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81.
The influence of rain and drought before, and air temperature during, weed control with hot water was studied in laboratory experiments on the test weed Sinapis alba (white mustard). The plants were grown in a greenhouse and treated outdoors. There was no difference in weed control effect when S. alba plants at the four‐leaf stage were treated at the air temperatures 7°C and 18°C. The effective energy dose for a 90% fresh weight reduction was 465 kJ m?2 for both air temperatures. Weed control of S. alba at the four‐ to six‐leaf stage in rainfall above the rainwater run‐off level increased the required effective energy dose by 20% (i.e. 120 kJ m?2) compared with dry plants. A short period of drought just before treatment on S. alba at the two‐ to four‐leaf stage increased the plant fresh weight reduction, which was 22% at low energy dose (190 kJ m?2) and 44% at high energy dose (360 kJ m?2). Hot water weed control should thus be carried out when the plants are drought stressed and avoided when the plants are wet. The air temperature seems to be of little importance in the range 7–18°C. 相似文献
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DING Gui-xia ZHANG Ai-hua HUANG Song-ming WU Yuan-jun FEI Li GUO Mei CHEN Rong-hua 《园艺学报》2004,20(10):1754-1758
AIM: To investigate the role of NF-κB/IκB signal pathway in the regulation of cyclooxygenase-2 (COX-2) expression in human mesangial cells (HMC). METHODS: The PGE2 concentration in supernatants of HMC was measured by radioimmunoassay. COX-2 mRNA and protein expression were determined by RT-PCR and Western blot. Electrophoretic mobility shift assay (EMSA) and Western blot were used to detect the activity of NF-κB and degradation of IκB. RESULTS: IL-1β significantly upregulated COX-2 expression and PGE2 production in HMC. Significant up-regulation of NF-κB activation, nuclear translocation of p65 subunit, and degradation of IκB α and IκB β were observed in IL-1β-induced HMC. CONCLUSION: Expression of COX-2 in IL-1β-induced HMC is mediated by NF-κB/IκB signal pathway. 相似文献
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Kunio SUGAHARA Mako MATSUMOTO Motoko YAMADA Fumiaki YAOSHIZAWA Yutaka KARASAWA 《Animal Science Journal》2004,75(5):431-434
In order to determine the role of the cecum on energy use in growing chickens, metabolizability of the dietary energy and energy expenditure were examined in the week following bilateral ligation and washing out of the cecum. Apparent metabolizable energy (AME) values were 14.30 and 13.69 kJ/g air‐dry matter for sham‐operated and cecally ligated chickens, respectively. These values were found to be significantly different (P < 0.05). Although AME intake and fasting heat production were decreased by cecal ligation, the distribution of AME (measured as fasting and feeding heat production, as well as heat increment and energy retention, as a proportion of AME intake) was not affected. These results suggest that the cecum helps chickens extract AME from corn‐soybean type diets with little, if any, effect on AME use, based on the present study of growing chickens in the week following cecal ligation. 相似文献
86.
几种牧草对河西走廊盐渍化土壤改土培肥的效应研究 总被引:13,自引:2,他引:13
在河西走廊盐渍化土地上种植老芒麦、扁穗冰草、碱茅和紫花苜蓿4种优质牧草,对盐渍化程度均有一定的改良效果.其中碱茅对盐渍化土壤的改土培肥效果最好,建植3年后的碱茅,与对照比较,0~20 cm土层中自然含水量增加125.99 g/kg,总孔度增加16.14%,容重降低0.27 g/cm3,pH值由8.43降到8.10,全盐含量降低52.90 g/kg,脱盐率达到76.12%,有机质增加3.67 g/kg,碱解氮含量增加18.63 mg/kg,速效磷和钾亦随之增加. 相似文献
87.
不同能量摄入水平对围产期奶牛生产性能及血浆瘦素浓度影响的研究 总被引:1,自引:0,他引:1
将健康的围产期奶牛30头随机分为3组, 每组10头。其中Ⅱ组为对照组, Ⅰ组和Ⅲ组分别为试验组。Ⅰ、Ⅱ、Ⅲ组均于产前28d开始分别饲喂NRC标准减少20%日粮(能量摄入80%组)、NRC标准日粮(能量摄入100%组)、NRC标准增加20%日粮(能量摄入120%组), 产后各组奶牛均饲喂标准日粮, 至产后56d结束。观察妊娠后期奶牛不同能量水平对干物质摄入量、产奶量、乳成分及体重等生产性能和血浆瘦素浓度的影响。试验结果表明: 奶牛产后干物质摄入量、产奶量、乳中蛋白质、乳脂率和非固体物质为Ⅰ组高于Ⅱ组、Ⅱ组又高于Ⅲ组(P>0 05 ); 同时血浆瘦素浓度为Ⅰ组高于Ⅱ组、Ⅱ组又高于Ⅲ组, 经统计分析组间差异极显著(P<0 01) 或差异显著(P<0 05); 但产前28~14d瘦素浓度组间差异均不显著(P>0 05 ), 此后Ⅰ组和Ⅲ组差异显著(P<0 05 )。此外, Ⅰ组体重消耗最小, Ⅲ组体重消耗最大, 各组间差异极显著(P<0 01)。可见, 围产期健康奶牛不同能量水平与干物质摄入量、产奶量、乳成分、体重等生产性能及血浆瘦素浓度之间存在着密切的关系。 相似文献
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89.
用传统开路式牛用呼吸面具对24月龄母水牛绝食产热(Fasting heat production,FHP)进行研究。结果表明:①24月龄母水牛FHP为306.013kJ/kgW0.75·d;每天排出内源尿氮(EUN)为39.66g;单位代谢体重每天排出EUN为0.48g;蛋白分解产热占总产热量为17.13%;EUN与FHP比值为1.60mg/kJ。②24月龄母水牛维持净能需要:NEm=397.817kJ/W0.75·d。 相似文献
90.