Seasonal Volatile Emission Patterns of the Endemic New Zealand Shrub Dracophyllum subulatum on the North Island Central Plateau

Abstract

Volatile organic compounds (VOCs) produced by plants are essential indicators of their physiological response to environmental conditions. But evidence of natural variation in VOC emissions and their contributing factors is still limited, especially for non-cultivated species. Here we explored the natural volatile emissions of Dracophyllum subulatum Hook.f., an endemic shrub to the North Island Central Plateau of New Zealand, and determined some environmental factors driving the plant’s emissions. Volatile emissions of D. subulatum were measured on four separate occasions from December 2017 to September 2018 using the “push-pull” headspace sampling technique and analyzed using gas chromatography-mass spectrometry (GC-MS). D. subulatum was classified based on the volatiles measured on each sampling occasion using linear discriminant analysis (LDA). On each sampling occasion, we also recorded and compared ambient air temperature, herbivory damage, total soil nitrogen (N), available phosphorus (P), potassium (K), and soil moisture content. The relationship between environmental variables that differed significantly between sampling occasions and volatile emissions were estimated using generalized linear models (GLMs). Based on VOCs measured on each sampling occasion, we were able to distinguish different chemical profiles. Overall, we found that total emission and the relative proportions of all major chemical classes released by D. subulatum were significantly higher during summer. The GLMs reveal that differences in environmental factors between the four sampling occasions are highly associated with changing emissions. Higher temperatures in summer had a consistently strong positive relationship with emissions, while the impacts of soil moisture content, P and K were variable and depended on the chemical class. These results are discussed, particularly how high temperature (warming) may shape volatile emissions and plants’ ecology.

Characterization of the Volatile Profiles of Six Industrial Hemp (Cannabis sativa L.) Cultivars

“…The VOC emissions of plants can be influenced by environmental conditions. For example, temperature, UV-radiation, and soil nutrients have been shown to affect the VOC emissions of different plant species (native and introduced) occurring in New Zealand [3,[36][37][38]. Soil, in particular, is a key factor driving volatile compounds' emissions in different systems because soil nutrients and soil water availability influence plant metabolism, and because soil structure (e.g., porosity) and associated biota can impact nutrient cycling, bioavailability, and root penetrability, among other factors [39].…”

Review of Predator Emitted Volatile Organic Compounds and Their Potential for Predator Detection in New Zealand Forests

“…VOCs emitted by these native plants in New Zealand have the potential to induce cross-sensitivity in the biosensors. For instance, Effah and co-workers identified 46 VOCs emitted from Dracophyllum subulatum foliage, an endemic plant exclusive to New Zealand [202]. As these VOCs exhibit a slight overlap with VOCs released by rodents (EE-α-farnesene), marsupials (decanal and limonene), and ferrets (heptanal, nonanal, and octanal), recognizing and addressing these potential cross-sensitivities is essential in the development of a suitable biosensor.…”

Herbivore intraguild interactions decrease ectoparasitoid Bracon nigricans parasitism of Phthorimaea absoluta and responses to tomato volatiles

“…HIPVs play an important role in priming and alerting neighboring plants to an impending herbivore attack by triggering host defenses (Thaler et al, 2002;Engelberth et al, 2004;Sugimoto et al, 2014;Sugimoto et al, 2021). Green leaf volatiles (GLVs) and plant defense elicitors (PDEs) are chemical signals released from plants, especially in response to stresses such as herbivory (Rodriguez-Saona et al, 2003;War et al, 2011;Soler et al, 2012), mechanical wounding (Piesik et al, 2010;Ameye et al, 2018), pathogenic infection (Piesik et al, 2011;Ameye et al, 2018), adverse climatic conditions (drought and heat) (Piesik et al, 2011;Ameye et al, 2018), and edaphic factors (Effah et al, 2021). However, when herbivory triggers the release of GLVs and PDEs, the amount and quality of these compounds might vary depending on the feeding mode of the insect (piercing/sucking vs. chewing) (Soler et al, 2012;Rowen and Kaplan, 2016), and this may define the type of interactions between conspecific or heterospecific species (Kaplan and Denno, 2007;Liu et al, 2021).…”