PEG-6000模拟干旱胁迫对不同甘蓝型油菜品种萌发和幼苗生长的影响

Effects of drought simulated by PEG-6000 on germination and seedling growth of rapeseed(Brassica napus L.)

采用10％聚乙二醇（PEG-6000）模拟干旱胁迫的方法，研究其对14个甘蓝型油菜品种发芽期生理生化性状的影响。结果表明，PEG-6000模拟干旱胁迫后，幼苗的相对活力指数在0．32～0．79之间，14个品种的平均相对活力指数为0．49。干旱胁迫后，14个油菜品种的平均苗高比对照降低40．68％，平均单株鲜重比对照降低34．2％，平均成苗率比对照降低18％。但干旱胁迫对根系生长的影响差异不显著。PEG-6000模拟干旱胁迫后，幼苗丙二醛（MDA）、可溶性糖、脯氨酸．可溶性蛋白的含量和电导率均比对照极显著提高，丙二醛的平均含量比对照提高96．7％，可溶性糖平均含量比对照提高75．0％，脯氨酸平均含量比对照增加2204．9％，可溶性蛋白的平均含量比对照增加56．2％，平均电导率比对照增加34．8％。在各种指标中，相对活力指数较为直观、综合地反映了发芽和生长性状，可作为油菜发芽期抗旱鉴定的主要指标。

The effects of drought stress simulated by 10% polyethylene glycol 6000 （PEG-6000） on physiological and biochemical traits of 14 rapeseed varieties （Brassica napus L. ） were studied during germination stage. The results showed that the relative vigor index of seedlings varied between 0. 32 0.79, with an average of 0. 49. Drought stress affected significantly （P〈0. 01） seedling height, fresh weightand survival rate. Compared with water control, 10% PEG-6000 treatment reduced seedling height by 40. 68%,fresh weight by 34.2% and survival rate by 18% on average. Also,malomdiadehyde （MDA）, soluble sugar, proline, soluble protein content, and electrical conductivity of seedlings increased significantly. Compared with water control, 10% PEG-6000 treatment increased the content of MDA by 96. 7% ,soluble sugar by 75.0% ,proline by 2 204.9% ,soluble protein by 56.2% and electrical conductivity by 34.8% on average. There were not significant differences between PEG treatment and control on numbers of adventitious roots and length of taproot. The results indicated that the relative vigor index could he used as the main index of drought tolerance in rapeseed during germination stage.