关键词: LED短期连续光照, 氮水平, 氮形态, 水培生菜, 营养品质

Abstract: By the method of plot investigation, a comparative study was made on the differences in the community characteristics among the exotic tree species Larix principisrupprechtii plantation, indigenous tree species Pinus armandii plantation, and P. armandii secondary forest in Huoditang forest area of Qinling Mountains. The similarity coefficient between L. principisrupprechtii plantation and P. armandii secondary forest was only 0.11, and the species number in the P. armandii secondary forest and P. armandii plantation was significantly greater than that in L. principisrupprechtii plantation (P<0.01). The Margalef index, Simpson index, ShannonWiener index, and Pielou evenness index in the arbor, shrub, and herb layers of P. armandii secondary forest and P. armandii plantation were significantly higher than those in L. principisrupprechtii plantation (P<0.001), but the four diversity indices in the shrub layer and herb layer in P. armandii secondary forest and P. armandii plantation had less difference (P>0.05). The compose index (CI) was the lowest (0.3) in L. principisrupprechtii plantation, 3.5 in P. armandii plantation, and the highest (5.2) in P. armandii secondary forest, showing a significant difference among the three forest types (P<0.001). This study indicated that exotic tree species introduction led to the decrease of species abundance, species diversity, and stand’s naturalized degree in the forest community in Qinling Mountains, while natural secondary forest succession or indigenous tree species plantation were more beneficial to the restoration of understory vegetation than exotic tree species plantation.

Key words: short-term continuous lighting with LED, nitrogen level, nitrogen form, hydroponic lettuce, nutritional quality.