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Leaf N content regulates the speed of photosynthetic induction under fluctuating light among canola genotypes ( Brassica napus L.)
Author(s) -
Liu Jiahuan,
Zhang Jing,
Estavillo Gonzalo M.,
Luo Tao,
Hu Liyong
Publication year - 2021
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.13390
Subject(s) - photosynthesis , canola , brassica , biology , stomatal conductance , light intensity , botany , agronomy , horticulture , physics , optics
Nitrogen is an essential element for plant growth, and the relationship between leaf N content and photosynthesis has been widely studied in different species under steady‐state light. However, under natural conditions, the light intensity at the leaf level is always changing, inherently heterogeneous in time and space. Therefore, the effect of leaf N content on photosynthesis under dynamic light conditions needs further study. At present, the effects of leaf N content on leaf non‐steady‐state photosynthesis have not been reported in canola ( Brassica napus L.). To clarify the relationship between leaf N content and the speed of the response leaf gas exchange to variations in light intensity, eight genotypes of canola varying in leaf N content were used to study the temporal response of gas exchange to a step increase in irradiance. We found there were significant differences in non‐steady‐state photosynthesis, physiological characteristics, and anatomical traits across genotypes (the maximum amplitude was about fivefold), despite the lack of contrast under normal, steady‐state photosynthesis. In addition, initial stomatal conductance to water vapor in the darkness and leaf N content per leaf area were negatively correlated with the time required to achieve 50% and 100% of the maximum photosynthetic rate. Contrarily, the time required to reach 50% of the maximum stomatal conductance was positively correlated with the time required to achieve 90% of the maximum photosynthetic rate across genotypes. It is concluded that the genotypes of canola with higher N content per leaf area show a faster induction of photosynthesis to fluctuating light conditions.