树锦鸡儿、柠条锦鸡儿、小叶锦鸡儿和鹰嘴豆干旱适应能力比较

The comparation of drought resistance between Caragana species (Caragana arborescens,C. korshinskii,C. microphylla) and two chickpea (Cicer arietinum L.) cultivars

对1年生豆科作物鹰嘴豆Rupali品种和Almaz品种以及多年生植物树锦鸡儿、柠条锦鸡儿和小叶锦鸡儿叶相对含水量和叶水势对逐渐干旱胁迫的响应进行了分析,比较了两类植物的干旱适应能力。结果表明鹰嘴豆叶相对含水量随叶水势的下降线性下降,树锦鸡儿、柠条锦鸡儿和小叶锦鸡儿叶相对含水量在叶水势分别下降到-2.4MPa、-2.5MPa和-1.5 MPa之前没有下降,之后随水势的下降线性下降。树锦鸡儿、柠条锦鸡儿和小叶锦鸡儿这种叶相对含水量下降的滞后性表明该类植物叶具有较硬而弹性较差的细胞壁,使得植物在干旱胁迫下叶具有良好的保水能力。鹰嘴豆叶具有的最低水势为-4.5MPa,对应的土壤相对含水量为14%,锦鸡儿植物叶具有的最低水势可达-6.7MPa,对应的土壤相对含水量为6%,说明锦鸡儿植物比鹰嘴豆具有更好的干旱适应能力,这种能力可能取决于锦鸡儿植物体内大量渗透调节物质的累积。

Water stress is the main environmental factor limiting plantproductivity,especially in arid and semi-arid areas.Within limits,plants adapt to water stress through physiological and morphological adaptations,and leaf water potential（LWP） and leaf relative water content（RWC） are widely used to determine plant water status.Several studies have demonstrated the relationship between RWC and LWP to quantify the dehydration tolerance of tissues： tissues which maintain a high RWC as LWP decreases are more tolerant to dehydration.Caragana arborescens,C.korshinskii,C.microphylla,deciduous shrubs,commonly found in desert and semi-desert zones,northwestern China,and have important ecological and economic values： including playing a key role in vegetation succession from shifting sand dune to sandy grassland,helping to restore degraded land and serving as supplemental forage for livestock.Chickpea（Cicer arietinum L.）,annual legume crop,is also considered one of the most drought-tolerant cool season food legumes in these areas.In the present study,predawn LWP and RWC were measured in C.arborescens,C.korshinskii,C.microphylla and two chickpea cultivars,a desi type,cv.Rupali,and a kabuli type,cv.Almaz,when subjected to water deficit in the glasshouse.For each species,20 plants were randomly designated to one of two treatments： well-watered control（WW） and water-stressed（WS）.The WS treatment was imposed by cessation of watering and WW plants were watered every 2-3 days to maintain the soil water content（SWC） above 80% field capacity.RWC and LWP were measured at 2-3 day interval.The results showed that RWC in chickpea decreased with declining LWP and had significant linear relationship with LWP.However,in C.arborescens,C.korshinskii and C.microphyll,RWC did not decreased（maintaining a steady high water content about 100%） until LWP dropped below-2.4MPa,-2.5MPa and-1.5 MPa,respectively.After that,RWC decreased with declining LWP and had significant linear relationship with LWP.The results showed that RWC was a good parameter to determine the water status in chickpea,but as far as C.arborescens,C.korshinskii and C.microphyll were concerned,it was not.The maintenance of steady high water content in C.arborescens,C.korshinskii and C.microphyll at the beginning of water-deficit period maybe result from rigid and inelastic leaf cell wall in these species,which would provide the basis for sustaining high pressure potential and enhanced plant drought resistance.LWP（ψ）-RWC（R） relationships of these species were analyzed and the regressive slope of Caragana species were slightly lower compared to that of chickpea species,but minimum value of LWP in chickpea species was-4.5 MPa,and the corresponding relative soil water content was 14%,while in Caragana species,equivalent values were-6.7MPa and 6%,respectively.The results indicated that Caragana species had stronger abilty to resist drought stress than chickpea.A better adaptation to drought in Caragana species maybe attribute to accumulation of osmotically-active solutes in plant tissues under water stress.