Application and progress of electron microscope in agriculture
Scanning Electron Microscope (Scanning Electron Microscope, SEM) has the advantages of large depth of field, strong three-dimensional image, high resolution, large image range and relatively simple sample preparation process, which has attracted great attention and attention from agricultural researchers. favor. In order to observe the microstructure and morphology of biological materials with a scanning electron microscope and obtain satisfactory observation results, in addition to mastering the operation techniques of the instrument, it is also necessary to understand the properties and characteristics of biological samples and master scientific sample preparation techniques¨1. The main characteristics of biological samples are high water content, soft texture, and easy to shrivel, shrink, and deform after drying and dehydration. Most biological samples are mainly composed of elements with low atomic numbers such as carbon, hydrogen, oxygen, phosphorus, and potassium, which are not easily excited to generate secondary electrons and have poor electrical conductivity. Scanning electron microscopy requires samples to be dry, free of moisture and other volatile substances, have certain mechanical strength, can withstand certain electron beam bombardment, can generate secondary electrons when excited by incident electrons, and have good electrical conductivity. Therefore, biological samples must be properly processed, and the samples are required to maintain their original appearance as much as possible and meet the requirements of the scanning electron microscope. Many researchers have done a lot of work and accumulated a lot of rich experience in the method and technology of SEM biological sample preparation.
Scanning electron microscopy sample preparation technologies mainly include: surface spraying, critical point drying technology, tissue conductive technology, freeze-drying technology, freeze-cutting technology, immune scanning electron microscopy technology, and low-temperature observation technology. Pay attention to the application of sample preparation technology, improvement and innovation are important links to improve the resolution of electron microscopy. Scanning electron microscopy is mainly used in agricultural scientific research to study the surface morphology and internal structure of different tissues and tiny organs such as animals, plants, microorganisms, and insects, so as to deepen the understanding of their application in physiological functions and explore the life rules of organisms.
For example, in the case of insects, it is mainly to improve the ability to distinguish their tiny organs, improve the level of classification, and at the same time further clarify the functions of organs, describe and compare the characteristics of insects' external forms, and study their shape changes and their regularity and structural characteristics. for a deeper understanding.
