Preliminary Research Of The Effects Of Sphingosine On Medicago Sativa L. And Cucumber Callus Induction And Resistance

Medicago sativa L.and Cucumis sativus L.were used in the experiment. After the treatment with sphingosine, the effects of the induction and the differentiation of callus and that of the drought and temperature stresses on some physiologic indexes were investigated. The experiment results showed that sphingosine have no influence on the can inhibit the the inductivity of callus in, and 0.6 mg/L sphingosine can increase the rate of differentiation. In the effect of sphingosine on the activity of superoxide dismutase (SOD) and peroxidase(POD) etc, the results indicated that during the induction the callus treated with sphingosine of 0.06 mg/L showed higher SOD activity and 0.02 mg/L showed h-igher POD activity. During the induction of Cucumis sativus L. with 0.15 mg/L, 0.3 m g/L or 0.6 mg/L sphingosine treated, the enzyme activities of SOD and POD appeare d a peak, but in the late stage the activities decreased.Under the osmotic stress induced by PEG, sphingosine enhanced the activity of POD, SOD of callus in Cucumis sativus Land the content of proline. Under water stress condition, sphingosine made the content of soluble sugar and protein of callus in Medicago sativa L. increased, and sphingosine of 0.6 mg/L made the content of soluble sugar and the protein increased 10 % and 25 %, respectively.Malondialdehyde (MDA) of callus in Cucumis sativus L.changed slowly in the earlier stage, but later it changed quikly and the range of variation enlarged; under the low temperature stress, MDA content of the control went up quickly than the callus treated. This illustrated that sphingosine can properly decreased the accumulation of MDA and enhanced the adaptability to low temperature. Following the prolong of water stress's time, protein kinase activity increased earlier and decreased later, and sphingosine delayed the appearance of the peak of activity. It showed that to a certain extent sphingosine inhibited protein kinase. In a word, with the treatment of some concentration, sphingosine can enhance the adaptability of Medicago sativa L. and cucumber under the adversity and improve the capability of anti-threatening.