Ye Jiayan, Jiang Yifan, Veromann-Jürgenson Linda-Liisa, Niinemets Ülo
Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia.
Estonian Academy of Sciences, Kohtu 6, 10130 Tallinn, Estonia.
Trees (Berl West). 2019 Feb;33(1):37-51. doi: 10.1007/s00468-018-1756-2. Epub 2018 Sep 3.
Poplar spiral gall aphid () forms galls on the petiole in poplars () and mass infestations are frequent in poplar stands, but how these parasite gall infestations can affect the leaf lamina structure, photosynthetic rate and constitutive and stress volatile emissions is unknown. We investigated how the infestation by the petiole gall aphids affects lamina photosynthetic characteristics (net assimilation rate, stomatal conductance), C and N contents, and constitutive isoprene and induced volatile emissions in × . The dry gall mass per leaf dry mass ( / ) was used as a quantitative measure of the severity of gall infestation. Very high fraction of leaf biomass was invested in gall formation with / varying between 0.5-2. Over the whole range of the infestation severities, net assimilation rate per area, leaf dry mass per unit area and N content decreased with increasing the severity of infestation. In contrast, stomatal conductance, leaf dry mass per fresh mass, constitutive isoprene emissions, and induced green leaf volatile (GLV), monoterpene, sesquiterpene and benzenoid emissions increased with increasing the severity of gall infestation. The rates of induced emissions were low and these emissions were associated with methyl jasmonate release from leaf laminas. The data demonstrate that petiole gall infestations lead to major changes in leaf lamina sink-source relationships and leaf water relations, thereby significantly altering lamina photosynthesis. Modifications in stress-induced emissions likely indicated systemic signaling triggered by jasmonate transported from the petiole galls to the lamina where jasmonate elicited a cascade of volatile emission responses. Enhance isoprene emissions and induced volatile emissions can play a major role in indirect defense against other herbivores, securing the food source for the gall aphids. In conclusion, a massive infestation by petiole gall aphids can profoundly modify the foliage photosynthetic performance and volatile emission profiles in poplars.
杨树螺旋瘿蚜在杨树叶柄上形成虫瘿，在杨树林中常有大量虫害发生，但这些寄生性虫瘿虫害如何影响叶片结构、光合速率以及组成型和胁迫挥发性物质排放尚不清楚。我们研究了叶柄瘿蚜的侵害如何影响×杨树叶片的光合特性（净同化率、气孔导度）、碳和氮含量以及组成型异戊二烯和诱导挥发性物质排放。每片叶干质量的干瘿质量（/）被用作衡量瘿害严重程度的定量指标。叶片生物量的很大一部分用于形成虫瘿，/在0.5 - 2之间变化。在整个虫害严重程度范围内，单位面积净同化率、单位面积叶干质量和氮含量随虫害严重程度增加而降低。相反，气孔导度、单位鲜质量叶干质量、组成型异戊二烯排放以及诱导的绿叶挥发物（GLV）、单萜、倍半萜和苯类化合物排放随瘿害严重程度增加而增加。诱导排放速率较低，这些排放与叶片中茉莉酸甲酯的释放有关。数据表明，叶柄瘿害导致叶片源库关系和叶水关系发生重大变化，从而显著改变叶片光合作用。胁迫诱导排放的改变可能表明由从叶柄虫瘿运输到叶片的茉莉酸触发的系统信号传导，其中茉莉酸引发了一系列挥发性排放反应。增强的异戊二烯排放和诱导挥发性排放可能在对其他食草动物的间接防御中起主要作用，为瘿蚜确保食物来源。总之，叶柄瘿蚜的大量侵害可深刻改变杨树叶片的光合性能和挥发性排放特征。
