Effect of environmental factors, different forms of carbon, inorganic and organic form of nitrogenous compounds on mycelial growth of alternaria alternata isolated from infected fruit of bottle gourd (Lagenaria siceraria (Molina)st.) Prakash Archita1, Prasad Preeti2 1Department of Botany, Bhoot Nath Degree College, Baghan, West-Champaran, Bihar, India 2Former Head, Department of Botany, Plant Pathology Laboratory, B.R. Ambedkar Bihar University, Muzaffarpur, Bihar, India Online published on 6 September, 2019. Abstract Alternaria alternata was isolated from the infected fruit of bottle gourd (Lagenaria siceraria) and pure culture was maintained in the laboratory. In vitro impact of different environmental factors, sources of carbon, inorganic and organic nitrogenous compound, was observed on mycelial growth, as determined by the radial growth on solid culture medium, while the dry mycelial weight in the same culture broth. The study was undertaken to assess mycelial growth of the fungus under different environmental conditions such as pH & temperature as well as under different nutritional conditions such as carbon and nitrogen sources. Ten different pH and seven different temperatures were used in which the fungus was cultured. Likewise, nine different carbon sources and six inorganic and eight organic sources of nitrogen compounds were tested. Among the pH, 6.5was found more favorable where the dry mycelial weight was the maximum, 695.75 mg/100ml of culture, while the radial growth was 84.66 mm, followed by 6.0 pH, where the dry mycelial weight was 672.56 and radial growth 72.85. At both pH 3.0 and 8.0, both the dry mycelial weight and the radial growth were the lowest. Highest dry mycelial weight, 688.72 mg/100 ml and radial growth 78.48 were noted at 28°C, followed by 626.28 mg/100 ml, dry mycelial weight and 68.34 mm radial growth at 32°C. Among the carbon sources tested, glucose promoted maximum dry mycelial weight (680.18 mg/100 ml), while the radial growth was 82.32 mm, followed by fructose, 672.84 mg/100 ml dry mycelial weight and 76.28 mm radial growth. These values were significantly superior over all the carbon sucrose evaluated followed by sucrose (628.88 mg/100 ml) and 72.56 mm as control. Among the nitrogen sources alanine induced maximum dry mycelial weight (682.32 mg/100 ml) and 82.38 mm radial growth, followed by potassium nitrate (678.24 mg/100 ml) and 78.15 mm radial growth. Minimum dry mycelial weight 422.38 and radial growth 46.26 mm were obtained in case of p-amino benzoic acid. Among the inorganic sources Aluminum nitrate promoted the minimum (538.18 mg/100ml) and 60.72 radial growths. Top Keywords Bottle gourd, Radial growth, Dry mycelial weight, In-organic nitrogen sources, p-aminobenzoic acid, Alternaria alternata. Top |