小麦种子成熟和萌发过程中的假萌发素活性

用SDS-PAGE方法研究了假萌发素(ψG)在小麦种子成熟和萌发过程中活性的变化.结果表明:在种子成熟过程中只有ψG表达,扬花后10 d,在颖壳、内外桴、种皮和果皮中皆可检测到ψG的草酸氧化酶活性,随着发育进程的推进,ψG的活性增大.在种子萌发过程中,在小麦品种中育5号的维管束过渡区中除了萌发素G和G'外,还可检测到ψG的草酸氧化酶活性.由于ψG在种子成熟过程中主要存在于颖壳、内外桴、果皮及种皮这些保护组织中,且开始大量表达的时间正是生长接近停止时,于是推测ψG很可能通过降解草酸产生H2O2而推动这些组织细胞壁的木质化.

Pseudogermin Activity During Maturation and Germination of Wheat Seeds

The OxO activities of psiG during maturation and germination of wheat seeds were measured by SDS-PAGE followed by OxO activity staining. The results showed that there was no expression of G and G', but only that of psiG during wheat seeds maturation (Fig. 2). 10 days after anthesis, the OxO activity of psiG was observed in glumes, palea, lemma, seed coat and pericarp, then the OxO activities in glumes, lemma, seed coat and pericarp increased rapidly and remained high until the seeds matured (Fig. 2). Basing on the observation that psiG was expressed mainly in the tissues abundant in lignin when cell growth just stopped, it was suggested that psiG may function in promoting lignification of cell wall of glumes, palea, lemma, seed coat and pericarp by producing H(2)O(2) by oxidation oxalate. During wheat seeds germination, psiG was present in vascular transition region in addition to G and G' in Zhongyu 5 (Fig. 3), but it was not necessary for germination.