Ratios of phosphatase activity to activities of carbon and nitrogen-acquiring enzymes in throughfall were larger in tropical forests than a temperate forest

Abstract

Tropical forests are considered as phosphorus (P)-poor ecosystems, where microorganisms are suggested to allocate more resources to P acquisition compared to carbon (C) and/or nitrogen (N) acquisition. Therefore, ratios of activities of acid/alkaline phosphomonoesterase (AP) to C-acquiring enzymes such as β-1,4-glucosidase (BG) and C and/or N-acquiring enzymes such as β-1,4-N-acetyl-glucosaminidase (NAG) and leucine amino peptidase (LAP) are generally larger in tropical forest soils (i.e., BG: AP and (NAG+LAP): AP are smaller). However, those ratios were never reported for enzymes in throughfall. In this short note, we reported that both BG: AP and (NAG+LAP): AP of throughfall samples were smaller in five tropical forests than those in a temperate forest, which was consistent with generally-observed patterns in soils. This implies that phyllosphere microorganisms may allocate more resources to obtain P in P-poor tropical forest canopy, which should be considered in future P cycling quantifications in forest ecosystems.