Studies On Induction Of Polyploid In Siraitia Grosvenorii

S. grosvenorii is an important economic plant grown in Guangxi locally,lls fruit can be used as Chinese medicine directly or for extracting of sweet triterpenoid glycosides,which may serve as a sweet substance for those who suffered from diabetes,adipose and hypertension. The S. grosvenorii varieties are facing problems of degeneration and hybridization and need improvement. It has been known that polyploid breeding is an effective way of improving variety qualities in other economic plants and can be employed for S. grosvenorii. Our present study is using colchicine treatments to get polyploid of S. grosvenorii . The effects of colchicine treatments,were detected by observation and cytological methods. It was found that colchicine concentrations between 0.2-0.4%,one drop per day for 3-4 days is most effective,in inducing bud chimeras of tetraploid and diploid . It is suitable for the induction when cotyledons of the tube seedling just opened. Cytological results showed that tetraploid cells (2n=56) and diploid cells (2n=28) coexisted inside the treated buds and young leaves,forming chimera tissues. Young leaves and tissues 0.5 mm below the shoot top formed more chimeras tissues. Compared with the normal buds ,the 'treated buds had retarded growing,small,thick,green and wrinkled leaves. Supplement of BA (ling/L) ,GA (0.5-lmg/L) or Coconut milk (10ml -20ml /L) to the culture medium did not enhance Ihe bud growth rate.The stem of (he treated buds was also become thicker and shorter. No difference was found in the length and width of stomata as compared to those of the normal ones. The effect of colchicines induction in full grown plants was very low although various methods were used .