营养元素缺乏对西洋参生长及皂苷积累的影响

矿质营养元素是维持西洋参正常生长和保证其品质的关键因素,为了解不同营养元素缺乏对西洋参的综合影响,以二年生西洋参为材料,采用温室砂培试验,设置Hoagland全营养对照和10种营养元素缺乏处理,观察缺素症状,测定株高、叶面积、生物量、光合指标、根系活力、人参皂苷含量。结果表明,缺氮、钾、铁可导致西洋参叶片明显失绿黄化;缺氮、钾、钙、镁和硼是导致株高和叶面积下降的主要因子;所有缺素处理西洋参的生物量均显著下降(P<0.05),其中缺氮、钾、钙、铁下降最多,全株生物量低于全营养对照的50%以上。氮、钾、铁缺乏是导致西洋参净光合速率、气孔导度、胞间二氧化碳浓度、蒸腾速率、叶绿素含量下降的主要因子;氮、钾、钙缺乏是降低根系活力的前3位因子;不同营养元素缺乏对西洋参6种单体皂苷的影响有差异,综合来看,氮、磷、硼、锌、铜缺乏对皂苷的合成影响最大。以上研究结果有助于明确西洋参对不同营养元素的需求特性,对栽培生产中缺素诊断、肥料合理使用、提高产量和质量具有重要意义。

Effects of nutrients deficiency on growth and saponin accumulation of American ginseng

Mineral nutrient elements are the key factors to maintain the growth and quality of American ginseng. In order to understand the comprehensive effect of different nutrient elements deficiency on American ginseng, 2-year-old American ginsengs were cultivated by Hoagland solution(CK) or 10 different nutrients deficiency solution in sand culture. During the cultivation, the deficient symptom was observed. The plant height, leaf area, biomass, photosynthetic index, root activity, ginsenoside content were measured. The results showed that N, K or Fe deficiency could lead to leaves of American ginseng yellowing. Deficiency N, K, Ca, Mg and B were the main factors that decrease plant height and leaf area. The biomass of plant decreased significantly in all the nutrient deficient treatments(P<0.05)compared with control group, and N, K, Ca or Fe deficiency groups descended over 50%. In the absence of N, K and Fe elements, the Pn, Gs, Ci, Tr and chlorophyll of leaves were decreased mostly. The first three factors decreasing root activity were N, K and Ca deficiency. The effects of nutrient deficiency on saponins of American ginseng were different.Generally, N, P, B, Zn and Cu deficiency resulted the synthesis of saponins decreased significantly(P<0.05). This study contributed to clarify the demand characteristics of American ginseng for different nutrient elements,which is of great significance for the diagnose of nutrient deficiency, the rational fertilizer and the improvement of yield and quality of American ginseng.