EDX measurements and SEM examination of surface of some imported woods inoculated by three mold fungi

Abstract

Wood samples of Pinus rigida, Juglans nigra, and Fagus sylvatica were superficially inoculated with three mold fungi (Penicillium selerotigenum, Paecilomyces variotii, and Aspergillus niger). The changes in wood surfaces and the elemental composition were observed by scan electron microscope (SEM) and the electron dispersive X-ray spectroscopy (EDX), respectively. Wood elemental composition was an indication of the growth of mold fungi, in which P. selerotigenum, and A. niger have consumed high amount of carbon (C) of F. sylvatica wood compared to control treatment. Also, P. selerotigenum consumed high amount of C of J. nigra wood compared to the control. While, the three mold fungi showed little changes in C content in P. rigida wood. The nitrogen element in the studied woods was completely consumed by the three mold fungi. Cl element increased in the three woods as inoculated by the three fungi compared to untreated woods. Other elements such as S, Si, Ca, Zn, Cu, and Fe varied in their content in accordance to the interaction among wood species and fungi. The growth of the three mold fungi showed distribution and structures of spores and hyphae covering deteriorated wood surfaces. The study suggests that the three mold fungi metabolize the carbon-rich constituents of the investigated wood species in a proportional manner and produce large fruiting structures that release vast numbers of spores in nature.