Phosphorus alleviates aluminum-induced inhibition of growth and photosynthesis in Citrus grandis seedlings |
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Authors: | Huan-Xin Jiang Ning Tang Jin-Gui Zheng Yan Li Li-Song Chen |
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Institution: | Institute of Horticultural Plant Physiology, Biochemistry and Molecular Biology, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China;College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China;College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China;Biotechnology Center, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China;College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China;Fujian Key Laboratory for Plant Molecular and Cell Biology, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China |
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Abstract: | Limited data are available on the effects of phosphorus (P) and aluminum (Al) interactions on Citrus spp. growth and photosynthesis. Sour pummelo (Citrus grandis) seedlings were irrigated for 18 weeks with nutrient solution containing 50, 100, 250 and 500 μM KH2PO4× 0 and 1.2 mM AlCl3· 6H2O. Thereafter, P and Al in roots, stems and leaves, and leaf chlorophyll (Chl), CO2 assimilation, ribulose‐1,5‐bisphosphate carboxylase/oxygenase (Rubisco) and Chl a fluorescence (OJIP) transients were measured. Under Al stress, P increased root Al, but decreased stem and leaf Al. Shoot growth is more sensitive to Al than root growth, CO2 assimilation and OJIP transients. Al decreased CO2 assimilation, Rubisco activity and Chl content, whereas it increased or did not affect intercellular CO2 concentration. Al affected CO2 assimilation more than Rubisco and Chl under 250 and 500 μM P. Al decreased root, stem and leaf P, leaf maximum quantum yield of primary photochemistry (Fv/Fm) and total performance index (PItot,abs), but increased leaf minimum fluorescence (Fo), relative variable fluorescence at K‐ and I‐steps. P could alleviate Al‐induced increase or decrease for all these parameters. We conclude that P alleviated Al‐induced inhibition of growth and impairment of the whole photosynthetic electron transport chain from photosystem II (PSII) donor side up to the reduction of end acceptors of photosystem I (PSI), thus preventing photosynthesis inhibition through increasing Al immobilization in roots and P level in roots and shoots. Al‐induced impairment of the whole photosynthetic electron transport chain may be associated with growth inhibition. |
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