Metabolically active hyphae were estimated by fluorescence microscopy. Soil samples were sieved through a 2-mm mesh, suspended in a solution (1 g of fresh soil in 100 ml) of phosphate buffer (60 mM, pH 7.5), and homogenized at 6,000 rpm for 2 min. 0.5 ml of suspension were collected and filtered under vacuum on nitrocellulose filter with a pore size of 0.45 mm. The sample was treated with fluorescein diacetate (FDA) (Soderstrom 1977, 1979). This stain penetrates rapidly in cells and is hydrolyzed to fluorescein by different enzymes such as protease, lipase, and esterase. After clearing by immersion oil, the preparations for active mycelia were observed at a magnification of 400 x and 20 microscopic fields were counted. Active mycelia were estimated by the intersection method (Olson 1950) and their mass calculated on the basis of an average hyphae cross section of 9.3 x 10-6 mm2, a density of 1.1 g ml-1 and a dry mass of 15% of wet mass (Berg and Soderstrom 1979). The fungal biomass was expressed as mg of fungal biomass per gram of soil dry weight.
Was this article helpful?
Your Alternative Fuel Solution for Saving Money, Reducing Oil Dependency, and Helping the Planet. Ethanol is an alternative to gasoline. The use of ethanol has been demonstrated to reduce greenhouse emissions slightly as compared to gasoline. Through this ebook, you are going to learn what you will need to know why choosing an alternative fuel may benefit you and your future.