In Vitro Induction Of Polyploidy In Scutellaria Barbata D.Don. By Trifluralin

Scutellaria barbata D.Don is a perennial herb of medicinal plants which is for lamium radix scutellariae genus. All the grass is used as medicines and valueble for antipyretic, antibacterial, anti-inflammatory, anticancer, antiviral effect and antioxidant which is a widely used drug. Now there are few studies about sculellaria barbata polyploid induction breeding, and if the method is used for scutellariae barbatae breeding, we may cultivate new germplasm with high medicinal value. So it is important to study on sculellaria barbata polyploid induction breeding.Firstly, in vitro chromosome doubling of Scutellaria barbata was carried out by treating stems (no section) with axillary buds with trifluralin which is less harmful to human and environment. The effects of different concentrations and time ducation were studied using the methods of drifting treatment and mixed culture. The results showed that with drifting treatment the appropriate combination was20μmol L’1trifluralin induced stems for20h, the best number of doubling seedlings was up to64.7%, while with mixed culture the appropriate combination was that10μmol/L trifluralin induced adventitious buds for21d, the induction rate was78.1%. So the method of adding trifluralin to the medium for mixing culture was better than drifting treatment.Secondly, the identifications of the polyploidy in the morphology, cytology and molecular biology were carried out. The ploidy level of treatment plants was measured by morphology, chromosome counts and flow cytometry. Variation in the morphological characteristic was found between the diploids and polyploids. Polyploid plants demonstrated significantly shorter and thicker plants height and internode length, thicker and darker green leaves, smaller leaf index, more chloroplasts, longer stomata and a higher stomatal index compared to those of the diploid control plants, but stomatal density was significantly reduced. The chromosome number of diploid plants was2n=2x=26, whereas that of polyploid plants was2n=4x=52. It found that the nuclear DNA content of tetraploid was doubled by flow cytometry.Finally the polyploids and diploids were determined in medicinal ingredients of total flavonoids content. The seedlings in vitro were transplanted and indexes of physiological resistant such as SOD, CAT, MDA were measured. The results indicated that the three polyploid lines of total flavonoids content were significantly higher than the control of diploid plants, respectively increased with average of42.69%,49.41%,50.98%. Five polyploid lines of SOD and CAT activity were significantly different from the diploid plants. They were respectively35.7%and29.6%higher than the diploid averagely. Five polyploid lines of MDA were significantly lower than the diploid plants, which was23.7%lower than the diploid lines averagely.