Sem studies of seed coat structures in mutants of catharanthus roseus (l.) g. don

The large demand and lower yield of bis indole alkaloids (vincristine and vinblastine), which are present in the leaves of catharanthus roseus, promote research effort for the development of superior stocks. The seeds of C. roseus have been treated with different doses of gamma rays and ethyl methane sulfonate alone and in combination with more attention towards increased percentage of bis indole alkaloid production to meet current medical demand. As a result of mutagenic treatment, five morphologically and chemically dissimilar mutants were isolated after critical examination upto M3 generation. These mutants have shown stable agronomic performance in the fields. The scanning electron microscopy of seeds of mutants along with control has revealed extensive variation in seed coat structure. The seed surface have irregular and unevenly arranged elevated area (ridges) and minute depressions of various geometrical shapes (lumina) were present between these elevations. The depressions were decorated with beaded structure.