Litter inputs and plant interactions affect nectar sugar content
Litter inputs and plant interactions affect nectar sugar content
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DOI：
10.1111/j.1365-2745.2011.01793.x
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发表时间：
2011-05-01
影响因子：
5.5
通讯作者：
Raynaud, Xavier
中科院分区：
文献类型：
--
作者：
Baude, Mathilde;Leloup, Julie;Raynaud, Xavier
传粉者可获得的植物资源的减少是传粉者丧失的一个主要原因。管理植物群落以增加花卉资源通常被认为是维持传粉者种群的一种方式。花蜜是传粉者的主要能量来源，在传粉者群落的行为和组成中起着核心作用。已知非生物和生物因素在物种和群落水平上影响花蜜性状，但植物群落组成本身的影响从未被调查过。植物群落中的地下相互作用可以通过(I)植物来源的凋落物改良土壤和(Ii)植物之间对土壤资源的竞争来诱导植物发育的变化。我们测试了植物地下相互作用如何影响与植物对传粉者的吸引力有关的地上花蜜性状。短期盆栽试验表明，3种温带草地植物滴水草、羊肚菌和紫花苜蓿对土壤资源具有明显的凋落物化学计量学和竞争能力。凋落物改良(无、单一和三种特定凋落物)和植物互作处理(单一栽培、两种和三种混合)采用析因设计。对土壤进行凋落物改良剂处理后，大叶锦鸡儿植株的总花蜜糖含量增加，而其他两种植物的花蜜总糖含量没有增加。我们还发现，竞争种斑潜蝇的存在通过减少每朵花的花蜜体积和花朵展示大小来降低花蜜总糖含量，但对其他物种没有影响。因此，观察到花蜜性状对土壤氮素有效性变化的物种特异性反应，表明植物物种和群落对传粉者的吸引力。然而，我们没有发现豆科植物紫花苜蓿影响任何邻近植物花蜜性状的证据。综合。我们的结果表明，凋落物输入和植物之间对土壤资源的竞争可以改变与植物对传粉者的吸引力有关的花蜜性状。这支持了这样的观点，即土壤资源的地下植物-植物相互作用可以影响地上植物-植物为授粉服务的相互作用。这为研究地下-地上相互作用在较高营养水平上的作用提供了很有前途的前景。
P>1. Declines in availability of plant resources to pollinators are a major cause of pollinator loss. The management of plant communities to enhance floral resources is often proposed as a way to sustain pollinator populations. Nectar, the main energetic resource for pollinators, plays a central role in behaviour and composition of pollinator communities. Abiotic and biotic factors are known to influence nectar traits at both the species and community levels, but the impact of plant community composition itself has never been investigated.2. Below-ground interactions in plant communities can induce changes in plant development through (i) plant-derived litter amendment of the soil and (ii) competition for soil resources between plants. We tested how plant below-ground interactions affect above-ground nectar traits involved in plant attractiveness to pollinators.3. A short-term pot experiment was carried out with three temperate grassland species Mimulus guttatus, Lamium amplexicaule, and Medicago sativa, showing distinct litter stoichiometry and competitive abilities for soil resources. Litter amendment (none, mono and tri-specific litter) and plant interaction treatments (monocultures, two- and three-species mixtures) were crossed in a factorial design.4. Litter amendment to the soil led to an increase in total nectar sugar content in L. amplexicaule plants but not in the two other species. We also found that the presence of M. guttatus, a competitive species, reduced the total nectar sugar content in L. amplexicaule through a concomitant decrease in nectar volume per flower and in floral display size, but not in other species. Species-specific responses of nectar traits to variation in soil nitrogen availability were thus observed, suggesting consequences for plant species and community attractiveness to pollinators. However, we did not find evidence that the legume M. sativa affected nectar traits of any neighbouring plants.5. Synthesis. Our results demonstrate that litter inputs and competition between plants for soil resources can alter nectar traits linked to plant attractiveness to pollinators. This supports the idea that below-ground plant-plant interactions for soil resources can influence above-ground plant-plant interactions for pollination services. This offers promising perspectives in studying the role of below-ground-above-ground interactions on higher trophic levels.