How specialized volatiles respond to chronic and short‐term physiological and shock heat stress in Brassica nigra

Abstract

Brassicales released volatile glucosinolate breakdown products upon tissue mechanical damage, but it is unclear how glucosinolate volatile release responds to abiotic stresses such as heat stress. We used three different heat treatments called as mild -and long-term stress and shock-heating to gain insight into stress-dependent changes in volatile blends and photosynthetic characteristics in Brassica nigra (L.) Koch. The reduction in net assimilation rate (A) in temperature response curve measurements was associated with decreases in stomatal conductance, while the moderate reduction due to long-term stress after exposure to 40-44 °C and collapse of photosynthetic activity after heat shock stress were associated with non-stomatal processes. Mild stress decreased constitutive monoterpene emissions parallel to photosynthesis, while long-term heat stress at 40-44 °C and heat shock stress resulted the emissisons of lipoxygenase (LOX) pathway and glucosinolate volatiles. However, glucosinolate volatile emission was more strongly elicited by long-term stress, and glucosinolate volatiles dominated the emissions in long-term stressed plants, while LOX products dominated the emissions after heat shock. These results demonstrate that glucosinolate volatiles constitute a major part of emission blend in heat-stressed B. nigra plants, especially upon chronic stress that leads to induction responses.

Role of Stomatal Conductance in Modifying the Dose Response of Stress-Volatile Emissions in Methyl Jasmonate Treated Leaves of Cucumber (Cucumis Sativa)

“…These quantitative relationships are in agreement with former studies demonstrating stress severity-dependent release of LOX compounds and methanol for a variety of stresses including ozone [46,47,83], heat [40,84], mechanical wounding [30], insect herbivory [35,36,62]. In a previous study, we have demonstrated analogous MeJA concentration-dependent LOX and methanol emission responses [39].…”

Heat Waves Change Plant Carbon Allocation Among Primary and Secondary Metabolism Altering CO2 Assimilation, Respiration, and VOC Emissions

“…Whereas several studies demonstrated the effects of heat on isoprene emission ( Sharkey et al., 2008 ; Pollastri et al., 2014 ; Niinemets and Sun, 2015 ; Bamberger et al., 2017 ), less information is available on the dynamic response of other VOC fluxes toward prolonged heat stress ( Fares et al., 2011 ; Kleist et al., 2012 ; Kask et al., 2016 ). H. halimifolium is not a strong isoprene emitter ( Yáñez-Serrano et al., 2018 ), similar to what has been reported for other members of the Cistaceae family ( Kesselmeier and Staudt, 1999 ; Bracho-Nunez et al., 2013 ).…”

The Association With Two Different Arbuscular Mycorrhizal Fungi Differently Affects Water Stress Tolerance in Tomato

“…Furthermore, a different effect of the AM fungal species was again evident, with R. intraradices -inoculated plants that showed similar level of all targeted metabolites in comparison with NS plants, suggesting an enhanced tolerance to this type of stress promoted by this AM fungal species. In tomato, a vast array of VOCs was found to be emitted under biotic ( Digilio et al, 2010 ) and abiotic stresses, including water deficit ( Catola et al, 2018 ), flooding ( Copolovici and Niinemets, 2010 ), cold and heat ( Copolovici et al, 2012 ; Kask et al, 2016 ). In our experimental study, where necessarily a MS has been used to permit the combined test with aphids, the emission of a typical tomato VOC bouquet under NS and water deficit conditions was determined.…”