The aim of the current study was to determine the floral phenology, nectar secretiondynamics, and honey production potentials of two naturally growing lavender species(L. dentata and L. pubescens), in southwestern Saudi Arabia. In both... more
The aim of the current study was to determine the floral phenology, nectar secretiondynamics, and honey production potentials of two naturally growing lavender species(L. dentata and L. pubescens), in southwestern Saudi Arabia. In both species, floweringis continuous. This means that, when open flowers on a spike are shaded, new flowersemerge. Such a flowering pattern might be advantageous to the plant to minimise competition for pollinators and promote efficient resource allocation. The flowering periods of the two species overlap. Both species secreted increasing amounts of nectar from early morning to late afternoon. The mean maximum volumes of accumulated nectar from bagged flowers occurred at 15:00 for L. pubescens (0.50 ± 0.24 μL/flower) and at 18:00 for L. dentata (0.68 ± 0.19 μL/flower). The volume of the nectar that became available between two successive measurements (three-h intervals) varied from 0.04 μL/flower to 0.28 μL/flower for L. pubescens and from 0.04 μL/flower to 0.35 μL/ flower for L. dentata, This variation reflects the differences in the dynamics of nectar secretion by these species, and indicates the size of the nectar that may be available for flower visitors at given time intervals. The distribution of nectar secretions appears to be an adaptation of the species to reward pollinators for longer duration. Based on the mean amount of nectar sugar secreted by the plants, the honey production potentials of the species are estimated to be 4973.34 mg and 3463.41 mg honey/plant for L. dentata and L. pubescens, respectively.
Acacias are the dominant woody plant species distributed over the vast tracts of land throughout the Arabian Peninsula. However, information on spatio-temporal structuring and pollination biology of the species is not precisely available.... more
Acacias are the dominant woody plant species distributed over the vast tracts of land throughout the Arabian Peninsula. However, information on spatio-temporal structuring and pollination biology of the species is not precisely available. To determine whether any variations exist among the Acacia species in their temporal distribution, their flowering period was determined through monitoring the commencing, peaking and ending of flowering of each species. Moreover, if any variations exist in release of floral rewards among the different co-existing and co-flowering species as mechanisms of partitioning of pollinators, to minimize competition for pollination, the progress of their anthesis over time was recorded by scoring polyads to anthers ratio at different hours of a day. In addition, the amount and dynamics of nectar sugar per inflorescence (N =225/species) was determined following flower nectar sugar washing technique. Types and frequencies of flower visitors and their preferences were determined by recording the visitors 6 times a day. The current study revealed that the Acacia species of the Arabian Peninsula are spatio-temporally structured: some species co-exist yet have different flowering seasons, whereas others co-exist, flowering concurrently yet exhibit a shift in their time of peak flowering and in the time at which the peak pollen is released during the day. This study demonstrates that all Acacia species examined secrete a considerable amount of nectar (2.24±1.72-10.02±4.0mg/inflorescence) which serves as a floral reward for pollinators. Insects of the Order Hymenoptera are the most prevalent visitors to Acacia species in the region. The variations in spatio-temporal structuring of the Acacia species could be due to their adaptation of reducing competition for pollinators and minimizing hetero-specific pollen transfer.
The aim of the current study was to determine the floral phenology, nectar secretion dynamics, and honey production potentials of two naturally growing lavender species (L. dentata and L. pubescens), in southwestern Saudi Arabia. In both... more
The aim of the current study was to determine the floral phenology, nectar secretion dynamics, and honey production potentials of two naturally growing lavender species (L. dentata and L. pubescens), in southwestern Saudi Arabia. In both species, flowering is continuous. This means that, when open flowers on a spike are shaded, new flowers emerge. Such a flowering pattern might be advantageous to the plant to minimise competition for pollinators and promote efficient resource allocation. The flowering periods of the two species overlap. Both species secreted increasing amounts of nectar from early morning to late afternoon. The mean maximum volumes of accumulated nectar from bagged flowers occurred at 15:00 for L. pubescens (0.50 ± 0.24 μL/flower) and at 18:00 for L. dentata (0.68 ± 0.19 μL/flower). The volume of the nectar that became available between two successive measurements (three-h intervals) varied from 0.04 μL/flower to 0.28 μL/flower for L. pubescens and from 0.04 μL/flow...
