摘要
以一年生刺槐(Robinia pseudoacacia)幼苗为研究对象,通过在生长季末期设置包含保持土壤含水量为田间持水量70%的对照组和停止水分补给的干旱处理组的盆栽试验,研究该时期干旱胁迫对刺槐幼苗非结构性碳水化合物(NSC)的影响。随着干旱胁迫时间的延长,处理组幼苗功能叶生物量、净光合速率、气孔导度均持续降低,至第12天时分别降至对照组的10.91%,5.70%和3.63%,且整个试验期间其均显著低于基本保持不变的对照组(P<0.01)。干旱处理组幼苗叶、枝、树干、粗根、细根可溶性糖含量均增加,且显著高于对照组,分别为对照组的1.12,1.05,1.13,1.26,1.29倍(P<0.05);但淀粉含量均降低,并显著低于对照组,分别为对照组的84.0%,94.8%,63.3%,70.5%,89.4%(P<0.05);NSC含量均降低,叶和细根NSC含量显著高于对照组,分别为对照组的1.03倍和1.01倍,枝、树干、粗根NSC含量均显著低于对照组,分别为对照组的96.6%,70.5%,78.2%(P<0.05);可溶性糖和淀粉含量的比值均增加,且显著高于对照组,分别为对照组的1.33,1.10,1.79,1.82,1.44倍(P<0.05)。就整株水平而言,干旱处理组幼苗NSC含量随干旱胁迫时间的延长而降低(P<0.05),在第6,9,12,15天时,其分别是对照组的84.0%,79.2%,76.3%,67.5%。除枝和细根NSC含量外,不同器官NSC及其组分含量、可溶性糖与淀粉含量的比值、整株水平NSC含量均与土壤含水量、叶生物量、气孔导度和净光合速率显著相关(P<0.05)。生长季末期干旱胁迫导致刺槐幼苗提前大量落叶、净光合速率降低、淀粉向可溶性糖转化增加,导致淀粉积累减少,进而NSC被提前消耗,且以树干和粗根中的消耗最显著。
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.
出处
《水土保持学报》
CSCD
北大核心
2016年第5期297-304,共8页
Journal of Soil and Water Conservation
基金
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)
关键词
淀粉
光合速率
可溶性糖
落叶
水分胁迫
叶生物量
starch
photosynthetic rate
soluble sugar
defoliation
water stress
leaf biomass
