Effect of pollution with certain heavy metals on the growth of the Nematophagous fungus, Arthrobotrys oligospora, trap formation, root-knot nematode infection and enzymes production

• Published in: Pakistan journal of biological sciences Vol. 2; no. 2; pp. 515 - 522
• Main Authors: Ashour, E.H, Mostafa, F.A.M. (Mansoura Univ. (Egypt). Faculty of Agriculture)
• Format: Journal Article
• Language: English
• Published: 01.04.1999
• Subjects: ARTHROBOTRYS; ATRAYENTES; ATTRACTANTS; ATTRACTIF; CADMIO; CADMIUM; CHAMPIGNON NEMATOPHAGE; CINC; CONTAMINACION; CONTAMINATION; CRECIMIENTO; CROISSANCE; ENZIMAS; ENZYME; ENZYMES; GROWTH; HEAVY METALS; HELIANTHUS ANNUUS; HONGOS NEMATOFAGOS; INFECCIONES POR NEMATODOS; LEAD; MANGANESE; MANGANESO; MELOIDOGYNE INCOGNITA; METAL LOURD; METALES PESADOS; NEMATODE INFECTIONS; NEMATODOSE; NEMATOPHAGOUS FUNGI; PLOMB; PLOMO; ZINC
• ISSN: 1028-8880; 1812-5735
• DOI: 10.3923/pjbs.1999.515.522

In vitro studies revealed that there was an inversely correlation between metal concentration and mycelial growth. Cadmium ion was the most toxic metals. ?However, zinc 10 ppm was the only metal that had stimulatory effect on mycelial growth. Results also showed that maximum number of traps produced by the fungus was performed with zinc 600 ppm and manganese 200 ppm. However, trap formation was greatly inhibited with all concentrations of cadmium except 0.1 ppm. Laboratory tests also revealed that the sensitivity of fungal growth to all tested metals was higher in broth than on solid media. Pot experiment showed that the four tested metals had stimulatory effect on shoot length and root weight of sunflower free of nematode infection. Single application of A. oligospora caused significant reduction in number of galls and egg masses produced by M. incognita besides a remarkable increase in enzymes activity. The effectiveness of such metals on protease activity was more pronounced with zinc or manganese. Application of zinc or manganese singly or in combination with A. oligospora caused significant reduction in number of galls as well as egg masses. Better suppression was performed in concomitant treatment. Moreover, fresh shoot and root weight of sunflower infected with M. incognita was greatly improved following the application of fungus plus either zinc 600 ppm or 1000 ppm with total plant fresh weight 18.50 and 16.58 respectively. On the other hand pots receiving fungus alone or in combination with cadmium or lead showed non significant difference in number of galls and egg masses. The inhibitory effect of the tested metal ions on enzyme production was less pronounced in vivo than in vitro. In addition application of such metals at higher concentrations showed no phytotoxicity in sunflower plant.