臭氧污染对不同品种小麦干物质与生物量碳积累与分配的影响

近地层臭氧(O3)污染对陆地生态系统及植物生长的危害备受关注.本研究利用开放式臭氧污染(Free-air O3concentration enrichment,O3FACE)研究平台,研究了大气O3浓度增加(比周围大气高50%)对长江三角洲地区5个冬小麦(Tritcium aestivum L.)品种(扬麦15、扬麦16、烟农19、扬幅麦2号和嘉兴002)的干物质与生物量碳的积累与分配以及作物残体C/N比的影响.结果表明,不同品种小麦的干物质积累和分配对O3升高的响应差异明显;O3升高具有降低扬麦15、嘉兴002和增加扬幅麦2号总生物量的趋势,但对扬麦16和烟农19几乎无影响,其中嘉兴002达到显著水平.O3升高显著增加了扬麦15、嘉兴002和显著降低了烟农19和扬幅麦2号的根/冠比,而对品种扬麦16无影响,导致干物质在地上和地下分配呈现品种差异.高O3环境下扬麦15、扬麦16和嘉兴002穗重降低,而烟农19和扬幅麦2号无明显变化;小麦籽粒占穗的比重在高O3条件下嘉兴002、烟农19和扬幅麦2号显著降低8.2%～15.5%,扬麦15呈增加趋势而扬麦16变化不大;表明O3升高将致嘉兴002、烟农19、扬幅麦2号和扬麦16不同程度减产.O3升高导致烟农19和扬幅麦2号秸秆碳量显著增加14.1%～22.9%和C/N比显著降低10.9%～29.1%,JX002秸秆碳量显著减少和C/N比显著增加,扬麦16和扬麦15的秸秆碳量与C/N比则分别呈增加和降低趋势.O3升高显著降低了扬麦16、烟农19和扬幅麦2号品种的根茬碳量和C/N比,对嘉兴002的根茬碳量无显著影响却显著降低了C/N比,但对扬麦15根茬碳数量与质量均影响不大.评价小麦干物质的形成与分配、根茬和秸秆固碳的质与量对O3污染的响应需考虑品种差异影响.

Effects of Ozone Pollution on the Accumulation and Distribution of Dry Matter and Biomass Carbon of Different Varieties of Wheat

Effects of surface ozone pollution on the terrestrial ecosystem and plant growth have drawn great attention. With the support of the Free-Air ozone Concentration Enrichment (O₃-FACE) system located in Jiangdu city, Jiangsu province, the effects of elevated atmospheric ozone (pO₃) on the accumulation and distribution of dry matter and biomass carbon as well as the C/N ratio of crop residue of five wheat (Tritcium aestivum L.) varieties (Yangmai 15, Yangmai 16, Yannong 19, Yangfumai 2 and Jiaxing 002) were investigated in the Yangtze River delta, the target pO₃ of which was 50% higher than the ambient pO₃. The results showed that the accumulation and distribution of different wheat varieties responded differently to elevated pO₃. Elevated pO₃ decreased the biomass of Yangmai 15 and Jiaxing 002, increased the Yangfumai 2 biomass, and had no effects on the total biomass of Yangmai 16 and Yannog 19, among which a significant difference was found for Jiaxing 002. Elevated pO₃ significantly increased the ratios of root to shoot for Yangmai 15 and Jiaxing 002 and significantly decreased the root/shoot ratios of Yannong 19 and Yangfumai 2, but had no effect on Yangmai 16, leading to an obvious difference in dry matter distributed among aboveground and belowground parts. O₃enrichment decreased the wheatear weight of Yangmai 15, Yangmai 16 and Jiaxing 002, and had no effect on that of Yannong 19 and Yangfumai 2. Elevated pO₃significantly decreased the proportion of grain weight to ear weight by 8.2%-15.5% for Jiaxing 002, Yannong 19 and Yangfumai 2, whereas the proportion was increased for Yangmai 15 and not affected for Yangmai 16, suggesting that O₃enrichment lead to different decreases in the yield of Jiaxing 002, Yannong 19, Yangfumai 2 and Yangmai 16. Elevated pO₃significantly increased the straw carbon of Yannong 19 and Yanfumai 2 by 14.1%-22.9% and significantly decreased the straw C/N ratio by 10.9%-29.1%. The rising pO₃significantly decreased the straw carbon of Jiaxing 002 and significantly increased the straw C/N ratio. Moreover, for Yangmai 16 and Yangmai 15, there was a decreasing straw carbon amount and an increasing straw C/N under rising pO₃. Elevated pO₃ significantly decreased the carbon quantity and C/N of root residue in Yangmai 16, Yannong 19 and Yangfumai 2. Elevated pO₃had not significant effect on the root residue carbon of Jiaxing 002, but significantly decreased its C/N ratio. However, elevated pO₃had no effect on the quantity and quality of the root residue of Yangmai 15. It is obvious that when evaluating the response of the formation and distribution of wheat dry matter and the quantity and quality of root and straw carbon to O₃ pollution, the difference in wheat varieties should be taken into account.