Exogenous brassinosteroids alleviate calcium deficiency-induced tip-burn by maintaining cell wall structural stability and higher photosynthesis in mini Chinese Cabbage.

Autor:	Li Y; Gansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou, China.; College of Horticulture, Gansu Agricultural University, Lanzhou, China., Ma J; College of Horticulture, Gansu Agricultural University, Lanzhou, China., Gao X; College of Horticulture, Gansu Agricultural University, Lanzhou, China., Tie J; College of Horticulture, Gansu Agricultural University, Lanzhou, China., Wu Y; College of Horticulture, Gansu Agricultural University, Lanzhou, China., Tang Z; College of Horticulture, Gansu Agricultural University, Lanzhou, China., Hu L; Gansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou, China.; College of Horticulture, Gansu Agricultural University, Lanzhou, China., Yu J; Gansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou, China.; College of Horticulture, Gansu Agricultural University, Lanzhou, China.
Jazyk:	angličtina
Zdroj:	Frontiers in plant science [Front Plant Sci] 2022 Dec 09; Vol. 13, pp. 999051. Date of Electronic Publication: 2022 Dec 09 (Print Publication: 2022).
DOI:	10.3389/fpls.2022.999051
Abstrakt:	Tip-burn has seriously affected the yield, quality and commodity value of mini Chinese cabbage. Calcium (Ca 2+ ) deficiency is the main cause of tip-burn. In order to investigate whether exogenous brassinosteroids (BRs) can alleviate tip-burn induced by calcium (Ca 2+ ) deficiency and its mechanism, in this study, Ca 2+ deficiency in nutrient solution was used to induced tip-burn, and then distilled water and BRs were sprayed on leaves to observe the tip-burn incidence of mini Chinese cabbage. The tip-burn incidence and disease index, leaf area, fluorescence parameters (Fv/Fm, NPQ, qP andφPSII) and gas exchange parameters (Tr, Pn, Gs and Ci), pigment contents, cell wall components, mesophyll cell ultrastructure and the expression of genes related to chlorophyll degradation were measured. The results showed that exogenous BRs reduced the tip-burn incidence rate and disease index of mini Chinese cabbage, and the tip-burn incidence rate reached the highest on the ninth day after treatment. Exogenous BRs increased the contents of cellulose, hemifiber, water-soluble pectin in Ca 2+ deficiency treated leaves, maintaining the stability of cell wall structure. In addition, BRs increased photosynthetic rate by increasing the activities of Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and fructose 1,6-bisphosphatase (FBPase) related to Calvin cycle, maintaining relatively complete chloroplast structure and higher chlorophyll content via down-regulating the expression of BrPPH1 and BrPAO1 genes related to chlorophyll degradation. In conclusion, exogenous BRs alleviated calcium deficiency-induced tip-burn by maintaining cell wall structural stability and higher photosynthesis. Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. (Copyright © 2022 Li, Ma, Gao, Tie, Wu, Tang, Hu and Yu.)
Databáze:	MEDLINE
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