Trichiliadregeana胚轴的脱水敏感性与抗坏血酸的抗氧化作用

以顽拗性TrichiliadregeanaSond.种子为材料,研究其胚轴的脱水敏感性与抗坏血酸的抗氧化作用。T.dregeana胚轴的脱水耐性随着脱水进程逐渐下降,50%的胚轴被脱水致死的含水量(W50)大约为0.16gH2O/gDW。在脱水过程中,胚轴的电解质渗漏速率逐渐增加,超氧物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)、过氧化氢酶(CAT)、谷胱苷肽还原酶(GR)和脱氢抗坏血酸还原酶(DHAR)的活性下降,硫代巴比妥酸(TBA)-活性产物的含量增加。2.5~10.0mmol/L抗坏血酸处理能有效地增加胚轴的脱水耐性和SOD、APX、CAT和GR的活性,降低电解质渗漏速率和TBA活性产物的含量。结果表明,T.dregeana胚轴的脱水耐性与抗氧化酶的活性增加和脂质过氧化作用的降低密切相关。

Desiccation Sensitivity of Trichilia dregeana Axes and Antioxidant Role of Ascorbic Acid

Recalcitrant seeds of Trichilia dregeana Sond. were used as experimental material, anddesiccation sensitivity of T. dregeana axes and antioxidant role of ascorbic acid were studied. Desiccationtolerance of T. dregeana axes progressively declined with dehydration, water content at which 50% of axeshas been killed by dehydration (W50) was about 0.16 g H2O/g DW. During dehydration, electrolyte leakagerate of axes gradually increased, the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX),catalase (CAT), glutathione reductase (GR) and dehydroascorbate reductase (DHAR) declined, and contentof thiobarbituric acid (TBA)-reactive products increased. Two point five-10 mmol/L ascorbic acid (AsA)treatment could significantly increase desiccation tolerance and activities of SOD, APX, CAT and GR inaxes, and decrease electrolyte leakage rate and content of TBA-reactive products in axes. The resultsshowed that desiccation tolerance of T. dregeana axes was strongly correlated with the increase in theactivities of antioxidant enzymes and the decrease in lipid peroxidation.