## 1 Introduction  
Plants have evolved a highly varied arsenal of defence mechanisms against a wide range of biotic and abiotic stresses to adapt for their sedentary existence. These mechanisms include the plant's capacity to release and react to volatile organic compounds (VOCs), triggering defence responses, which may confer some degree of tolerance in the plants against the stressors [1, 2, 3, 4, 5, 6, 7, 8]. Interestingly, plants have also adapted to 'eavesdrop' VOC signals from their stressed neighbours to modulate their phenotypes against impending stresses [9]. The role of these phytochemical signal molecules in interplant communication has been well-documented and they have been shown to provide fitness benefit to both the emitter and the receiver [10]. The ecological significance of this aerial communication may depend on the ability of a non-stressed plant to perceive these volatile cues from its stressed neighbours in order to prime for defensive reactions without depleting its fitness by maturing the response before the actual stress is imposed. The ability of stress-induced VOCs to prime nearby plants that are not under stress to mount a quicker and/or more effective defence to subsequent stress challenges has been demonstrated in several studies involving biotic stress [11; 12; 13; 14; 15; 16], with only a few studies being related to abiotic stress [17; 18; 19; 20; 21]. The priming effect of stress-induced VOCs, including terpenoids [11; 16; 20; 22], green leaf volatiles (GLVs) such as (\(Z\))-3-hexen-1-ol [12; 13; 14; 15], and methyl ester forms of jasmonic acid (MeJA) [13; 23] and salicylic acid (MeSA) [19; 21; 24], on the non-stressed receivers have been demonstrated to trigger anixenosis and/or antibiosis resistance mechanisms against herbivory as well as increased tolerance against abiotic stressors. Cold-stress-induced VOCs from tea plants, including nerolidol, geraniol, linalool, and MeSA, were shown to elicit the overexpression of genes for antioxidant enzymes, such as glutathione reductase and ascorbate peroxidase, in the receivers in comparison to control plants [19]. Gene expression of transcription factors associated with cold stress and C-repeat (CRT)-binding factors (CBFs; CBF1 and CBF2) was remarkably upregulated in the receivers [19]. Several studies have also demonstrated that salt-induced VOCs from _Arabidopsis_[17], _Ocinum basilicum_[20], and _V. faba_[18] were significant in priming for salt tolerance in neighbouring receiver plants. Studies involving constitutive [25], stress-induced [18; 21], and exogenously applied [26; 27; 28; 29] VOCs have provided evidence of the role of VOCs in decreasing stomatal conductance (\(g_{s}\)) in non-stressed plants. Studies by [PERSON] et al. [29] confirmed the role of GLV esters; (\(Z\))-3-hexenyl propionate and (\(Z\))-3-hexenyl butyrate; in triggering stomatal closure in tomato as a response to _Pseudomonas syringae_ infection. Another study by [PERSON] et al. [25] noted a decrease in \(g_{s}\) in response to monoterenes from _Prinsepia utilis_ in _V. faba_. Studies suggesting that drought- [30] and salt- [18] stress-induced VOCs elicit entrainment behaviour between co-located stressed and non-stressed plants have been documented. In these studies, a synchronised decrease in \(g_{s}\) in both the emitter and receiver plants has been demonstrated. Although this entrainment behaviour has been mostly observed in \(g_{s}\), it is plausible to assume that VOC-mediated interplant communication may induce entrainment behaviour between co-located stressed and non-stressed plants in other defence-related physiological, metabolic, or molecular responses to biotic and abiotic stressors. Most studies in VOC-mediated interplant communication, either involving biotic or abiotic stresses, have focused on how stress-induced VOCs modulate responses in the non-stressed plants, often referred to in these studies as the'receivers'. This one-way channel communication assumes that the so-called'receivers' have no influence on their stressed neighbours.