干旱胁迫对小麦幼苗根系生长和叶片光合作用的影响  

Responses of wheat seedlings root growth and leaf photosynthesis to drought stress

作　　者：马富举[1] 李丹丹[1] 蔡剑[1] 姜东[1] 曹卫星[1] 戴廷波[1] 

机构地区：[1]南京农业大学,南京210095

出　　处：《应用生态学报》2012年第3期724-730,共7页Chinese Journal of Applied Ecology

基　　金：国家自然科学基金项目(30871481);江苏省科技支撑计划项目(BE2009426)资助

摘　　要：采用水培试验方法,以2个耐旱性不同的小麦品种(敏感型望水白和耐旱型洛旱7号)为材料,研究了干旱胁迫对小麦幼苗根系形态、生理特性以及叶片光合作用的影响,以期揭示小麦幼苗对干旱胁迫的适应机制.结果表明:干旱胁迫下,2个小麦品种幼苗的根系活力显著增大,而根数和根系表面积受到抑制;干旱胁迫降低了望水白的叶片相对含水量,提高了束缚水/自由水,而对洛旱7号无显著影响;干旱胁迫降低了2个小麦品种叶片的叶绿素含量、净光合速率、蒸腾速率、气孔导度和胞间CO2浓度,但随胁迫时间的延长,洛旱7号的叶绿素含量和净光合速率与对照差异不显著;干旱胁迫降低了2个小麦品种幼苗的单株叶面积,以及望水白的根系、地上部和植株生物量,而对洛旱7号无显著影响.水分胁迫下,耐旱型品种可以通过提高根系活力、保持较高的根系生长量来补偿根系吸收面积的下降,保持较高的根系吸水能力,进而维持较高的光合面积和光合速率,缓解干旱对生长的抑制.Taking drought-sensitive wheat cultivar Wangshuibai and drought-tolerance cultivar Luohan 7 as test materials,a hydroponic experiment was conducted to study the effects of drought stress on root system morphology,physiological characteristics and leaf photosynthesis of wheat seedlings,aimed to elucidate the adaptation mechanisms to drought stress.Under drought stress,the root vitality of the cultivars increased markedly,but the root number and root surface area decreased.Drought stress decreased relative water content and increased the ratio of bound water to free water in leaves of Wangshuibai,but had less effects on Luohan 7.Drought stress decreased,the leaf chlorophyll content,Pn,gs,Ci,and transpiration rate of the two cultivars,but had no significant effects on leaf chlorophyll content and Pn of Luohan 7.Drought stress decreased the leaf area of the two cultivars and the root biomass,shoot biomass,and plant biomass of Wangshuibai,but had no significant effects on Luohan 7.The results indicated that under drought stress,drought-tolerant wheat cultivar was able to compensate decreased root absorption area and retain higher root water uptake capability via enhancing root vitality and maintaining higher root biomass,and further,to keep higher leaf photosynthetic area and Pn to mitigate the inhibition of drought on wheat seedlings growth.

关 键 词：小麦 干旱胁迫 耐旱性 光合作用 根系 

分 类 号：S512.1[农业科学—作物学]