Effects of temperature on growth and total gypenosides accumulation in Gynostemma pentaphyllum and Gynostemma pentagynum

Temperature is one of the important environmental factors that affect the growth,development and accumulation of total gypenosides in Gynostemma pentaphyllum.Seedlings of G.pentaphyllum and G.pentagynum were grown in illumination incubators with temperatures of 10 ℃,15 ℃,20 ℃,25 ℃ and 30 ℃ respectively for 40 d.Then the morphological index and total gypenosides content were determined.The results showed that G.pentaphyllum had the highest values of leaf area,petiole length,stem length,sprouted leaves,biomass and total content of chlorophyll at the temperature of 25 ℃.The growth trend of G.pentagynum was similar to that of G.pentaphyllum.So 25 ℃ was suggested to be the optimum temperature for the growth of above two species.Both G.pentaphyllum and G.pentagynum had the highest content of total gypenosides at the temperature of 30 ℃.The yield of total gypenosides was composed of biomass and content of gypenosides.The temperature which was in favor of accelerating the yield of total gypenosides for G.pentaphyllum was 25-30 ℃,and that for G.pentagynum was 30 ℃.