Zhao Z.,Yunnan Climate Center |
Wang P.Y.,Kunming Agromcteorological Station |
Zheng Y.F.,Kunming Agromcteorological Station |
Wu R.J.,Kunming Agromcteorological Station |
Zhang J.E.,Kunming Agromcteorological Station
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2015
Dry matter accumulation, photosynthetic pigments content and chlorophyll a fluorescence parameters (via IMAGIN-PAM, H. Walz, Effeltrich, Germany) in the pericarp were studied in developing wheat grains in response to varying ozone concentration: charcoal filtered air (CF, O3ranging over 4—28 nL/ L), ambient air (NF, O3ranging over 7—78 nL/ L), 100 nL/ L O3(CF100, O3ranging over 96—108 nL/ L) and 150 nL/ L O3(CF150, O3ranging over 145— 160nL/ L) and beside, a closed Open Top Chamber(5H, O3ranging over 15—68 nL/ L) was set up for comparison. It was observed that CF100 and CF150 treatment significantly reduced the length of winter wheat grain along with its maximum width, maximum thickness, volume, number of grain per ear, grain filling duration and the average filling rate before the end of peak compared with NF. Their 1000-grain weight of CF100 and CF150 was constantly lower than NF (and CF), finally, there was 10.7% and 17.8% decline, respectively. From 8thto 16thday after anthesis, CF100 and CF150 were significantly higher than other three groups, yet after 16 days, they declined rapidly to the extent that they lag the other groups significantly after 18th day. Under enhanced O3, grain yield decrease resulted mainly from the declining of volume, grain filling duration and number of grain per ear. In conclusion, high concentration of O3delayed the grain development process at the earlier period of grain filling but advances senescence at the later period which sharply shorted the grain filling duration. The potential electron transport rate, equivalent to the parameter ETRmax, was suppressed at the beginning of grain filling stage but promoted in middle stage. And then it fell rapidly due to the grain aging in advance. In addition, under high concentration of O3, the green layer of pericarp played a more important role in dry matter accumulation and nutrient synthesis. © (2015), Ecological Society of China. All rights reserved.