不同臭氧熏气方式对油菜光合速率、生物量和产量的影响

为准确评价臭氧(O3)浓度升高对农作物的影响,运用田间原位开顶气室(open-topchamber,OTC)研究了高浓度O3对油菜光合作用、生物量和产量的影响.实验包括3种O3水平,一种为经活性炭过滤的空气(CF),两种高浓度O3处理:经活性炭过滤后的空气加入恒定浓度为100nL·L-1的O(3CF100);经活性炭过滤后的空气加入具有日变化特征,其平均浓度和剂量与CF100相同的O3(CF100D).结果表明,CF100和CF100D均能使油菜叶片膜透性和H2O2自由基含量增加,光合色素含量和光合速率(photosynthesisrate,Pn)降低,最终导致油菜生物量和产量降低.与CF相比,CF100和CF100D熏气下油菜单位面积产量分别降低3.7%和18.6%.同时,实验还表明,CF100D对油菜的影响大于相同剂量的CF100.以上结果表明:1)高浓度的O(3CF100和CF100D)能够破坏细胞膜系统,减少光合色素数量,降低光合速率,从而降低作物生物量和产量;2)相同平均浓度和剂量的高浓度O3对油菜的影响因熏气方式的不同而有明显差异,目前采用的O3平均浓度和O3剂量指标不能准确评价O3浓度升高对油菜的影响.

Impact of Different Ozone Exposure Regimes on Photosynthetic Rate, Biomass and Yield of Field-Grown Oilseed Rape

In order to provide scientific data for exactly evaluating effects of O3 on crops, the research has been carried out on responses of oilseed rape to elevated O3. In present study, the oilseed rape was exposed to two O3 regimes: CF100 exposure to consistent concentration of O3 of 100nL·L-1 and CF100D exposure to mean O3 concentration of 100nL·L-1 with obvious diurnal variation of O3 concentration for about 35d. The results showed that CF100 and CF100D aggravated lipid per-oxidation, increased H2O2 content in oilseed rape leaves, and decreased their photosynthetic pigments content and photosynthesis rates(Pn). Subsequently, reductions of biomass and yield were found in oilseed rape. In comparison to CF, CF100 exposure decreased oilseed rape yield by 3.7%, and CF100D exposure by 18.6%. Besides, the experiment also indicated that CF100D exposure had more detrimental impact on oilseed rape than CF100 exposure did, although both regimes had nearly same mean concentration and dosage. It indicated that the available mean concentration and dosage indices could not be enough accurate to estimate the damage of elevated O3 to crops.