不同脱水速率对木奶果种子脱水敏感性及抗氧化酶活性的影响

研究了脱水速率对木奶果种子脱水敏感性和抗氧化酶活性的影响。木奶果种子初始含水量高达1.72gH2O·g^-1DW,萌发率为86.67%。含水量降至0.90gH2O·g^-1DW左右时,慢速脱水种子的萌发率为97.78%,而快速脱水的种子萌发率仅为64.44%。快速脱水至含水量为0.76gH2O·g^-1DW时萌发率为21.67%,而慢速脱水至0.68gH2O·g^-1DW时,萌发率仍高达55.56%。确定了木奶果种子是对慢速脱水耐受性更高的顽拗性种子。在种子脱水过程中,相对电解质渗透速率和脂质过氧化产物（TBARs）都呈升高趋势,但慢速脱水后的种子,其TBARs升高的速率较快速脱水的慢。快速脱水的种子中超氧化岐化酶（SOD）、脱氢抗坏血酸还原酶（DHAR）和抗坏血酸过氧化物酶（APX）的活性较慢速脱水的高,而过氧化氢酶（CAT）活性较慢速脱水的低,未检测出谷胱甘肽还原酶（GR）的活性。这些结果表明,在木奶果种子脱水耐性获得过程中过氧化氢酶比其他抗氧化酶作用更大。

Effect of Different Drying Rates on the Desiccation Tolerance and Antioxidant Enzyme Activities of Baccaurea ramilfora (Euphorbiaceae) Seeds

The effects of different drying rate on desiccation tolerance and ntioxidant enzyme activities of Baccaurea ramilfora seeds were studied in this paper. The initial water content（WC） of B.ramilfora seeds was high 1.72 g H2O·g^-1DW,and germination was 86.67%,respectively. When the seeds dehydrated to the same water content （0.90g H2O·g^-1DW）,the germination of seeds increased with slwo-dehydrated method （ 97.78%）,while decreased with rapid-dehydrated method （ 64.44%）. The germination of rapid-dehydrated seeds with 0.76 g H2O·g^-1DW WC was 21.67%,while that of slow-dehydrated seeds with 0.68 g H2O·g^-1DW WC was 55.56%. The B.ramilfora seeds were recalcitrant seeds which showed higher tolerance to slow dehydration. Both of relative electrolyte leakage and lipid peroxidation increased following hedehydration,and the increase rate of slow-dehydrated seeds were slower than rapid-dehydrated seeds. Among these antioxidant enzymes,the activities of SOD,DHAR and APX were higher in rapid-dehydrated seeds than slow-dehydrated seeds,while CAT was lower,and GR was not found. These results indicated that CAT played more important role in desiccation tolerance of B.ramilfora seeds than the other antioxidant enzymes.