Studies On Pollen Chromosome Doubling Technique Of Eucommia Ulmoides Oliv. By High Temperature Induction

Eucommia ulmoides Oliv. is a single species belonging to Section Eucommia and is dioecious. It is a rubber-resource plant which can be used as a substitution for natural rubber. To improve the amount of Eucommia leaf gum by polyploidy species selection can have a great value for gutta-percha industrial development.This research used Eucommia ulmoides Oliv as the material, based on the result of its pollen mother cells meiosis (PMCs) development, has carried out studies on pollen chromosome doubling and 2n pollen germination characteristics of Eucommia ulmoides Oliv. Some progresses have been made.(1) The correlation between the meiosis stages of PMCs of Eucommia ulmoides and its male bud morphological changes was learned. Eucommia ulmoides pollen occurrence and development usually started in the late March and early April every year, and its meiosis process last approximately 3-5 d; some differences existed in the PMCs process of different plants and flower buds of the same plant of Eucommia ulmoides; as the development of the PMCs underwent, certain morphological changes of flower bud length, anther base opening angle of the flower appeared correspondently; PMCs stages of Eucommia ulmoides can be preliminary speculated through its flower buds morphological observation, which could be used as a guideline to the immediately determination of pollen chromosomes doubling treating period.(2) Pollen chromosome doubling technique by high temperature induction of Eucommia ulmoides was preliminary learned. And a certain percentage of 2n pollen was obtained. The results showed that, the "Trees High Temperature Doubler Device" for the tall trees of Eucommia chromosome doubling in vitro status could achieve good results; We had treated several stages including the Late leptotene, pachytene, anaphaseⅠ, telophaseⅡ, etc, and the result showed that using temperature of 42℃-46℃and treating time of 4h to treat pachytene stage of Eucommia ulmoides could gain better result, among which when the treating temperature and time are of 42℃and of 4h respectively can obtain the highest 2n pollen ratio of 24.35%. The relatively low rates of 2n pollen may attribute to a high asynchronism of meiosis of degree of Eucommia ulmoides and an improper treating stage.(3) The thesis selected the suitable vitro culture medium for measuring rates of pollen germination and had initially proved 2n pollen of Eucommia was also violable. Single factor test results showed that sucrose concentration of 100g.L-1, H3BO3concentration of 30mg.L-1 and CaCl2 concentrations of 10mg.L-1 were conducive for pollen germination of Eucommia ulmoides; further selection by orthogonal design was showed the optimal medium for Eucommia pollen germination was combination of sucrose concentration of 150g.L-1+H3BO3 concentration of 20mg.L-1+CaCl2 concentration of 10mg.L-1; by the pollen culture, pollen tube length measurements, and immunofluorescence observation, proved 2n pollen germination speed and amount were weaker than these of haplotype pollen, and its germination viability was weaker, too often was at a disadvantage in the competition.