Wilkens Richard T, Shea Gabriel O, Halbreich Stephen, Stamp Nancy E
Southern Research Station, 2500 Shreveport Highway, RWU-4501, 71360, Pineville, LA, USA.
Department of Biological Sciences, Binghamton University, State University of New York, 13902-6000, Binghamton, NY, USA.
Oecologia. 1996 Apr;106(2):181-191. doi: 10.1007/BF00328597.
We conducted two experiments to determine how resource availability influenced allocation by tomato (Lycopersicon esculentum) to trichomes, and how different patterns of trichome allocation by plants grown in different resource environments might then influence the behavior of tobacco hornworm (Manduca sexta) caterpillars. In the first experiment we used high and low levels of light and water, and then, using scanning electron microscopy, determined trichome densities on the leaves and stems. We sampled leaves and stems at several places throughout the plant to determine whether there were within-plant differences in allocation to trichomes. The results of the first experiment showed that resource availability influenced allocation to trichome growth. Patterns in high and low-light supported both the growth-differentiation balance hypothesis (GDBH) and the carbon-nutrient balance hypothesis (CNBH). However, the GDBH was not supported by differences among water treatments. Contrary, to predictions of the GDBH, plants with intermediate growth did not have the highest trichome densities, and plants with similar growth differed in trichome density. Possible biological and artifactual explanations are discussed. The first experiment also showed that there was within-plant variation in allocation to trichomes, and that plant resource availability may influence within-plant variation in allocation to trichomes. In the second experiment, we grew plants in high and low-light, and then monitored the behavior of tobacco hornworms on the stems of these plants in the laboratory. This experiment demonstrated that the light environment that tomato plants were grown in influenced the resting behavior of caterpillars. Furthermore, it demonstrated that both glandular and non-glandular trichomes impeded caterpillars from searching for food. Overall, this study indicated that plant resource availability can influence allocation to trichome defenses, and that these differences may affect insect herbivores.
我们进行了两项实验，以确定资源可利用性如何影响番茄（Lycopersicon esculentum）对毛状体的分配，以及在不同资源环境中生长的植物的不同毛状体分配模式如何影响烟草天蛾（Manduca sexta）幼虫的行为。在第一个实验中，我们设置了高、低光照和水分水平，然后使用扫描电子显微镜确定叶片和茎上的毛状体密度。我们在整株植物的多个部位采集叶片和茎，以确定植物内部在毛状体分配上是否存在差异。第一个实验的结果表明，资源可利用性影响了对毛状体生长的分配。高、低光照模式同时支持生长-分化平衡假说（GDBH）和碳-营养平衡假说（CNBH）。然而，水分处理之间的差异并不支持GDBH。与GDBH的预测相反，生长中等的植物并没有最高的毛状体密度，生长相似的植物在毛状体密度上也存在差异。文中讨论了可能的生物学和人为因素解释。第一个实验还表明，植物内部在毛状体分配上存在差异，并且植物资源可利用性可能影响植物内部在毛状体分配上的差异。在第二个实验中，我们在高、低光照条件下种植植物，然后在实验室中监测烟草天蛾在这些植物茎上的行为。该实验表明，番茄植株生长的光照环境影响了幼虫的静止行为。此外，该实验还表明，腺毛和非腺毛都会阻碍幼虫觅食。总体而言，这项研究表明，植物资源可利用性会影响对毛状体防御的分配，并且这些差异可能会影响食草昆虫。
