Severe heat stress leads to a major reduction in foliage photosynthetic characteristics and the initial reduction and degree of recovery depend on species heat resistance. However, how the emissions of biogenic volatile organic compounds (BVOC) from different biochemical pathways are coordinated with photosynthetic modifications from the initial stress response through recovery are poorly understood, and the data are especially limited for short-living tropical crop species. We exposed leaves of five tropical crop species (A. cruentus, A. hybridus, S. aethiopicum, T. occidentalis and V. unguiculata) to severe heat treatment of 49 °C and a control treatment of 25 °C for 5 min and studied the modifications in foliage photosynthetic characteristics and constitutive BVOC emissions and elicitation of stress-induced volatiles through a 48 h recovery period upon return to non-stressed conditions. Overall, heat shock application resulted in a major inhibition of net assimilation rate similarly in all species indicating cellular damage and photosynthetic decay. However, species strongly varied in photosynthetic recovery with A. hybridus recovering the most and S. aethiopicum the least. Heat shock stress led to enhancement of emissions characterizing increased leaf oxidative status, in particular to enhanced emissions of lipoxygenase pathway volatiles (LOX). Surprisingly, LOX emissions were not associated with species heat resistance, but were greater in physiologically more active species with greater photosynthetic capacity. Species with greater constitutive isoprenoid emission capacity were generally more heat resistant, but terpenoid emissions were induced to a greater degree in less heat resistant species that likely suffered the most from the applied level of stress. Heat stress affected different groups of terpenoids - isoprene, monoterpenes and sesquiterpenes - to a different degree in different species, resulting in unique species-specific emission blends at different times of recovery. Heat stress had relatively minor effects on benzenoid emissions with moderately enhanced emissions primarily in V. unguiculata that differed from the other species by lower constitutive terpenoid emissions correspondent to its relatively high heat resistance. The results collectively demonstrate that species heat resistance is associated with the quantitative and qualitative characteristics of heat stress-dependent volatile emissions in different tropical crop species. We argue that these species-specific patterns need consideration in simulating volatile emissions under heat stress.

严重的热胁迫导致叶片光合特性大大降低，初始降低和恢复程度取决于物种的耐热性。然而，人们对如何从不同的生化途径排放生物挥发性有机化合物（BVOC）与从初始胁迫反应到恢复的光合修饰进行协调的了解很少，而且对于短命热带作物而言，数据尤其有限。我们暴露了5种热带作物（A. cruentus，A. hybridus，S. aethiopicum，T. occidentalis和V. unguiculata）的叶片。）进行49°C的严格热处理和25°C的对照处理5分钟，并研究了叶片光合特性和本构性BVOC排放量的变化以及恢复至非冰激凌后48小时的恢复过程中引起的胁迫诱导挥发物的变化。紧张的条件。总体而言，在所有物种中，施加热休克均会导致净同化率的显着抑制，这在所有物种中均显示出细胞损伤和光合衰变。然而，物种的光合作用恢复差异很大，杂种曲霉的恢复最多，而沙门氏菌的恢复最多。至少。热激胁迫导致以叶片氧化状态增强为特征的排放增加，特别是脂氧合酶途径挥发物（LOX）的排放增加。令人惊讶的是，LOX的排放与物种的耐热性无关，但是在具有更高光合能力的生理活性更高的物种中，LOX的排放却更大。具有较高本构类异戊二烯释放能力的物种通常更耐高温，但是在耐热性较低的物种中，萜烯的排放在更大程度上被诱导，这些物种可能在施加的应力水平下遭受的损失最大。热应力影响不同种类的萜类化合物（异戊二烯，单萜和倍半萜）在不同物种中的影响程度不同，从而在不同的恢复时间产生独特的物种特异性排放混合物。V. unguiculata与其他物种的不同之处在于其组成型萜类化合物的较低排放与其相对较高的耐热性相对应。结果共同表明，物种耐热性与不同热带作物物种中与热胁迫有关的挥发物排放的定量和定性特征有关。我们认为，在模拟热胁迫下的挥发性排放时，需要考虑这些特定于物种的模式。