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Open Access item Intraplant variation in nectar traits in Helleborus foetidus (Ranunculaceae) as related to ﬂoral phase, environmental conditions and pollinator exposure
Herrera, Carlos M.
García, Isabel M.
|Keywords:||Andalusia, Cazorla, Fructose, Glucose, Growth conditions, Sucrose|
|Citation:||Flora 206 (2011) 668–675|
|Abstract:||Factors that contribute to variation in nectar sugar composition, nectar concentration and volume have been a central concern in studies of pollinator assemblages in angiosperms. In an effort to better under- stand the mechanisms underlying variation in nectar traits, we designed a series of experiments with ﬂowering Helleborus foetidus individuals under natural and glasshouse conditions, to identify intraplant variation in nectar traits which depend on both intrinsic (sexual phases of individual ﬂowers) and exter- nal (pollinator visits and plant growth conditions) factors. The results showed that nectar volume, sugar composition and concentration in Helleborus foetidus varied between ﬂoral sexual phases, environmental growing conditions, and levels of ﬂower exposure to pollinator visits. Processes of mate-limitation in male reproductive success or pollen-limitation in female success, as well as ﬂower protogyny and holocrine secretion of nectaries may be involved in nectar variability between ﬂoral phases. By comparing different environments we observed that nectar volume and concentration at the nectary and ﬂower level were plastic traits sensitive to external conditions, emphasizing responsiveness to environmental changes and a consequent plasticity in nectar traits such as sugar concentration and volume. Nectar sugar composi- tion did not respond to different growing conditions, suggesting that this is an intrinsic characteristic of this species, but pollinator exposure produced signiﬁcant changes in the nectar of single nectaries, particularly in the sucrose–fructose balance. Future research on nectar ecology and nectar chemistry will need to consider that nectar traits exhibit different kinds of variation at the intraplant level and under different environmental conditions.|
|Publisher version (URL):||http://dx.doi.org/10.1016/j.flora.2011.02.003|
|Appears in Collections:||(EBD) Artículos|
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