The superiority of cv ‘rosea’ over cv ‘alba’ of periwinkle (Catharanthus roseus L.) in alkaloid production and other physiological attributes

Abstract

A pot experiment was conducted during the winter season of 2006, on 2 cvs. of periwinkle (Catharanthus roseus L.), namely "rosea" (Pink) and "alba" (White), to investigate their performance in terms of growth, yield, and alkaloid production, as well as other physiological and biochemical attributes. The plants were harvested at 60, 90, and 150 days after planting (DAP) and the yield was recorded at 210 DAP. The results showed that "rosea" was superior to "alba" in plant height, total and individual leaf area, and fresh and dry weights at 90 DAP. Net photosynthetic rate, stomatal conductance, carbonic anhydrase activity and nitrate reductase activity were also higher in "rosea" than in "alba" at 60 and 90 DAP. Likewise, nitrogen content in leaf was also higher in "rosea". At harvest, "rosea" registered higher number of pods, number of seeds, and seed-yield per plant than did "alba". Furthermore, alkaloid content was found to be maximum in leaves at 90 DAP and in roots at 60, 90, and 150 DAP in "rosea" compared to "alba". The contents of alkaloids, viz., vincristine and vinblastine, were also found to be maximum at 90 DAP in both cultivars. Thus, "rosea" excelled over "alba" in the overall performance of the plant.