谷子苗期对低温胁迫的生理生化响应

Physiological and Biochemical Responses of Foxtail Millet to Low Temperature Stress at Seedling Stage

研究谷子幼苗对低温胁迫的生理响应机制,筛选耐冷种质,为耐冷品种选育提供理论依据。以耐冷谷子品种晋谷21号和冷敏感谷子品种长农48号为试验材料,设置低温(8℃)和对照(25℃)2个处理,分别在低温处理前、低温处理3 d后和恢复处理3 d后测定各处理下幼苗的苗高、苗鲜重和干重、抗氧化酶活性及渗透调节物质。结果表明,与对照相比,谷子经低温胁迫处理3 d后,幼苗农艺性状各指标均显著降低,冷敏感品种的降幅高于耐冷品种。低温胁迫处理3 d后,耐冷品种幼苗叶片的超氧化物歧化酶(SOD)、过氧化物酶(POD)及过氧化氢酶(CAT)活性均呈增加趋势,丙二醛(MDA)含量显著增加;冷敏感品种的MDA含量增加幅度显著高于耐冷品种(P<0.05),具有更强的保护性酶活性。

This study investigated the physiological response mechanism of foxtail millet seedlings to low temperature stress,screening of cold-tolerant germplasm,and provided theoretical basis for the selection and breeding of cold-tolerant cultivar.The cold-tolerant foxtail millet cultivar Jingu 21 and the cold-sensitive foxtail millet cultivar Changnong 48 were used as test materials,and two treatments of low temperature(8℃)and control(25℃)were set up,and height,fresh and dry weights,antioxidant enzyme activities and osmoregulatory substances of seedlings under each treatment were determined before the low temperature treatment,after three days of the low temperature treatment and after three days of the recovery treatment,respectively.The results showed that,compared with control,after three days of low-temperature stress treatment in foxtail millet,all the indicators of seedling agronomic traits were significantly reduced,and the reduction of cold-sensitive cultivar was higher than that of cold-tolerant cultivar.After three days of low-temperature stress treatment,SOD,POD and CAT activities of seedling leaves of cold-tolerant cultivar showed increasing trend,and MDA contents increased significantly.The MDA content of cold-sensitive cultivar was significantly higher than that of cold-tolerant cultivar(P<0.05),and they had stronger protective enzyme activities.