Morphological observation of fungi from plant diseases

plant diseases are divided into three categories: bacterial diseases,
eccum bacteria
diseases and viral diseases, of which fungal diseases account for about 95% of plant diseases. The source
microorganisms
infected plants, resulting in serious effects on the normal physiological function of host plant cells and
tissues
, and caused lesions. That is, abnormal changes in the shape, physiology and growth of plants, which can lead to local damage to plants or the death of whole plants, resulting in the loss of plant product quality and yield.
fungi are widely distributed, a wide variety, has been reported nearly 45,000 kinds, is the most important group of plant pathogens, it causes diseases accounted for more than 80% of plant diseases, although the fungal form is very different, but the basic structure is similar, most fungi have nutrients and reproduction, nutrients refers to the absorption of nutrients organs, reproduction refers to various types of spores produced from nutrients.
the mechanism by which fungi produce spores, whether tangible or asethile, collectively referred to as sub-entities. Fungal spores are divided into asexual and sexual spores.
asexual spores have swimming spores, spore spores, spores, and thick spores; The morphological characteristics of fungal spores are an important basis for identification and taxonomy, and their nutrients and their perverts and bacterial tissues are important references for fungal classification, and some are important for identifying characteristics and classification.
First, the experimental purpose
through this experiment familiar with the fungal nutrients and the basic form of reproduction, for the future fungal disease pathogen identification and fungal classification to lay a preliminary foundation.
, experimental principle
the nutrients of mold are branched silky bodies. Its individuals are much larger than bacteria and line-out bacteria, divided into sterilization and gas-based mycelium. The breeding silk can be differentiated in the gas mycelium. The reproductive mycelium of different molds can form different spores. Mold mycelium is thick, cells are easy to contract and deform, and spores are easy to fly away, so the specimen is commonly used in lactic acid charcoal acid cotton blue dyeing solution.
This dye made of mold specimen is characterized by: cells do not deform, with bactericidal anti-corrosion effect, and not easy to
dyrive
, can be maintained for a long time, the solution itself is blue, there is a certain dyeing effect. Using
culture
mold on cellulo as an observation material, we can get clear, complete and maintain the natural state of mold form, or we can directly pick the mold system leaching tablets growing in the tablet to observe.
This, content, materials and methods
(i) the nutrients of fungi
1. Mycelium and mycelium
in addition to a few primitive groups, the typical nutrient of fungi is a very small filament, this filament is called mycelium, growing into a clump of mycelium called mycelium, the mycelium of low-class fungi is insular, most fungi are isolated.
(1) select potato late-oncology bacteria (Phytophthora infestans) or Pythium aphanidermatum to be filmed without screening for sterile filaments.
(2) selected Rhizoctonia solani filming lenses to detect mycelium.
(3) observe the formation of various pathogenic fungi on the plane and slope
plant medium
of the bacteria, pay attention to the size, shape, thickness, texture, color and other morphological characteristics of the fall.
2. Mycelium
Some fungal mycelium, under certain conditions or at a certain stage of development, can form a special tissue, commonly has a bacterial nucleus, sub-constellation and root-like mycelium.
(1) Microcycle: The microcycle is a kind of sleeping body formed by thin wall tissue and loose silk tissue, which is not only the organ of fungus storage nutrients, but also the sleeping mechanism used by fungi to get through the bad environment, the nucleus size is different, the color and shape are different. The mycelium tissue in the micronuclear core has been differentiated phenomenon, the skin tissue cells are arranged closely, the color deep wall thick, has the protective effect, is the thin wall tissue, the inner cell wall is thin, the arrangement is loose, can still maintain the nutritional effect, is the loose silk tissue.
The naked eye observed the samples of wheat horn disease, rape bacteria nucleosis, cucumber bacteria nucleosis and onion bacteria nucleosis, comparing the shape, size and color of the microcycles;
(2) Substation: A sub-seat is a cushion-like structure of a sub-body formed by thin-walled and loose tissue, or a prosthetic constellation called a combination of mycelium and part of the host tissue. A constellation is a transition mechanism of a fungus from a nutrient to a reproductive body, which, in addition to forming sub-entities on or within it, also has the effect of weathering a bad environment.
looked at the spores of the Ustilaginoidea virens with the naked eye, and examined the sub-constellations formed by valsa mali and Epichloe typhina, paying attention to the constellation shape, the living site and the type of internal reproduction.
(3) root-like mycelium: a small number of higher fungal mycelium can also be tangled into rope-like tissue, shaped like the root of higher plants, so called root-like mycelium, its role is to help the spread of bacteria and resist the adverse environment, genosome tissue also has a skin and internal tissue differentiation.
the outer shape of the root-like bacterial rope on the forest with the naked eye, pay attention to the comparison with the nucleus, and find out the difference between the two.