设施番茄长期连作土壤微生物群落结构及多样性分析

 利用PCR-DGGE 技术，研究了裸地及不同连作年限的设施番茄栽培土壤中细菌和真菌的群 落结构及多样性的变化情况。结果表明：设施条件下种植番茄明显改变了土壤土著细菌的群落结构，但 连作年限对土壤细菌多样性影响较小，细菌群落结构变化不大；土著真菌的群落结构稳定性优于土著细 菌，但土壤真菌的优势种群在不同连作年限的土样中变化较大，连作显著降低了某些真菌的数量，同时 显著增加了另一些真菌的数量，其中，连作20 年番茄的土壤真菌新出现的优势种群最多，且与非优势种 群的真菌数量差异较大，这种番茄连作后改变土壤真菌种群平衡的现象可能是导致番茄产生连作障碍的 重要原因之一。通过电泳条带的回收、测序，可知所取土样中的细菌优势种群属于Clostridium butyricum、 Uncultured bacterium、Bacillus 和Arthrobacter，真菌优势种群属于Saccobolus dilutellus、Uncultured fungus、 Lasiobolus ciliatus、Spooneromyces laeticolor 和Lasiobolidium orbiculoides。

Effect of Long-term Continuous Cropping of Protected Tomato on Soil Microbial Community Structure and Diversity

OBSTRUCT] AIM: To study the mechanisms of acute pulmonary embolism (APE) in rabbits by investigating the cardiac structures and functions through electrocardiography(ECG)-gated 64 slice computed tomography(CT). METHODS: The rabbit model of APE was established by injecting autologous blood clots. ECG-gated 64 slice CT detection was applied before and 2 h, 4 h and 8 h after APE. The left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), right ventricular end-diastolic volume (RVEDV), right ventricular end-systolic volume (RVESV), left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), right ventricular end-diastolic diameter (RVEDD) and right ventricular end-systolic diameter (RVESD) were determined by Volume and View softwares through CT reconstruction. RESULTS: No significant change of LVESV and LVESD after APE was observed. The RVEDV, RVESV, RVEDD and RVESD significantly increased 2 h, 4 h and 8 h after APE. The LVEDV, LVEDD, the left ventricular stroke volume (LVSV) and right ventricular stroke volume (RVSV) decreased 2 h, 4 h and 8 h after APE. The thrombosis in large pulmonary arteries displayed eccentric filling defect, and branch defect was showed in small pulmonary arteries. Compared with the anatomic examination, the accuracy of detecting large artery thrombosis by ECG-gated 64 slice CT was up to 100%. CONCLUSION: Enlarged right ventricle and decreased LVSV and RVSV are the characteristics of APE. ECG-gated 64 slice CT displays the important value in the judgment of the cardiac dysfunction after APE.