关键词: 蓬莱松(Asparagus retrofractus L.), 遮阴, 生物量, 生理特征, 营养元素

Abstract: To explore the effects of different shading environments on the growth and physiological characteristics, as well as nutrient absorption of Asparagus retrofractus L. seedlings, 4-month-old A. retrofractus seedlings were taken as the research objects. Four shading intensity treatments (0%, 25%, 50% and 75% shading) were set up to determine the biomass, physiological and biochemical characteristics, and nutrient element contents of A. retrofractus seedlings under different shading conditions after 5 month treatments. The results showed that there were extremely significant differences in most indexes among different shading environment. Among them, under the T3 (50% shading) treatment, the biomass, the activities of antioxidant enzymes (SOD, CAT), and the total phosphorus content in the aboveground part all reached the maxima and were superior to those under the full light (T1) treatment. However, under the T4 (75% shading) treatment, the MDA content was the lowest, and the accumulation of nitrogen and potassium elements in the aboveground part and nitrogen and phosphorus elements in the underground part increased. With the increasing canopy densities, most indexes (such as biomass and antioxidant enzyme activity) generally showed a trend of first increasing and then decreasing, but the degree of membrane lipid peroxidation gradually decreased. 3 principal components with eigenvalues greater than 1 (with a cumulative contribution rate of 100%) were extracted from 15 growth, physiological and element content indexes. These principal components mainly reflected the biomass and dry matter accumulation of A. retrofractus seedlings, the accumulation of nutrients in the aboveground part, the accumulation of nitrogen in the underground part, and the plant resistance. The mean scores of the principal components for each treatment, from largest to smallest, were T3, T4, T2, T1. It could be seen from this that both overly strong and overly weak light environments could lead to a decrease in the biomass accumulation of young plants of A. retrofractus and nutrient limitations. Moderate shading could promote the growth and development of young seedlings of A. retrofractus during the seedling stage and enhance the activity of some antioxidant enzymes. The environment with a shading degree of 50% was the most suitable. At this time, appropriate fertilization methods (such as combined application of nitrogen and potassium fertilizers) should be adopted to promote the growth and development process.

Key words: Asparagus retrofractus, shading, biomass, physiological characteristics, nutritional elements