Effect of R∶FR ratio on the growth and photosynthetic physiology of Ginkgo biloba seedlings under salt stress
[Objective]Establishing varied ratios of red light to far-red light environments to investigate their impact on the growth and photosynthetic characteristics of Ginkgo biloba seedlings under salt stress.This study aims to provide a theoretical basis for a deeper understanding of the mechanisms underlying improved salt tolerance in G.biloba through light quality regulation.[Method]The experiment used one-year-old Ginkgo seedlings as the research subjects and had four treatments:CK(0 NaCl,R∶FR=7),T1(0.3%NaCl,R∶FR=7),T2(0.3%NaCl,R∶FR=1.2),and T3(0.3%NaCl,R∶FR=0.8).Measurements of chlorophyll content and relative conductivity were taken at 14,28,and 42 days of treatment.Measure growth indicators,leaf morphology,and photosynthetic parameters at the end of the 42-day experiment.Analyzing the effects of R∶FR ratio on the growth,development,and photosynthetic capacity of Ginkgo seedlings under salt stress.[Result]Compared with CK,various growth indicators of Ginkgo seedlings under T1 and T2 treatments significantly decreased.However,under the T3 treatment,the fresh and dry mass of Ginkgo seedling leaves increased significantly compared to T1.In terms of leaf morphology parameters,all salt-treated groups showed a decrease in leaf area,leaf perimeter,leaf width,and leaf length compared to CK,with T1 showing the greatest decrease.As the R∶FR ratio decreased,the inhibitory effect of salt stress on leaf growth in Ginkgo seedlings decreased.With increasing stress duration,the relative conductivity of leaves in all salt-treated groups showed an upward trend,with the smallest increase observed in the T3 treatment group.Regarding the changes in chlorophyll a(Chla),carotenoids(Car),chlorophyll a/b(Chla/b),chlorophyll b(Chlb),and total chlorophyll(Chla+b)content in Ginkgo seedling leaves under different treatments over time,they generally exhibited a trend of initially decreasing and then increasing,while Chlb and Chla+b showed the opposite trend.The overall trend in Chla+b content among different treatments was CK＞T3＞T2＞T1.At 42-day,the Chla/b ratio among treatments was CK＞T3＞T1＞T2.In terms of photosynthetic gas exchange parameters and characteristics of the light response curve,under the T3 treatment,the net photosynthetic rate(Pn),maximum net photosynthetic rate(Pn,max),and intrinsic quantum efficiency(φ0)of leaves showed no significant difference compared to CK but were significantly higher than T1.As the R∶FR ratio decreased in the light environment,the dark respiration rate(Rd)and light compensation point(Ic)of Ginkgo seedlings under salt stress significantly increased.[Conclusion]The inhibitory effect of salt stress on the growth,membrane system damage,respiration,and photosynthetic characteristics of Ginkgo seedlings was effectively alleviated as the R∶FR ratio decreased in the light environment.Furthermore,when the R∶FR ratio was 0.8,there was a significant improvement in photosynthetic performance,indicating the most effective alleviation effect.
Ginkgo bilobaNaCl stressred light and far-red lightphotosynthesislight response curve
万方数据
维普
