低温胁迫对不同木薯品种幼苗生理特性的影响

目的]研究不同木薯品种幼苗在不同低温胁迫程度下耐寒生理指标的变化,为木薯抗寒品种选育和抗寒栽培提供参考.方法]以华南205、华南124、辐选01为材料,试验设置4、8、12、25℃4个不同温度分别处理1、3、5、7d,处理后测定叶片的相对电导率、SOD、POD、MDA、脯氨酸含量等生理指标.结果]在4、8、12、25 ℃温度条件下,随着胁迫温度的下降与胁迫时间的延长,木薯幼苗叶片的相对电导率、脯氨酸含量不断上升,SOD、POD、MDA、可溶性糖呈先上升后下降的变化趋势,可溶性蛋白、叶绿素及含水量则不断下降.低温胁迫下,木薯叶片相对电导率与脯氨酸呈极显著正相关,与可溶性蛋白、叶绿素、叶片含水量呈极显著负相关;脯氨酸与可溶性蛋白、叶绿素、叶片含水量呈极显著负相关,MDA与脯氨酸、可溶性糖呈显著正相关.结论]在低温胁迫下耐寒性强木薯品种和耐寒性弱品种的相对电导率、MDA和脯氨酸差异较大且比较稳定,可作为鉴定木薯品种间耐寒性强弱的生理指标.

Seedling physiological characteristics of different cassava varieties under low-temperature stress

Objective]Changes of seedling physiological indexes of different cassava varieties were studied to provide references for breeding cold-tolerant cassava cultivar and anti-cold cultivation.Method]Cassava varieties SC 205,SC 124 and Fuxuan 01 were taken as test materials.Four different temperature treatments （4,8,12,25 ℃） on 1,3,5,7 day were set.After the treatment,the relative conductivity,enzyme activity of SOD and POD,and the contents of MDA,proline and other physiological indicators were measured.Result]In four different temperature treatments （4,8,12,25 ℃）,as temperature decreased and time elogating,cassava seedling leaves＇ relative conductivity rate and proline content increased,enzyme activity of SOD and POD and of MDA,soluble sugar increased firsdy and decreased finally,and contents of soluble protein,chlorophyll,and water content decreased.Under cold stress,cassava relative conductivity rate was significantly positively correlated to proline content,while significantly negatively correlated to soluble protein,chlorophyll,and water content.Proline content was significantly negatively correlated to soluble protein,chlorophyll and water content.MDA content was significantly positively correlated to contents of proline and soluble sugar.Conclusion]SC 205 and SC 124 had stronger cold-resistance than Fuxuan 01.In varying low-temperature stress,strong and weak cold-resistant cassava cultivars had great differences in relative conductivity rate,MDA content and proline,which could be used as physiological indices to identify cold resistance of cassava varieties.