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11.
The relationships between the changes of relative water content (RWC), malondialdehyde (MDA) contents, superoxide dismutase (SOD) activity and free proline contents in sweet potato leaves, and drought resistant ability under different concentration of polyethylene glycol (PEG) treatment applied at rhizosphere of sweet potato seedlings were studied. A highly positive correlation between RWC and drought resistance (r =0.783, P〈0.01), a highly negative correlation between MDA contents and drought resistance (r = -0.848, P〈0.01), a highly positive correlation between SOD activity and drought resistance (r = 0.777, P〈0.01) was observed. Free proline contents in leaves was not related obviously to the sweet potato drought resistance under 25% PEG treatment. The stronger the drought resistance of variety, the less decrease of RWC and increase of MDA contents, the more increase of SOD activity. By determining these physiological indices in sweet potato leaves under 25% PEG treatment, rapid identification of drought resistant ability of different varieties can be obtained in the lab.  相似文献   
12.
给休情期性成熟母犬肌注 PGF2α(0 .5 m g/ kg) ,2 4 h后肌注 e CG(5 0 IU/ kg) ,再经 12 0 h后肌注 h CG(2 0 U/ kg) ,诱导其发情。将诱导发情的母犬与公犬交配 ,于交配后 16 d,摘取卵巢、子宫 ,观察其卵泡发育和胚胎着床情况。结果表明 ,药物处理可明显促使母犬提前结束休情期而进入发情期 (9/ 10 ) ,促进卵巢内卵泡发育 (P<0 .0 1) ,并使更多的胚胎着床 ,每只母犬子宫胚胎着床点为 (17.4± 2 .2 )个 ,提示 3种生殖激素联合应用可提高母犬繁殖率  相似文献   
13.
1995~2000年,对杨干象对杨树生长的影响和防治指标进行了研究。结果认为,不同虫口密度对杨树生长的影响明显,通过建立虫口密度与杨树生长(树高、胸径、材积)损失率回归预测模型表明,随着虫口密度的增加,胸径、材积生长明显下降,其关系呈直线、对数回归关系;高生长总的趋势是下降的,呈多项式回归关系;杨干象防治指标确定为:5年生以下杨树为2头/株,6~8年生杨树为3头/株,9年生以上杨树为4头/株。  相似文献   
14.
旅游城市化现象初探——以新疆吐鲁番市为例   总被引:18,自引:0,他引:18  
旅游城市化是随着城市化和旅游业的不断发展而出现的一种必然现象 ,本文以吐鲁番为例阐述旅游城市化对城市发展的作用 ,并在此基础上说明实施旅游城市化应注意的问题如 :要选择和确定城市发展的主题 ,城市规划和旅游规划要协调一致 ,城市要有较为完善的旅游服务设施体系及城市的社会经济发展不能完全依赖于旅游城市化等。  相似文献   
15.
The fate of fluroxypyr in the soil in an oil palm agroecosystem   总被引:1,自引:0,他引:1  
A study on the fate of fluroxypyr in Malaysian agricultural soils was carried out under natural conditions in an oil palm plantation. Three experimental plots in the oil palm estate were selected and three types of treatments were administered, namely fluroxypyr at the recommended dosage, double the recommended rate, and the untreated control. Residues of fluroxypyr in the soil, water, and oil palm leaf were monitored at regular intervals up to 90 days after treatment (DAT). The recovery of fluroxypyr in the water and soil samples ranged from 91–102% when fortified at 1–25 p.p.b. and 91–98% when fortified at 4–50 p.p.b. The recovery from the oil palm leaf ranged from 76–114% when the oil palm leaf sample was fortified at 0.05–1.0 p.p.m. The results showed that fluroxypyr leached down to 50 cm depth at 1 DAT when the plots were treated with either dosage. However, fluroxypyr was not detected in the soil residue at 14 and 21 DAT. Fluroxypyr was not detected in the oil palm leaf samples irrespective of the rates of herbicide application or sampling intervals. The residue of fluroxypyr was detected in water from a nearby stream up to 5 DAT at levels ranging from 0.06–0.21 µg L−1. This result suggests that fluroxypyr persists for a short period in the soil and water ecosystems, but not in the oil palm leaf.  相似文献   
16.
