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Leaf photosynthetic capacity is regulated by the interaction of nitrogen and potassium through coordination of CO 2 diffusion and carboxylation
Author(s) -
Hu Wenshi,
Ren Tao,
Meng Fanjin,
Cong Rihuan,
Li Xiaokun,
White Philip J.,
Lu Jianwei
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.12919
Subject(s) - carboxylation , photosynthesis , cmax , potassium , chemistry , stomatal conductance , nitrogen , nutrient , photosynthetic capacity , agronomy , botany , horticulture , biology , biochemistry , bioavailability , bioinformatics , organic chemistry , catalysis
Combined application of nitrogen (N) and potassium (K) fertilizer could significantly enhance crop yield. Crop yield and photosynthesis are inseparable. However, the influence of N and K interaction on photosynthesis is still not fully understood. Field and hydroponic experiments were conducted to examine the effects of N and K interaction on leaf photosynthesis characteristics and to explore the mechanisms in the hydroponic experiment. CO 2 conductance and carboxylation characteristic parameters of oilseed leaves were measured under different N and K supplies. Results indicated that detectable increases in leaf area, biomass and net photosynthetic rate ( A n ) were observed under optimal N and K supply in field and hydroponic experiments. The ratio of total CO 2 diffusion conductance to the maximum carboxylation rate ( g tot / V cmax ) and A n presented a linear‐plateau relationship. Under insufficient N, increased K contributed to the CO 2 transmission capacity and improved the proportion of N used for carboxylation, promoting g tot / V cmax . However, the low V cmax associated with N insufficiency limited the A n . High N supply obviously accelerated V cmax , yet K deficiency led to a reduction of g tot , which restricted V cmax . Synchronous increases in N and K supplementation ensured the appropriate ratio of N to K content in leaves, which simultaneously facilitated g tot and V cmax and preserved a g tot / V cmax suitable for guaranteeing CO 2 transmission and carboxylation coordination; the overall effect was increased A n and leaf area. These results highlight the suitable N and K nutrients to coordinate CO 2 diffusion and carboxylation, thereby enhancing photosynthetic capacity and area to obtain high crop yield.