Chlorophyll fluorescence characteristics of Elaeagnus angustifolia L. and Grewia biloba G.Don var. parviflora (Bge.)Hand.-Mazz. seedlings under drought stress.

Abstract

Elaeagnus angustifolia L. and Grewia biloba var.parviflora(Bge.)Hand.-Mazz. 2-year-old seedlings as materials,using weighing method to set up control(soil moisture 25.6%~27.2%),light stress(19.2%~20.8%), moderate stress(12.8%~14.4%), severe stress(6.4%~8.0%), the effects of drought stress on pigment content and Chlorophyll fluorescence characteristics of E.angustifolia L. and G.biloba G.Don var. parviflora(Bge.)Hand.-Mazz. seedlings were studied.The results showed:(1)Along with the increasing degree of drought stress, the content of chlorophyll a, value of chlorophyll a/b, content of total chlorophyll of two species decreased,and the response of chlorophyll a to drought stress more is sensitive than chlorophyll b,but content of chlorophyll b and content of carotinoid of two species changed inconsistently.(2)Fm,Fv of G.biloba var.parviflora(Bge.)Hand.-Mazz. decreased, E. angustifolia L. is opposite;but F0 increased, Fv/F0,F′v/F′m decreased, Fv/Fm were not significantly different,PhiPS2,ETR,qP first increased, then decreased, NPQ first decreased, then increased in two species.(3)Although the two species showed strong drought resistance, pigment content and Chlorophyll fluorescence parameters were impacted greatly in severe drought stress(6.4%~8.0%), so it is possible that the content of soil moisture at this point is the tolerance limit of photosynthetic pigment and PSⅡof two species,compared with E. angustifolia L., G.biloba var.parviflora(Bge.)Hand.-Mazz. is more sensitive to drought, in the future management, garden irrigation should be guided according to the soil moisture situation and the differences between species.