الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Tomato plants (Lycopersicon esculentum) are considered one of the most important vegetable crops cultivated in all regions of Egypt and other different countries of the world.
Root-knot nematode disease is the most aggressive phytopathogens infecting tomato plants causing the great loss in the tomato yield. The systematic chemicals used for control many different diseases and their toxicity was known to be environment pollutions. Therefore it is very necessary to find another methods of control on disease instead of the chemical control. So the present investigation was conducted to explain the effect antioxidants Selenium, VC and VE to reduce root-knot harmful effect on tomato plants.
Root-knot disease parameters (no. of nematode galls, no.of egg masses no. of egg/egg-masses no. of J2/250 g soil, no. of development stage and no. of females) were evaluated.
The obtained results could be summarized as follow:
1- Antioxidants Selenium, Vitamin C and Vitamin E with their different treatments (spraying, irrigating and soaking) on disease parameters, caused a high decrease in no. of galls by % 75.31 at 50 ppm irrigating Selenium , 65.43 at 50ppm.V. C irrigating and 64.81 % at 50 ppm.V .E irrigating respectively. Also decreased number of egg-masses were decreased too.
2- Selenium at 50 ppm was the most effective treatment against the development of nematode galls, egg masses, no, of egg egg masses and no. of females of tomato roots infected with M. incognita as compared with control plants.
3- Plant growth parameters of tomato plants i.e. root, shoot length and plant height as well as root, shoot, fresh and dry weight of the plant were increased in plants infected with M. incognita. when exposed to all antioxidants treatment at different levels. The most increase observed at spraying ,irrigating and soaking respectively compared with control .
4- All treatments with antioxidants decreased egg hatching between (33– 50%), the highest reduction occurred on egg hatching recorded with Selenium, followed by V. C and V. E which decreased egg hatching by (40-50%) compared with the control.
5- Treatments with antioxidants increased the number of inactive second stage juveniles of root knot nematode in different period ( 24, 72 and 96 hours ) respectively. Selenium showed the highest effective during the exposure period till 96 hours, inactive juveniles recorded was 68%, followed by V. C 60% and V.E 44% compared with control.
6- Results indicated that all Selenium , V.C and V. E treatments ( irrigating, spraying and soaking respectively ) indicated that seven days before nematode inoculation was the optimum treatment date, followed by treated plants at the same time then treated tomato plants seven days after inoculation.
7- The highest antioxidant treatments effect in increasing photosynthetic pigments occurred with spraying antioxidants on tomato plants. Data concerning the effect of antioxidants (Selenium, Vitamin C and Vitamin E) with different treatments on tomato plants infected with M.incognita , increased chl.a ,b ,a+b as well as carotonoids , The maximum increase was noticed when tomato plants treated with spraying Selenium at 50 ppm, Vitamin C comes second, while the lowest increase of
photosynthetic pigments recorded with vitamin E compared with control plants.
8- In concern with the effect of some antioxidants on the activity of peroxidase enzyme, data indicated the highest effect occurred with Spraying plants with 50 ppm Selenium, great increase on activity of peroxidase enzyme in tomato plants infected with M. incognita recorded too followed by irrigating plants at 50 ppm and the lowest increase on the activity of peroxidase enzyme observed when soaking plants at 25 ppm Selenium compared with control plants.
9- Application methods of spraying, irrigating or soaking plants at 50 ppm VC gave the highest effect on the activity of peroxidase enzyme. Vitamin E, spraying or irrigating or soaking with 50 ppm gave the same trend in increasing activity of peroxidase enzyme in tomato plants infected with M. incognita in comparison with control plants.
10- Spraying tomato plants infected with M. incognita with the three antioxidants at 50 ppm was more effective on increasing activity of peroxidase enzyme than that in other treating plants with irrigating and soaking or control plants.
11- Antioxidants treatments markedly increased the activity of polyphenoloxidase of tomato plants infected by M. incognita compared to nematode alone and healthy plants.
12- All antioxidants treatment significantly increased the activity of poly phenol enzyme (ppo) on tomato plants infected with M. incognita and the most effective increase was observed at spraying Selenium at 50 ppm , followed by irrigation of Selenium at 50 ppm, the lowest increase was observed at soaking tomato plants at 25 ppm.
13- Antioxidants effects on tomato plants infected with M. incognita showed gradual increase in total carbohydrate , soluble sugars and non-soluble sugars with the increase of the concentrations of all antioxidants. The highest increase in total carbohydrate ,soluble and non-soluble sugars occurred with 50 ppm spraying Selenium, followed by irrigating plants with 50 ppm Selenium and the lowest increase was observed with soaking plants at 25 ppm Selenium as compared with control plants .
14- All antioxidants treatments increased proline concentrations recorded with tomato leaves infected with M. incognita. Spraying plants with different antioxidants was more pronounced than that tomato plants irrigated with antioxidants. The highest effect in increasing proline concentration when spraying tomato plants with 50 ppm Selenium followed by irrigating plants with 50 ppm vitamin C. The lowest increase was noticed when soaking plants with 50 ppm V. E compared with other treatments or control.
15- Tomato plants infected with M. incognita and treated with the three antioxidants increased phenolic content gradually with increasing the concentration of antioxidants at all different treatments The highest increase of phenolic content observed at spraying tomato plants with 50 ppm Selenium, V. C or V. E followed by irrigating plants with 50 ppm Selenium, V. C or V. E. The lowest increase in phenolic content in leaves of tomato plants was pronounced with soaking plants at 25 ppm Selenium , 50 ppm V. C. or V.E compared with control plants.
16- Spraying 50 ppm Selenium on tomato plants infected with M. incognita and gave the highest increase in concentration of Nitrogen in roots, shoots, and leaves of tomato plants, followed by spraying treatment
at 50 ppm of V.C, and 50 ppm VE Spraying tomato plants the control plants.
17- The levels of all antioxidants treatment gave gradually increase in phosphorus in roots, shoots and leaves of tomato with increasing the concentration of antioxidants especially spraying Selenium at 50 ppm. Selenium irrigating treatment showed the lowest increase in phosphorus concentration in different organs. However, soaking tomato plants at 25 ppm Selenium was pronounced. Vitamin E gave the same trend of Vitamin C that a highly significant increase in phosphorus concentration was observed at 50 ppm spraying, irrigating, and soaking V. E respectively compared with control.
18- All antioxidants treatment increased the concentration of potassium in tomato organs and Spraying tomato plants infected with M. incognita at different levels at different plant organs The highest significant increase in this respect was observed at spraying Selenium 50 ppm than with irrigating or soaking plants at the same level of Selenium as compared with other levels or control plants.
19- Histological observation, cleared that few giant cells in the cortex and vascular cylinder, giant cells appeared more at irrigating tomato roots with Selenium 50 ppm treatment compared with nematode alone.
20- Histological observation cleared too that, irrigation with 50 ppm. VC, or VE, seven days before, in the same time, and seven days after inoculation tomato plants showed more giant cells in the cortex and in vascular cylinder ,with multinucli and dense cytoplasm and some of eggs in giant cells at treatment before inoculation. The highest number of giant cells observed in treatment of VE seven days after inoculation.
21- Our obtained data confirmed the role of antioxidants substrates Selenium, VC and VE of suppressing the harmful of root-knot nematode disease when compared with vaydate treatment. Nematode parameter reduction using Selenium 50 ppm were almost as much as obtained with the use of nematicide vaydate.