糜子叶表面抗旱结构的扫描电镜观察   总被引：1，自引：0，他引：1  

慕芳  冯佰利  王鹏科  高小丽  高金锋  柴岩 《河北农业科学》2010,14(11):65-67

为探讨糜子适应干旱的机理,对糜子叶表面抗旱结构特征进行了扫描电镜观察。结果表明：糜子上下表皮都被有表皮毛,具有发达的角质层,下表皮为粗糙角质层;叶上、下表皮细胞形状规则,细胞表面凹凸明显,由长型细胞、短型细胞组成,基本上顺叶长轴成行排列;在上下表皮都有气孔分布,气孔下陷,但气孔的副卫细胞相对保卫细胞突出。  相似文献   

Effects of Amino Acid By-products on Fermentation Quality and Digestibility of Silage     

NUERHATI&#  Silafuer  MAIMAITITUERSUN&#  Abudukeremu  WUSIMAN&#  Yimiti 《中国畜牧兽医》2007,47(10):3183-3192

This study was conducted to investigate the effects of amino acid by-products(ABP) on fermentation quality and digestibility of red sorghum and sweet corn,and explore the mechanism of action by scanning electron microscopy(SEM).There was a control group without additives,an experimental group Ⅰ with 2.0% ABP,and an experimental group Ⅱ with 2.0% ABP mixed with forage fungus for red sorghum and sweet corn,respectively.The results showed that:①2.0% ABP reduced the pH of red sorghum and sweet corn silage to 3.90 and 3.28 respectively,and they were belonged to the high-quality silage range by sensory evaluations.②For the red sorghum silage,compared with the control group,the dry matter (DM) contents of the experimental groups were slightly increased,but the difference were not significant (P>0.05),while the crude protein (CP) contents were significantly increased (P<0.05).The fiber content of the experimental group Ⅱ was slightly lower than the control group,but the difference was not significant (P>0.05).The lactic acid and acetic acid contents of experimental groups were significantly higher than that of control groups (P<0.05).The content of butyric acid in experimental group Ⅱ was significantly lower than that of the other groups (P<0.05).The dry matter and neutral washing fiber (NDF) digestibilities of the experimental groups were higher than the control group,but the difference were not significantly (P>0.05),and acidic washing fiber(ADF) digestibility was significantly higher than control group (P<0.05).③ For sweet corn silage,the dry matter and fiber contents of experimental groups were lower than those in the control group,but the differences were not significant (P>0.05),the crude protein content was significantly higher than the control group (P<0.05).The lactic acid content of the experimental group Ⅰ was significantly higher than the other groups (P<0.05),the acetic acid content of experimental group Ⅱ was significantly higher than that of the other groups (P<0.05),and the butyric acid content of each experimental group was significantly higher than the control group (P<0.05).The digestibilities of the experimental groups were lower than the control group but higher than the raw materials,and the differences of dry matter and acid washing fiber digestibilities were significant (P<0.05).④SEM results showed that ABP promoted the adhesion of forage bacteria by destroying the waxy layer on the surface of red sorghum silage,and degraded the cell wall fiber components to improve the quality of the silage fermentation and improve the digestibility during the silage process.But the destructive effect of ABP on sweet corn silage was not obvious.In conclusion,the addition of ABP could improve the fermentation quality and digestibility of red sorghum,but the effect on sweet corn silage was not obvious.  相似文献   

荔枝、龙眼叶片表皮结构的研究   总被引：1，自引：0，他引：1  

王心燕  何惠玲  肖德兴 《园艺学报》2006,33(4):825-828

 用扫描电镜观察了荔枝、龙眼各3个品种的叶表皮。结果表明, 龙眼叶片上表皮角质层平均厚度2.36μm , 显著大于荔枝(1.93μm) 。荔枝、龙眼叶片下表皮具有大量的乳状突; 乳状突的密度, 荔枝为7 855.1个/mm² , 龙眼为7 708.8个/mm² ; 荔枝的乳状突呈近半圆形, 宽9.55μm, 高5.71μm; 龙眼的乳状突为长形, 宽5.94μm, 高10.38μm; 荔枝、龙眼气孔长×宽分别为6.98μm ×3.09μm、7.14μm×2.30μm。荔枝、龙眼表皮结构特征差异明显。  相似文献   

