Naturalis Biodiversity Center, Leiden, The Netherlands.
Research Center for Biosystematics and Evolution, National Research and Innovation Agency (BRIN), Cibinong, Bogor, Indonesia.
PLoS One. 2023 Aug 18;18(8):e0285731. doi: 10.1371/journal.pone.0285731. eCollection 2023.
Protective structures in the epidermis are essential for land plants to defend themselves against herbivores. In this study, we investigated the effect of different types of trichomes of three orchids, Calanthe triplicata, Dendrochilum pallidiflavens and Trichotosia ferox, on attachment of herbivorous land snails, using histochemistry and centrifuge experiments. Size, ornamentation and histochemistry of epicuticular trichomes on the orchid leaves were assessed with light microscopy, scanning electron microscopy and transmission electron microscopy. Total forces needed to detach two differently shaped snail species, Subulina octona and Pleurodonte isabella, were measured using a turntable equipped with a synchronized strobe. Snails were placed in two positions, either perpendicular or parallel to the main veins on the orchid leaves, both on the adaxial (= upper) or abaxial (= lower) side. The results obtained provided three new insights. First, a perpendicular or parallel position of the snails to the main veins did not significantly affect the attachment performance of either species tested. Secondly, snails detached significantly easier on leaf sides covered with a high density of lignin filled epicuticular trichomes. Thirdly, the removal of glandular trichomes did not affect the attachment forces; however, the absence of lignified trichomes increased the attachment of the snails. Our study highlights the importance of studying micro-ornamentation in combination with performance for obtaining a better understanding of the defense mechanisms employed by different species of orchids to deter herbivorous snails.
表皮中的保护结构对于陆生植物防御草食动物至关重要。在这项研究中，我们使用组织化学和离心实验研究了三种兰花（Calanthe triplicata、Dendrochilum pallidiflavens 和 Trichotosia ferox）的三种不同类型的毛状体对草食性陆生蜗牛附着的影响。使用光学显微镜、扫描电子显微镜和透射电子显微镜评估了兰花叶片上的表皮毛状体的大小、装饰和组织化学。使用配备同步频闪器的转盘测量了两种不同形状的蜗牛（Subulina octona 和 Pleurodonte isabella）需要的总分离力。蜗牛被放置在两个位置，一个与兰花叶片的主叶脉垂直或平行，分别在叶片的上侧（=上侧）或下侧（=下侧）。获得的结果提供了三个新的见解。首先，蜗牛与主叶脉垂直或平行的位置不会显著影响两种测试物种的附着性能。其次，在覆盖有高密度木质素填充表皮毛状体的叶片侧，蜗牛更容易脱落。第三，去除腺毛状体不会影响附着力；然而，缺乏木质化毛状体增加了蜗牛的附着。我们的研究强调了研究微观装饰与性能相结合的重要性，以更好地理解不同兰花物种用来抵御草食性蜗牛的防御机制。
