Alkaloid variations in Catharanthus roseus seedlings treated by different temperatures in short term and long term

Abstract

A study was conducted to investigate the effects of high temperature on variations of alkaloid metabolism in C. roseus seedlings in Key Laboratory of Forest Plant Ecology, Northeast Forestry University, Heilongiang, China. 60-day-old C. roseus seedlings with 3–4 pairs of leaves were incubated in chambers with temperature of 30°C and 40°C for short-term heat shock experiment and 20°C, 25°C and 35°C for long-term experiment. The contents of vindoline, catharanthine, vinblastine and vincristine in C. roseus leaves and root were checked at different temperatures in short term (1–6 h) and long term (1–16 d). Results showed that under short-term heat shock, the contents of vindoline, catharanthine and vinblastine in leaves of the seedlings were higher at 40°C than at 30°C, but after 6 h treatment, the contents of vindoline and catharanthine under the two temperatures came to the same level. Catharanthine was exclusively distributed in C. roseus roots and its content was increased by 40% after two hours incubation at 40°C, while increased slowly at 30°C incubation and reached the highest value at 6 h. In the Long-term experiment, concentrations of monomeric alkaloids catharanthine and vindoline were higher at 20°C than at 25°C and had a sharp increase under the condition of 35°C. While for dimeric alkaloid, it showed that the higher the temperature, the earlier the peak value of vinblastine content appears. Vincristine had a continuous enhancement and attained 0.027 mg·g⁻¹ at 16th day under 35°C condition which was higher than those in the other conditions. It was concluded that high temperature could promote the accumulation of different alkaloids in C. roseus and the accumulation characteristic is highly related to treatment time.