phosphorylated PEPC and electron transport rate (ETR) near vascular tissues, supplying chemical energy for an effective CCM. These results suggest that the key traits for drought and heat tolerance in maize are limited transpiration rate, allied with a synchronized regulation of the carbon assimilation metabolism. These findings can be exploited in future breeding efforts aimed at improving maize resilience to climate change.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据