Duarte Miguel A, Woo Sabrina, Hultine Kevin, Blonder Benjamin, Aparecido Luiza Maria T
School of Life Sciences, Arizona State University, 427 E Tyler Mall, Tempe, AZ 85281, USA.
Department of Research, Conservation and Collections, Desert Botanical Garden, 1201 N. Galvin Parkway, Phoenix, AZ 85008, USA.
AoB Plants. 2023 Jan 24;15(2):plad002. doi: 10.1093/aobpla/plad002. eCollection 2023 Feb.
Herbivory can impact gas exchange, but the causes of interspecific variation in response remain poorly understood. We aimed to determine (1) what effects does experimental herbivory damage to leaf midveins have on leaf gas exchange and, (2) whether changes in leaf gas exchange after damage was predicted by leaf mechanical or venation traits. We hypothesized that herbivory-driven impacts on leaf gas exchange would be mediated by (1a/1b) venation networks, either by more vein resistance, or possibly trading off with other structural defenses; (2a/2b) or more reticulation (resilience, providing more alternate flow pathways after damage) or less reticulation (sectoriality, preventing spread of reduced functionality after damage). We simulated herbivory by damaging the midveins of four leaves from each of nine Sonoran Desert species. We then measured the percent change in photosynthesis (), transpiration () and stomatal conductance () between treated and control leaves. We assessed the relationship of each with leaf venation traits and other mechanical traits. varied between +10 % and -55%, similar to (+27%, -54%) and (+36%, -53%). There was no tradeoff between venation and other structural defenses. Increased damage resilience (reduced , , ) was marginally associated with lower force-to-tear ( < 0.05), and higher minor vein density ( < 0.10) but not major vein density or reticulation. Leaf venation networks may thus partially mitigate the response of gas exchange to herbivory and other types of vein damage through either resistance or resilience.
食草作用会影响气体交换，但对于种间反应差异的原因仍知之甚少。我们旨在确定：（1）实验性食草作用对叶片中脉造成的损伤对叶片气体交换有何影响；（2）损伤后叶片气体交换的变化是否可由叶片机械特性或叶脉特征预测。我们假设食草作用对叶片气体交换的影响将通过以下方式介导：（1a/1b）叶脉网络，要么通过更大的叶脉阻力，要么可能与其他结构防御进行权衡；（2a/2b）或者更多的网状结构（弹性，损伤后提供更多的替代流动途径）或更少的网状结构（扇形分布，防止损伤后功能降低的扩散）。我们通过损伤九种索诺兰沙漠植物中每种植物的四片叶子的中脉来模拟食草作用。然后我们测量了处理叶片和对照叶片之间光合作用（）、蒸腾作用（）和气孔导度（）的变化百分比。我们评估了每种特性与叶片叶脉特征和其他机械特性之间的关系。变化范围在 +10% 至 -55% 之间，与（+27%，-54%）和（+36%，-53%）相似。叶脉与其他结构防御之间没有权衡关系。损伤恢复能力增强（降低，，）与较低的撕裂力（<0.05）和较高的小叶脉密度（<0.10）略有相关，但与大叶脉密度或网状结构无关。因此，叶片叶脉网络可能通过阻力或弹性部分减轻气体交换对食草作用和其他类型叶脉损伤的反应。
