Portillo-Estrada Miguel, Kazantsev Taras, Niinemets Ülo
Centre of Excellence PLECO, Department of Biology, University of Antwerp, Universiteitsplein 1, 2610, Wilrijk, Belgium.
Department of Plant Physiology, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, 51014, Tartu, Estonia.
J Plant Res. 2017 Jan;130(1):157-165. doi: 10.1007/s10265-016-0880-6. Epub 2016 Nov 24.
The release of stress-driven volatiles throughout leaf development has been little studied. Therefore, we subjected poplar leaves during their developmental stage (from 2 days to 2 weeks old) to wounding by a single punch hole, and measured online the wound-induced volatile organic compound emissions. Our study shows that the emission of certain volatile compounds fades with increasing leaf age. Among these compounds we found lipoxygenase products (LOX products), acetaldehyde, methyl benzoate, methyl salicylate, and mono- and sesquiterpenes. In parallel, we studied the fading of constitutive emissions of methanol during leaf maturation, as well as the rise in isoprene constitutive emission during leaf maturation and its relationship to leaf photosynthetic capacity. We found highly significant relationships between leaf chlorophyll content, photosynthetic capacity, and leaf size during leaf ageing. As the level of constitutive defences increases with increasing leaf age, the strength of the volatile signal is expected to be gradually reduced. The higher elicitation of volatile organic compound emissions (especially LOX products) in younger leaves could be an evolutionary defence against herbivory, given that younger leaves are usually more subjected to infestation and herbivory.
在叶片整个发育过程中，应激驱动的挥发性物质释放情况鲜有研究。因此，我们对处于发育阶段（2天至2周龄）的杨树叶片进行单孔打孔创伤处理，并在线测量创伤诱导的挥发性有机化合物排放。我们的研究表明，某些挥发性化合物的排放随叶片年龄增长而减弱。在这些化合物中，我们发现了脂氧合酶产物（LOX产物）、乙醛、苯甲酸甲酯、水杨酸甲酯以及单萜和倍半萜。同时，我们研究了叶片成熟过程中甲醇组成型排放的减弱情况，以及叶片成熟过程中异戊二烯组成型排放的增加及其与叶片光合能力的关系。我们发现叶片衰老过程中叶片叶绿素含量、光合能力和叶片大小之间存在高度显著的关系。由于组成型防御水平随叶片年龄增长而增加，挥发性信号的强度预计会逐渐降低。鉴于幼叶通常更容易受到侵害和食草动物的攻击，幼叶中挥发性有机化合物排放（尤其是LOX产物）的更高诱导可能是一种针对食草动物的进化防御。
