Dynamics of Nectar Production and Nectar Homeostasis in Male Flowers of Cucurbita pepo L.

Abstract

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Floral Phenology, Nectar Secretion Dynamics, and Honey Production Potential, of Two Lavender Species (Lavandula Dentata, and L. Pubescens ) in Southwestern Saudi Arabia

“…The decline in the amount of nectar in bagged L. pubescens flowers after 15:00 might be attributable to the reabsorption of secreted nectar by the plants. The reabsorption and modification of unconsumed nectar is considered a strategy for the partial recovery of the energy cost invested in nectar production for numerous species (Nepi and Stpiczyńska, 2008;Nepi et al, 2011). The mean temperature (35.7°C for L. pubescens and 28.3°C for L. dentata) and relative humidity (28.7% for L. pubescens and 37.7% for L. dentata) at which the highest nectar volumes were recorded, might be considered the optimal weather conditions for maximum nectar production and effective pollination for each species.…”

Amino acids and protein profile in floral nectar: Much more than a simple reward

“…Although the C. pepo invertase is certainly apoplastic, its exact location remains unknown. It may be a true secretion protein or, alternatively, it may be a cell wall-bound invertase that is leached by the high nectar flow through the nectary tissue (Nepi et al, 2011a).…”

“…dilution) and viscosity (Nicolson and Thorburg, 2007). Nectar homeostatic mechanisms enable regulation of nectar volume, concentration and thus, viscosity by compensating for water loss due to evaporation (Nepi et al, 2011a). Dilution influences the concentration of sugars and their availability to pollinators.…”

“…Depending on humidity, nectar may lose or gain water from the atmosphere. Variation in nectar concentration due to water loss or water uptake can be adjusted within a certain range (nectar homeostasis, Nepi et al, 2011a). The functions of each chemical component are also indicated (in italics).…”

“…Moreover, new unpublished results relating to the floral nectar of Cucurbita pepo L. are presented. This plant is a monoecious species bearing unisexual flowers, and much information concerning the composition of its nectar and the dynamics of nectar production is currently available (Nepi and Stpiczyńska, 2007;Nepi et al, 1996Nepi et al, , 2001Nepi et al, , 2011a. For this reason, C. pepo was chosen by us as an experimental model for the study of nectar biology, together with determination of nectar amino acids and proteins, in an ecological and evolutionary context, and this approach may in turn open up a new and exciting field of research.…”