Tropospheric ozone（O3） is a major air pollutant and causes serious injury to vegetation. To protect sensitive plants from O3 damage, several agrochemicals have been assessed,including cytokinin（e.g., kinetin, KIN）...Tropospheric ozone（O3） is a major air pollutant and causes serious injury to vegetation. To protect sensitive plants from O3 damage, several agrochemicals have been assessed,including cytokinin（e.g., kinetin, KIN） and ethylenediurea（EDU） with cytokinin-like activity.In higher plant, leaves are primarily injured by O3 and protective agrochemicals are often applied by leaf spraying. To our knowledge, the mitigating abilities of EDU and KIN have not been compared directly in a realistic setup. In the present research, impacts of elevated O3（2 × ambient O3, 24 hr per day, for 8 days） on an O3 sensitive line（S156） of snap bean（Phaseolus vulgaris）, which is often used for biomonitoring O3 pollution, were studied in a free air controlled exposure system. The day before starting the O3 exposure, plants were sprayed with a solution of EDU（300 ppm）, KIN（1 mmol/L） or distilled water, to compare their protective abilities. The results demonstrated that 2 × ambient O3 inhibited net photosynthetic rate and stomatal conductance, increased the minimal fluorescence yield of the dark-adapted state, decreased the maximal quantum yield of PSII photochemistry, and led to visible injury. KIN and EDU alleviated the reduction of the photosynthetic performance, and visible injury under O3 fumigation. The plants sprayed with EDU showed greater ability to mitigate the O3 damage than those sprayed with KIN. Chlorophyll fluorescence imaging may have detected more precisely the differences in O3 response across the leaf than the conventional fluorometer.展开更多
Seed size and composition are important traits in food crops and can be affected by nutrient availability in the soil. Phosphorus （P） is a non-renewable, essential macronutrient, and P deficiency limits soybean （G1...Seed size and composition are important traits in food crops and can be affected by nutrient availability in the soil. Phosphorus （P） is a non-renewable, essential macronutrient, and P deficiency limits soybean （G1ycine max） yield and quality. To investigate the associations of seed traits in low- and high-P environ- ments, soybean recombinant inbred lines （RILs） from a cross of cultivars Fiskeby III and Mandarin （Ottawa） were grown under contrasting P availability environments. Traits including individual seed weight, seed number, and intact mature pod weight were significantly affected by soil P levels and showed transgressive segregation among the RILs. Surprisingly, P treatments did not affect seed composition or weight, suggesting that soybeanmaintains sufficient P in seeds even in Iow-P soil. Quantitative trait loci （QTLs） were detected for seed weight, intact pods, seed volume, and seed protein, with five significant QTLs identified in Iow-P environments and one significant QTL found in the optimaI-P environment. Broad-sense heritability estimates were 0.78 （individual seed weight）, o.go （seed protein）, 0.34 （seed oil）, and 0.98 （seed number）. The QTLs identified under low P point to genetic regions that may be useful to improve soybean performance under limiting P conditions.展开更多
基金supported by the National Natural Science Foundation of China (No. 31401895)‘Young Talents’ project of Northeast Agricultural University of China (No. 14Q10)+2 种基金financial support to the first author for his visiting research in Italy (No. 201606615002)The ozone FACE was financed by the Foundation Cassa di Risparmio of Florence (No. 2013/7956)supported in part by the LIFE15 ENV/IT/000183 project MOTTLES
文摘Tropospheric ozone（O3） is a major air pollutant and causes serious injury to vegetation. To protect sensitive plants from O3 damage, several agrochemicals have been assessed,including cytokinin（e.g., kinetin, KIN） and ethylenediurea（EDU） with cytokinin-like activity.In higher plant, leaves are primarily injured by O3 and protective agrochemicals are often applied by leaf spraying. To our knowledge, the mitigating abilities of EDU and KIN have not been compared directly in a realistic setup. In the present research, impacts of elevated O3（2 × ambient O3, 24 hr per day, for 8 days） on an O3 sensitive line（S156） of snap bean（Phaseolus vulgaris）, which is often used for biomonitoring O3 pollution, were studied in a free air controlled exposure system. The day before starting the O3 exposure, plants were sprayed with a solution of EDU（300 ppm）, KIN（1 mmol/L） or distilled water, to compare their protective abilities. The results demonstrated that 2 × ambient O3 inhibited net photosynthetic rate and stomatal conductance, increased the minimal fluorescence yield of the dark-adapted state, decreased the maximal quantum yield of PSII photochemistry, and led to visible injury. KIN and EDU alleviated the reduction of the photosynthetic performance, and visible injury under O3 fumigation. The plants sprayed with EDU showed greater ability to mitigate the O3 damage than those sprayed with KIN. Chlorophyll fluorescence imaging may have detected more precisely the differences in O3 response across the leaf than the conventional fluorometer.
基金supported by the National Science Foundation grants IOS-1031416 and IOS-1444456sabbatical leave funding from the Florida Agricultural and Mechanical University
文摘Seed size and composition are important traits in food crops and can be affected by nutrient availability in the soil. Phosphorus （P） is a non-renewable, essential macronutrient, and P deficiency limits soybean （G1ycine max） yield and quality. To investigate the associations of seed traits in low- and high-P environ- ments, soybean recombinant inbred lines （RILs） from a cross of cultivars Fiskeby III and Mandarin （Ottawa） were grown under contrasting P availability environments. Traits including individual seed weight, seed number, and intact mature pod weight were significantly affected by soil P levels and showed transgressive segregation among the RILs. Surprisingly, P treatments did not affect seed composition or weight, suggesting that soybeanmaintains sufficient P in seeds even in Iow-P soil. Quantitative trait loci （QTLs） were detected for seed weight, intact pods, seed volume, and seed protein, with five significant QTLs identified in Iow-P environments and one significant QTL found in the optimaI-P environment. Broad-sense heritability estimates were 0.78 （individual seed weight）, o.go （seed protein）, 0.34 （seed oil）, and 0.98 （seed number）. The QTLs identified under low P point to genetic regions that may be useful to improve soybean performance under limiting P conditions.
