不同基因型谷子对花期干旱胁迫的生理响应及耐旱性综合评价OA

To investigate the effects of drought stress on the growth and drought tolerance of foxtail millet(Setaria italica),this study employed 26 diverse foxtail millet genotypes at the heading-flowering stage.Two treatments,well-watered control(soil moisture maintained at 60％field capacity,CK)and drought stress(soil moisture maintained at 30％to 35％field capacity,DS)were designed during the heading to flowering period.Physiological characteristic of flowering stage and yield traits at maturity were measured.Drought resistances were evaluated using the yield-based drought resistance index(DRI).The results demonstrated that:Drought stress significantly reduced chlorophyll content,photosynthetic rate(Pn),maximum photochemical efficiency of PSⅡ(Fv/Fm),and maximum photochemical energy conversion potential(Fv/F0)across all genotypes.Compared with CK,'Zhenggu 678'exhibited the smallest reductions in chlorophyll content,photosynthetic rate,and Fv/Fm(decreased by 30.0％,3.3％,and 1.9％,respectively)under drought conditions,while'Yugu 27'and'Yugu 101'showed minimal decline in Fv/F0(decreased by 1.3％).Drought stress remarkably elevated leaf soluble sugar,soluble protein,and proline contents,as well as the activities of superoxide dismutase(SOD),peroxidase(POD),and catalase(CAT).'Chiyou Jinmiao 1'displayed the greatest increase in soluble sugar by 68％.'Yugu 29'showed the highest soluble protein accumulation(37％up).'Gongmi 1'exhibited the most pronounced increases in proline content(11.40 times)and POD activity(2.16 times).'Jigu 22'demonstrated the highest SOD activity elevation(1.19 times),and'Jigu 168'showed maximal CAT activity enhancement(3.33 times).Based on yield DRI analysis,'Zhenggu 678'(DR I=1.111),'Zhonggu 989'(DR I=1.192)and'Jigu 30'(DRI=1.144)were identified as genotypes with strong drought resistance.Result of principal component analysis identified the thousand-kernel weight,plant height,photosynthetic rate,Fv/Fm,chlorophyll content,proline content,and SOD enzyme activity as key indicators for assessing drought tolerance at the flowering stage.