气相色谱法测定人参中BHC残留量

本文研究了一种快速、简便、准确地测定人参中ＢＨＣ残留量的气相色谱法。人参样品经正己烷—丙酮冷浸泡,超声萃取,磺化法处理后,萃取液直接上机测定。本方法对人参中ＢＨＣ各异构体的回收率均在８５％以上。变异系数小于１０％。与其它方法相比,本法耗时少,价格廉,结果准确,适合批量样品测定。     

亚临界丙烷萃取条件对人参提取物中有机氯农药残留脱除的影响

以人参提取物为原料,利用亚临界丙烷萃取技术脱除其中的有机氯农药残留,研究了一定范围内的萃取压力(4～12 Mpa)、萃取温度(50～80 ℃)、萃取时间(60～180 min)和溶剂流量(1 96～3 92 kg/h)对亚临界丙烷萃取脱除人参提取物中农药残留的影响.由正交实验确定了最佳萃取条件: 萃取压力8 Mpa,萃取温度65 ℃,萃取时间120 min,溶剂流量2.94 kg/h.在此条件下,γ-BHC、op-DDT残留的脱除率接近100%,TCNB、pp-DDT脱除率大于60%,人参皂甙损失小于6.53%.     

Iron (Fe2+)-induced toxicity produces morphological and physiological changes in roots in Panax ginseng grown in hydroponics

ABSTRACT

Rusty roots markedly influence on ginseng cultivation, and this phenomenon often attributed to iron (Fe) induced toxicity. To examine the physiological mechanisms underlying Fe-initiated toxicity as evidenced by rusty roots in Panax ginseng, morphological and physiological changes in roots were investigated in hydroponics using Fe²⁺ concentrations of 50 (control), 100, 200, 400 or 600 µM. Compared with control, reddish-brown deposition at the root surface increasingly appeared as Fe²⁺ concentration increased (≥200 µM). The pH also rose as Fe levels were elevated. Higher external Fe²⁺ concentrations produced changes in root organelles and cell structures. Structural alterations in mitochondria due to excess Fe storage, protoplast shrinkage and cell vacuolation as well as formation of central vacuole with deposits in roots were observed. In addition, apparent cell wall thickening, cell wall folding and shrinkage, damage of cell membranes and a large amount of cell debris occurred at higher external Fe²⁺ concentrations (≥400 µM). The Fe²⁺ mediated damage resulting in morphological and physiological changes in ginseng roots was concentration and pH dependent.