不同马铃薯品种苗期叶片对低温胁迫的生理响应
时间：2020-10-28 07:59:40 来源：达达文档网 本文已影响 人 
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摘要：【目的】研究不同馬铃薯品种苗期对低温胁迫的生理响应，为探索马铃薯耐寒机制及耐寒品种的早期选育提供理论依据。【方法】以低温敏感型品种费乌瑞它、中薯3号和耐寒品种桂农薯1号、桂农薯4号苗期植株为试验材料，利用人工气候箱进行5 ℃低温胁迫处理，于处理后0、1、2、3、5和7 d分别取样并测定叶片中过氧化物酶（POD）、过氧化氢酶（CAT）和超氧化物歧化酶（SOD）活性及可溶性糖、可溶性蛋白、丙二醛（MDA）和脯氨酸含量。【结果】5 ℃持续胁迫3 d对叶片造成的伤害在外观形态上开始出现，胁迫5 d后品种间存在明显差异。受低温胁迫后，各品种叶片POD、CAT和SOD活性及可溶性糖、可溶性蛋白和脯氨酸含量整体上均呈升高趋势，峰值出现时间存在差异；随着低温胁迫时间的延长，各生理指标升降变化趋势不同。在低温胁迫5 d时，耐寒品种的酶活性和脯氨酸含量均高于低温敏感型品种，费乌瑞它的可溶性糖和可溶性蛋白含量则显著低于其他品种（P<0.05，下同）。低温胁迫提高了各品种的叶片MDA含量，在低温胁迫第5 d时，低温敏感型品种的MDA含量高于耐寒品种。相关性分析结果表明，SOD活性与可溶性糖含量呈显著正相关，与MDA含量呈显著负相关；POD活性与CAT活性和脯氨酸含量呈显著正相关；CAT活性与脯氨酸含量呈极显著正相关（P<0.01）。【结论】POD、CAT和SOD活性及MDA和脯氨酸含量可作为鉴定马铃薯品种耐寒性强弱的生理指标，低温胁迫第5 d可作为早期筛选耐寒材料的时间节点。4个马铃薯品种苗期耐寒性强弱依次为桂农薯4号>桂农薯1号>中薯3号>费乌瑞它。
关键词： 马铃薯；低温胁迫；抗寒性；生理指标
中图分类号： S532.01 文献标志码：A 文章编号：2095-1191（2016）11-1837-07
Abstract：【Objective】In order to provide theory basis for understand cold-resistant mechanism and early breeding of cold-tolerant potato varieties， physiological responses of different potato varieties to cold stress was studied at seedling stage. 【Method】Cold-sensitive varieties viz.， Favorita， Zhongshu 3 and cold-tolerant potato varieties viz.， Guinongshu 1， Guinongshu 4 were used as tested materials， and treated by cold stress at 5 ℃ in artificial climate box. Activities of peroxidase（POD）， catalase（CAT） and superoxide dismutase（SOD） and contents of soluble sugar， soluble protein， malonaldehyde（MDA） and proline under were determined after 0， 1， 2， 3， 5 and 7 days of cold stress， respectively. 【Result】Results showed that， leaf damage began to appear on exterior of potato seedling after 3-day prolonged cold stress at 5 ℃， and there was distinctive difference among varieties after 5-day cold stress. In addition， after cold stress， activities of POD， CAT， SOD and contents of soluble sugar， soluble protein and proline in leaves of all varieties increased gradually as a whole， and their peak values for different varieties were different. However， variation trends of all physiological indexes in different varieties were different with the increase of cold stress time. After 5-day cold stress， enzyme activities and proline contents of cold-resistant varieties were higher than those of cold-sensitive varieties， contents of soluble sugar and soluble protein in the potato variety Favorato were significantly lower than those in the other varieties（P<0.05， the same below）. Furthermore， MDA content in the leaves of all potato varieties increased after cold stress， and MDA content in cold-sensitive varieties was higher than that in cold-resistant varieties after 5-day cold stress. Correlation analysis showed that， SOD activity was significantly positively correlated with soluble sugar content， but significantly negatively correlated to MDA content； POD activity was significantly positively correlated with CAT activity and proline content； CAT activity was extremely significantly positively correlated with proline content（P<0.01）. 【Conclusion】Activities of POD， CAT and SOD， and contents of MDA and proline in potato leaves can be used as physiological indexes to identify cold resistance， and the optimal time for early screening cold-resistant materials is at the 5th day after cold stress. Cold resistances of four potato varieties at seedling stage are ranked as follows： Guinongshu 4>Guinongshu 1>Zhongshu 3>Favorita.
