外源亚精胺对荇菜抗Hg2+胁迫能力的影响

3 mg/L的Hg2降低了叶内亚精胺(spermidine,Spd)、精胺(spermine,Spm)含量,促进了腐胺(put resci ne,Put)合成,喷施Spd可提高叶内Spd、Spm含量,对Put含量则在低浓度下使其下降、高浓度(将近1mmo1/L)下使之上升.3mg/L的Hg2 可显著降低SOD、CaT、APx活性,提高02-产生速率,导致膜脂过氧化物(MDA)过量积累,造成叶绿素、可溶性蛋白大幅度下降.而喷施Spd可减轻Hg2 处理的这些作用,喷施的最适浓度为0.1～0.5 mmol/L.

Effects of Exogenous Spermidine on Resistance of Nymphoides peltatum to Hg2+ Stress

Effects of different exogenousspermindine concentrations on the activities ofsome enzymes(SOD, CAT, POD, APX), O2 gen-eration rate, the MDA, chlorophyll, soluble pro-tein and polyamine contents in leaves ofNymphoides peltatum without Hg2 stress or un-der Hg2 stress were studied. The results showedthat: (1) The spermidine(Spd) and spermine(Spm) content dropped significantly under Hg2 (3 mg/L) stress 4 d, while that of putrescine(Put)was increased markedly(Fig.1). Exogenous Spdcould increase the Spd and Spm content inleaves, while that of Put lowered at first and roselater.(2) Hg2 3 mg/L decreased drastically theactivities of SOD, CAT and APX(Fig.2), in-creased the O2 generation rate(Fig.3), led to theaccumulation of a large amount of MDA(Fig.4)and loss of chlorophyll and soluble protein(Figs.5,6). Exogenous Spd could enhance the activi-ties of SOD, CAT and APX, decrease O2 genera-tion rate and reduce the MDA content. Inaddition, Spd could also decrease the loss ofchlorophyll and soluble protein content inducedby Hg2 stress, enhance the ability of Nymphoidespeltatum to resist Hg2 stress. The most suitableconcentration of Spd was in the range 0.10.5mmol/L.