近60年来20个冬小麦品种叶片对臭氧生化、生理和生长反应的基因型差异

Biwas D. K., 徐宏, 李永庚, 孙家柱, 王贤忠, 韩兴国, 蒋高明*

中国科学院植物学研究所植被与环境变化重点实验室，中国北京100093南辛村20

中国科学院遗传与发育生物学研究所植物细胞与遗传工程国家重点实验室，北京，100101

印第安那大学生物学系，普渡大学，印第安那波利斯，723 W.Michigan St.，Indianapolis，IN 46202，USA 

山东农业大学作物科学学院，泰安岱宗大街61号

全球变化生物学, 2008, 14: 46-59. (影响因子：8.88)

【摘要】 东亚城市周边地区臭氧（O3）浓度升高，足以降低作物产量。然而，冬小麦O3敏感性与品种推广年代的基因型差异却鲜为人知。本文报道了近60年来中国20个冬小麦品种对O3敏感性基因型变化，揭示了O3的诱导机制。小麦植株暴露于高O3（82 ppb O3，7h d-1）或木炭过滤空气（<5 ppb O3）中，在开顶式同化箱内处理21天。通过抗氧化活性、蛋白质改变、膜脂过氧化、气体交换、叶绿素含量、暗呼吸和生物量变化来评价不同年代推广的小麦品质对O3的响应。结果表明，O3显著降低了叶片抗坏血酸（14%）和可溶性蛋白（22%）含量，但过氧化物酶活性（+46%）和丙二醛（+ 38%）显著增加。高浓度O3降低了光饱和净光合速率（－24%）、气孔导度（－8%）和总叶绿素含量（－11%），同时刺激了暗呼吸（+28%），胞间CO2浓度（+39%）升高。O3也降低了植物整体生长量，但根（-32%）生物量比茎（-17%）的生物量受影响更大。对O3的潜在敏感性存在显著的基因型差异，与观察到的O3耐受性无关。冬小麦品种对O3的敏感性随推广年份的增加而增加，并与O3暴露植株的气孔导度和暗呼吸有关。O3诱导的光合速率下降主要是由于叶肉细胞活性下降和细胞膜完整性丧失，细胞间CO2浓度升高和脂质过氧化增加。结果表明，气孔导度高、抗氧化能力降低、暗呼吸水平低，导致对蛋白质的氧化损伤和细胞膜的完整性，导致了新品种对O3敏感性增强。

关键词：抗氧化剂、暗呼吸、生长、臭氧敏感性、气孔导度、冬小麦、推广年代

Genotypic differences in leaf biochemical, physiological and growth responses to ozone in 20 winter wheat cultivars released over the past 60 years

Global Change Biology, 2008, 14: 46-59. (IF=8.88)

Biwas D. K., Xu H., Li Y. G., Sun J. Z., Wang X. Z., Han X. G. & Jiang G. M*

Abstract  Ozone (O3) concentrations in periurban areas in East Asia are sufficiently high to decrease crop yield. However, little is known about the genotypic differences in O3 sensitivity in winter wheat in relation to year of cultivar release. This paper reports genotypic variations in O3 sensitivity in 20 winter wheat cultivars released over the past 60 years in China highlighting O3-induced mechanisms. Wheat plants were exposed to elevated O3 (82 ppb O3, 7 h day−1) or charcoal-filtered air (<5 ppb O3) for 21 days in open top chambers. Responses to O3 were assessed by the levels of antioxidative activities, protein alteration, membrane lipid peroxidation, gas exchange, leaf chlorophyll, dark respiration and growth. We found that O3 significantly reduced foliar ascorbate (−14%) and soluble protein (−22%), but increased peroxidase activity (+46%) and malondialdehyde (+38%). Elevated O3 depressed light saturated net photosynthetic rate (−24%), stomatal conductance (−8%) and total chlorophyll (−11%), while stimulated dark respiration (+28%) and intercellular CO2 concentration (+39%). O3 also reduced overall plant growth, but to a greater extent in root (−32%) than in shoot (−17%) biomass. There was significant genotypic variation in potential sensitivity to O3 that did not correlate to observed O3 tolerance. Sensitivity to O3 in cultivars of winter wheat progressed with year of release and correlated with stomatal conductance and dark respiration in O3-exposed plants. O3-induced loss in photosynthetic rate was attributed primarily to impaired activity of mesophyll cells and loss of integrity of cellular membrane as evidenced by increased intercellular CO2 concentration and lipid peroxidation. Our findings demonstrated that higher sensitivity to O3 in the more recently released cultivars was induced by higher stomatal conductance, larger reduction in antioxidative capacity and lower levels of dark respiration leading to higher oxidative damage to proteins and integrity of cellular membranes.

Key words: antioxidants, dark respiration, growth, ozone sensitivity, stomatal conductance, Triticum

aestivum L., winter wheat, year of release