The Culture Of Virus-free Bulbs Of Lilium Brownii Var. Viridulum And Research Of Their Dormancy Physiology

Lilium brownii var.viridulum Baker is perennial herb belonged to Lilium, Liliaceae.The edible part is its bulbs underground,not only food,but also a kind of medicine.It has higher nutritional value and health-keeping function. The main cause of degeneration of variety,decreasing of yield and quality,is its virus disease.Until now,there is not effective medicine to prevent and treat it.The most convenient and reliable way is acquiring virus-free bulbs seedball by stem apex culture.The dormancy of Longya lily influences the time and number of bulbs germination,uniformity,growth status and yield.When the bulbs are used as materials to processing,the dormancy relieving could cause consumption of water and nutrition.So,it is meaningful to do the following research,not only for the storage,keeping fresh and processing of bulbs,but also for the producing and application of virus-free bulb seedballs.The bulbs of Longya lily were used as materials in this paper.We studied the heat-treatment and chemical inhibitor on the surviving rate of stem apex and the virus-free efficiency,and the rapid propagation method of virus-free bulbs.The carbohydrate,protein,nucleic,exogenous hormone,isoenzyme, constituent of protein,distribution of Ca2+—ATPase and ultrastructure of stem apex of bulbs during the dormancy broken in low temperature were studied by absorption spectrometry,HPLC,PAGE,IEF-SDS 2D eletrophoresis,cell chemistry and transmission electron microscope.The followings are the results.There was negative relevance between the size of stem-tip and virus-free rate.The inhibition effect of high temperature on virus is CMV,LSV,TBV and LRV in order.Ribavirin could passivate virus effectively and increase the virus-free rate.The stem apex from the plantlet was easier to derive virus than litte bulb.The combination of two or three technologies was the primary method to produce virus-free bulb seedballs of Longya lily.The important regulator of somatic embryogenesis of Longya lily was 2,4-D.Its developmental process of morphology was similar with zygoticembryo,globular,heart-shaped,torpedo shaped,cotyledonary embryo stages and plantlet.During the cold storage,the starch content in bulbs was decreased,but soluble sugar and protein was increased obviously.The sugar decomposed from starch provided substance and energy for dormancy relieving of bulb,for the growth and development of stem apex after germinating.The changes trend of RNA content was parabolic,but trend of DNA was not obvious.The content of GA3 and IAA,GA3/ABA and IAA/ABA was increased obviously.The content of ABA was decreased totally.The changes and balances of exogenous hormones had close correlation with dormancy relieving. It was caused by the interaction between promoting substances,such as GA3 and inhibiting substances,such as ABA.The bounds of POD isoenzyme in the scales of bulbs were more than others,and new bounds appeared in succession after 40th days.The bounds of PHO isoenzyme were less,and only one new bound appeared at 60th days.The new bounds of EST appeared after 30th days,and its activities became stronger gradually.It was concluded from our results that new isoenzymes appearing and changes of their activities were accompanied with dormancy relieving.There were rich low molecular weight protein in bulbs.Two kinds of protein,21kD and 23kD,were the main proteins and expressed obviously.The changes of there kinds of proteins during the cold storage were detected,one of them was a new polypeptide.Not only the abundance of protein expression changed,but also new protein appeared during the storage course.The activities of Ca2+—ATPase on the mitochondral membrane and plasma membranes of stem tip was highest at 30th day and 40th day separately,but 50th day on tonoplast.On nucleolus and chromatin,it was highest as cells division.At 30th day,it was observed that the volume of nuclear enlarged,the number of mitochondrion and the tubular cristae on it,liposome and endoplasmic reticulum were increased too.Vacuolar was divided many small ones,amyloplast converted to proplastid gradually.The time and space distribution of Ca2+-ATPase and changes of regularity of ultrastructure could be used as the morphological index of dormancy relieving.