Climate change effects caused by an increasing concentration of CO2 and ozone represent an issue of major concern both for scientists and policy-makers. In a concerted program funded by the Commission of the European Union, a European network of experiments (in open-top chambers (OTC), and free air carbon dioxide enrichment systems (FACE)) and modelling was carried out to investigate the effects of increasing atmospheric CO2 and ozone concentrations, under different climatic conditions, on potato (Solanum tuberosum L. cv. Bintje). This contribution describes the experimental network and the standard protocol set-up for the assessments that served to improve and to validate process oriented potato growth simulation models leading to scenarios of future productivity of potato in Europe. 相似文献
Out of a total of 224 bovine eye secretions, 126 Moraxella bovis and 64 Neisseria ovis strains were isolated. The pathogenesis and histological lesions caused by Neisseria ovis have been studied on the eyes of three calves naturally affected with IBK, using electron microscopy.
Neisseria ovis caused in 1–12 weeks old calves acute, transient and mostly benign serous conjunctivitis with only slight affection of the cornea. More rarely erosions and even ulceration of the cornea have been observed.
Moraxella bovis and Neisseria ovis strains proved nearly unanimously sensitive in vitro to chloramphenicol, neomycin, oxytetracyclin, nitrofurantoin, erythromycin and cefoperazone. Other antibiotics and chemotherapeutics inhibited the growth of these agents only partly or were ineffective.
Experimental therapy has been carried out using a single i.m. injection of Terramycin/LA inj. (Pfizer) in a dose of 20 mg/kg body mass, repeated if necessary after 72–96 h. This formulation proved more effective and practical than treatments used earlier. 相似文献
A solution culture experiment was performed to investigate the effects of oxytetracycline (OTC) on wheat (Triticum aestivum L.) growth,chlorophyll contents,and photosynthesis at five levels of 0,10,20,40,and 80 mmol L-1 OTC.OTC is toxic to wheat.The wheat growth,especially wheat root was significantly decreased.Further OTC also significantly decreased root activity,chlorophyll contents,and photosynthetic parameters except for intercellular CO2 concentrations.The different responses of indicators such as root number,root activity and so on to OTC were also observed.The IC50 values for the tested indicators to OTC ranged from 7.1 to 113.4 mmol L-1 OTC.The order of indicator sensitivity to OTC was root number > stomatal conductance > chlorophyll a > total chlorophyll > photosynthetic rates > total surface area >transpiration rate > chlorophyll b > fresh weight of root > dry weight of root > total length > dry weight of shoot =fresh weight of shoot> total volume.The root number was more sensitive than other indicators with the ICs0 value of 7.1 mmol L-1 OTC,and could be taken as the sensitive indicator to predict the hazards of OTC to wheat. 相似文献
为深入认识高寒草甸温室气体通量对长期气候变暖的响应,利用开顶式生长室(OTC,Open Top Chamber)模拟增温2a(2Y,2015-2016年)和6a(6Y,2011-2016年)对藏北高寒草甸生长季CO2、CH4和N2O通量的影响。结果表明:与对照相比,生长季(6-8月)增温6Y处理和增温2Y处理分别增加和降低高寒草甸土壤CO2排放通量,其中7月增温6Y处理CO2排放通量显著高于增温2Y处理;增温6Y和2Y处理增加了高寒草甸CH4吸收通量,但是处理间差异均不显著;高寒草甸N2O排放通量表现为增温6Y>2Y>CK,处理间无显著差异。环境因子与温室气体排放通量的相关分析表明,CO2、CH4和N2O排放通量与0~5cm土壤温度相关不显著;土壤湿度、植物地上生物量、微生物生物量碳和蔗糖酶是影响高寒草甸CO2排放通量的关键因子;NO3--N是影响CH4吸收通量的关键因素;脲酶和NO3--N是影响N2O排放通量的主要因子。因此,增温6Y处理通过增加植物地上部生物量、蔗糖酶活性,从而提高了土壤CO2排放通量,增温6Y和2Y处理通过增加土壤脲酶和NO3--N含量,从而促进了土壤N2O排放和CH4的吸收通量。 相似文献
Potato cv. Bintje was grown in open-top-chambers and free-air-CO2-enrichment systems at 7 sites across Europe for 2 years (1998–99). The effect of different treatments (CO2 enrichment and O3 fumigation) on the chlorophyll content of fully expanded upper and lower canopy leaves was investigated collecting Minolta SPAD-502 meter readings. In both CO2 treated and O3 fumigated plants, leaves had lower chlorophyll content than those in ambient air controls; season-long chlorophyll averages were 9.3% lower in the ‘CO2’ treatments, 9.1% lower in ‘O3’ treatments and 12.3% lower in ‘CO2+O3’ treatments. The analysis of chlorophyll content in three different growth phases (Emergence–Tuber Initiation; Tuber Initiation–Maximum Leaf Area; Maximum Leaf Area–Harvest) showed that in the early growth period, i.e. before tuber initiation there was a slight indication for an higher chlorophyll content at elevated CO2 (+3.8%) or O3 (+1.7%). However, from tuber initiation onwards the leaves of plants grown under elevated CO2 or O3 showed a progressively lower chlorophyll content (−4.8% for CO2 treatments and −2.6% for O3 treatments) indicating a faster senescence of leaves that increased during the late growth period (−12.8% for CO2 treatments and −12.7% for O3 treatments) and that was enhanced by CO2–O3 interaction (−17.8%). 相似文献