社鼠（Niviventer confucianus）视器结构及辨色能力研究

【作者】 王宁；

【导师】 李金钢；

【作者基本信息】 陕西师范大学 ， 动物学， 2015， 硕士

【摘要】 社鼠在我国分布较广泛,主要栖息在山区和丘陵的灌木草丛以及岩石缝隙中。其食性广泛,取食木本植物的种子和果实、植物嫩叶及部分淀粉类农作物,主要在夜间活动,是一种重要的农林业害鼠。同时社鼠自身含有多种病原体,对疫源区人及兽类的生命安全造成威胁,在流行病学的研究中也占有一定的地位。目前对社鼠的研究主要集中在生理学、行为学以及防治等方面,对社鼠视觉系统的特点及其与社鼠生活习性的相关性研究较少。视觉是动物获取外界信息的重要途径,在动物的捕食、配偶选择及讯息传递等方面均有重要作用,对动物的进化具有深远而广泛的影响,视觉器官是研究动物行为及进化的主要研究对象。视觉包括光觉、色觉和形觉,光觉是色觉和形觉的基础。感光细胞是视觉器官中唯一可接受光并对光敏感的部位。一般地,感光细胞有视杆细胞和视锥细胞两种类型。视杆细胞介导暗视觉,无色觉功能；视锥细胞介导明视觉,具有色觉功能。生物体在进化的过程中表现出对环境的适应性特征,视觉适应即是生物体的感觉器官在视觉生理上的适应性表现,对动物的生存具有重要的意义。目前对啮齿动物视觉的研究主要集中在视觉器官结构、感光细胞的类型和分布、视蛋白、视色素和色觉系统等几个方面。本研究采用组织解剖学、免疫组织化学和行为学方法,主要研究社鼠的视网膜结构、感光细胞类型和分布、辨色能力。旨在探讨社鼠视觉系统的特点及其与社鼠生活习性的相关性,同时可为啮齿动物的视觉进化提供新的理论依据。研究结果表明：1.社鼠视觉器官较大,眼球发育正常,具备眼睑、角膜、巩膜、虹膜、晶状体、脉络膜以及视网膜等结构。视网膜分层明显,与典型哺乳动物的视网膜结构相似。2.社鼠外核层细胞数目与神经节细胞层的细胞数目有差异,两者细胞数目比例为105：1。该比例接近于夜行性鼠的外核层细胞数和神经节细胞层的细胞数目之比,说明社鼠视觉系统与夜行性鼠相似。3.社鼠感光细胞结构完整。感光细胞有视杆细胞和视锥细胞两种类型,视杆细胞的数目远大于视锥细胞。这与社鼠主要在夜间活动相适应。4.社鼠视网膜含有对短波长敏感的S-视锥细胞及对长波长敏感的L-视锥细胞,所以社鼠为二色色觉。S-视锥细胞数目远大于L-视锥细胞,且两种视锥细胞在视网膜上分布不均匀,在视网膜中央区分布较密集,向边缘区呈逐渐递减趋势。视锥细胞的分布与一般夜行性鼠的视锥细胞分布相似。5.在不同波长的光照环境中,社鼠行为产生变化。蓝光环境中,社鼠的运动时间较少,休息时间较多；而在红光环境中,.休息时间较少,运动时间相对较多。说明社鼠可以辨别不同波长的光,具有辨色能力。总之,社鼠的视觉器官结构完整,具有感光能力,视觉系统适应短时间外出。社鼠可以辨别不同波长的光,有一定的辨色能力。社鼠的视觉系统与其生活习性相适应。更多还原

【Abstract】 Niviventer confucianus,as a species of rodents widely distributed in our country, mainly habitat in the mountains, shrubs and bushes of hills and rock crevices. They mainly feed on the seeds, fruits and young leaves of woody plants, as well as some starch crops. They always are active at night. Their feeding habits are wide, so they are harmful agroforestry rodents. Meanwhile N. confucianus itself contain a variety of pathogens, threaten the life safety of people and beasts in epidemic source area. So N. confucianus also occupy an important position in epidemiology study. Now the study of N. confucianus mainly focus on its physiology, behavior, prevention, and so on. Researches on the vision system characteristics of N. confucianus and the correlation between their visual system and living habits are less and unclear. Currently, rodents visual research mostly focuses on the visual organ structure, type and distribution of photoreceptor cells, opsins, visual pigments and color vision systems and other aspects.Vision is an important way for animals to obtain outside information. It plays important role in feeding, mate selection and message passing. It also has profound and extensive influence on animal evolution. So visual organ is the main object in most animal behavior and evolution study. Vision is composed of light sense, color sense and form sense, and the light sense is the basis of other two sense. Photoreceptor cells, as the only part of visual organ who can accept light, are sensitive to light. Generally, photoreceptor cells have two types of cells, rods and cones. Rod cells mediate scotopic vision, have no color vision function. While cone cells mediate photopic vision, have color vision function. In the process of evolution, organisms exhibit of adaptive features on the environment, and visual adaptation is the visual physiological adaptability performance of sense organs, which has vital significance to animal’s survival.With the methods of histology, immunofluorescence and ethology, this research studied the retinal structure, the type and distribution of photoreceptor cells and the ability of color discrimination of the visual system of N. confucianus in order to learn the characteristics of the N. confucianus visual system, make out whether this specie have color discrimination ability and discuss the relationship between the visual system and habit. The results were as bellow:1. The vision organ of N.confucianus is larger with the structure of eyelid, cornea, sclera, iris, lens, choroid and retinal. The ocular growth is normal and the retinal layers are obvious, which is similar to the structure of retina of the typical mammalian.2. We found obvious difference of the cell number between the outer nuclear layer and the ganglion cell layer in N. confucianus, with a proportion of 105:1. This ratio is similar to nocturnal rats’, that is to say, the visual system of N. confucianus is similar to the nocturnal rats.3. The structure of photoreceptor cells of N. confucianus is integral. The photoreceptor cells are composed of rod cells in majority and few cones. The rod cells mediate dark vision while the cone cells mediate photopic vision, which are adapt to the fact that N. confucianus are mainly active at night.4. S-cones (short wavelength-sensitive) and L-cones (long wavelength-sensitive) are included in N. confucianus retina, so N. confucianus is a typical dichromatic color vision rat. The number of S-cone cells is much larger than L-cone cells. The distribution of both cone cells in the retina is uneven as the central area is dense distribution area. There is a trend of decline of cone cells number from the central to the fringe area. The distribution of cones is generally similar to nocturnal mouse.5. Under different wavelengths of light irradiation, N. confucianus act differently. N. confucianus exercise less time and rest more under the blue light, on the contrary, while under the red light irradiation, it rest less and exercise more. This phenomenon state that N. confucianus can distinguish different wavelengths of light with the ability of color discrimination.In summary, the visual organ of N. confucianus is normal, with photosensitive ability, and the visual system adapts to short term ground activity. N. confucianus can distinguish the different spectrum and have the ability of color discrimination. The visual system of N. confucianus get used to its living habits.更多还原