Effects of Light and Nitrogen Level on Leaf Growth and Photosynthesis of Rauvolfia vomitoria

A pot culture experiment was conducted to study leaf growth and photosynthetic characteristics of Rauvolfia vomitoria plants under different light intensities (15%,40%,and 70% of full sunlight) and nitrogen levels (15,30,and 60 g/per plant).Results showed that the net photosynthesis rate (Pn),stomatal conductance (Gs),water utilization efficiency (WUE),chlorophyll contents (Chl),specific leaf area (SLA),and leaf mass ratio (LMR) were significantly influenced by light intensity and nitrogen level (p<0.01). The Pn and Gsincreased with the increase in light intensity and nitrogen level.In addition,the values of Pn and Gs under 70% light intensity were much higher than those under 15% and 40% light intensity.Conclusively,low light intensity is more beneficial to the synthesis of chlorophyll.The combination of low light and high nitrogen level favored SLA and leaf biomass allocation.As for the fluorescence parameter, Fv/Fm did not differ significantly according to light intensity and nitrogen level.Light intensity and nitrogen levels also had significant interaction on the Pn,Gs,and WUE (p<0.05).