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排序方式: 共有4412条查询结果,搜索用时 15 毫秒
1.
利用祁连圆柏整株生物量与生长指标数据,为估算祁连圆柏林的生物量估算提供参考。通过野外调查,共获取了63株祁连圆柏天然林样木生物量与生长指标实测数据。用其中50株样木数据进行回归模拟,用其余的13株样木数据对模型可靠性进行检验,构建器官生物量与生长指标间的回归模型。结果表明,祁连圆柏单木水平下,树干生物量模型的R2adj为0.96,均方根、模型有效性和残差系数分别为0.50、0.85和0.05;枝条生物量模型的R2adj为0.897,均方根、模型有效性和残差系数分别为0.69、0.80和-0.66;叶生物量模型的R2adj为0.61,均方根、模型有效性和残差系数分别为0.54、0.86和0.15;根生物量模型的R2adj为0.93,均方根、模型有效性和残差系数分别为0.12、0.997 和-0.01。在调查数据范围内构建的模型较好地反映了祁连圆柏生物量与生长指标间的关系,形式简单、使用方便;与实测值相比,树干与叶生物量模拟值偏小,枝和根偏大。 相似文献
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覆盖免耕在休闲期的节水和生育期的调温效应 总被引:10,自引:2,他引:8
对免耕覆盖、秸秆还田和常规耕作在休闲期的节水效果研究表明:在夏季休闲期,免耕覆盖比常规耕作多贮水30.62mm,比秸秆还田多23.91mm;在冬季储水灌溉期间,可将储水定额从2100m3/hm2减少到600和975m3/hm2。对春小麦生育期土壤表层,5、10、15、20和25cm处温度变化观测发现:免耕覆盖土壤温度在气温较低的8:00可以提高土壤表层温度,在气温较高的14:00可以减缓土壤温度的升高,而在19:00气温降低时可以减缓土壤温度的降低,使土壤温度一直保持在一个稳定的状态,这有利于调节农田小气候,创造作物良好的生长环境。 相似文献
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中国香瓜与菜瓜地方品种资源白粉病抗性评价 总被引:5,自引:0,他引:5
春秋2个季节在温室利用风媒接种方法对搜集的102份香瓜和14份菜瓜种质资源进行了白粉病抗性评价,结果鉴定出7份香瓜和1份菜瓜高抗白粉病,其病情指数为零,1份菜瓜抗病,其病情指数0.9,表明我国香瓜和菜瓜地方品种资源中蕴涵着潜在的改良甜瓜白粉病抗性的基因资源。 相似文献
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AIM:To determine the effects of Angiotensin II(AngII) on migration of rat smooth muscle cells and to investigate the mechanisms underlying Ang II action in the development of injured vascular disease. METHODS:VSMCs isolated from aortic media of Wistar rats and cultured by the modified explant method were adopted. In prersence and absence of AngII, the expression of AngII receptor and reorganization of the actin cytoskeleton of VSMCs were studied by immunocytochemistry technique, fluorocytochemistry technique. The migration assays were performed by a modified Boyden's chamber. And the effects of AT1R antagonist (CV-11974), AT2R antagonist (PD123319) on aforementioned target were studied.RESULTS:VSMCs migration was stimulated by addition of AngII. The dynamic reorganization of actin cytoskeleton may be an important mechanism by which AngII facilitates VSMC motility. The expression of AT1R in VSMCs can be upregulated after treatment with AngII initially, then decreased gradually. The expression of AT1R was downregulated by AT1R antagonist. The effect of AngII on VSMCs migration was mediated by AT1R, while AT2R had no significant effect.CONCLUSION:The dynamic reorganization of actin cytoskeleton is required for AngII-induced VSMC migration, and this effect is mediated by AT1R . 相似文献
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Nitric oxide (NO) and matrix metalloproteinases (MMPs) are important in vascular remolding, especially in abdominal aortic aneurysm. NO may be associated with aneurysms by modulating MMPs expression and activity. 相似文献
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XUE Ying-sheng WANG Jing-feng NIE Ru-qiong WU Wei-kang LUO Han-chuan CHEN Xiao-wei 《园艺学报》2004,20(4):603-607
AIM: To investigate the influence of Sini decoction (SND) on the proliferation and apoptosis of rabbit abdominal aorta smooth muscle cells after ballon injury and discuss the effect of vascular smooth muscle cell's (VSMCs) proliferation and apoptosis in post-percutaneous coronary intervention (PCI) restenosis (RS) and the feasibility of SND preventing post-PCI RS. METHODS: The animal model of rabbit abdominal aorta ballon injury was set up and the therapertic group was treated with SND. The shape of proliferative and apoptotic cell were investigated by electron microscope. Immunohistochemistry staining was performed using α-actin,PCNA and Cyclin E monoclonal antibodies. In situ Cell Death Detection Kit was used to identify apoptotic cells. Abdomial aorta angiography was operated in the 84th day subgroup and the stenosis degree was evalued by quantitative angiographic analysis. RESULTS: As compared with the control group, the therapeutic group displayed a lower proliferative percentage and a higher apoptosic percentage (P<0.05). Moreover, the apoptosic peek time was on the 14th day after operation,which was longer than the control group. CONCLUSION: SND effectly inhibited the proliferation of VSMCs and iuduced apoptosis in VSMCs. 相似文献
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