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71.
    
Plant pathogens cause substantial crop losses annually, posing a grave threat to global food security. Fungicides have usually been used for their control, but the rapid development of pesticide resistance renders many ineffective, therefore the search for novel and efficient green pesticides to prevent and control plant diseases has become the top priority in crop planting.  相似文献   
72.
家兔亚硒酸中毒的病理形态学研究   总被引:1,自引:0,他引:1  
给家兔分别肌肉注射不同剂量的亚硒酸钠,历时入周,复制出亚急性硒中毒的动物模型。病理形态学变化为:家兔的生长受到明显抑制,肝,肾,心,脾等组织器官损害严重如肝实质细胞变性,坏死;肾实质退行病变;心肌纤维变性,充血,肺淤血,水肿:脾萎缩,淋巴细胞坏死,肝,肾,心细胞内线粒高度肿胀,嵴减少,断裂或消失成空泡。  相似文献   
73.
利用可见/近红外光谱技术对梨枣轻微损伤的分类判别建模方法进行研究。分别采用PLS-LDA(线性)和LS-SVM(非线性)建立判别模型,分析比较不同预处理方式和建模波段对模型精度的影响。结果表明:经9点平滑预处理后的短波近红外(780~1100nm)PLS-LDA模型判别效果最佳,校正集和预测集的正确识别率分别达到97.8%和96.7%。  相似文献   
74.
75.
Subclinical endometritis is a physiological inflammation that serves to clear persistent contaminants from the uterus. To investigate the alteration of antioxidant, such as vitamin E(VE) and vitamin C(VC), total oxidant capacity(TOC) and nitric oxide(NO) in cows with normal and subclinical endometritis(SCE), we examined the concentrations of NO, VC and VE, TOC and polymorphonuclear neutrophils(PMN) percentage in uterine secretion. The cows were divided into two groups, normal(n=20) and subclinical endometritis(SCE, n=60), based on endometrial cytology(presence of PMN≥5%). Uterine secretion and blood were collected as described previously. Griess reaction was used to determine the concentration of NO. The concentrations of TOC, VC and VE were detected by a commercially available assay kit. The results showed that the concentrations of NO, TOC and PMN percentage were significantly higher(P0.01, P0.05, and P0.01, respectively) in uterine secretion with SCE compared to those from normal; however, the levels of VC and VE were significantly lesser(P0.01). In conclusion, the concentrations of NO, TOC, VC, VE and PMN percentage differed between normal and SCE cows. Meanwhile, the relationship between the concentration of NO and PMN percentage from uterine secretion in cows with subclinical endometritis were positively correlated. Consequently, these alterations in NO, TOC, VC, VE levels and PMN percentage contributed to as a diagnostic index of the uterine inflammation, with the aim to increase the reproduction of the cows and the decrease economic losses.  相似文献   
76.
依据犬的大脑皮层的兴奋和抑制过程的强度、均衡性和灵活性,及其相互关系来分类,可把犬分为兴奋型、活泼型、安静型和弱型四种神经类型。  相似文献   
77.
    
Husk number (HN) and husk length (HL) influence the mechanical harvesting of maize grain. We investigated the genetic basis of HN and HL using a population of 2...  相似文献   
78.
The batch sorption experiments were carried out using a novel adsorbent, freshwater macrophyte alligator weed, for the removal of basic dye malachite green from aqueous solution. Effects of process parameters such as initial solution pH, contact time, adsorbent concentration, particle size, and ion strength were investigated. The adsorbent was characterized by FT-IR. The adsorption of malachite green by alligator weed was solution pH dependent. The adsorption reached equilibrium at 240 min for two particle size fractions. The pseudo-first-order equation, Ritchie second-order equation, and intraparticle diffusion models were tested. The results showed that adsorption of malachite green onto alligator weed followed the Ritchie second-order equation very well and the intraparticle diffusion played important roles in the adsorption process. The Langmuir and Freundlich equations were applied to the data related to the adsorption isotherms and the observed maximum adsorption capacity (q max) was 185.54 mg g?1 at 20°C according to the Langmuir model. The effects of particle size, adsorbent concentration, and ionic strength on the malachite green adsorption were very marked. The alligator weed could serve as low-cost adsorbents for removing malachite green from aqueous solution.  相似文献   
79.
80.
    
When a cut slope is excavated, the ecological environment in the footprint is destroyed. Soil spray seeding technique is used for the ecological rehabilitation of cut slopes in the mountain areas of Southwest China. However, there have been few studies of the temporal variation in soil phosphorus (P) fractions during the rehabilitation of the cut slopes. In this study, time-dependent changes in soil inorganic P (Pi) and organic P (Po) fractions of the cut slopes were assessed at selected post-rehabilitation ages (i.e., 1 year, 1a; 3 years, 3a; 5 years, 5a; and 11 years, 11a). The results showed that the amounts of Pi and Po fractions in soils on rehabilitated cut slopes varied with time. The reduction in the total Po (TPo) content was mainly caused by the change in high concentration hydrochloric acid-soluble Po (HHCl-Po) in the soil. The reason for the highest TP content in 3a was the addition of inorganic fertilizer and straw in the artificial soil. The analyses of Pearson correlation and multiple stepwise linear regression showed that TPo and N:P were the main factors affecting the availability of soil P. With the increase in the post-rehabilitation age, the limitation of soil P gradually weakened, but nitrogen became one of the limiting factors for plant growth. Overall, soil nutrient monitoring is very important for vegetation restoration of the cut slopes. Applying organic fertilizer after 5 years of ecological rehabilitation is conducive to long-term supply of nutrients required for plant growth.  相似文献   
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