短葶飞蓬黄酮及咖啡酸酯的含量与土壤氮供应量的关系

 通过对短葶飞蓬(Erigeron breviscapus)不同产地的44个种群植株的总黄酮、灯盏乙素和总咖啡酸酯含量与产地土壤全氮(N)和速效N含量的相关分析, 探讨了产地间土壤N含量变化在药用植物短葶飞蓬植株次生代谢有效成分含量变化中的作用机制。结果显示: 土壤全N含量与种群植株中总黄酮含量呈显著的负相关(r=–0.391, p<0.01), 而与总咖啡酸酯和灯盏乙素关系不显著; 土壤速效N含量与种群植株中总黄酮(r=–0.528, p<0.01)、灯盏乙素(r=–0.490, p<0.01)和总咖啡酸酯含量(r=–0.471, p<0.01)都表现出更高的极显著负相关关系。全部44个种群中, 有效N供应量变化只能解释次生代谢产物含量的17%~30%的变化。非石灰土壤与石灰土壤的种群分开进行线性回归, 可解释总黄酮含量产地间约80%的变化, 以及灯盏乙素和总咖啡酸酯含量约60%的变化。植株总黄酮、灯盏乙素和总咖啡酸酯含量都与植株含N量存在显著的负相关关系。研究表明: 土壤丰富的有效N供应不利于黄酮和咖啡酸酯的合成积累, 与“碳素/营养平衡假说”的预测一致; 土壤有效N对植物次生代谢产物的影响会受到植物体内外因素的影响。不同产地的短葶飞蓬的黄酮等酚类次生代谢产物含量的差异, 可能是产地间不同的土壤N供应量和其他生态因子及遗传变异共同作用的结果。

EFFECTS OF NITROGEN AVAILABILITY IN SOIL ON THE CONTENTS OF FLAVONOIDS AND CAFFEATES IN A MEDICINAL PLANT, ERIGERON BREVISCAPUS

Aims Our objectives are to explore the effect of nitrogen availability in soil on the accumulation of the secondary metabolites of plants growing in different areas, to test the C/N hypothesis, and to address reasons for the variability of content of active constituents in medicinal herbs growing in different areas. Methods We surveyed plants and soils in 44 populations of a medicinal plant, Erigeron breviscapus. We analyzed total and active nitrogen of soil samples and total flavonoids, scutellarin, caffeates and ni-trogen in plant samples. Linear regression analysis was used to study relationships between soil nitrogen availability and active constituents of plants. Important findings The contents of flavonoids and caffeates in plants were negatively correlated with soil nitrogen availability and plant nitrogen content, as predicted by the carbon/nutrient balance hy-pothesis. Variation in available soil nitrogen accounted for 17%–30% of the variation in the content of secondary metabolites of plants. In contrast, variation in available nitrogen accounted for about 80% of the variation in content of total flavonoids in the rendizina and about 60% of content of scutellarin and caffeates in the non-rendizina. It appeared that effects of nitrogen availability on the accumulation of secondary metabolites in the plant were affected by other factors, such as genetic and environmental variation. The content of flavonoids and caffeates in plants growing in different areas varied with dif-ferences in nitrogen availability, ecological factors and genotypes.