Effects of Exogenous Methyl Jasmonate on the Photosynthetic Characteristics of Black Highland Barley in Saline-Alkali Habitat

Zhao Xianglong; Chen Gongxi; Wang Jianlin

doi:10.3969/j.issn.1004-3403.2025.02.002

Abstract：Salt-alkali stress in the flowering period has limited the efficiency of grain filling and fruiting of black highland barley,and methyl jasmonate can mitigate the damage caused by it.In order to investigate the effects of dif-ferent concentrations of methyl jasmonate on the photosynthetic characteristics of black highland barley in saline-al-kaline habitat,5 concentration levels:0,50,100,150 and 200 μmol L-1(labeled as M1,M2,M3,M4,and M5 respec-tively)were sprayed for 5 days in the flowering period,and then measured the photosynthetic indexes such as flag leaf area,relative chlorophyll content(SPAD),net photosynthetic rate(Pn),stomatal conductivity(Gs),intercellular CO2 concentration(Ci),and transpiration rate(Tr).The results show that an appropriate concentration of methyl jas-monate could improve the photosynthesis of black highland barley leaves,among which the 100 μmol L-1 of methyl jasmonate had the best effect.From 7 to 35 days after flowering,the flag leaf area and net photosynthesis rate showed a decreasing trend,peaking at 7 days after flowering,among which M3 treatment was 16.12％and 21.62％higher than those of M1 respectively,showing the most obvious effect and significant differences;The relative chloro-phyll content,stomatal conductivity and transpiration rate of flag leaves showed and overall trend ofincreasing first and then decreasing,peaking at 14 days after flowering,among which M3 was 16.26％,26.21％and 39.66％higher than those of M1 respectively,showing the best effect,The intercellular CO2 concentration showed an overall in-creasing trend,peaking at 35 days,among which the intercellular CO2concentration of black highland barley flag leaves under M3 treatment was 27.92％higher than that of M1,demonstrating a remarkable promotion effect.