臭氧对水稻生长的影响及外源抗坏血酸的防护作用

利用开顶式气室研究了臭氧浓度升高对水稻（Oraza sativa L.）生长的影响及外源抗坏血酸（Exogenous Ascorbic Acid）的防护作用。臭氧处理共设4个水平：空气NF（No-Filter，臭氧浓度约20-50 nL·L^-1）、过滤CF（Charcoal-Filter，臭氧浓度约为5-15 nL·L^-1）、臭氧Ⅰ（8 h平均100 nL·L^-1）、臭氧Ⅱ（8 h平均200 nL·L^-1），外源抗坏血酸浓度设置为0.1％（m/V）。结果表明，与NF处理相比，高浓度O3（200 nL·L^-1）处理会造成水稻叶片的叶绿素a、水稻的株高、叶面积、穗粒数及粒重，分别下降了47.9％、17. 8％、31.6％、45.7％和42.9％；喷施外源抗坏血酸后，与各自的对照相比，以上各生长指标分别上升了11.6％、7.7％、17.4％、5.6%、11.1%。可见外源抗坏血酸能有效缓解O3对水稻的胁迫作用，提高了水稻对O3的抗性，促进水稻的生长。

Effects of Ozone on Growth of Rice and Prevention of Exogenous Ascorbic Acid

The ozone is the primary gaseous pollutant with significant adverse effects on vegetation.Those effects include visible leaf injury, growth and yield reductions, accelerated senescence and altering sensitivity to biotic and abiotic stresses.Reductions in photosynthesis rate, stomata conductance, and root/shoot ratio, increasing in respiration, and changing in crop quality has also been observed in many crops.With fast industrial development, tropospheric ozone in the Yangtze River Delta,in Eastern China,as risen since the later of the last century.The elevated ozone has became a prominent environmental and economic issue in this region. In order to alleviate the phytotoxin of elevated level O3 to crops, the prevention of exogenous ascorbic acid （ ExAsA ） on growth of rice （ Oryza sativa L. ） was investigated.Rice was grown in open top chambers（OTCs ） under field conditions and exposed to four levels of O3 ： NF（No-Filter） with a daily average of 20-50 nL·L^-1; CF（Charcoal-Filter） with an 8 h average of 5-15 nL·L^-1; Ozone Ⅰ with an 8 h average of 100 nL·L^-1; Ozone Ⅱ with an 8 h average of 200 nL·L^-1. The concentration of exogenous ascorbic acid was 0.1%（m/V ）. The results showed that compared to CF, the chlorophyll a content of rice leaves, the plant height of rice, leaves area, per panicle total grain and weight decreased under the treatment of high ozone concentration （ 200 nL·L^-1）, 47.9%, 17.8%, 31.6%, 45.7% and 42.9% respectively. But with exogenous ascorbic acid spraying, there was a rising trend in the chlorophyll a content of rice leaves, the plant height of rice , leaves area, per panicle total grain and weight, 11.6%,7.7%,17.4%,5.6%, 11.1% respectively. From these results, it can thought that ExAsA defers leaf senescence, increases the tolerance ability of rice under elevated O3 and improved effectively rice growth.