Effects of Drought Stress on Non-structural Carbohydrates of Robinia pseudoacacia Saplings at the End of the Growing Season
ZHANG Ting;CAO Yang;CHEN Yunming;LIU Guobin;Institute of Soil and Water Conservation,Chinese Academy of Sciences and Ministry of Water Resources;State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Northwest A&F University;
One-year-old Robinia pseudoacacia saplings were subjected to 70% of field capacity(control)and progressive drought stress(treatment)to study the effects of drought stress on non-structural carbohydrates(NSC)of R.pseudoacaciasaplings at the end of the growing season.While leaf biomass,stomatal conductance and net photosynthetic rates of saplings under control generally exhibited no significant differences throughout the experiment(P0.05),those under treatment decreased with the intensification of drought stress(P0.01).Soluble sugar concentrations and the ratios of soluble sugars to starch in different tissues under treatment all increased with drought progression,but were significantly higher than those under control(P0.05).Contrarily,starch and NSC concentrations in each tissue under treatment all decreased with drought progression(P0.05).Except NSC in leaves and fine roots,starch and NSC concentrations under treatment were all lower than those under control(P0.05).NSC concentrations in branches,stems and coarse roots were 96.6%,70.5%,and 78.2% of those under control,respectively.At the whole sapling level,NSC concentrations under treatment decreased throughout the experiment,and were significantly lower than those under control(P0.05),and were 84.0%,79.0%,76.3%and 67.5% of those under control on the 6th,9th,12 th and 15 th days,respectively.Soluble sugar,starch and NSC concentrations and the ratios of soluble sugars to starch in different sapling tissues,except NSC concentrations in branches and fine roots,and NSC concentrations at the whole sapling level were all significantly correlated with soil water content,leaf biomass,stomatal conductance and net photosynthetic rates.Our results suggested that the premature defoliation and decrease of photosynthetic rate of R.pseudoacaciasaplings resulted from drought stress at the end of the growing season could facilitate the transformation of starch to soluble sugars and then decrease the accumulation of starch,as a result,would induce the premature consuming of NSC,which would mainly occur to stems and coarse roots.
【Fund】： 国家自然科学基金(41201088 41371506);; 教育部博士点基金(20120204120014);; 中国科学院西部之光(K318021304)
【CateGory Index】： S792.27
【CateGory Index】： S792.27