连作对西洋参根系生长及酶活性的影响

在新地及种植过一年、二年、三年参地里播种西洋参，三个月后进行西洋参根重、根系活力、根系酶活性的试验，研究连作对西洋参生理机能的影响。结果表明，随种植年限增加西洋参根重逐年下降；根系活力逐年升高；抗坏血酸过氧化物酶（APX）、过氧化氢酶（CAT）、过氧化物酶（POD）活性先升后降。超氧化物歧化酶（SOD）始终表现为下降趋势。谷胱甘肽还原酶（GR）则呈现上升趋势。丙二醛（MDA）含量在2年生地连作、3年生地连作与对照间没有显著差异，在4年生地连作有明显的升高。

Effect of Continuous Cropping on Growth and Activities of Enzymes in roots of American Ginseng

Abstract: In this paper, the root growth and protective enzymes of American ginseng after continuous cropping were studied to reveal the mechanism for the effects of continuous cropping on the American ginseng physiology. The root weight, root vigor and root enzyme activity containing the ascorbic peroxidase (APX), the catalase (CAT), the peroxidase (POD), superoxide dismutase (SOD), glutathione reductase (GR), and malondialdehyde (MDA) were carried out after three months American ginseng was planted in new soil, one- year, two- year and three-year continuous cropping land, respectively. American ginseng’s root weight in two- year, three- year, four-year planting land was 0.76, 0.83, 0.68 times of that in new soil respectively with significant differences (P<0.05). Root vigor was 1.30、1.35、1.65 times compared with the control (P<0.05). The differences of APX activity (3.52, 0.25, 0.12 times) was significant. SOD activity (0.72, 0.36, 0.37 times). CAT activity (1.86, 0.79, 0.74 times) in two-year continuous crop was remarkable (P<0.05), while three-, four-year continuous crop didn’t vary significantly. POD activity of two-year, three-year continuous crop (2.22, 2.50 times) showed significant differences while no significant distinction was detected in four-year continuous crop (1.43 times). which was similar variation to GR activity (2.57, 2.75, 2.41 times), Significant distinction of MDA was revealed in four-year continuous crop (1.18 times), but no distinction in two- year, three-year continuous crop (1.05, 1.06 times) was gained. With the increasing continuous cropping year, root weight declined, and root vigor went up. APX, CAT, POD and GR activity firstly rose and then decreased. SOD activity showed downtrend. MDA content was remarkably rising in four-year continuous crop.