Biological characteristics of a long-culm upland cotton mutant Gaogan 1

In order to analyze the differences of biological characteristics between a long-culm upland cotton mutant Gaogan 1 and a wild-type normal height material N089,the plant height,internode length,height of the first fruiting branch and internode number at different growth stages of cotton were measured. The results suggested that the first fruiting height and internode length contributed to the height of the tall mutant. Internode number did not affect the height. Enzyme-linked immunosorbent assay showed that the contents of GA3,IAA and ZR in seed embryos of Gaogan1 were 2. 368 times,1. 677 times and 2. 791 times greater than those in the wild type,respectively. However,ABA content was significantly lower than that in wild type,only accounting for seventy-six percent of wild type. Cytological observation showed that the number and length of cells of vertical internodes in the mutant were significantly greater than those in the wild type,and there was no significant difference in transverse cell diameter between the mutant and the wild type. Therefore,a conclusion could be drawn that the increase of cell length and number in the stem longitudinal sections might be responsible for the heightened cotton plant.