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5种恒定温度下苜蓿斑蚜实验种群生命表的研究 总被引：1，自引：0，他引：1
通过对苜蓿斑蚜Therioaphis trifolii(Monell)实验种群在不同恒定温度下生长与繁殖的观察与统计,组建了苜蓿斑蚜在5种恒定温度(18,20,23,25,28℃)下的实验种群生命表,并对其实验种群参数进行了计算分析。结果表明:在18~28℃,苜蓿斑蚜Therioaphis trifolii(Monell)的发育速度随着温度的升高而加快,单雌一生平均生殖力分别为49.89,64.51,76.42,84.73和64.76头;其净增殖率(Ro)、内禀增长率(rm)和周限增长率(λ)在18~25℃之间均随着温度的升高而提高,在25℃最高,分别为71.802,0.2843和1.3289,到28℃时又下降;而随着温度的升高苜蓿斑翅蚜世代历期(T)在缩短。 相似文献
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宁夏沙坡头人工植被区土壤真菌种群的动态研究(英文) 总被引：5，自引：0，他引：5
[Objective] The changes of fungi in different soil layers and sand dunes of artificial vegetation areas in Ningxia Shapotou during different times were studied. [Method]The number of soil fungi in different soil layers at same plot and in same soil layer at different plots were changed significantly.The quantitative distribution of fungi was the most in Cuiliugou but the fewest in quicksand among all soil types.[Result] The quantity of soil fungi in grasslands was varied in different soil layers at the same sample and in the same soil layer at different sample plots. The quantity of fungi from different soil types distributed mostly in Cuiliugou, a natural desert steppe, but little in quicksand. The species and quantity of fungi in CuiLiugou was the most in different types of sand-fixing lands. [Conclusion] The quantity of soil fungi in artificial vegetation areas raises with the increase of sand-fixing ages, The enhancement of vegetation construction and artificial management measures in inland is helpful for improving present situation of desertification. 相似文献
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在沙坡头人工固沙植被区,调查了掘穴蚁蚁穴密度在不同固沙年代和不同地形的分布,并研究了蚁穴密度与土壤参数的关系.研究结果表明:地形、固沙年代及其互作显著影响掘穴蚁的蚁穴密度.随着固沙年代的延长,掘穴蚁的蚁穴密度增加;不同地形之间的大小顺序为:丘间地>迎风坡>丘顶>背风坡;蚁穴密度与土壤沙粒含量(P<0.05)和土壤容重(P<0.01)呈负相关,与土壤粘粒(P<0.05)、全钾(P<0.05)、CaCO3(P<0.05)、全氮(P<0.01)、有机质(P<0.01)、盐分(P<0.01)和结皮厚度(P<0.01)呈正相关. 相似文献