Studies On The Anatomocal Structures And Utilization In Cotton Breeding For The Pigment Gland

The biological characters, anatomical structure, chromosome behavior, gossypol contents, and the zymogram of the superoxide dismutase and peroxidase of some cotton species in Gossypium and their hybrids with different traits of pigment gland, such as G.stocksii, G.nelsonii, G.bickii, G.arborewn-G.bickii amphiploid, G.anomalum-G.nelsonii FI and upland cotton cultivars with different genotypes of gland, as well as the three pairs of isogenic lines of upland cotton with or without glands, were studied mainly in this paper. The purpose of this research work were to study the relationship and evolutionary process among different species of Gossypium, especially for G.stocksii, develop and utilize their own character, and supply a theoretical basis for taxonomic and genomic classification for Gossypiwn, especially for the cotton breeding with the glandless seeds and glanded plant trait. The experiments also tried to find out the relationship between gland expression and gossypol contents, as well as the key time for the gene expression of gland and gossypol during the development of the cotton embryo, which will supply the basis works for gene cloning of gland or gossypol. The main results were as follows:l.Tke anatomical structure of gland in some cotton species: The anatomical structures were observed on dormant seeds, the embryos during seed maturity and the cotyledons during the seed germination. The results shown that there was the structure of "gland primodium" on the embryos during seed development of G.stocksii, however, for the G.bickii, the gland primodium can be observed on the dormant seed and the embryos during seed maturity. The gland primodium was composed with some special cells, which differed from other cells with heavy density of cytoplasm and large nucleolus, although they are invisible to our naked eyes. The cells of gland primodium was close each other but irregulation in arrangement. The outside cells were extruded to form a few layers of flat cells and the whole structure looked like the pigment gland, The appearing time of gland cells was differ in different species, even in different part of the embryo in same species. For G.bickii, the gland cells are appeared in the hypocotyls of the dormant seeds and in the cotyledons during seed development. But the time the gland cells exist in cotyledon is longer than in hypocotyls. For the G.stocksii, the gland cells are appeared only in the hypocotyls during seed development, and they exist only in shorter time, then are corroded, and there are cavities appeared. Comparing the gland primodiums of G.bickii with G.stocksii, the number of gland cells composing gland primodium in G.bickii was more than that in G.stocksii. But the color the cells stain in G.stocksii was deeper than in G.bickii. Comparing the glands of G.bickii with G.stocksii, the cavities in gland of G.stocksii were filled with some death tissues. The appear time of the gland in G.bickii was later than that in G.stocksii, and the diameter and the numbers of gland in G.stocksii were higher than that in G.bickii. In the dormant seeds of G.somalense. there were some glands whose structure was similar to that of G.stocksii. In the embryos of zhongwuJ2. there were not any special structure such as gland and gland primodium, however, in the embryos ofzhongl2 and GLjglj, gljGLj, the gland occurred in the embryos during seed development. The observation also shown that there were some types of glands in the seeds and/or seedlings of G.stocksii and G.bickii. Light could influence the formation of new gland primodium during seedling growth of G.bickii, but for some cotton species that glands had existed in dormant seeds, the light only affects the velocity gland formation and gland inclusions.2.The relationship of gland and gossypol: The gossypol contents of the kernels for the G.stocksii and G.bickii were very low, although the glands on the seeds of both are differ greatly. The number of gland and the diameter of glands and the content of gossypol in different development phases of the e...