Knight Susan E
Center for Limnology, University of Wisconsin, 53706, Madison, WI, USA.
Oecologia. 1992 Mar;89(3):348-355. doi: 10.1007/BF00317412.
Carnivorous plants are usually restricted to nutrient-poor environments, suggesting that there is a cost to caputuring animals that is offset by the benefits of carnivory only under unusual circumstances. One such cost could involve a reduced photosynthetic capacity associated with the growth and maintenance of prey-capture organs. This hypothesis is tested using the common bladderwort, Utricularia macrohiza, which bears numerous distinct prey-capture bladders. Measurements of the photosynthetic and respiration rates of leaves and bladders were incorporated into growth models to estimate the growth rates of plants with and without bladders. Comparisons were made in three lakes which differed in nutrient status and in which plants exhibited marked differences in their densities of prey-capture bladders. Overall, photosynthetic rates for leaves were approximately twice those for bladders while respiration rates did not differ significantly between tissues. Calculations incorporating these values indicate that plants producing both bladders and leaves would grow to as little as 21% or as much as 83% of plants that produced leaves alone. Comparisons among lakes led to the rejection of the hypothesis that plants from some lakes are able to produce more bladders per leaf because bladders differ in their photosynthetic productivity.
食虫植物通常生长在营养贫瘠的环境中，这表明捕捉动物存在一定代价，只有在特殊情况下，食肉的益处才能抵消这一代价。其中一个代价可能与猎物捕捉器官的生长和维持相关的光合作用能力下降有关。本研究使用常见的狸藻——大根狸藻来验证这一假设，大根狸藻有许多独特的猎物捕捉囊。将叶片和捕虫囊的光合速率和呼吸速率测量值纳入生长模型，以估计有捕虫囊和没有捕虫囊的植物的生长速率。在三个营养状况不同的湖泊中进行了比较，这些湖泊中的植物在猎物捕捉囊的密度上表现出显著差异。总体而言，叶片的光合速率约为捕虫囊的两倍，而不同组织之间的呼吸速率没有显著差异。结合这些值的计算表明，同时产生捕虫囊和叶片的植物生长量仅为只产生叶片的植物的21%至83%。湖泊之间的比较导致否定了以下假设：来自某些湖泊的植物能够在每片叶子上产生更多的捕虫囊，因为捕虫囊的光合生产力不同。
