The role of deadwood substrates in promoting moss growth: Decay class and particle size effects

Plagiomnium acutum has a high value of landscape application and medicinal value, but there is a lack of related research on propagation and cultivation techniques. The deadwood substrate has rich nutrients and superior water retention properties, which will be conducive to promoting the growth of moss. Nevertheless, the underlying mechanisms by which deadwood influences moss growth are not yet fully unclear. In this study, we pulverized deadwood from five decay classes of Pinus massoniana into three distinct particle sizes. Through a pot experiment, we investigated the effects of decay class and physicochemical properties on the growth and physiology of Plagiomnium acutum, aiming to identify the most suitable growth substrate. The results indicated that both the decay class and particle diameter of deadwood significantly affect the substrate's physicochemical characteristics and the growth indexes of P. acutum, with the decay class exerting a more pronounced effect. The water-holding porosity, water-holding capacity, total nitrogen, total phosphorus, total potassium and lignin content of the substrate positively affected the growth of P. acutum, while the bulk density, void ratio, total carbon, carbon-to-nitrogen ratio, condensed tannin content and cellulose content had negative impacts. A comprehensive evaluation using a fuzzy membership function indicated that deadwood with higher decay classes (IV and V) was more conducive to the growth of P. acutum. Specifically, substrates from decay class IV with particle sizes of 10–20 mm provided the most favorable conditions for P. acutum and were recommended as the optimal cultivation substrate. The results of this study provide theoretical basis and technical support for the propagation and cultivation of P. acutum, and provide a foundation for further development of the industrial, pharmaceutical and environmental biotechnology potential of P. acutum.