Effects of shading on non-structural carbohydrate metabolism in leaves of Emmenopterys henryi Oliv. seedlings

Artificial shading treatments were applied to examine the effects of different light intensities (100%, 40% and 10% light transmittance) on the concentrations of soluble sugar, starch and non-structural carbohydrate (NSC) and their related metabolic enzyme activities in the leaves of Emmenopterys henryi Oliv. (E. henryi). Results showed that under 40% light transmittance, the concentrations of soluble sugars, starch, and NSC, along with the soluble sugar-to-starch ratio all reached the maximum values; meanwhile, the activities of ribulose-1,5-bisphosphate carboxylase/oxygenase, phosphoenolpyruvate carboxylase, sucrose synthase, and sucrose phosphate synthase were the highest. Acid invertase activity exhibited a progressive increase with diminishing light intensity, while soluble starch synthase and amylase activities declined progressively under reduced light intensity. These results demonstrate that 40% light transmittance optimizes the accumulation of soluble sugars, starch, and non-structural carbohydrates (NSC) in the leaves of E. henryi.