Eco-physiological Responses of Juglans regia Seedling to Different Light Intensity

To reveal the relationship between light environments and 1-year J.regia seedling,the investigation on eco-physiological responses of 1-year J.regia seedling to different light intensity was done.The result showed that:(i) The stem diameter decreased,and the net increment of stem diameter reached the maximum under full sunlight.Moreover,J.regia got maximum height growth ability under moderate shading;(ii) In biomass,with the degree of shading reduction the plant gradually increased investment of resources on fronds and decreased investment of resources on stems,the root biomass/shoot biomass ratio increased at the same time.The biomass per plant reached the maximum under moderate shading;(iii) With the degree of shading reduction,the net photosynthetic rate(Pn) and stomatal conductance(cond) first increased and then decreased,besides,the net photosynthetic rate(Pn) and stomatal conductance(cond) leaves increased to maximal levels under moderate shading and light shading;(iv) Under shading,the leaf chlorophyll a,chlorophyll b and total chlorophyll contents of J.regia had significant differences to those in full sunlight,and the chlorophyll a/b ratio under severe shading decreased significantly.In general,moderate shading might be beneficial in 1-year J.regia seedling growth.