Site Selection Of Panax Quinquefolium Under The Forest And Its Seedling Growth Regular

The roots of American ginseng have significant medicinal and health benefits because they are rich in physiologically active substances-saponins,volatile oils,polysaccharides,and etc.The quality and price of ginseng under the forest are significantly higher than under the greenhouse.This paper compares the growth,net photosynthetic rate and understory environment of American ginseng at different altitudes,stand types,aspect,and cultivation years,so that to study the suitable site conditions and growth patterns under the forest of American ginseng.The results are as follows:(1)Alerican ginseng grows better at altitudes of 1200-1300 m in the Dabie Mountains.There were significant differences in plant height,diameter,stem-leaf fresh weight,stem-leaf dry weight,root fresh weight and root dry weight of American ginseng between the altitude of 1200-1300m and the altitude of 1000-1100m.The former are 1.46 times,1.16 times,2.53 times,2.55 times,3.19 times and 3.10 times of the latter,respectively.The net photosynthetic rate of American ginseng is higher at an altitude of 1200-1300 m.(2)There were no significant differences in growth indexes such as main root length,main root thickness,root fresh weight and root dry weight of broad-leaved forest and coniferous and broad-leaved mixed forest.There were also no significant differences in chlorophyll relative content and net photosynthetic rate among the four-year-old American ginseng leaves under the two forest types.(3)American ginseng on the shady slope grows better.The 4-year-old American ginseng on the shady slope is significantly higher than the sunny slope in the diameter,the length of the leaf,the width of the leaf and the main root length,which are 1.18 times,1.10 times,1.14 times and 1.18 times of the American ginseng on the sunny slope,respectively.The roots with medicinal values are also significantly different at the shady slope and sunny slope.And the root fresh weight and root dry weight of the 4-year-old American ginseng on the shady slope were 1.66 g and 0.53 g higher than that on the sunny slope,respectively.(4)Plant height,diameter,stem-leaf dry weight and root dry weight of American ginseng increase with the seedling age.Among them,the dry weight of stem-leaf and roots of American ginseng increased slowly in 1-3 years,and the differences are not significant.But the stem-leaf dry weight and root dry weight of the 4-year-old American ginseng are significantly higher than the 3-year-old American ginseng.(5)The diurnal variation of net photosynthetic rate of American ginseng(red fruit period)showed a bimodal curve with peaks at 11 o'clock and 15 o'clock,respectively,and photosynthetic "noon break" appeared at 13 o'clock.The net photosynthetic rate of 1-year-old and 2-year-old American ginseng is similar,and 3-year-old and 4-year-old American ginseng is similar,with an average of 1.35?mol m-2 s-1 and 1.60?mol m-2 s-1,respectively.