Induction and biological significance of polyploidy in medicinal plants Induction of Microspores-derived Embryos and Calli from Anther Culture in Carrot Induction of Microspores-derived Embryos and Calli from Anther Culture in Carrot Studies on the Effect of Bleeding Sap of Towel Gourd(Luffa Cylindrica Roem)on Rice Anther Culture