This document discusses the effects of virus, bacterial, and fungal infections on plant physiology. It summarizes that virus infections can reduce chloroplast numbers and chlorophyll content, as well as stimulation of early CO2 incorporation but decline after several days of infection. Bacterial infections can decrease chloroplast stroma and destroy chloroplast integrity, suppressing CO2 fixation. Fungal infections can reduce chloroplast content and inhibit processes like photophosphorylation and electron transport, suppressing CO2 fixation. It also discusses the process of plant respiration and how respiration rates increase in diseased plants as they use reserve carbohydrates faster than healthy tissues.

1. COLLEGE OF AGRICULTURAL TECHNOLOGY
Affiliated to Tamil Nadu Agricultural University, Coimbatore
Kullapuram,Via Vaigai dam, Theni-625 562
STUDENTS
Ms. DHARSHINI S
Mr. GOWTHAM M

4. Influence of Virus Infection
• Reduction of chloroplast numbers
• Reduction in chlorophyll content
• Chlroplast abnormolities
• Stimulating CO2 incorporation at early stage of infection , but declined after
infection for several days
• Reduction in sucrose content

5. Influence of Bacterial Infection
• Decrease the chloroplast stroma
• Disorientation of chlroplasts
• Destroy of chlroplast integrity
• Suppression of CO2 fixation

6. Effect of Fungal Infection
• Reduce chlroplast content
• Inhibit photophosphorylation coupling mechanism
• Inhibit electron transport
• Suppress CO2 fixation

7. Wheat Leaf rust Leaf spot of Egg Plant

8. Leaf spot of Barley Mosaic of Mung Bean

9. Leaf spot of cucurbits Alternaria leaf spot in sunflower

10. Respiration
• Respiration is the process by which the cells, through enzymatic
oxidation of organic material produce energy for various activities and
carbon skeletons
• In plants the process of respiration takes place in two major steps :
• 1. Glycolysis or EMP pathway
• 2. the terminal phase

11. Respiration in Diseased Plant
• Infected plant shows increased respiration rate and slight rise in temprature.
• Affected tissue use up their reserve carbohydrates faster than the healthy
tissue.
• Increase in plant metabolism and protoplasmic streaming.
• Increased respiration has been noticed in cereal rusts, powdery mildews,
blast of rice, late blight of potato, and many other diseases.
• Diseased plants carry out more fermentation than healthy plants.

12. Effect of Bacteria
• Resistant tissue : Immediate increase in O2 consumption
• Susceptible tissue : Do not reflect an increase in respiration until about 30 hours after
inoculation
• Eg: Xanthomonas vesicatoria
Effect of viruses
• Non hypersensitive hosts : Slightly increase in respiration rate of inoculated leaves
• Hyper sensitive hosts : a much more considerable increase in respiration activity than the
systemic hosts

13. Rice Blast Late Blight of Potato

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