Preliminary Study on the Isolation of Endophytic Fungus of Catharanthus roseus and Its Fermentation to Produce Products of Therapeutic Value Analysis of Karyotype of Catharanthus roseus (Apocynaceae) Effects of salt stress on growth and ajmalicine accumutation of Catharanthus roseus calli Biotransformation of artemisinin by Catharanthus roseus and Ginkgo biloba cell suspension cultures Application of biotechnology in studies of Catharanthus roseus Effects of salt stress on growth and ajmalicine accumutation of Catharanthus roseus calli