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通过微卫星标记技术对中国西南地区5个家鸭资源群体(云南麻鸭、三穗鸭、兴义鸭、建昌鸭、四川麻鸭)的遗传结构进行评估。结果表明:5个群体的平均杂合度都较高,最低的为四川麻鸭,最高的为三穗鸭,杂合度范围为0.567 9~0.616 5,群体平均杂合度为0.587 4;各鸭种间存在较大的遗传分化,19.86%的遗传变异来源于群体间的差异。5个家鸭群体间的DA遗传距离较远,分化时间较长;NJ聚类结果表明5个家鸭资源聚为3类,聚类结果与这5个鸭种的地域分布和经济用途有一定关系。 相似文献
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不同覆盖方式对旱作马铃薯生长及土壤水热特征的影响 总被引:1,自引:0,他引:1
【目的】探讨不同覆盖方式对西北旱作区农田土壤水热和马铃薯生长的影响。【方法】2015—2016年连续2年设置沟垄地膜全覆盖(DD)、沟垄地膜半覆盖(DB)和沟垄二元覆盖(DJ)3种覆盖方式大田试验,以平作不覆盖为对照(CK),研究不同覆盖方式下土壤水温变异特征及对马铃薯生长及块茎形成的影响。【结果】覆盖处理全生育期0—200 cm土层土壤含水量均高于CK,DJ处理在播后70—90 d土壤保水效果最佳。覆盖能降低0—200 cm土层土壤水分变异系数,以DJ处理的土壤水分垂直稳定性最强。与CK相比,DD处理在播后30—50 d的0—15 cm土层土壤增温效果显著,而DJ处理在全生育期0—25 cm土层土壤温度表现"降温和增温双重效应"。各覆盖处理能降低0—25 cm土层土壤温度变异系数,以DJ处理最小,其土壤温度垂直稳定性最强。覆盖能提高马铃薯出苗率和影响出苗天数,其中DD处理平均出苗天数较CK提前4.5 d,而DJ处理推迟3.5 d。马铃薯生育期生物量累积动态变化符合Logistic生长模型,以DJ处理生物量理论值和生长速率最大,快速生长持续期最长。通过主成分分析发现,除马铃薯生物量、单... 相似文献
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西北地区东部耕作层土壤湿度近22年变化分析 总被引:3,自引:1,他引:2
利用西北地区东部17个测站1981~2002年3~10月固定地点测得0~30 cm土壤湿度资料,分析了近22 a来西北地区东部耕作层土壤湿度的空间变化和时间变化。结果表明:土壤湿度自西南向东北减少;1981~2002年呈现明显下降趋势,20世纪80年代前半期处于峰值;湿度变化大多有5~6 a的周期,1986~1988年为较为一致的干旱时期;春、夏、秋三季中春季湿度最小,秋季最大;22 a中春、秋季湿度下降明显,显著减少区位于陇中。 相似文献
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为探究LED水下集鱼灯光色、功率、放置深度和海水叶绿素质量浓度对光场分布的影响,基于蒙特卡罗模拟方法建立了水下光束传输数值计算模型,通过控制变量法计算了不同条件下的水下光场分布,并提出以0.1~10.0 lx等值线所包围的面积与计算截面面积比值为相对有效光照范围(relative effective illumination range, REIR)。以REIR为评价指标,对不同条件下的光场分布进行了分析。结果显示:(1)相同功率条件下,REIR依次为绿光>白光>蓝光,以功率420W、叶绿素质量浓度0.1mg/m3为例,3种光色的REIR比值为1.58∶1.31∶1;(2)相同光色条件下,当叶绿素质量浓度为0.1mg/m3时,集鱼灯功率由420W增至1200W,蓝、绿、白3种集鱼灯的REIR分别由31.68%、50.27%、41.78%增至38.59%、56.91%、50.15%,功率增加近3倍,但REIR增幅有限;(3)随着集鱼灯放置深度增加,REIR先增加后稳定;以叶绿素质量浓度1.0mg/m3、功率为4... 相似文献
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AIM:To investigate the expression of Th1-typed cytokine IFN-γ and Th2-typed cytokine IL-4 on T lymphocytes that infiltrate in nasal polyps for searching the pathogenesis of nasal polyps. METHODS:Nasal polyps tissue samples and peripheral blood were obtained from 21 patients. Normal human inferior turbinate mucosa and peripheral blood were obtained as well. Flow cytometry was adopted to detect the expression of IFN-γ and IL-4 of T lymphocytes. RESULTS: Th cytokines were rarely detected in inferior turbinate from normal human. Nasal polyps tissue consisted of abundant T lymphocytes. The expression of IL-4 and IFN-γ increased in peripheral blood from patients compared with normal human (P<0.05). The expression of IL-4 increased but the expression of IFN-γ decreased in nasal polyps compared with that of peripheral blood from the same patient (P<0.05). CONCLUSION:There were generous of T lymphocytes infiltrating in nasal polyps. There was abnormal immune status in the local nasal mucosa from the patients, and the predomination of Th cytokine secretion changed compared with peripheral blood from the same patients, which resulted in the change of microenvironment of nasal mucosa and possibly close related to the formation of nasal polyps. 相似文献
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EGF in mouse neurons LI Juan WANG Li CHEN Rong LIU Xiao-yan MEI Zhi-qiang HE Tao 《园艺学报》2011,27(4):779-782
AIM: To explore the mechanism of signaling transduction and cross talk between cholecystokinin octapeptide (CCK8) and epidermal growth factor (EGF) in mouse neurons and to observe the effect of CCK8 in coordination with EGF on neuron growth and cell viability. METHODS: For determining which kind of CCK receptor mediated the phosphorylation of EGF receptor, the cultured neurons were randomly divided into control group, CCK8 stimulation group, CCKA receptor antagonist group, CCKB receptor antagonist group, and CCKA+CCKB receptor antagonist group. Control and stimulation groups were stimulated with DMEM and CCK8 (10-7 mol/L) for 5 min, respectively, while antagonist groups were pre-incubated with different types of receptor antagonists (10-8 mol/L) for 10 min and followed by stimulating the neurons with CCK8. For observing the effect of CCK8 and EGF on the phosphorylation of EGFR in neurons and on neuron growth and cell viability, the cultured neurons were randomly divided into control group, CCK8 stimulation group, EGF stimulation group and CCK8+EGF stimulation group, which were stimulated with DMEM, CCK8 (10-7 mol/L), EGF (40 μg/L) and CCK8+EGF for 5 min, respectively. Reactions were terminated by freezing the neurons in liquid nitrogen and the phosphorylated EGFR was detected by Western blotting. Meanwhile, the viability of the neurons was observed by MTT method after stimulated for 24 h, 48 h, 72 h and 96 h. RESULTS: The phosphorylation levels of EGFR were decreased in the neurons treated with either of the two CCK receptor antagonists, and more obvious decrease was observed when the two CCK receptor antagonists were used in combination. Compared with control group, the phosphorylation levels of EGFR in the neurons were significantly increased(P<0.05) after stimulated with CCK8 or EGF, and the increase was more remarkable in CCK8+EGF stimulation group. CCK8 or EGF improved the viability and prolonged the life span of the neuron, and synergism of these two reagents was observed. CONCLUSION: Both CCKA and CCKB receptors are involved in the phosphorylation of EGFR in the neurons stimulated by CCK8, and the type A receptor may play a more important role. There is cross-talk between CCK8 and EGF signaling pathways in neurons. The signaling cross-talk between CCK8 and EGF may be the underlying molecular mechanism responsible for the synergistic effect on the neuron growth and viability in vitro. 相似文献
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