Research On Tissue Culture And Dormancy Of Chinese Water Chestnut (Eleocharis Dulcis)

This study discussed on Chinese water chestnut(Eleocharis dulcis(Burm.f.))was divided into four parts,including foundation of regeneration system,browning problem in the tissue culture,dormant physiology and the comparison of different varieties.Regeneration system was established used shoot tips to explore the fittest disinfectant mode,the preferably fetch time of the explants,the choice of the optimal medium and training methods,the rooting of shoots and the management of transplanting,the study of the callus induction,etc.We have summed up the methods of inhibiting browning in the tissue culture,the relation ship among the temperature, storage time and germination of corms in during the dormant.Also we have some suggestions for how to introduce different varieties of Chinese water chestnut in Zhejiang province.The results are as follows:1.Foundation of regeneration system in vitro of Chinese water chestnuts.Taking the full apical buds as the explants,we analyzed the relation between disinfecting time and polluted rate of different disinfectors to choose the most optional method of disinfection.Comparing different culture modes and PGR concentrations,to select the best medium to induce shoot tips,root and callus. Observing different fetching time to seek for the best,we tried to reduce the occurring rate of browning in tissue culture of tissue culture of Chinese water chestnut through adding different browning inhibitor and choosing different culture modes.The results showed that following procedure gained the most efficient effect that is,explants were soaked 40 s by 70%alcohol,then soaked 20 min by 10%NaClO₂,finally rinsed by sterile water more than 3 times.The optional medium to induce shoot tips is MS+6-BA 2.0-3.0 mg/L+NAA 0.3-0.5 mg/L+3%sucrose(pH=5.8)which is a kind of liquid culture.The optional medium to induce callus is MS + 2,4-D 2.0 mg/L + 6-BA 2.0 mg/L + 3%sucrose + 0.7%agar.The explants fetched in late Feb.or early Mar. had the highest rate of inducing and subsistence.The best solution to inhibit browning is liquid culture or adding 0.7%AC to solid medium.2.The dormant physiology of Chinese water chestnuts.Taking the intact corms stored below 4℃after post-harvest as materials,we analyzed the relationship between lengths of storage period and germination as an evidence of the existence of dormancy.We analyzed the relationship between the storage temperature and germination in order to finding out the method of dormancy-breaking by keeping the corms under different temperature situation.The results showed that corms were hard to germinate normally even under favorable circumstances without cold storage.In other words,there might be dormancy in corms in winter.Putting the corms below 4℃for 1-8 weeks,the germination rate was on rising.To a certain extent alternate storage under different temperature could promote dormancy-breaking.The germination rate increased through storing below 4℃for 3 weeks and below 10℃for 1 week.3.The comparison of different varieties.We compared the adaptability,performance and characteristic of four cross-sectional varieties,pointed to Zheda No.1,Zheda No.3,Guangxi No.1 and Lishui No.1,by planting experimentally in Zhejiang province.The result showed that No.3 of Zhejiang University is the best.There was heavier re-corm,much more large corms,better taste,higher water,protein and sugar content,less residue.