柑橘裂皮病是由柑橘裂皮病类病毒(Citrusexocortisviroid,CEVd)引起的一种重要的柑橘病害。分别采用快速微量核酸提取法和SDS-KAc抽提法在表现症状的Etrog香橼中提取核酸,采用一步RT-PCR法对CEVd进行检测,结果显示SDS-KAc法可以消除带毒样品中非特异性条带。从嫁接接毒的铜水72-1锦橙植株的接穗部取嫩叶、老叶、皮,从砧木部茎杆上取老皮以及根皮分别提取总核酸进行RT-PCR检测,分析CEVd在甜橙体内的分布情况。初步检测结果表明在接穗的嫩叶、老叶、皮,砧木部茎杆的老皮和根皮上都可以检测到CEVd,以接穗部叶和皮检出稳定性高。  相似文献   
17.
AIM:To observe the effects of Sini decoction on atherosclerosis(AS) and ceramide content of aorta in rabbits. METHODS:28 rabbits were randomly divided into three groups. Control group was fed with a normal diet; High cholesterol group was fed 1% cholesterol and 5% fat diet; Sini decotion+ high cholesterol group was fed 1% cholesterol and 5% fat diet plus Sini decotion (4.2 g·kg-1·d-1). At the end of study, the plaque area were measured, the atorta ceramide and cell apoptosis were also detected. RESULTS:Sini decotion diminished lipid plaque area on the aortic endothelium, reduced the levels of aorta ceramide and the apoptosis index. CONCLUSION:Sini decoction has an inhibitory effect on AS, the mechanism may be that Sini decotion reduces concentration of ceramide in aorta.  相似文献   
18.
AIM: To investigate the effect of Chinese herbs, Ganxianfang(GXF), on rat hepatic stellate cells (HSC) proliferation and collagen synthesis. METHODS: Two types of herb serum, portal venous serum and circumferential venous serum, were prepared from rats infused intragastrically with 16, 8, 4 times adult dose of GXF decoction. HSC isolated from rat liver were processed with the above sera in vitro. Then we mensurated the radioactivity of HSC admixed with [[3H]H]proline and [[3H]H]thymine to judge the effect on proliferation and collagen synthesis of HSC. RESULTS: Both two types of serum collected 0.5, 1, 2 h after intragastrical infusion inhibited HSC proliferation (P<0.05), and the serum collected 1 h after intragastrical infusion had the strongest effect (P<0.05). Portal serum decreasea collagen synthesis (P<0.05), but circumferential serum had no effect (P>0.05). CONCLUSION: Inhibition of HSC proliferation and decrease of collagen synthesis may contribute to the GXF antifibrotic action.  相似文献   
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20.
水稻不同品种或组合对甲磺隆耐药性差异的机制研究   总被引:2,自引:2,他引:2  
以水稻乙酰乳酸合成酶(ALS)比活力为研究对象,通过在离体和活体条件下比较其对甲磺隆的敏感性水平,探讨了水稻不同品种或组合的耐药性差异机制。结果表明,离体条件下不同水稻品种或组合ALS对甲磺隆均较敏感,当甲磺隆浓度为100 μg/L时,对ALS比活力抑制率达60%以上,且活力百分比与甲磺隆浓度对数成直线负相关关系,相关程度显著或极显著;活体条件下ALS活力均受到甲磺隆不同程度的抑制,但同一品种ALS活力不随甲磺隆浓度的变化而呈现规律性变化。在甲磺隆浓度相同时,活体条件下所有供试水稻品种ALS活力均显著高于离体条件下的ALS活力,影响程度与植株耐药性差异基本一致,说明甲磺隆在水稻体内存在较强代谢失活作用,代谢失活差异是水稻不同品种或组合对甲磺隆的耐药性差异机制。  相似文献   
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