Effects of low light intensity on photosynthetic capacity, photosynthetic nitrogen utilization efficiency and nitrogen partition in non-heading Chinese cabbage leaves.

摘要

Non-heading Chinese cabbage (Brassica campestris L. ssp. chinensis Makino) originated in China, and is very important and popular there. However, the protected culture of non-heading Chinese cabbage formed a low light intensity-growing environment, which has an adverse influence on the yield and quality of the plant. In this paper, using low light tolerant 'Aiwang' and low light intolerant 'Lvyou' as materials, giving the light intensity of 12.5%, 25%, 60% and 100% sunlight respectively, growth and photosynthesis, leaves nitrogen content and the leaves nitrogen distribution in the two cultivars were studied. The results showed that the maximum net photosynthesis (Pmax), light saturation point (LSP), lamina mass per unit area (LMA), plastochron index (PI) decreased with reduction of light intensity, but the indices of 'Aiwang' were all higher than 'Lvyou'. The two cultivars are susceptible to photoinhibition while 'Aiwang' is mild. The fraction of leaf nitrogen in thylakoid light harvesting systems (PL) enhanced with the decline of light intensity. The distribution coefficient for leaf nitrogen in bioenergetics (PB) changed insignificantly under different light intensity. The partitioning coefficient for leaf nitrogen in Rubisco (PC) of the two cultivars reached its peak at the light intensity of 60% sunlight. All above indices of 'Aiwang' were higher than 'Lvyou' under low light intensity.