Microvasculature of the hamster eye: scanning electron microscopy of vascular corrosion casts   总被引：1，自引：1，他引：0  

Ninomiya H  Inomata T 《Veterinary ophthalmology》2005,8(1):7-12

The architecture of the retina, choroid and anterior eye segment was investigated in 12 Syrian hamsters using scanning electron micrographs of methylmethacrylate corrosion casts. The hamster eye receives its primary blood supply from the long posterior ciliary artery, which directly enters the optic nerve head, and divides into three branches: the central retinal artery and medial and lateral long posterior ciliary arteries. In the retina the central retinal artery divides into six radiating branches. Retinal arterioles form a slender and long course to capillaries. Retinal capillaries are extremely thin in diameter and form a sparse capillary network. The choroid is supplied by the long posterior ciliary arteries. Choroidal arterioles exhibit a thick and short course to the choriocapillaris. The choriocapillaris is thick and sinusoid-like, forming a dense network in the choroid. The ciliary body, iris and bulbar conjunctiva are supplied by the anterior ciliary arteries, which are branches of the long posterior ciliary arteries. Capillaries supplying the anterior margin of the ciliary process are large in diameter with an irregular bore, forming a thoroughfare channel draining blood in the ciliary arterioles into the pars plana vessels. Blood from the retina is drained by the central retinal veins. Venules from the anterior eye segment empty into the vortex veins via the pars plana vessels. Venous blood from the choroid is drained only by vortex veins via the choroidal veins. The functional significance of the vascular architecture and species differences are discussed.  相似文献   

Effects of starch composition and type of non-solvent on the formation of starch nanoparticles and improvement of curcumin stability in aqueous media     

《Journal of Cereal Science》2017

In this study, we evaluated the effects of amylopectin/amylose ratio and non-solvent type on starch nanoparticle formation including the average particle size, polydispersity index, size distribution, and nanoparticle morphology using dynamic light scattering (DLS) and scanning electron microscopy (SEM). The most uniform particles were obtained from normal corn starch with ethanol. The average particle size was 98.8 ± 1.8 nm using DLS while combination of size distribution study and SEM images showed that particle size ranged between 60 and 90 nm. A bimodal distribution was observed with two defined groups of nanoparticles when waxy corn starch (Amioca) was nanoparticulated with ethanol. SEM images of freeze dried samples and DLS size distribution curves of fresh samples showed that high amylose starch including Hylon V and Hylon VII gave uniform, spherical and small nanoparticles in the size range of 20–60 and 15–50 nm, respectively. The smallest nanoparticles were fabricated by precipitation with methanol, followed by ethanol and the largest nanoparticles were formed using acetone. Re-dispersion of nanoparticles was good when nanoparticles were fabricated using ethanol and acetone especially for Amioca, whereas redispersion of samples in aqueous PBS solution, precipitated using methanol was difficult especially in the case of Hylon VII. Stability of curcumin in the presence of 1 mg/ml native starch nanoparticles was much higher (83.7 ± 3.1%) than curcumin in phosphate buffered saline at pH 7.0 (5.5 ± 1.5%) over 10 days at ambient temperature. Interaction between iodine-potassium iodide solution and starch nanoparticles showed that the helical structures of amylose and amylopectin molecules remain in the nanoparticles and curcumin may interact with these helical structures giving it the stability which is not observed in water.  相似文献   

Visitors’ and residents’ perceptions of urban forests for leisure in Washington D.C     

