Floral nectar production: what cost to a plant?

Abstract

Floral nectar production is central to plant pollination, and hence to human wellbeing. As floral nectar is essentially a solution in water of various sugars, it is likely a valuable plant resource, especially in terms of energy, with plants experiencing costs/trade‐offs associated with its production or absorption and adopting mechanisms to regulate nectar in flowers. Possible costs of nectar production may also influence the evolution of nectar volume, concentration and composition, of pollination syndromes involving floral nectar, and the production of some crops.There has been frequent agreement that costs of floral nectar production are significant, but relevant evidence is scant and difficult to interpret. Convincing direct evidence comes from experimental studies that relate either enhanced nectar sugar production (through repeated nectar removal) to reduced ability to produce seeds, or increased sugar availability (through absorption of additional artificial nectar) to increased seed production. Proportions of available photosynthate allocated by plants to nectar production may also indicate nectar cost. However, such studies are rare, some do not include treatments of all (or almost all) flowers per plant, and all lack quantitative cost–benefit comparisons for nectar production. Additional circumstantial evidence of nectar cost is difficult to interpret and largely equivocal.Future research should repeat direct experimental approaches that relate reduced or enhanced nectar sugar availability for a plant with consequent ability to produce seeds. To avoid confounding effects of inter‐flower resource transfer, each plant should experience a single treatment, with treatment of all or almost all flowers per plant. Resource allocation by plants, pathways used for resource transfer, and the locations of resource sources and sinks should also be investigated.Future research should also consider extension of nectar cost into other areas of biology. For example, evolutionary models of nectar production are rare but should be possible if plant fitness gains and costs associated with nectar production are expressed in the same currency, such as energy. It should then be possible to understand observed nectar production for different plant species and pollination syndromes involving floral nectar. In addition, potential economic benefits should be possible to assess if relationships between nectar production and crop value are evaluated.

Utilization of solid organic waste as a biofertilizer formulation for upland rice plants supports sustainable rice farming

“…One of the nutrients that can affect flowering age is P element. The presence of P in plants functions as a storage and transfer of energy that is useful for spurring flower formation and fruit/seed maturation [18]. The biofertilizers given contains the nutrients needed by rice plants.…”

Flowering phenology differs among wet and dry sub-alpine meadows in southwestern China

“…Floral longevity is a key reproductive trait in animal-pollinated species that determines the chances of pollen dispersal and pollen capture by stigmas ( Primack, 1985 ; Ashman and Schoen, 1994 ; Ashman et al , 2004 ; Miller-Rushing and Primack, 2008 ; Song et al , 2022 ). Furthermore, it is also associated with the mating system ( Primack, 1985 ; Ashman et al , 2004 ; Lozada-Gobilard et al , 2019 ), the cost of flower production and floral rewards ( Stratton, 1989 ; Ashman and Schoen, 1994 ; Gao et al , 2015 ; Descamps et al , 2020 , 2021 ; Pyke and Ren, 2023 ), and as such, can influence the number and quality of offspring produced ( Ashman and Schoen, 1994 ; Evanhoe and Galloway 2002 ; Itagaki and Sakai 2006 ; Song et al , 2022 ). Although determining the magnitude of floral longevity variation across contrasting habitats (e.g.…”

“…Abiotic factors, those associated with the surrounding ecological environment, i.e. temperature and water availability, can influence the cost of flower maintenance through respiration and transpiration, directly affecting flowering phenology ( Primack, 1985 ; Yasaka et al , 1998 ; Ashman et al , 2004 ; Pacheco et al , 2016 ; Pyke and Ren, 2023 ). For example, drier habitats can influence those floral characteristics significantly associated with pollination, fertilization and viable seed production.…”

How many animal‐pollinated angiosperms are nectar‐producing?

“…Despite the overwhelming importance of nectar in the ecology and evolution of plant–pollinator mutualisms, there are still elementary unanswered questions regarding nectar spatiotemporal distribution and its role in shaping ecological communities (Pacini et al ., 2003; Mitchell, 2004; Pyke, 2016; Roy et al ., 2017; Pyke & Ren, 2023). For instance, over decades, numerous authors have recurrently asserted that ‘most flowering plants produce nectar’, often concluding that most animals visiting flowers rely on nectar as one of the main floral resources angiosperms produce for pollinators (e.g.…”