التحري عن سمية الأنواع التابعة للجنس Alternaria المعزولة من أوراق نباتات الزينة

The isolation, diagnosis, and purification of pathogenic fungi causing leaf stains for a variety of ornamental plants were done.Two-hundred and ninety nine fungal isolates belonging to fungal species were obtained and Alternaria species were selected for experimentation. To determine the toxic effect of some species of Alternaria on the percentage of germination of the seeds of Sativum lepidium, the fungal toxin at a concentration of (50,100)% was used. The germination percentage of seeds treated with fungal toxin was 0% for both concentrations (100,50)% for A.dianthi3 , as to mean 100% inhibition and A.alternata4 was 96.43% at 100% and 58.9% for 50% concentration. The electrolytic perfusion of plant leaves was studied, The highest yield value after 72 hours when the concentration of leachate was 100% was (9*10-6) Siemens/hr. compared with the value of the perfusion of leaves in comparison and treated with distilled water, It reached(1*10-6) Siemens/hour. The chlorophyll content of the plant leaf was estimated to be known toxic affected and estimate chlorophyll a, b ratio and total chlorophyll and percentage of loss, The percentage was 72% when the concentration of leachate was 100% and total chlorophyll was 5.865 mg/g wet weight; while the percentage of loss 33.95% and total chlorophyll 13.98 at concentration 50% compared to the total chlorophyll of the treatment 21.2 mg/g wet weight.