Key Laboratory of Geographical Processes and Ecological Security in Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Changchun, China.
State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, Institute for Peat and Mire Research, Northeast Normal University, Changchun, China.
Plant Biol (Stuttg). 2024 Mar;26(2):214-222. doi: 10.1111/plb.13610. Epub 2024 Jan 8.
Defence theories provide predictions about trade-offs in the allocation of resources to defence and growth. However, very little is known about how pressure from herbivores influences the allocation of resources during reproduction. Two common peatland bryophyte species, Sphagnum angustifolium and S. capillifolium, were chosen as study species. Vegetative and reproductive shoots of both Sphagnum species were subjected to treatments with and without herbivores in a lab experiment. After 4 weeks of exposure to herbivores in a growth chamber, we measured biomass production, net photosynthesis rate, defence traits (phenolics in leachate and phenolics in extract), nonstructural carbohydrates (soluble sugar and starch), and reproductive traits (capsule number, weight and diameter, and spore germination) of both Sphagnum species. Reproductive shoots had higher constitutive defence than vegetative shoots in S. angustifolium, and a similar pattern was observed in S. capillifolium. With herbivory, reproductive shoots showed stronger induced defence (released more phenolics) than vegetative shoots in S. capillifolium, but not in S. angustifolium. Herbivory had no effect on capsule number, weight, or diameter, but reduced spore germination percentage by more than half in both species. Our study highlights the hidden effects of herbivory on reproduction of Sphagnum and indicates the presence of maternal effects in bryophytes. Ecologists will benefit from examining both quality- and quantity-based traits when attempting to estimate the herbivory effect on plant fitness.
防御理论提供了关于资源分配在防御和生长之间权衡的预测。然而，关于食草动物压力如何影响繁殖过程中资源分配的信息知之甚少。两种常见的泥炭藓植物，狭叶泥炭藓和细叶泥炭藓，被选为研究物种。在实验室实验中，对这两种泥炭藓的营养和生殖枝分别进行了有无食草动物的处理。在生长室中暴露于食草动物 4 周后，我们测量了两种泥炭藓的生物量生产、净光合速率、防御特性（渗出液中的酚类和提取物中的酚类）、非结构性碳水化合物（可溶性糖和淀粉）和生殖特性（胶囊数量、重量和直径以及孢子萌发）。在狭叶泥炭藓中，生殖枝的组成型防御高于营养枝，在细叶泥炭藓中也观察到类似的模式。在有食草动物的情况下，与营养枝相比，生殖枝的诱导防御更强（释放出更多的酚类物质），而在狭叶泥炭藓中则没有这种情况。食草动物对胶囊数量、重量或直径没有影响，但在两种物种中，孢子萌发率都降低了一半以上。我们的研究强调了食草动物对泥炭藓繁殖的隐藏影响，并表明在苔藓植物中存在母体效应。生态学家在试图估计食草动物对植物适应性的影响时，将受益于同时检查基于质量和数量的特性。
