Dependance of isoprene emission flux on leaf mass per area of Phyllostachys pubescens (moso bamboo)

Abstract

It is challenging to estimate isoprene emissions from plants and determine the basal isoprene emission rate (i.e., isoprene emission capacity under a specific light and leaf temperature) of plant species. Previous studies have investigated the effect of physiological factors on isoprene emission capacity; however, the effect of leaf morphology on isoprene emission capacity has seldom been mentioned. This study aims to clarify the relationship between the basal isoprene emission rate and leaf mass per area (LMA) of a woody bamboo (Phyllostachys pubescens). Since there was no observation of isoprene emission from low-LMA leaves of P. pubescens, we conducted measurements on culms exhibiting lower LMA (27.5-47.9 g m⁻²). By observing leaf-scale isoprene emission flux under a specific incident light (1000 μmol m⁻² s⁻¹) and temperature (30 °C) to represent basal isoprene emission fluxes, we found a series of varied area-based isoprene emission rate among leaves (1.4-32.2 nmol m⁻² s⁻¹) and a strong correlation between area-based isoprene emission rate and LMA without any distinction between culms. A further comparison with other studies demonstrated that even for the culms that exhibited larger LMA and isoprene emission flux, a generally consistent pattern in the relation of area-isoprene emission flux and LMA could be found across these sites. This result suggests the importance of detecting LMA in the determination of the basal isoprene emission rate, which can improve the current emission estimation method.