内源抗坏血酸对水稻种子萌发及幼苗生长的影响

Effects of Endogenous Ascorbic Acid on Seed Germination and Seedling Growth of Rice

摘要:

为了解内源抗环血酸在水稻(Oryza sativa)种子中的作用,以野生型品种‘中花11’(ZH-11)、抗坏血酸合成关键酶GLDH基因的上调(超表达)株系GO-2及下调(干涉)株系GI-2为材料,研究了抗环血酸含量对其种子萌发和幼苗生长的影响。结果表明,GO-2株系的种子萌发率比野生型ZH-11高6%,比干涉型GI-2高60%。外源添加1 mmol L^-1抗坏血酸后,干涉型GI-2萌发率提高了22%,GO-2及ZH-11则没有明显增加。GO-2株系在幼苗的根长、株高、分蘖数和鲜重等指标上均高于ZH-11和GI-2。实时荧光定量测定结果表明,GO-2株系叶片的GLDH基因表达量显著上调,而GI-2株系则显著下调。这说明抗坏血酸有助于维持水稻种子活力和促进水稻种子发芽和幼苗生长。

Abstract:

The aim was to understand the function of endogenous ascorbic acid in rice (Oryza sativa) seeds. The homozygote transgenic lines GO-2 with the up-regulated GLDH (the key enzyme that catalyzes the final step of Asc biosynthesis in plants gene) and GI-2 with the down-regulated GLDH had been established from the cultivar ‘Zhonghua 11’ (ZH-11). The effect of endogenous ascorbic acid on seed germination and seedling growth of rice was studied among ZH-11, GO-2 and GI-2. The results showed that the germination rate of GO-2 was 6% and 60% higher than that of wild type (ZH-11), and GI-2, respectively. After treatment with 1 mmol L^-1 exogenous ascorbic acid, the germination rate of GI-2 increased by 22%, but no significant effect was observed in that of GO-2 and the wild type (ZH-11). The root length, plant height, tiller number and fresh weight of seedling in GO-2 were higher than those in ZH-11 or GI-2. The expression of GLDH gene in GO-2 leaves was higher than that in ZH-11 or GI-2, too. So, these indicate ascorbic acid plays an important role in maintaining seed vigor and improving germination and seedling growth of rice.