不同穗发芽抗性的小麦胚对ABA敏感性及抗性机制研究

以20个小麦品种为材料,测定了不同穗发芽抗性的小麦品种处于种子发育过程中的胚对ABA敏感性和后熟过程中种子的萌发能力,以揭示小麦对穗发芽的抗性机制。结果表明,在种子发育过程中,不同抗性品种的胚萌发能力和胚对ABA敏感性存在差异。胚萌发能力随胚龄的增加,呈"低～高～低"的变化趋势。扬花后25d到35d的胚萌发势的降幅值在抗穗发芽基因型中所占的比重明显较易穗发芽基因型大。易穗发芽基因型对ABA的敏感性随胚萌发能力的提高而下降,而抗穗发芽的基因型对ABA的敏感性随胚萌发能力的提高则有升有降。因此,胚休眠主要在发育后期获得。红皮易穗发芽品种的成熟胚因脱离母体而提高的萌发势明显较白皮易穗发芽品种的高。品种的成熟胚离体萌发能力越高,则种子休眠期越短。

Embryonic ABA Sensitivity and Resistant Mechanism of Sprouting Resistance and Susceptible Cultivars

Pre-harvest sprouting (PHS)is one of the most damaging diseases in rain-affected wheat (Triticum aestivum L.) crops. Sprouting resistant mechanism in cereal grains has focused on the regulation of (germination) by phytohormone abscisic acid, (especially) (embryonic) sensitivity to ABA. Comprehension on (embryonic) sensitivity to ABA will help to understand the resistant mechanism of cultivars. Using different sprouting resistant genotypes,we studied the (embryonic) sensitivity to ABA during seed (development) as well as mature seed (germination) ability. The results are as follows: During seed (development), the (embryonic) (germination) ability and sensitivity to ABA are varied among genotypes. The descendent values of (germination) index from 25 d to 35 d in sprouting resistant genotype are higher than in sprouting (susceptible) genotype. Therefore, the (embryo) dormancy is acquired in late stage of seed (development). In mature seed, the increased values of (germination) index of (embryo) in red coat grain cultivars, (especially) genotype (susceptible) to PHS, are higher than in white seed. The higher (germination) ability of (mature) (embryo) is,the (shorter) seed dormancy stage is.