Study On Seed Germination, Tissue Culture And Root Microstructure Of Polygala Tenuifolia Willd. In Shanxi Province

Polygala tenuifolia with high medicinal value is one of the five native medicinal materials in Shanxi province.It has been put into large-scale production with its demand increasing.However,there still existed three problems that have not yet been resolved:1.The cultivation research of P. tenuifolia is still at the very beginning time,and there are no details about the germplasm resources in Shanxi province.Moreover,at present,the cultivation technology of P.tenuifolia differs from each other,and the germplasm resource is short of unified standards or norm;2.The seed of P. tenuifolia is underproduction and the collection is difficult;3.The planting periodic time of P.tenuifolia is relatively long,and the treatment of it is hard and time-wasting.Such problems have affected the quality and the sustainable development of P.tenuifolia.It is expected to develop a new breed of high quality and low mutation rate through tissue-cultured method, so as to supply the market.In this paper,we researched on P.tenuifolia including:The best pretreatment was selected through seed sprouting test;using the twelve type P.tenuifolia which come from different regions in Shanxi province,we investigated the effect of different factors on the induction of callus,and the callus culture system was found;the effect of different hormone on the multiplication and radication of test tube-plantlet was discussed;the root microstructure of twelve type P.tenuifolia which origin from Shanxi province was observed.The result showed that 1.0 mg/L 6-BA was the best effective on seed of P.tenuifolia in that year,and the germination rate can be improved by 15%; the low temperature freezing treatment does not work effectively;the seed over year is nearly disabled in sprouting.The induction of callus can be affected by the type,size,collecting time of explant,and exogenous hormone concentration.The MS combined 2,4-D 1.5 mg/L and KT 0.2 mg/L was the suitable medium for the callus induction through the experiment;the tender root was the original materials for inducing the callus;the root explants about 1.0cm long was more favorable to the induction and growth of callus;the best sampling period for the induction and growth of callus was from April to the the first 10 days of May.Multiplication rate of callus was highest when callus were cultured at the 30^th day.The tissue cultured result showed that the highest induction rates of callus were P.tenuifolia from Xinjiang and "Fenyuanyihao". Through the optimization of incubating condition,it can be determined that the suitable medium for the bud differentiation was MS added 6-BA 2.0 mg/L and NAA 0.5 mg/L;the best bud differentiation of callus were P. tenuifolia from Lanxian and "Fenyuanyihao".In test propagation of P.tenuifolia,the MS medium added 6-BA 1.5mg/L,KT 0.1 mg/L and NAA 0.2 mg/L was suitable for bud propagation, the 1/2MS medium added DSC 1.0 mg/L,IBA 0.5 mg/L and NAA 0.2 mg/L was suitable for rooting of test-tube plantlets.The best effect of bud propagation were P.tenuifolia from Wenxi and Taiyuan;The best rooting variety of test-tube plantlets were P.tenuifolia from Wenxi.The microstructure of twelve P.tenuifolia roots from Shanxi showed: The periderm is thick and phellem cells which arrange in order and tightness were quadrate;the proportion of phloem was more 1/2 than transverse section and phloem-ray was not in evidence;the xylem was strong and xylem-ray was in evidence.But there were difference in the ply of phellem layer,size of phellem cells,proportion of phloem and the type of trachea. The biggest proportion of phloem in transverse section was P.tenuifolia from Taiyuan.The annulus grain trachea was existed in P.tenuifolia from Pingyao and Xinjiang.The ladder grain trachea was found only in P. tenuifolia from Xinzhou.