| In this study,'Shi Yan NO.1'was materials,MS+sucrose(30g·L-1)+agar (30g·L-1)+2,4-D(1mg·L-1)+NAA(0.25mg·L-1) +6-BA (0.5mg·L-1) was the induction medium. MS+sucrose (30g·L-1) +agar (6g·L-1) and MS+sucrose (30g·L-1) +agar (6g·L-1) +activated carbon (1.0g·L-1) were the differentiation and regeneration medium. The origin of somatic embryo which was produced from unfertilized ovules of pumpkin was researched. Meanwhile,the somatic embryo morphogenesis, somatic embryogenesis and endogenous hormones and physiological changes of soluble protein content were reasearched,in order to establish a technological and theoretica foundation for somatic embryos of pumpkin. The pumpkin was treated with triflualin and colchicine.The main results of our reaserch are showed as follows:1. Morphologic observation showed that somatic embryo morphgenesis of unfertilized ovules of pumpkin was similar to zygotic embryo.They passed through the same process that included globular embryo, heart embryo, torpedo embryo and cotyledonous ebryo stage, until regeneratived plantlets.2. Embryology results showed that the gynogenic plants regenerated from the embyoid.The origin of the gynogenic embyoid may be the egg appratus which locating the micropyle end.3. Endogenous hormonal levels and their balance played a key role in regulating somatic embryogenesis in pumkin.The endgenous hormones (IAA, ABA, ZR and GA3) levels had significant changes in the induction process of somatic embryogenesis with unfertilized ovules of pumpkin. IAA and ABA contents increased significantly in the early, and then reached a plateau.ZR and GA3 contents also increased at different times, and then quickly dropped to a lower level.The four endogenous hormones contents were all declined trend in the differentiation and regeneration stage.This showed that the lower levels of endogenous hormones were easy to differentiate seedling from somatic embryo.The balance of endogenous hormones in the induction stages and differentiation stages was also regular. The ratios of ABA/ZR,ABA/GA3,IAA/ZR gently increased in the first 60d,and then increased rapidly and ABA/ZR changed greatest. The ratios of ABA/GA3,IAA/ZR gengly decreased in the differentiation stages,while the ABA / ZR had a great change.These results showed that somatic embryogenesis of pumpkin and regeneratived plantlets were related to the changes of endogenous hormones and their balances.4. There was a lower peak emerged from solube protein contents in the induction stages for 20d, and then slowly declined.In the differentiation and regeneration stage emerged a peak at 30d.5. The method of dripping apical point with different trifluralin and colchicine solution drip apical point seedling of pumpikin to induce chromosome doubling.The result indicated that the best concentration for inducing tetraplont was the 0.18 mmol·L-1 trifluralin solution, the induction frequency was 15.0%. In the experiment germinative pumpkin seeds were socked with different trifluralin and colchicine solution for 4, 6,8h.The best treatment for inducing tetraplont was obtained by socking seeds with 0.18 mmol·L-1 trifluralin solution for 8 hours, the induction frequency was 36.7%. The secondary... |
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