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Variability of leaf photosynthetic characteristics in rice and its relationship with resistance to water stress under different nitrogen nutrition regimes
Author(s) -
Xiaochuang Cao,
Chu Zhong,
Chunquan Zhu,
Junhua Zhang,
Lianfeng Zhu,
Lianghuan Wu,
Qianyu Jin
Publication year - 2019
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/ppl.12909
Subject(s) - photosynthesis , stomatal conductance , water use efficiency , photosystem ii , nitrogen , biomass (ecology) , rubisco , shoot , chemistry , agronomy , chlorophyll , nutrient , horticulture , biology , botany , organic chemistry
The negative effects of water stress on rice can be alleviated by NH 4 + nutrition. However, the effects of mixed nitrogen (N) nutrition (NO 3 − + NH 4 + ) on resistance to water stress are still not well known. To investigate the response of rice growth to water stress and its relationship with photosynthetic characteristics, a hydroponic experiment supplying different N forms was conducted. Compared with NO 3 − nutrition, mixed‐N and NH 4 + nutrition greatly alleviated the reduction of leaf area, chlorophyll content, and photosynthesis under water stress, whilst subsequently maintaining higher biomass. In contrast, water stress inhibited the root‐shoot ratios in NH 4 + ‐ and mixed‐N‐supplied plants, indicating reduced root growth and higher photosynthate availability to shoots. The following key observations were made: (1) a similar stomatal limitation and low proportion of activated Rubisco were observed among the three different N nutrition regimes; (2) increased mesophyll conductance in NH 4 + ‐ and mixed‐N‐supplied plants simultaneously stimulated leaf photosynthesis and improved the water use efficiency and (3), the maximum carboxylation rate and actual photochemical efficiency of photosystem II in NH 4 + ‐ and mixed‐N‐supplied plants were significantly higher than that in NO 3 − ‐supplied plants, thus resulting in higher photochemical efficiency under water stress. In conclusion, mixed‐N and NH 4 + nutrition may be used to develop strategies for improved water stress resistance and stimulated biomass production under conditions of osmotic stress and possibly drought.