Physiological response characteristics and comprehensive evaluation of seven cruciferous green manure varieties under drought stress
[Objectives]In order to provide a theoretical basis and technical parameters for screening suitable cruciferous green manure(GM)crops for the development of green agriculture systems under dryland conditions in China,we carried out an indoor cultivation experiment to investigate the effects of drought stress on the growth and physiological responses of cruciferous GM crops during their growth period.[Methods]The changes in photosynthetic and physiological characteristics of seven cruciferous GM varieties under normal watering(80%field water capacity)and drought stress(40%field water capacity)conditions were analyzed,and their drought resistance capacities were comprehensively evaluated using principal component analysis(PCA),aiming to select the suitable cruciferous GM variety with strong drought resistance.[Results]1)Compared to the normal watering treatment,the net photosynthetic rate and transpiration rate of GM leaves under drought stress decreased(P<0.05).2)Under drought stress,the germination rate,root length,and fresh biomass of GM crops increased by 6.1%,147%(P<0.05),and 238%(P<0.05),respectively.3)Drought stress increased the activity of catalase(CAT)in the leaves of Qinyou 10 by 26%(P<0.05)and significantly promoted the activity of superoxide dismutase(SOD)in the leaves of Qinyou 10,and Qingza 11,and increased the activity of peroxidase(POD)in all GM leaves(P>0.05).4)Drought stress increased the proline(Pro)content in the leaves of Zhonglüyou 2,Purple Mustard,Qinyou 10,and Zhongyoufei 1(P<0.05),but significantly decreased the malondialdehyde(MDA)content in Purple Mustard,Zhonglüyou 1,and Zhonglüyou 2.5)Principal component analysis showed that fresh biomass,malondialdehyde content,and CAT and POD activity could be regarded as key indices to evaluate the drought resistance of cruciferous GM crops.The comprehensive drought resistance score for Zhonglüyou 1 was the highest among the seven tested cruciferous GM varieties,indicating strong drought resistance[Conclusions]Overall,due to its strong antioxidant capacity,osmotic regulation ability in the leaves,and long root length,Zhonglüyou 1 exhibites outstanding drought resistance under drought stress conditions and can be regarded as a suitable drought-resistant cruciferous GM variety in the Loess Plateau of China.
drought stresscruciferous green manurephotosynthetic characteristicphysiological characteristicprincipal component analysis
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