Different responses of tobacco antioxidant enzymes to light and chilling stress
Different responses of tobacco antioxidant enzymes to light and chilling stress
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DOI：
10.1078/0176-1617-00753
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发表时间：
2003-05-01
影响因子：
4.3
通讯作者：
Minkov, I
中科院分区：
文献类型：
--
作者：
Gechev, T;Willekens, H;Minkov, I
研究了强光处理（25 ℃，PPFD 360 mumol m-2 sec-1）或低温结合强光处理（5 ℃，PPFD 360 mumol m-2 sec-1）对烟草（Nicotiana tabacum1.11.1.9.小哈瓦那SR 1。两种处理均未引起光氧化损伤，但低温引起短暂萎蔫。光处理增加了抗坏血酸过氧化物酶（APx，EC 1.11.1.11）和愈创木酚过氧化物酶的活性，而过氧化氢酶（EC 1.11.1.6）、超氧化物歧化酶（SOD，EC 1.15.1.1）、单脱氢抗坏血酸还原酶（MDHAR，EC 1.6.5.4）、脱氢1.8.5.1坏血酸还原酶（达尔，EC1.6.4.2）和谷胱甘肽还原酶（EC www.example.com）没有变化。与此相反，低温处理没有增加任何抗氧化酶的活性，但降低过氧化氢酶和在较小程度上达尔活性，葡萄糖过氧化物酶蛋白水平增加零星的光处理和持续的低温处理。低温和光应力引起的谷胱甘肽合成和氧化型谷胱甘肽的积累诱导，虽然谷胱甘肽池的主要部分仍然在还原形式。在25摄氏度和5摄氏度下测量来自冷冻处理的植物的抗氧化酶。在5 ℃下的测量结果显示，与在25 ℃下测量的结果相比，过氧化氢酶活性降低了3倍，这表明在冷却4天后过氧化氢酶的总体降低约为10倍。其他抗氧化酶的活性在冷却4天后的总体下降是2倍的GR和APx，MDHAR的1.5倍，达尔的3.5倍。SOD活性在25 ℃和5 ℃时无明显变化。这些结果表明，过氧化氢酶和达尔是最强烈的影响，在低温处理，可能是抗氧化系统的限速因子。
The effect of elevated light treatment (25 degreesC, PPFD 360 mumol m(-2) sec(-1)) or chilling temperatures combined with elevated light (5 degreesC, PPFD 360 mumol m-2 sec-1) on the activity of six antioxidant enzymes, guaiacol peroxidases, and glutathione peroxidase (GPx, EC 1.11.1.9) protein accumulation were studied in tobacco Nicotiana tabacum cv. Petit Havana SR1. Both treatments caused no photo-oxidative damage, but chilling caused a transient wilting. The light treatment increased the activities of ascorbate peroxidase (APx, EC 1.11.1.11) and guaiacol peroxidases while catalase (EC 1.11.1.6), superoxide dismutase (SOD, EC 1.15.1.1), monodehydroascorbate reductase (MDHAR, EC 1.6.5.4), dehydroascorbate reductase (DHAR, EC 1.8.5.1), and glutathione reductase (EC 1.6.4.2) were unchanged. In contrast, chilling treatment did not increase any of the antioxidant enzyme activities, but decreased catalase and to a lesser extent DHAR activities, Glutathione peroxidase protein levels increased sporadically under light treatment and constantly under chilling. Both chilling and light stress caused induction of glutathione synthesis and accumulation of oxidised glutathione, although the predominant part of the glutathione pool remained in the reduced form. Antioxidant enzymes from the chilling treated plants were measured at both 25 degreesC and 5 degreesC. Measurements at 5 degreesC revealed a 3-fold reduction in catalase activity, compared with that measured at 25degreesC, indicating that the overall reduction in catalase after four days of chilling was approximately 10-fold. The overall reduction in activity for the other antioxidant enzymes after four days of chilling was 2-fold for GR and APx, 1.5 fold for MDHAR, 3.5-fold for DHAR. The activity of SOD was the same at 25 and 5 degreesC. These results indicate that catalase and DHAR are most strongly affected by the chilling treatment and may be the rate-limiting factor of the antioxidant system at low temperatures.