Isoprene Emission in Polytrichaceae Mosses

Abstract

Our first aim was to identify and quantify Biological Volatile Organic Compound (BVOC) emissions, specifically emissions of isoprene, from the moss Polytrichum juniperinum during its earliest stage of life. Isoprene emission from mosses could be a significant component of the total global budget of BVOC emissions. Data concerning the spatial and temporal variability of these emissions are lacking due to poor characterization of the physical and biological factors controlling isoprene synthesis in both vascular and non-vascular plants. We found that P. juniperinum in its early life stage (protonema) can emit isoprene at detectable levels at day five after spore germination. These results suggest that protonema is capable of isoprene emission, shown here for the first time, and media affects emission rates. We saw a negative trend with leaf emergence and protonema growth. Chlorophyll fluorescence ratio had a positive correlation with isoprene emission, and isoprene emission was both temperature and light dependent in early protonema. Our second aim was to determine the effects of sex and sexual expression on isoprene emission in mosses. Sex is a biologically costly, but it can result in genetic adaptability and variety for resulting offspring. Using three Polytrichaceae species, we measured isoprene emission between plants sexually expressing and non-expressing and between male and female moss plants. We found that non-sexually expressing gametophytes had significantly higher isoprene emission than gametophytes expressing sex, suggesting that sex expression may be costly and that additional resources are v Table of Contents

Measuring volatile emissions from moss gametophytes: A review of methodologies and new applications

“…The GC‐RGD experiments were performed at a controlled temperature of 30°C. This temperature is a widely used standard for testing isoprene emissions in both vascular plants (Sharkey and Loreto, 1993; Monson et al, 1994; Geron et al, 2000; Bracho‐Nunez et al, 2013; Sharkey and Monson, 2017) and nonvascular plants, such as Polytrichum juniperinum (Hanson et al, 1999; Janson et al, 1999; Deakova, 2019). All collection methods for the GC‐RGD experiments used lighting set to a standard photosynthetic photon flux density (PPFD) of 1000 μmol photons m −2 s −1 to simulate standard conditions (Geron et al, 2000).…”

Evaluation of isoprene light response curves for bryophyte-dominated ecosystems and implications for atmospheric composition

“…Bryophytes have developed numerous physiological (including morphology and structure) and biochemical adaptations since diverging from vascular plants [22] which mean there may be fundamental differences in how isoprene emissions from these species respond to environmental conditions. For example, as well as light and temperature, isoprene emissions from bryophytes are known to also be influenced by exposure to ultraviolet B radiation [9,11,12], sex [23], nutrient loading [23], ozone exposure [11] and water availability [8,9,13]. In addition, mosses have phyllids rather than true leaves and their canopy architecture differs from that of vascular plants; these differences are not represented in the Guenther algorithms.…”