ABSTRACT
In this study we investigate the effects of cadmium stress on Astragalus membranaceus seedlings and the alleviative effects of attapulgite clay in growth substrate on cadmium stress to A. membranaceus seedlings. The results showed that the Y (Ⅱ) (effective photochemical quantum yield of PSⅡ photosynthetic), qP(photochemical quenching coefficient), ETR(the rate of non-cyclic electrontransport through PSⅡ), and chlorophyll content of the leaves were significantly decreased with the increase of cadmium concentrations, while the cadmium content, non-photochemical quenching(NPQ, qN) of the leaves and cadmium content, MDA content, plasma membrane permeability, and the damage degree of root apical membrane of the roots were significantly increased. Simultaneously, the activities of APX(ascorbate peroxidase), SOD(superoxide dismutase), POD(peroxidase), CAT(catalase), soluble protein content, and soluble sugar content of roots were increased first but then decreased with the increasing cadmium concentration. Under the condition of without Cd stress, the attapulgite clay into the growth substrate did not significantly affect above physiological indexes of leaves, but significantly increased SOD activity and soluble sugar content of roots and decreased the MDA content, damage degree of root apical membrane of roots, while other physiological indexes did not significantly change. Under cadmium stress, the presence of attapulgite clay in the growth substrate significantly alleviated the cadmium-induced decreases Y (Ⅱ), qP, ETR and chlorophyll content of leaves, and the CAT activity, soluble protein content, and soluble sugar content of roots. Under condition with cadmium stress, the presence of attapulgite clay significantly alleviated the cadmium-induced increases of leaves cadmium content, qN and NPQ, and the cadmium content, MDA content, plasma membrane permeability, damage degree of root apical membrane, SOD, POD, and APX activity of the roots. And, the alleviative effects of attapulgite clay on cadmium stress to A. membranaceus roots were more obvious with the increase of cadmium stress time. The above results showed that the addition of attapulgite clay into the growth substrate has certain alleviative effect on the cadmium stress to A. membranaceus seedlings.
ABSTRACT
OBJECTIVE:To screen decolorizing agents suitable for the extracts from the fruit and stem of Schisandra chinen-sis. METHODS:HPLC was adopted to determine the contents of 4 kinds of lignans(schizandrin,schisandrol B,deoxyschizandrin and γ-schizandrin) in the extract solution from the fruit and stem of S. chinensis which was treated with 8 kinds of decolorizing agents (activated clay,activated carbon,diatomite,calcium bentonite,kaolin,activated aluminium oxide,magnesium oxide,at-tapulgite clay),and the decolourization rates of the samples of the fruit and stem of S. chinensis and the retention rates of lignans in such samples were calculated respectively. RESULTS:The above-mentioned decolorizing agents were arranged in order as fol-lows respectively based on the decolourization effects on the extract solution from the fruit and stem of S. chinensis:attapulgite clay>activated carbon>activated aluminium oxide>kaolin>magnesium oxide>diatomite>calcium bentonite>activated clay,and activated carbon>diatomite>attapulgite clay>magnesium oxide>kaolin>activated aluminium oxide>activated clay>calcium ben-tonite. The attapulgite clay and activated carbon have the best decolourization effects on the extracts from the fruit and stem of S. chinensis,with the decolourization rates of 60.47% and 69.24% respectively,and the retention rates of schizandrin,schisandrol B,deoxyschizandrin and γ-schizandrin were 77.43%,77.73%,77.07%,77.53%,and 72.18%,70.17%,70.32%,70.28%,re-spectively. CONCLUSIONS:Among the 8 decolorizing agents,attapulgite clay and activated carbon have the best decolourization effects on the extract solution from the fruit and stem of S. chinensis.