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研究转胆碱氧化酶(codA)基因杨树对干旱胁迫的响应机制可为杨树耐旱育种及应用提供理论依据.在盆栽条件下研究土壤干旱胁迫及复水对转基因杨树(T)和野生型(NT)生长的影响及叶片中MDA、H_2O_2、甜菜碱含量和抗氧化酶活性等生理指标的影响.结果显示:(1)干旱胁迫后,转基因杨树和野生型的株高、总生物量增长都减慢,但转基因杨树生长状况优于野生型且复水后恢复较快;胁迫5周后,转基因杨树地上地下部的干重分别降低了21.01%和22.97%,而野生型地上地下部的干重则较对照分别降低了47.21%和52.11%,与正常供水相比,转基因植株地上地下部的干重显著高于野生型.(2)杨树叶片中过氧化氢(H_2O_2)、丙二醛(MDA)含量在干旱胁迫后先增加后降低,复水后继续下降,但转基因杨树积累量低于野生型;干旱胁迫下,转基因杨树叶片中游离脯氨酸和甜菜碱的含量显著高于野生型,干旱胁迫3周后,转基因杨树叶片中甜菜碱含量是野生型的2.38倍.(3)随干旱时间延长,杨树叶片中SOD、POD、CAT和APX酶活性逐渐增加,复水后下降,除POD外,转基因杨树抗氧化酶活性普遍高于野生型.本研究结果说明渗透调节物质含量的增加及抗氧化能力的增强是转基因杨树耐旱性和复水后恢复能力增强的内在生理机制.
To study the mechanism of drought stress response of poplar (COA) gene can provide a theoretical basis for drought tolerant breeding and application of poplar.Drought stress and rehydration of soil under potted condition were studied on transgenic poplar (T) and wild type (NT) and MDA, H_2O_2, betaine content and antioxidant enzyme activity in leaves.The results showed that: (1) After drought stress, the plant height and total biomass of transgenic poplar and wild-type all increased But the recovery of transgenic poplar trees was better than that of wild type and recovered quickly after rewatering. After 5 weeks of stress, the dry weight of aboveground and underground parts of transgenic poplars decreased by 21.01% and 22.97%, respectively. However, (47.21% and 52.11% respectively) compared with the control. Compared with the normal water supply, the dry weight of above-ground parts of the transgenic plants was significantly higher than that of the wild type. (2) The content of hydrogen peroxide (H 2 O 2) The content of MDA increased at first and then decreased after drought stress, then continued to decline after rewatering, but the accumulation of transgenic poplars was lower than that of wild type. Under drought stress, the content of free proline and betaine in transgenic poplar leaves Significantly higher than the wild-type, drought threat Three weeks later, the content of betaine in transgenic poplar leaves was 2.38 times of that in wild type. (3) With the prolongation of drought time, the activities of SOD, POD, CAT and APX in poplar leaves gradually increased, POD, the activity of antioxidant enzymes of transgenic poplars was generally higher than that of wild type.The results of this study indicated that the increase of osmoregulation substances and the enhancement of antioxidant capacity are the intrinsic physiological mechanisms of drought tolerance of transgenic poplars and enhanced resilience after rehydration.