Observation of plant pathogenic bacteria and their pathogenic symptoms

1. Experimental Purpose
Bacteria are another important kind of pathogens that cause plant diseases, although not as numerous as plant pathogens
ethogy
species, but because of their small individuals, the difference in morphology is not obvious enough, the resulting disease symptoms are complex, all bring some difficulties to the study of bacterial diseases, the form of pathogenic bacteria Observation and classification identification needs unique experimental techniques, through this experiment, mastering the classification and identification of plant bacterial diseases needs unique experimental techniques, familiar with the types of plant bacterial disease symptoms and the basic form of pathogenic bacteria, learning the simple diagnosis methods of plant bacterial diseases and the procedures and techniques for the initial identification of pathogenic bacteria, for the correct diagnosis of plant bacterial diseases and the classification and identification of pathogenic bacteria lay a good foundation.
II, content, materials and methods
(i) Symptoms of bacterial diseases in plants observed
symptoms of bacterial diseases in plants are often used as an auxiliary symptom of the identified genus, i.e. there is a certain correlation between the type of symptoms and the genus of the pathogen, such as the bacteria of the genus Lollipop. Withering symptoms; the genus prosthetic monocytobacteria mainly causes leaf spots, decay and wilting symptoms; the genus jaundial monocytobacteria mainly causes leaf spots and leaf withering symptoms; the wild bacillus genus causes progeny symptoms such as tumors; and the Eugenic genus generally causes soft decay and sometimes wilting.
In addition, most bacterial diseases in the early stages of the disease, especially in the wet natural conditions often appear water immersion or oil stains, in saturated humidity on the spot often bacteria pus formation, dry become bacteria, master the type of symptoms (attached 1) and its ecological conditions, the correct diagnosis of bacterial diseases is very important. Observe the following disease specimens to distinguish between symptom types.
rice white leaf disease (Xanthomonas oryzae)
cotton bacteria horn plaque disease (X.malvacearum)
potato cyclosis (Clavibacter sepedonicum
cabbage soft rot (Erwinia carotovora)
cucumber bacteria horn plaque disease (X.malvacearum)
apple root cancer (Agrobac)
apple root cancer (Agrobac). tumefaciens)
soy bacterial spot disease (P.glycinea)
pick bacterial perforation disease (X.pruni)
vegetable bean bacterial leaf burning disease (X.phaseoli)
rice plaque disease (X.oryzicola)
(ii) plant bacterial disease easy diagnosis
plant bacterial disease diagnosis and pathogen identification is more complex, The initial diagnosis is based on symptom characteristics and
microscope
segnosis of bacteria in the disease
tissue
to complete, bacterial diseases, with the exception of a few (such as apple root cancer), the vast majority of the affected site in the maintenance bundle or thin wall cell tissue can produce a large number of bacteria, and water absorption to form a bacterial overflow, therefore, the mirror disease tissue has a large number of bacteria (the emergence of bacterial overflow) is an easy way to diagnose bacterial diseases.
Take the new disease leaves of rice white leaf disease, cut 2×2 mm small disease tissue at the junction of disease spot disease, put it on the slide, add a drop of distilled water, cover the glass, immediately under the microscope to observe, pay attention to whether there are a large number of bacteria at the branch of the leaf tissue, cloud-like overflow, such as the field of vision dim observation is easier to see, according to the same method of healthy tissue for anti-examination.
(iii) Plant pathogenic bacterial morphological observation and species identification
the individual bacteria are very small, regardless of morphological observation or species identification, must be dyed before they can be observed clearly under the microscope, plant pathogenic bacteria are currently found only five genus: genus identification is mainly based on the Gram staining reaction, the number of whiplash and the place of birth, the color of the bacteria and the resulting disease symptoms.
1.
Culture
Observations
Rice White Leaf Withered Bacteria (X.oyzae), Potato Cyclosis (C. Sepedonicum), Burkholder (Burkholder) ia solanacearum) and cabbage soft rot bacteria (E.carotovora) and so on, pay attention to observe the color, size, texture, whether fluorescent pigments, etc. , and plant pathogen fungal culture bacteria, what is the fundamental difference?