大豆苗期茎秆对荫蔽胁迫响应的生理机制初探

以自然光为对照，用遮阳网模拟荫蔽胁迫环境，对耐荫抗倒性具有典型差异的两个大豆基因型（南豆12和南冬抗022-2）的茎秆形态建成、乙烯释放量、内源赤霉素（GA3）含量及扩张蛋白活性进行研究。结果表明：苗期荫蔽胁迫致使不耐荫品种南冬抗022-2节间过度伸长、变细、株高增加，初花期及成熟期倒伏率极显著高于强耐荫品种南豆12；荫蔽胁迫下的南冬抗022-2在保持低水平GA3含量同时，乙烯释放量显著增加；而强耐荫性品种（南豆12号）通过降低GA3含量、维持低水平的乙烯释放量，从而保持其正常的茎秆形态建成，防止倒伏的发生。虽然荫蔽胁迫提高了两基因型扩张蛋白活性，但南冬抗022-2始终较南豆12号高，这与其节间伸长情况一致。有望应用扩张蛋白活性，并与赤霉素含量和乙烯释放量相结合，及时反映并提前预测大豆节间的伸长趋势，为在间套作条件下、通过生理指标、在苗期筛选耐荫抗倒大豆品种奠定基础。

Preliminary study on physiological response mechanism of soybean (Glycine max) stem to shade stress at seedling stage

Using natural light as control,the shade stress environment was created by sunshade screen to study stem morphogenesis,ethylene production,endogenous gibberellin(GA3) content and expansion-protein activity of two typical soybean genotypes(Nandou12 and Nandongkang 022-2) which differed in shade-tolerance and lodging resistance.The results indicated that under the shade stress,the internodes of shade-tolerant genotype(Nandongkang 022-2) grew much longer and thinner,which resulted in taller plants.Their lodgin...