Effects Of Plant Hormones On Elongation And Development Of Fiber In Cotton Mutant Li-1

This study was conducted with two types of upland cotton, super short fibermutant Li-1 and normal genotype TM-1. Some certain types and concentrations ofplant growth substances were applied to recover the deficiency of fiber elongation bymeans of cotton ovule culture in vitro. Also the endogenous plant hormones includingIAA, GA₃, Z and ABA of cotton ovules were measured at pre- and post-anthesis toreveal the effects of endogenous plant hormones on growth and development ofcotton fibers. The results were as follows.1. Differences of Morphological and physiological parameters between Li-1and TM-1.Some morphological and physiological parameters of Li-1 and TM-1 weremeasured in this experiment. It showed that the contents of chlorophyll in Li-1 washigher than that in TM-1, but leaves areas and photosynthetic rate of Li-1 were lowerthan that of TM-1. The results indicated that lower photosynthetic efficiency and lackof assimilates would decrease the biomass of Li-1, and exhibited other abnormalphenotype such as curled leaves and fiber hypogenesis.2. Differences of endogenous plant hormones between Li-1 and TM-1 ovulesunder field condition.The endogenous plant hormones including IAA, GA₃, Z and ABA of cottonovules were measured with samples on -1, 0, +3, +6, +9, +12, +15, +18, +21 dayspost-anthesis. The results showed that the peak of IAA content occurred at 9dpost-anthesis in mutant Li-1, that miss the quick growing stage of fiber; GA₃ contentin the mutant did not change much than that in the normal genotype and have nodistinct peak, shortage of Z might have an effect on both ovule expansion and fiberelongation; the peak of ABA occurred at 3d post-anthesis seriously repressed ovulegrowth and fiber elongation. It was suggested that, some certain hormones contentand their peaks and values in the ovule of Li-1 mutant grown in field spots might bethe reasons of restriction to elongation of fiber. 3. Fiber elongation of Li-1 and TM-1 by means of ovules culture in vitro.Fiber length of the Li-1 and TM-1 were 4.1 mm and 13.2 mm in GA₃+IAAmedia which were 63.1% and 43.8% of that under field condition. There was acooperation effect between GA₃ and IAA on the fiber elongation. When GA₃ and IAAexist simultaneously, the cooperation effect can stimulate the potential capability offiber growth in the mutant Li-1.And the restriction of fiber elongation could bereleased by this cooperation effect.