عوامل الأمراض النباتية

Pathogen Factors in Plant Diseases

• Plant diseases require three factors: a pathogen, a host, and a conducive environment.
• A conductive environment is influenced by factors like magnesium, sodium hydroxide, sodium chloride, and the presence of other particular elements.

Signs and Symptoms of Plant Diseases

• Symptom: A visible response of the plant to infection by a pathogen. Examples: Smut, Rust, Chlorosis.
• Sign: The presence of the pathogen itself or a part of it on the infected plant part. Example: Necrosis.
• Chlorosis: Yellowing of leaves instead of their typical green color.
• Necrosis: Death and decay of plant tissues. Enzymes from pathogens cause this.

Hypoplasia and Hypertrophy

• Hypoplasia: Reduced growth rate due to decreased cell division.
• Hypotrophy: Reduced growth rate due to decreased cell size.
• Hyperplasia: Increased growth rate due to increased cell division.
• Hypertrophy: Increased growth rate due to increased cell size.

Plant Pathogens and Growth

• Rot: Decomposition or decay of plant tissue.
• Wilting: Loss of turgidity in plants, often due to water stress.
• Stunting: Reduced growth rate.
• Tumors: Abnormal growths on plants.

Other Plant Pathogen Factors

• Spitzenkorper: Structures related to the apical growth of fungi.
• Woronin bodies: Specialized structures in fungal cells.
• Parentheosome: A specific structure in some fungi.
• Swelling: An increase in the size of a part of the plant.

Additional Plant Disease Information

• Biotrophic fungi: Fungal pathogens that cannot be cultivated, meaning they can't be grown on artificial laboratory media.
• Necrotrophic fungi: Fungal pathogens that feed on dead tissue.
• Saprotrophic fungi: Fungal pathogens that feed on dead organic material.
• Hemi biotrophic fungi: A type of fungal pathogen with a unique growth pattern.
• Disease cycle: The stages that a plant disease goes through from infection to symptom development. It includes Penetration, Inoculation, and Infection.
• Inoculum: The infectious material of a pathogen, which may be spores, etc.
• Incubation period: Time between infection and the plant showing signs of the disease.
• Field observation techniques: Includes various staining methods using DAPI, Giemsa, acetocarmin, lactophenol cotton blue, etc.
• Pulsed field gel electrophoresis: Method for determining the number of chromosomes in fungi.