الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The objective of the present work is to study the effect of Tomato yellow leaf curl virus on growth and some metabolic activities of tomato plants. Tomato plants (Lycopersicon esculentum cv. Castle Rock ) which showed naturally distinct geminivirus symptoms were collected from Fac. Agri., Ain Shams Univ. farm. The collected infected plants samples were examined for the presence of the virus serologically.
The main experimental results can be briefly summarized in the following points:-
1- TYLCV was isolated from infected tomato plants Castle rock exhibited viral like symptoms in open land. The virus was deteced by DBIA and TBIA and ELISA methods. The virus isolated was confirmed according to host range, stability, insect and mechanical transimmision , serolegically detected and study the charachters of virus isolate.
2- The obtained results revealed that all growth criteria ( shoot and root length, leaf area, number of leaves per plant, fresh and dry weights of both shoot and root system) were markedly reduced in infected tomato plants compared with healthy plants.
3- Infection of tomato plants with tomato yellow leaf curl virus cause marked decrease in membrane stability and increasing electrolyte leakage in tomato plants as compared with their reference control.
4- The contents of photosynthetic pigments (chlorophyll a, chlorophyll b, carotenoids and total pigments) were reduced in infected tomato plants when compared with those of non infected tomato plants.
5- soluble, insoluble sugars and total carbohydrates of leaves and stem decreased in infected tomato plant although total insoluble sugars increased in root system of infected tomato plants in contrast to healthy tomato plants.
6- Infection the tomato plant with tomato yellow leaf curl virus cause an increase in total nitrogen (T.N.) in leaves and root system while decreased in stem system. Infection cause also decrease in the total protein content in leaves, stem and root system of infected tomato plants as compared with their reference control.
7- The accumulation of both proline and Amino-N content in infected tomato plants were highly increased in contrast to healthy plant.
8- Mg++ magnesium ions contents were decreased in leaves, stem and root system of infected plants. While K+ potassium ion and Na+ sodium ion were increased in leaves, stem and root system of infected tomato plants in compared with non infected plants.
9- Phosphte ions were accumulated and increased in leaves and root system while decreased in stem system of infected tomato plants in contrast to healthy one.
10- Phenylalanine ammonia lyase activity and total phenol were observed to be increased in infected tomato plants in contrast to healthy tomato plant.
11-the content of lipid peroxidation as indicated by accumulated MDA content and glutathione content where both increased in infected tomato plants as compared with control healthy plant.
12-Activity levels of superoxide dismutase, peroxides and catalyses enzymes showed an progressive increase in infected tomato plants while nitrite reductase and carbonic anhydrase enzymes showed an opposite response were their activity decreased in infected tomato plants as compared with health tomato plants as control.
13-Histopathological changes as response to virus infection was examined in the inoculated tomato leaves using light microscope. Generally, healthy plants were stronger in their growth than infected plants as result to the decrease in lignin precipitation, numbers of xylem arms, phloem layers, skin hairs and decreasing thickness of cell wall, and blade. Infected plants showed plasmolysis in the mesophyll cells, cell walls collapsed and plastids become deformed and swollen a loss of orientation along the inner cell wall. These alterations were intensified with progressive tissue-shrinkage and desiccation causing the walls of the palisade and spongy parenchyma to fold in a layering fashion as well as reduction in vascular bundles.
14-Methods of treatment of TYLCV infected tomato plants including the integrated virus and integrated pest mangment needed more research to study.