The Effect Of Vernalization-relate Gene MAF On Vegetative Phase Change In Arabidopsis Thaliana

After the embryonic development of higher plants, the development of plant including seed germination, seedling growth, juvenile and adult vegetative stage and flowering reproductive stage. Juvenile phase and adult phase composed to vegetative growth period.Juvenile plants(That is, the juvenile phase of fruit) cann’t induce flowering, adult plants can induce flowering. The transition from juvenile phase to adult phase is referred to as vegetative phase change(VPC). Juvenile and adult phenotypes in some woody plants are obvious changes, such as Anacacia, juvenile plants have a compound leaf, maturity have a single leaf.However, the plant vegetative growth of the phenotypic variation is mostly gradual, nearly circular blades herb of juvenile Arabidopsis, entire, long petioles; adult leaves were lanceolate,serrated blade edge, and downward curl, short petiole. The length of the juvenile period is a genetic properties of plants, juvenile period too long is a sticking point factor leading to the orientation of fruit breeding cycle long. Currently mechanism of flowering woody plants main draw Arabidopsis research ideas and methods, and has made great progress. Only juvenile rosette leaves have adaxial trichome in Arabidopsis, this phenotype can be used as the vegetative phase transition morphological signs. Studies have shown that juvenile have high expression of miR156, the expression in adult was reduced, its target genes SPL3 expression opposite.Plants regulation flowering by vernalization, vernalization-related genes MAF1, MAF2,MAF3, MAF4 expressing flowering inhibition effect. Their functional deletion mutant of Arabidopsis promote early flowering. However, the relationship between these genes and vegetative phase change is unclear.In order to further clarify the regulation of these genes in plant vegetative phase change,provide a reference for improving the yield of fruit in early period, shorten the juvenile period of fruit,this study use Arabidopsis T-DNA insertion MAF mutants as materials, planted under normal growth conditions, to explore the role of these genes when the vegetative phase change. The results are as follows.1.The ratio of length to width of the first leaf of maf3 and maf4 is greater than 1, indicating that the morphological characteristics of the leaf initiation growth tends to that of mature le-aves. The ratio of length to width of maf1, maf2, maf3 and maf4 in the previusfifth leaves is larger than that of wild type, and the morphological characteristics trend to that of mature leaves. The growth rate that before 13-14 d is lower than that of wild type, and the growth trend is higher than that of wild type.2.The abaxial trichomes of Col-0 first appear in the sixth true leaf, namely growth of 16 days. The abaxial trichomes of maf1, maf2, maf3, maf4 first appears in the fifth true leaf, nam ely growth of 15 days. The timing of the Vegetative phase change of the mutantis 1 day earlie-r than that of wild type. It shows that the Vegetative phase change of the mutant is in advanc e than that of the wild type.3.The paraffin sections showed that the shoot apical menstem raised high in 15 th d. Mult-ilayer cell(original set) was observed clearly at the outermost edge of the stem. Irregular cell-s was contained in original set which has obviously characteristics of muture per-iod. While the shoot apical menstem was plain and stayed in earlier period. Futhermore, flower bud diffie retiation was observed and and entered into reproductive period in 19 th d. The wild-type was i-n mature period and flower bud diffieretiation was observed in 20 th day. The time of vegetati on growth period in Col-0 was 23 d, which was longer than that of mutant plant. Moreover,the time of vegetation growth period in maf1 and maf2 was 19 day, maf3 and maf4 was 20 d.T he time of flower bud diffieretiation was ahead of wild-type. Therefore gene MAF could inhib it the flower bud diffieretiation cause the MAF mutant could bloom earlier.4. Compared to 15 th d, the relative expression of mi R156 in mutant MAF for 11 th d increased by half. While the relative expression of miR156 for 19 th d is 2-fold of 15 th d in Col-0.The result proved that the vegetative phase change advanced in maf1, maf2, maf3 and maf4 mumtation. Altogether, MAF had no negative effect on the vegetative phase change.