Study On Efficient Domestication Technology Of Tissue Culture Plantlets Of Nelumbo Nucifera Gaertn

Nelumbo nucifera Gaertn is a hydrophytic perennial vegetable, originated from India and China, it is widely planted, and is one of the important export vegetables in China.Lotus root is mainly propagated by asexual measure and has low propagation coefficient, Virus easily infects and accumulates in it by that breeding measure, which results in idioplasmatic degeneration, and influences the yield and quality. For example, stiff lotus is found recently in Jiangsu province, and it has become a great obstacle for the production. Nowadays, questions about detoxification, idioplasmatic degeneration and low propagation coefficient have been resolved by tissue culture for many plants propagated by asexual measure. The successful technology about detoxification and tissue culture of lotus root has already been reported, but the technology of domestication has less research reports, and it has become the main obstacle for industrialization of tissue culture.So, we studied effect of Increasing sucrose content of substrate before domestication and disposing plantlets by extrinsic CC and CaCl2, the results showed as follow: 1. The effect of sucrose contents on lotus root tissue culture plantlets domestication survival rates and carbohydrate metabolism was studied. The survival rate of plantlets disposed by 5% sucrose was the highest, up to 93%, the 6% sucrose disposal took second place, and the 3% was the lowest, only 81%. The 5% disposal distinctly increased plantlets growth potential. On the 15th day, their rooting rates, top sprout-elongating rates both exceeded 93%, and after domestication, plantlets growth indexes of their roots, stems and leave were also better than others. The 3% disposal rooting rates, top sprout-elongating rates and growth indexes of their roots, stems and leave after domestication was the lowest.Along with the increasing of sucrose content of substrate, tissue culture plantlets' soluble sugar contents increased from 3.3% to 7.8%, while content of the 8% disposal was lower than the 7% by 7.2%. Content changing trend of dextrose, fructose, sucrose and starch was the same as the soluble sugar.During ten days after transplanting, contents of soluble sugar, dextrose and fructose in plantlets disposed by low sucrose content increased, those contents of plantlets disposed by high sucrose content had no distinct changing, further more, those content of 8% disposal even descended. After ten days, contents of different disposal became similar. Sucrosecontents of the plantlets disposed by different sucrose contents had no obvious distinction in ten days, but began to increase after ten days. Starch contents of plantlets disposed by different sucrose contents always reduced during domestication.Chl.a content in leave of the 5% sucrose content disposal was highest, up to 2.02mg · g-1, the 8% disposal is lowest, for the disposal of 3-6% sucrose content, Chl.a contents descended promptly in 6 days after transplant, and then increased. Chl.a contents in leave of plantlets disposed by sucrose contents higher than 6%, had no distinct change after transplant and showed rising trend after the 6th days too. Chl.b contents of all the disposal were about 0.43 mg · g-1 before and after transplant.2. Effect of substrate sucrose contents on domestication lotus root plantlets protective enzyme activity was studied. The results showed: after transplant, plantlets soluble protein and protective enzyme activity of plantlets disposed by lower sucrose contents than 6% reduced. The 5% disposal reduced most slowly, and the data were higher than others in the same time. The plantlets disposed by 8% sucrose content always kept low soluble protein content and protective enzyme activity in the initial domestication stages. Before domestication, carotenoid content of the 8% disposal was highest, up to 2.24mg · g-1.Carotenoid contents of disposal whose sucrose contents were lower than 6% reduced after domestication, and began to increase after 4-6 days. Disposal whose sucrose contents were higher than 6% always kept the reducing trend.3.