Eco-physiological Responses Of Water Stress And Rewatering In Different Adzuki Bean Varieties

Soil moisture is the main factor limiting crop production in dryarea. It is essential to reveal crop’s responses to water stress andrewater effect for breeding and setting up high yield andwater-saving technology system. With three differentdrought-resistant adzuki bean varieties (drought-tolerant‘Jingnong2’,‘Zunhuahong’ and drought-sensitive ‘B1783’), theeco-physiological characteristics were studied under the conditionof moderate and severe drought stress at the seedling stage andrewatering in pot culture. The main results were as follows:(1) A series of process from growth, eco-physiologicalcharacteristics to yield formation were inhibited by drought stress.With the decrease in water,the chlorophyll content of leaves,leave’s Fv/Fo and Fv/Fm, leaf net photosynthetic rate, transpirationrate, intercellular CO2concentration, stomatal conductance, plantheight, leaf area, dry weight of root, main root length, root activityand soluble protein content showed a downward trend. At the sametime, the specific leaf weight, ratio of root and shoot, root’s SOD andPOD activities, MDA content, proline content and soluble sugarcontent showed a riseward trend with the decrease in water. The effects of severe drought stress were significantly greater thanmoderate drought stress.(2) After rewatering,the growth and the tested physiologicalindexes of three adzuki bean varieties had different degrees ofrecovery, but most of the compensation effects did not reach thecontrol level. The compensation effects of moderate drought stresswere significantly greater than severe drought stress, thissuggested that plants were much more effected under severedrought stress, the compensation effects were poor.(3) The variation range of the tested eco-physiological indexeswere different under drought stress and rewatering condition ofthree adzuki bean varieties. The drought-tolerant ‘Jingnong2’ had aclear advantage of rather strong drought resistance capacity andcompensation capability. While the drought-sensitive ‘B1783’ wasgreatly affected by the drought stress,and had a poor ability ofrecovery.‘Zunhuahong’ lies omewhere in between these twovarieties.(4) Seed yields were decreased under drought stress, thereduction of yield in sequence of ‘B1783’>‘Zunhuahong’>‘Jingnong2’, and the effects were stronger under severe droughtstress than moderate drought stress.Compared with drought stress,rewatering increased yields. The compensation effects of moderatedrought stress were stronger than severe drought stress. It wasconsidered that, drought-tolerant ‘Jingnong2’ kept high yields,which had stronger adopt ability under drought stress andrewatering.