Abstract:

Four capsicum inbred lines were used to study the response of photosynthesis in detached leaves from seedlings to low light under water loss stress in a phytotron. The results showed there was a close relationship between photosynthesis and water conditions under normal or low light. Capsicum seedlings expressed stomatal limitation to photosynthesis under both mild and middle water stresses. However, the decrease of Pn was considered as a result of non-stomata restriction under severe water stress. The response of photosynthesis to low light was slow, i.e. as the decrease of the relative leaf water content (RLWC), the Pn of leaves under low light declined slowly, and photosynthesis was not sensitive to the changes of water. The tolerant capability of photosynthesis to low light under water loss stress in hot pepper was stronger than that in sweet pepper. The leaf water potential of capsicum young plants grown under low light environment was relatively high but the water compensation point showed a declined trend.

Key words: capsicum, low light, water loss stress, relative leaf water content, net photosynthetic rate, water compensation point