Study On Establishment Of In Vitro Propagation Systems And Regeneration Pathways Of Yixing Lily

Yixing lily, also called 'tiger lily' or 'yellow lily', is denominated Lilium lancifolium Thunb (L. tigrinum ker.-Gawl.) according to the plant classification. Its origins are Huzhou and Yixing in Tai Lake area, Jiangsu province. The edible parts of Yixing lily are bulblets which not only has plentiful nutrition but also important medicinal value. Yixing lily is know as 'Tai Lake Ginseng' or 'Zhongtiao Ginseng'. Yixing lily mainly depends on asexual propagation, i.e. vegetative propagation. Lower propagation coefficient, accumulation of viruses and varietal degeneration after long periods of vegetative propagation in the traditional reproduction method reduce the yield and quality of lily. Recently, tissue culture has been extensively applied in the introduction and cultivation, virus removal, variety regeneration, and rapid propagation of fine varieties of lily, expediting the propagation rate and shortening the growth period.Although there has a lot of work been done on lily, little attention has been paid to theYixing lily. Since the genotype differences among varieties of lily, differences also exist in tissue culture. It is very important to study on the factors related to the regeneration of Yixing lily in vitro and to discuss different methods in solving the problems in the production.In this study,Yixing Lily was used as explant to study effects of different explant and different treatment on in vitro regeneration pathways of Yixing Lily,meanwhile preliminary study on bulblet formation were curried out.The main results were as follow.1.Bulblet is an ideal source of explant.the medium contained MS+NAA0.2mg/L+6-BA1.5mg/L+30g/Lsucrose+6g/Lagar is more effective in inducing adventitious buds from bulblets,with inductivity 98.3% and differentiation coefficient 5.32. While 2,4-D1.0mg/L combined with 6-BA0.5mg/L,plantlet's leaf can obtain high inductivity and differentiation coefficient.In vitro culture of Yixing Lily,not only bulbscale but bulblet and leaf have position effect. So the bottom part of the organ shoud be used as explant and it may success easily. 2.2,4-D is the essential plant growth regutor in inducing callus from bulbscale and bulblet of Yixing Lily.Different cytokinin has different effects on callus induction.KT has the better effect on callus induction than 6-BA.Both bulbscale and bulblet in vitro of Yixing Lily can be inducted to form embryogenic callus in the medium contained.Plant growth regulator especially KT and GA₃ may also influent the type of organ regenerated directly from bulblet in vitro,which can improve bulblet regeneration.Furthermore,Basic media influent organogenesis from bulbscale,not only to twice KH₂PO₄ but to remove NH₄NO₃ and twice KNO₃ can improve bulblet to regenerate directly.But basic media has less influence on the type of organs regenerated by organogenesis from bulblet in vitro,and adventitious buds regenerated directly in every test.3. Sucrose had great effect on the diameter,fresh mass of bulblet,90g/L was the ideal concentration in inducing and swelling bulblet from plantlet of Yixing Lily.Extending subculture cycle appropriately could improve nutritive material transferred to bulblet,which could improve bulblet swelling.Plant retardant PP₃₃₃ can restrain plant growth and at the same time it can promote bulblet forming and swelling.The best effect was 5mg/L PP₃₃₃.SA can retain the growth leaves and roots obviously.and it can increase the bulblet formation rate, the diameter and uniformity of bulblet. The best effect was 0.1 mg/LSA.But bulblet formed in the media with SA have less fresh mass than the CK.So it is a moot question how to take some protect measures to maintain the advantage of SA and enhance bulblet fresh mass.