《Urban Forestry & Urban Greening》2017

While there is an increasing number of studies on the experience of urban forests, few have examined the similarities and differences between first time visitors, repeat visitors, and local residents in their perceptions of urban forests for leisure. This study fills this research gap using Analysis of Covariance (ANCOVA) and Structural Equation Modeling (SEM), based on data collected on-site from a year-long survey of 1090 participants in Washington D.C. Results indicate that participants are generally positive on urban forests’ value for leisure and are highly satisfied with their leisure experience in the city, with “beliefs in parks and gardens” and “beliefs in street trees” being assessed the highest and lowest, respectively. The study also finds that interaction effects do exist between gender, season, location, and past experience, suggesting respondents’ visiting experience with urban forests is multidimensional, contextual, and situational. Specifically, the older the respondents are, the more positive their responses would be. A location with diverse and dense urban forests is more likely to stimulate positive perceptions, particularly for first timers. In addition, residents tend to focus on recreational aspects of urban forests as opposed to visitors, especially repeaters who are more likely to value the visual and aesthetic aspects of urban forests. This is not only evidenced by the ANCOVA results whereas fall and summer, the best seasons for pursuing outdoor activities, are highly positively perceived by residents, but also by the SEM analyses which show that street trees significantly contribute to repeaters’ satisfaction via their perceptions of “leisure value of urban forests” while no such relationship exists for first timers and residents. Urban parks and gardens are found to significantly and positively contribute to respondents’ visiting experience, which, in turn, leads to satisfaction for each respondent group. Finally, research limitations and theoretical, methodological, and managerial implications are discussed.  相似文献   

基于结构方程模型的农民专业合作社性质漂移研究———以河南省为实证     

赵黎明 《广东农业科学》2014,41(23):215-220

利用结构方程模型,分析了影响农民专业合作社性质漂移的综合因素.结果表明,农民专业合作社自我服务性质的各观测变量产生了显著的共变关系,对合作社性质漂移的影响显著,而表现农民专业合作社民主控制的各观测变量没有产生共变关系,对合作社性质漂移产生的影响不显著.合作社成员异质性影响到了合作社性质的漂移,但合作社的性质漂移没有造成合作社成员的异质性,即二者没有产生相互的影响作用.  相似文献   

柞蚕丝素粉多孔性结构的电子显微镜观察     

付田霞  王学英  李群  杨金琛 《沈阳农业大学学报》2005,36(4):485-487

柞蚕丝具有多孔性结构。将脱胶后的柞蚕丝经物理及化学方法处理，控制反应时间以制得水解程度不同的柞蚕丝素粉：用扫描电子显微镜及透射电子显微镜观测不同水解时间的柞蚕丝紊粉孔径的大小、分布及形状。研究结果发现，物理粉碎及磷酸水解2h以内制得的柞蚕丝素粉内部均具有多孔性结构。  相似文献   

吉林省绣线菊属花粉形态的研究   总被引：1，自引：0，他引：1  

杜凤国  刘玉安  厉锡亮  王守军  张运吉 《吉林林学院学报》1994,(3)

本文对吉林省绣线菊属的９种花粉用光学显微镜和扫描电子显微镜进行了观察和照相，并对它们进行了统计学上的光学测量，详细描述了各种花粉的形态特征，编制了分种检索表，从而为绣线菊属的分类以及该属在蔷薇科中进化上的位置提供了孢粉学方面的资料。  相似文献   

芸苔属作物种皮形态学研究   总被引：3，自引：0，他引：3  

胡东维  蒋选利  姚雅琴  王居仓 《西北农林科技大学学报(自然科学版)》1990,(Z1)

用扫描电镜对芸苔属作物6种4变种,32个品种的种皮表面纹饰进行了系统研究。结果表明,种皮表面纹饰可分为基本网纹与次要网纹,利用这两种网纹的特征,可以将绝大多数种或变种区分开,并能对某些作物的部分品种进行鉴定,同时把其它品种分成多组;种皮纹饰较花粉形态具有更高的分类价值。本文还就不同作物间的进化关系及种皮纹饰在种子鉴定方面的应用问题进行了讨论。  相似文献