| Heracleum moellendorffii Hance,as an important wild vegetable of medicine and food,exists some problems such as wild resources destroyed seriously,shorter harvest time,perennial plants emerging questions including the premature senility and the quality deterioration due to premature bolting,which can not meet the market demand.In this research,effects of soil moisture,nitrogen fertilizer using and foreign substances spraying on bolting of H.moellendorffii Hance were studied,meanwhile,the research about harvesting numbers,planting densities and storage methods impacting the ageing delaying was also studied,which can obtain methods inhibiting and delaying the bolting and the premature senility of H.moellendorffii Hance,and providing references for scale cultivation of H.moellendorffii Hance.The following conclusions were obtained through the research:(1)With soil moisture contents increasing,the budding stage and bolting stage were retarded,accompanied with the bolting rate decreased.Compared with the treatment of low soil moisture contents(W1,50%-65%),the time of the beginning,middle and end of the budding and bolting stage was delayed,following with the bolting rate decreasing under the treatment of high soil moisture content.(2)The application of ammonium nitrogen,nitrate nitrogen and amide nitrogen at a certain level could delay the stage of budding and bolting,reducing the bolting rate,and the treatment with a high level of nitrate nitrogen acquired best effects.As the application amount of amide nitrogen(N)and nitrate nitrogen(X)increased,the budding stage and bolting stage were retarded with lower bolting rate.Compare with the control treatment,applying amide nitrogen at high level(N3)and nitrate nitrogen at middle and high level(X2 and X3)can significantly decrease the bolting rate of H.moellendorffii Hance.(3)The research demonstrated that paclobutrazol with the concentration 250 mg/kg can acquire best results that delayed the bolting time,reducing the bolting rate of H.moellendorffii Hance,showing that the budding stage and bolting stage were the last,and the bolting rate was the lowest.In addition,exogenous application of cyanin,to some extent,can put off the budding stage and bolting stage,decreasing the bolting rate of H.moellendorffii Hance.(4)High activities of POD,SOD and CAT and low contents of soluble sugar and soluble protein can result in delaying the budding and bolting of H.moellendorffii Hance.Whether treatments of different soil moisture,forms of nitrogen fertilizer or exogenous material were applied,the POD,SOD and CAT activities of the control plants showing the budding and bolting emerging easily were at low level,accompanied with high contents of soluble sugar and soluble protein,while,the POD,SOD and CAT activities of the treatment that showed the budding and bolting emerging last were at high level,along with low contents of soluble sugar and soluble protein.(5)Repeated harvesting and increasing planting density could reduce the content of cellulose and lignin in H.moellendorffii Hance,effectively delaying the aging of H.moellendorffii Hance,while which was not beneficial to the accumulation of coumarin,flavonoids,polysaccharides and saponins.Repeated harvesting was conductive to keep fresh and tender,prolonging harvesting period of H.moellendorffii Hance,and four time of harvesting can acquire best effects with the aging time showing the longest.The aging time increased along with planting densities increasing,which resulted in the accumulation of cellulose and lignin of H.moellendorffii Hance.(6)After being precooled at 10 ℃ for 12 hours and stored at 5 ℃ after harvesting,the aging time of H.moellendorffii Hance could be delayed effectively along with leaf yellowing time delayed.After stored at 5 ℃ for 24 h,the content of cellulose started to decrease significantly,and the lignin content were reduced significantly after 48 h.The contents of coumarin,polysaccharide,flavonoids and saponins were increased after pre-cooling treatments. |
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