3种作物(莴笋、茄子、小白菜)对香樟凋落叶化感作用的生理响应

Physiological Responses of Three Crops (Lettuce, Eggplant and Pakchoi) to Allelpathy of Cinnamomum camphora Litter Leaves

摘要:

为了解香樟（Cinnammum camphora）凋落叶对作物的生长和土壤微生物生物量碳、氮的影响，采用盆栽试验，施用不同添加量的香樟凋落叶，对3种作物莴笋（Lactuca sativa）、茄子（Solanum melongena）和小白菜（Brassica chinensis）的形态指标、生理指标和土壤微生物量C、N进行测定。结果表明，香樟凋落叶分解对3种作物的叶面积、叶片数量和生物量积累均产生明显抑制效应，且随凋落叶量增大抑制更加强烈，随时间延长呈先强后弱的变化趋势；3种作物叶片的MDA和可溶性糖（SS）含量在凋落叶分解初期均显著增加，而可溶性蛋白（SP）含量显著降低；到分解末期，各处理间的MDA含量差异不显著，SS含量的促进作用也明显降低，但SP含量的抑制作用仍在持续。凋落叶处理下土壤中的微生物生物量C、N含量均显著提高，且随凋落叶添加量的增加而升高；随分解时间延长缓慢降低。因此，香樟凋落叶经分解释放的化感物质可能在两方面起作用，一方面通过影响作物体内SP、SS等渗透调节物质的积累水平，另一方面通过改变土壤微生物量来影响有效养分供应，最终对作物的营养生长和生物量积累产生明显影响。

Abstract:

In order to understand the effects of Cinnamomum camphora litter leaves on the growth of crops and soil microbial biomass C and N, the morphological and physiological characteristics of three crops, such as lettuce (Lactuca sativa), eggplant (Solanum melongena) and cabbage (Brassica chinensis), and soil microbial biomass C and N were studied by supplied litter leaves of C. camphora with different dosage in pots. The results showed that the decomposition of C. camphora litter leaves inhibited the growth (leaf area, leaf number) and biomass accumulation of three crops. The inhibition effects were stronger with increment of litter dosage, but those were stronger at first and then weaker along the time. The contents of malondialdehyde (MDA) and soluble sugar (SS) in leaves of three crops treated with litter leaves increased significantly at early stage (20-40 days after sowing), but the soluble protein (SP) content decreased significantly. At the later stage (80 days after sowing), the difference of MDA content among the treatments was not significant, and the promoting effect of SS content was also significantly reduced, but the inhibiting effect of SP content was still continuous. The contents of soil microbial biomass carbon and biomass nitrogen increased significantly, which increased with the increment of litter dosage, and decreased slowly along the time. Therefore, allelochemicals decomposed from C. camphora litter leaves would act in two ways:on the one hand, it affects the accumulation of osmotic regulation substances, such as soluble protein, soluble sugar in crops, on the other hand, it affects the available nutrient supply by changing soil microbial biomass. Finally, it had a significant influnence on the vegetative growth and biomass accumulation of crops.