模拟三峡库区消落带土壤干旱对桑树生理特性的影响  

Effects of Simulated Soil Drought on Physiological Characteristics of Young Mulberry (Morus alba L.)Trees in the Hydro-fluctuation Belt of the Three Gorges Reservoir Area

作　　者：黄小辉[1,2] 刘芸[1] 李佳杏[1] 熊兴政[1] 尹小华[1] 陈阳[1] 冯大兰[2] 李沙[3] 

机构地区：[1]西南大学资源环境学院,重庆400716 [2]重庆市林业科学研究院三峡库区森林生态保护与恢复重庆市市级重点实验室,重庆400036 [3]中国民主同盟广西壮族自治区委员会,广西南宁530023

出　　处：《西南大学学报（自然科学版）》2013年第9期127-132,共6页Journal of Southwest University(Natural Science Edition)

基　　金：世界自然基金会(瑞士)项目(No.10000757-1.3.01.02);西南大学资源环境学院本科生科技创新“光炯”培育项目(No.20110104)

摘　　要：在温室条件下模拟三峡库区消落带夏季伏旱时土壤水分变化特征,以盆栽桑树为材料,设置对照（CK）、中度干旱胁迫（T1）和特大干旱胁迫（T2）3个含水量梯度,研究了不同程度干旱胁迫对桑树生理特性的影响.结果表明：（1）随着干旱胁迫的加剧,各时期桑树叶片的叶绿素含量、净光合速率和瞬时水分利用效率都有不同程度的增加,气孔导度和蒸腾速率逐渐下降,胞间CO2 摩尔分数呈不同程度的降低,叶片脱落酸含量呈上升趋势,且各处理组间差异显著（p〈0.05）.（2）随着处理时间的延长以及桑树生长逐渐进入休眠期,各处理组桑树叶绿素含量、气孔导度和蒸腾速率呈下降的趋势,胞间CO2 摩尔分数呈先降后升的趋势,而净光合速率基本呈下降的趋势,但 T1,T2在实验中期（30~45d）有明显的回升;瞬时水分利用效率和脱落酸含量都呈逐渐上升的趋势.可见,桑树能够通过调节自身生理代谢来减少水分消耗,增加水分利用效率,提高光合能力,从而维持其正常生长,表现出很强的抗旱耐旱能力.To examine possible effects of soil water conditions in summer in the hydro-fluctuation belt of the Three Gorges Reservoir Area on mulberry, we grew potted mulberry in a greenhouse under three soil water regimes designed to simulate normal irrigation （CK）, moderate drought stress （T1） and extraordi-nary drought stress （T2）. With increasing drought stress, chlorophyll content, photosynthetic rate （Pn） and instantaneous water use efficiency of mulberry trees all increased to different degrees, stomatal con-ductance （Gs） and transpiration rate （Tr） decreased gradually, intercellular CO2 concentration （Ci） de-creased to different degrees and abscisic acid （ABA） content showed an increasing trend, the differences in these effects being significant between different treatment groups （p〈0.05）. With extending treatment time, the mulberry trees entered into growth dormancy gradually, chlorophyll content, Gs and Tr showed a decreasing trend in all treatment groups, Ci decreased first but then increased, Pn, on the whole, de-creased gradually, but rose again markedly in T1 and T2 during the 30-45 d period of the experiment, and instantaneous water use efficiency and ABA content showed an increasing trend. It is concluded that under drought stress the mulberry tree can actively adjust its physiological metabolism to decrease its wa-ter consumption, increase its water use efficiency and enhance its photosynthetic capacity so as to keep its normal growth.

关 键 词：干旱胁迫 三峡库区消落带 桑树幼苗 生理特性 

分 类 号：S888.2[农业科学—特种经济动物饲养]