芽变红地球葡萄的倍性结构鉴定

Identification of the ploidy structure of bud sport of Red Globe grape cultivar

芽变红地球葡萄是新近发现的自然变异新种质。为搞清其倍性结构,以芽变红地球、红地球为试材,根据组织发生层学说推断材料的倍性结构。测定保卫细胞大小和统计叶绿体数目的试验表明,芽变红地球保卫细胞长略大于红地球,宽略小于红地球;保卫细胞中的叶绿体粒数,芽变红地球为11.35个,红地球为10.63个,均没有显著差异,从而推断芽变红地球的L1层为二倍体。测定花粉粒大小的试验结果表明,芽变红地球花粉粒长度为35.46μm,宽度为22.95μm,红地球的花粉粒长度为33.03μm,宽度为18.04μm,存在显著差异,表明芽变红地球的LⅡ层为四倍体。根尖染色体数目观察结果表明,芽变红地球的染色体数目为2n=4x=76,红地球的为2n=2x=38,表明芽变红地球的LⅢ为四倍体。另外,通过对梢端切片观察,芽变红地球的LⅠ层的细胞与红地球的没有明显差异,而LⅡ、LⅢ则显著大于红地球。由此证明,芽变红地球的倍性结构为2-4-4型,为周缘嵌合体。

Red Globe＇ s bud sport is discovered in recent years from the vines of Red Globe grape cuhivar. In order to identify its ploidy structure the size of stomatal guard cell and chloroplast number in these cells were measured and counted; the chromosome number of the root tip cell was also counted. The ploidy of LI, LII, LIII in the sport and matemal cuhivar were examined. Results showed that the stomatal guard cells of the sport （Red Globe＇s bud sport） were a little longer than those of Red Globe and a little shorter in width. The chloroplast number in stomatal guard cells of the sport and Red Globe were 11.35 and 10.63 respectively. Both the size and chloroplast number ofstomatal guard cells had no significant difference, therefore, it indicated that the ploidy of L 1 of the sport was diploid. The length of pollen grains in the sport and Red Globe was 35.46 and 33.03μm respectively, and the width of pollen grains was 22.95 and 18.04 μm respectively. Both the length and width of pollen grains of the sport of Red Globe were significantly longer, so it was concluded that the ploidy of LII of the sport was tetraploid. The chromosome number in the root tip cell of sport was 2n=4x=76, while that of Red Globe was 2n=2x=38. There-fore it showed that the ploidy of LIII of the sport of Red Globe was tetraploid. In addition, by observing the stem apex section, no significant difference was noted between the cells of L I in Red Globe and its sport. Yet the cells of LII and LIII in the sport were obviously bigger than Red Globe. All of the above mentioned proved that the ploidy structure of Red Globe＇ s bud sport is a periclina3 chimera （2-4-4）.