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

作者：Kask Kaia^*; Kaennaste Astrid; Talts Eero; Copolovici Lucian; Niinemets Ulo

来源：Plant, Cell and Environment, 2016, 39(9): 2027-2042.

DOI：10.1111/pce.12775

• Brassicales
• glucosinolate breakdown products
• heat shock
• high temperature
• lipoxygenase pathway
• terpenoid emission
• volatile organic compounds

Brassicales release volatile glucosinolate breakdown products upon tissue mechanical damage, but it is unclear how the release of glucosinolate volatiles responds to abiotic stresses such as heat stress. We used three different heat treatments, simulating different dynamic temperature conditions in the field to gain insight into stress-dependent changes in volatile blends and photosynthetic characteristics in the annual herb Brassica nigra (L.) Koch. Heat stress was applied by either heating leaves through temperature response curve measurements from 20 to 40 degrees C (mild stress), exposing plants for 4h to temperatures 25-44 degrees C (long-term stress) or shock-heating leaves to 45-50 degrees C. Photosynthetic reduction through temperature response curves was associated with decreased stomatal conductance, while the reduction due to long-term stress and collapse of photosynthetic activity after heat shock stress were associated with non-stomatal processes. Mild stress decreased constitutive monoterpene emissions, while long-term stress and shock stress resulted in emissions of the lipoxygenase pathway and glucosinolate volatiles. Glucosinolate volatile release was more strongly elicited by long-term stress and lipoxygenase product released by 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.
The goal of the manuscript was to study the impact of different heat stresses called as mild stress, long-term stress and shock stress on the photosynthetic characteristics and emissions of volatile organic compounds of B.nigra plants. We found out that all different heat stress treatments affected the net assimilation and stomatal conductance of plants. Additionally, volatile glucosinolate degradation products and lipoxygenase pathway compounds dominated in the emissions and stressed B.nigra plants.

• 出版日期2016-9