连作条件下地黄药用品质及土壤微生态特性分析

Effects of continuous cropping on the quality of Rehmannia glutinosa L. and soil micro-ecology

  • 摘要: 怀地黄是我国著名“四大怀药”之一, 在其种植过程中存在着非常严重的连作障碍。本研究探讨了连作对地黄药用品质的影响, 并从土壤微生态方面分析了连作障碍造成地黄药用品质下降的原因。从怀地黄道地产区河南省焦作地区和地黄主产区山西省临汾地区分别采集正茬地黄及其正茬土壤、重茬地黄及其重茬土壤和未种植地黄的对照土壤, 利用生药学研究方法对两个产区正茬和重茬地黄的药用品质进行评价, 并对4种土样的自毒作用潜力、土壤微生物群落和土壤酶活性指标进行测定分析。结果表明, 道地产区与非道地产区地黄品质的差异达到显著水平(P<0.05, 下同), 但正茬与重茬地黄的品质差异显著高于产区之间差异; 两产区地黄连作均显著抑制地黄幼苗生长; 连作还造成根际土壤细菌数量减少, 土壤真菌和放线菌数量增多, 土壤微生物类型由“细菌型”向“真菌型”过渡; 与正茬土壤相比, 连作根际土壤中土壤脲酶、蔗糖酶和过氧化氢酶的活性显著下降, 土壤多酚氧化酶、纤维素酶和蛋白酶的活性有所增加, 但土壤磷酸酶活性在两个产区连作土壤中呈现相反的变化趋势。由此可见, 连作会引起土壤酶活性和土壤微生态区系的变化, 降低了地黄对营养物质的吸收利用, 进而造成地黄药用品质下降。

     

    Abstract: Rehmannia glutinosa L. is one of Chinese herbal medicines with serious cultivation obstacles. In this study, samples of newly cultivated and continuously cropped R. glutinosa soil and uncultivated soil were collected in R. glutinosa genuine producing area in Jiaozuo City of Henan Province and R. glutinosa production area in Linfen City of Shanxi Province. R. glutinosa samples also were collected from the same areas. The soil samples were then evaluated in relation to R. glutinosa quality under continuous cropping, and R. glutinosa quality decline mechanisms were explored in terms of soil micro-ecological (soil microbes and enzyme) activities. The results showed that R. glutinosa quality in the genuine producing area was significantly different (P<0.05) from that in the production area. However, the quality differences of R. glutinosa between newly cultivation and continuous cropping were significantly higher than those between different producing areas. Continuous cropping in the two areas significantly inhibited R. glutinosa seedling growth. While continuous cropping reduced the number of rhizosphere bacteria, it increased fungi and actinomycetes populations. This resulted in the transition from bacteria-populated to fungi-populated soil type. Compared with newly cultivated R. glutinosa soil, continuously cropped R. glutinosa soil significantly decreased the activities of urease, sucrase and catalase (P < 0.05) while slightly increased the activities of polyphenoloxidase, cellulose and protease in the two areas. However, phosphatase activity in continuously cropped R. glutinosa soil exhibited the opposite trend for the two areas. Therefore, speculation was put forward that auto-toxicity changed the soil micro-ecology and somehow affected soil enzyme activity, thereby reducing R. glutinosa ability to absorb nutrients.