Morphological characteristics of mycelia growth of two strains of the indigenous medicinal mushroom, Lentinus squarrosulus Mont. (Singer), on solid media

Abstract

Morphological characteristics of the mycelia growth of two wild strains of Lentinus squarrosulus Mont.(Singer), Sqw and Lsf, collected from the Volta and Greater Accra regions of Ghana respectively, were studied. Growth characteristics including mycelia growth rate and mycelia density and morphology by the 7 th and 26 th days of incubation on solid media formulated from four lignocellulosic wastes: elephant grass (EG), rice straw (RS), thatch (TH) and sawdust (SD) were classified. Tissue cultures of the fruit bodies were prepared on Malt Extract Agar (MEA). Eight-day old cultures of the subsequently prepared 1 st generation cultures were inoculated on the media and incubated at 25°C. Strain Sqw recorded lower growth rates (between 0.47 and 0.64 cm/day) on the solid media than Lsf (between 0.69 and 0.93 cm/day). The maximum growth rate of strain Sqw was 0.64 cm/day on both SD and TH whereas that of Lsf was 0.93 cm/day on EG. L. squarrosulus mycelia density is not dependent on the growth rate and vise-versa, irrespective of the strain. Although both strains generally had the longitudinally radial morphology with concentric rings, with extended incubation, the culture morphology of both strains changed, usually into thick mats. Mycelia of both strains on all the media were white at the initial stages of incubation. Cultures of strain Sqw largely remained whitish and turned brownish only on EG, whereas strain Lsf turned into different shades of brown on all media with extended incubation. These colour changes were not uniform on the entire plate, appearing in undefined sectors. Mycelia growth characteristics were seen to be substrate and strain-dependent. Futher investigations of these observations could uncover some behavior of L. squarrosulus such as changes in enzyme profile and the phenolic content, which could have applications in biotechnology.