Effect of water stress on the physiological and biochemical characteristics of diploid and tetraploid pellicle melon _ | 水分胁迫对二、四倍体薄皮甜瓜苗期生理生化特性的影响_

Chinese. ［目的］揭示甜瓜倍性与抗旱性的关系，为多倍体甜瓜抗旱育种提供理论依据。［方法］测定并比较二倍体和同源四倍体薄皮甜瓜在水分胁迫下苗期的生长指标、叶片水分状况、叶绿素含量、可溶性糖含量、脯氨酸含量。［结果］ 在水分胁迫下，二倍体和同源四倍体薄皮甜瓜苗期株高、茎粗、干物质重量、叶绿素含量都有不同程度减少，而叶片中可溶性糖和脯氨酸含量均呈上升趋势，说明水分胁迫抑制了二、四倍体薄皮甜瓜植株的生长。四倍体的薄皮甜瓜株高胁迫指数、茎径胁迫指数、干物质胁迫指数、叶绿素含量、相对可溶性糖含量和脯氨酸含量显著高于二倍体，二倍体叶片中自由水含量和水分饱和亏明显高于四倍体，说明四倍体薄皮甜瓜在苗期抗旱性比二倍体强。［结论］多倍体育种可以作为甜瓜抗性育种的一种有效途径。

English. ［Objective］The research’ aimed to reveal the relationship between the ploidy of melon and drought resistance and provide theoretical basis for the drought-resistant breeding of polyploid melon.［Method］The growth indices, water situation, chlorophyll content, soluble sugar content, proline content in the leaves of diploid and tetraploid pellicle melon in seedling stage under water stress were determined and compared.［Result］Under water stress, the plant height，stem diameter，dry matter weight and chlorophll content in the leaves of diploid and tetraploid pellicle melon in the seedling stage all decreased to different extent and the content of soluble sugar and proline content in the leaves all showed an increasing trend，which indicated that water stress inhibited the plant growth of diploid and tetraploid pellicle melon. The plant height stress index，stem diameter stress index，dry matter stress index，chlorophyll content，relatively soluble sugar content and proline content of tetraploid melons were significantly higher than those of diploid ones. The free water content，water saturation deficit in the leaves of diploid melon were obviously higher than tetraploid ones，which indicated that the drought resistance of tetraploid pellicle melon in the seedling stage was stronger than diploid ones.［Conclusion］The polyploid breeding can be taken as an effective way for the resistance breeding of melon._