甜椒对不同程度水分胁迫-复水的生理生化响应

对甜椒穴盘苗进行了不同程度的水分胁迫-复水处理，探讨了叶片某些生理生化特性的变化。结果如下：叶片RWC、渗透势随基质水分减少而降低，渗调能力逐步增强。POD、SOD、CAT酶活性随水分减少而上升，SOD对水分胁迫最敏感，复水后主要由POD、CAT负责清除H2O2和过氧化物；游离氨基酸、脯氨酸随基质水分减少急剧上升，复水后大幅下降，可能为轻度胁迫下主要的渗调物质。RWC降至45%(停水后3d)时，可溶性蛋白和可溶性糖显著积累，明显晚于氨基酸，但它们基础含量高，主要在较为严重的水分胁迫时发挥作用。虽然水分胁迫使保护酶活性和渗透调节能力均提高，但任何程度的胁迫均不可避免地伤害幼苗。穴盘苗生产中，建议“水分胁迫锻炼”时间以不超过3d(RWC≥45%)为宜。

Response of Physiological-biochemical Characters of Sweet Pepper Seedlings

Some physiological-biochemical characters were investigated when sweet pepper potting seedlings were exposed to different degree water stress and rewatering. The main results were as follows: the lower RWC in media, the lower osmotic potential and saturated osmotic potential, but the higher osmotic adjustment and injury degree as well. The activity of POD,SOD,CAT increased with the decreasing moisture content. Of the above three defense enzymes, SOD was the most sensitive to water stress. Whereas after rewatering, probably it was POD and CAT that were mainly responsible for eliminating H2O2 and peroxides. Free amino acid and proline could principally play osmotic role under earlier light stress, accumulating sharply under water stress, yet rapidly reduced after rewatering. Soluble protein and soluble sugar obviously accumulated until RWC reduced to 45%, a little later than amino acid, and that they seemed to play osmotic role when relatively serious stress during later period. Although water stress could make protective enzymes activity and osmotic adjustment promote, but any stress would inevitably damage seedlings. Therefore, considering long-distance transportation and high-quality seedlings production, 2~3days stress hardening was more appropriate.