Filipiak Michał, Shields Morgan W, Cairns Sarah M, Grainger Megan N C, Wratten Stephen D
Institute of Environmental Sciences, Faculty of Biology, Jagiellonian University, Kraków, Poland.
Bio-Protection Research Centre, Lincoln University, Lincoln, New Zealand.
Front Plant Sci. 2022 Nov 1;13:1042348. doi: 10.3389/fpls.2022.1042348. eCollection 2022.
Sodium (Na) concentrations are low in plant tissues, and its metabolic function in plants is minor; however, Na is a key nutrient for plant consumers. Previous studies have thus far focused on Na concentration. Nevertheless, a balanced potassium (K) to Na ratio () is more important than Na concentration alone since food with high has detrimental effects on consumers irrespective of Na concentration. Therefore, plants may actively regulate in their tissues and products, shaping plant-insect interactions. Studies considering nutritional aspects of plant-insect interactions have focused on nonreproductive tissues and nectar. In this study, we consider pollen as serving a primary reproductive function for plants as well as a food of pollinivores. Plants might regulate in pollen to affect their interactions with pollinivorous pollinators. To investigate whether such a mechanism exists, we manipulated Na concentrations in soil and measured the proportion of K, Na, and 13 other nutrient elements in the pollen of two sunflower () cultivars. This approach allowed us to account for the overall nutritional quality of pollen by investigating the proportions of many elements that could correlate with the concentrations of K and Na. Of the elements studied, only the concentrations of Na and K were highly correlated. Pollen was high in both cultivars irrespective of Na fertilization, and it remained high regardless of pollen Na concentration. Interestingly, pollen did not decrease as pollen increased the Na concentration. We hypothesize that high in pollen might benefit plant fertilization and embryonic development; therefore, a tradeoff might occur between producing low pollen as a reward for pollinators and high pollen to optimize the plant fertilization process. This is the first study to provide data on pollen regulation by plants. Our findings broaden the understanding of plant-bee interactions and provide a foundation for a better understanding of the role of the soil-plant-pollen-pollinator pathway in nutrient cycling in ecosystems. Specifically, unexplored costs and tradeoffs related to balancing the by plants and pollinivores might play a role in past and current shaping of pollination ecology.
植物组织中的钠（Na）浓度较低，其在植物中的代谢功能也较小；然而，钠是植物消费者的关键营养素。以往的研究迄今为止主要集中在钠浓度上。尽管如此，钾（K）与钠的平衡比（）比单独的钠浓度更为重要，因为无论钠浓度如何，高的食物对消费者都有有害影响。因此，植物可能会积极调节其组织和产品中的，从而塑造植物与昆虫的相互作用。考虑植物与昆虫相互作用营养方面的研究主要集中在非生殖组织和花蜜上。在本研究中，我们认为花粉对植物具有主要的生殖功能，同时也是食花粉者的食物。植物可能会调节花粉中的以影响它们与食花粉传粉者的相互作用。为了研究这种机制是否存在，我们操纵土壤中的钠浓度，并测量了两个向日葵（）品种花粉中钾、钠和其他13种营养元素的比例。这种方法使我们能够通过研究许多可能与钾和钠浓度相关的元素比例来考虑花粉的整体营养质量。在所研究的元素中，只有钠和钾的浓度高度相关。无论是否施用钠肥，两个品种的花粉都很高，并且无论花粉钠浓度如何，其都保持在较高水平。有趣的是，随着花粉钠浓度的增加，花粉并没有降低。我们假设花粉中的高可能有利于植物受精和胚胎发育；因此，在生产低花粉作为对传粉者的奖励与生产高花粉以优化植物受精过程之间可能会出现权衡。这是第一项提供植物调节花粉数据的研究。我们的发现拓宽了对植物与蜜蜂相互作用的理解，并为更好地理解土壤-植物-花粉-传粉者途径在生态系统养分循环中的作用提供了基础。具体而言，植物和食花粉者在平衡方面相关的未被探索的成本和权衡可能在过去和当前授粉生态学的形成中发挥作用。
