《植物生理学报》 2017, 53(4): 695-704

小麦幼苗内源一氧化氮与胞间活性氧生理调控机制的研究

高晓霞, 殷金梅, 陆昱成, 吕丽荣, 杨颖丽^*

西北师范大学生命科学学院, 兰州730070

通信作者：杨颖丽；E-mail: xbsfxbsdyang@163.com

摘　要：

本文用PTIO (2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide, NO清除剂)、过氧化氢酶(CAT, H₂O₂清除剂)和二亚苯基氯化碘盐(DPI, 质膜NADPH氧化酶抑制剂)处理小麦(Triticum aestivum)新品种‘陇春27’, 探讨了内源NO与活性氧(ROS)的产生及其对幼苗生长、抗氧化反应以及渗透性调节的影响。结果显示: CAT只抑制小麦根的生长, 而PTIO或DPI处理均抑制小麦幼苗根和茎的生长。PTIO处理下幼苗根叶中NO、叶中总ROS含量均减少, 而根中总ROS和胞间ROS含量增加; CAT的加入导致叶中NO、总H₂O₂及根质外体H₂O₂含量均降低, 而叶中羟自由基(·OH)含量及根NO、总超氧阴离子(O₂·−)和质外体O₂·−含量均升高; 相比, DPI处理下幼苗叶中NO量减少而根中的量增加, 同时, DPI诱导幼苗叶中总H₂O₂及根质外体ROS含量均减少, 而使根中总H₂O₂及根叶中总O₂·−和·OH含量显著增加。PTIO、CAT或DPI处理下小麦幼苗根叶中超氧化物歧化酶(SOD)、CAT和过氧化物酶(POD)的活性均呈现不同的变化趋势。此外, PTIO处理使幼苗可溶性糖和可溶性蛋白含量增加, CAT不影响渗透性调节物的含量, 但DPI处理下脯氨酸、可溶性糖和可溶性蛋白含量均增加, 显著提高渗透调节能力。PTIO或DPI均诱导了幼苗丙二醛(MDA)含量的增加, 且DPI处理下的增幅最大。研究表明小麦幼苗根叶中内源性NO和胞间ROS的产生相互影响, 特别是NO和胞间ROS影响ROS和抗氧化酶的代谢, 导致小麦根和叶表现出不同的抗氧化反应。

关键词：小麦; 一氧化氮; 活性氧; 抗氧化反应; 渗透性调节

收稿：2017-02-20   修定：2017-03-17

资助：国家自然科学基金(31470464和31360094)。

Study on physiological regulation mechanism of endogenous nitric oxide and apoplastic reactive oxygen species in wheat seedlings

GAO Xiao-Xia, YIN Jin-Mei, LU Yu-Cheng, LÜ Li-Rong, YANG Ying-Li^*

College of Life Sciences, Northwest Normal University, Lanzhou 730070, China

Corresponding author: YANG Ying-Li; E-mail: xbsfxbsdyang@163.com

Abstract:

In this study, new spring wheat (Triticum aestivum) ‘Longchun 27’ seedlings were treated with 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO, NO specific scavenger), catalase (CAT, H₂O₂ scavenger) and diphenyleneiodonium chloride (DPI, plasma membrane NADPH oxidase inhibitor) to investigate the generation of endogenous nitric oxide (NO) and apoplastic reactive oxygen species (ROS), and to explore their effects on seedlings growth, antioxidation response and osmotic adjustment. The length of roots lowered in CAT-treated seedlings. Differently, PTIO or DPI significantly inhibited growth of roots and shoots. PTIO treatment resulted in the reduction of NO content in leaves and roots as well as total ROS contents in leaves but the increase of total and apoplastic ROS’s in roots. After the seedllings were treated with CAT, the amount of NO and total H₂O₂ in leaves and apoplastic H₂O₂ content in roots lowered, while hydroxyl radical (·OH) content in leaves and NO together with total and apoplastic superoxide anion (O₂·−) contents in roots significantly increased. In contrast, NO and total H₂O₂ contents decreased in roots but rose in leaves in DPI-treated seedlings. Meanwhile, DPI resulted in significant reduction of apoplastic ROS in roots but increases of total O₂·− and ·OH in roots and leaves. The activities of superoxide dismutase (SOD), CAT and peroxidase (POD) showed different trends in roots and leaves of seedlings under PTIO, CAT or DPI treatment. In addition, the amount of soluble sugar and soluble protein rose in PTIO-treated in seedlings, and DPI resulted in the accumulation of proline, soluble sugar and soluble protein, thus significantly improved the capacity of osmotic adjustment. Besides, PTIO or DPI induced the increases of malondialdehyde (MDA) content, with the largest elevation due to DPI treatment. These results suggest that the generation of endogenous NO and apoplastic ROS influenced each other in wheat seedlings, especially that NO and apoplastic ROS effect the metabolism of reactive oxygen species and antioxidant enzymes, which leads to different oxidation responses in the roots and leaves of wheat seedlings.

Key words: wheat; nitric oxide; reactive oxygen species; antioxidation response; osmotic adjustment