干旱胁迫对不同抗旱性小麦种子萌发及幼苗根芽生物量分配的影响

为探讨冬小麦种子萌发期抗旱性与幼苗生物量分配的关系,以小麦抗旱型品种长旱58和干旱敏感型品种漯麦18为材料,采用聚乙二醇(PEG-6000)模拟干旱胁迫的方法,测定和分析了干旱胁迫后小麦种子发芽率、幼苗根冠比、叶绿素含量等16个指标的变化。结果表明,干旱胁迫后,长旱58种子发芽率无明显变化,漯麦18种子发芽率显著下降。干旱胁迫下长旱58种子发芽势、发芽指数、活力指数和干物质转移量显著大于漯麦18,平均发芽时间显著小于漯麦18,长旱58幼苗根、芽的长度和干重及总干重均显著高于漯麦18。干旱胁迫显著增加漯麦18幼苗根冠比,对长旱58萌发第五和第七天的幼苗根冠比无显著影响。干旱胁迫显著降低漯麦18幼苗叶绿素含量,对长旱58无显著影响。由于小麦萌发期幼苗干物质累积取决于种子中营养物质的转移和呼吸消耗,因此推测种子营养物质的快速转移和低呼吸消耗有助于提高小麦萌发期的抗旱能力,促进干旱胁迫下种子萌发和幼苗生长。

Effect of Drought Stress on Seed Germination and Biomass Allocation of Root and Shoot of Different Drought Resistant Wheat Cultivars

In order to explore the effects of drought stress on seed germination and seedling growth of different drought resistant wheat cultivars,an experiment was conducted to determine and analyze 16 indices,including germination rate,root and shoot dry weight,ratio of root to shoot,etc. with drought-tolerant variety Changhan 58 and drought-sensitive variety Luomai 18 under the treatments of 15% PEG-6000 and control. The results showed that drought stress had no effect on seed germination rate of Changhan 58,but seed germination rate of Luomai 18 was significantly decreased under drought stress. The seed germination vigor,germination index,vitality index and translocation of seed reserves of Changhan 58 were significantly greater than those of Luomai 18,but the average germination time was significantly lower than that of Luomai 18;root length,shoot length,root dry weight,shoot dry weight and accumulation of seedling dry matter of Changhan 58 were significantly higher than those of Luomai 18 under drought stress. In addition,the root-shoot ratio of Luomai 18 was increased significantly under drought stress,but there was no significant effect on seedling root-shoot ratio of Changhan 58 on the 5th and 7th day. The leaf chlorophy content of Luomai18 was significantly decreased under drought stress,however,there was no significant difference between 15% PEG-6000 and control for Changhan 58. From these results,it can be concluded that Luomai 18 and Changhan 58 can be selected as ideal model cultivars for research on drought resistance in future.