Correlation between the Change in the Number of Apis mellifera Worker Bees and Nectar Secretion of Nectariferous Plants

[Objective] This study aimed to clarify the correlation between changes of Apis mel ifera and the nectar secretion characteristics of nectariferous plants. [Method] Considering the nectar secretion characteristics of major and auxiliary nec-tariferous plants, six Apis mel ifera colonies were selected for measure the number of eggs, larvae, pupae and adult bees from Jan. to Dec. in 2012; based on that, their annual change curves were also plotted. [Result] The results showed that there were three peaks of the total number of A. mel ifera workers throughout the year：the first occurred on May 15th, with bees developed into an ideal population for col-lecting pomegranate nectar, and the second and third peaks occurred on July 15th and Oct. 15th, respectively, with bees developed into an ideal population for col ect-ing E. ciliate （Thuab） Hyland. [Conclusion] Prevention of Varroa jacobsoni should be carried out with two or more types of acaricides at the late nectar flow stages of the two nectariferous plants（pomegranate and E. ciliate （Thuab） Hyland） when there was a nectar deficiency. Prevention of Tropilaelaps clareae should be timely per-formed with sublimed sulfur in conjunction with acaricides. This study provides a theoretical basis for the high-quality and high-yielding production of honey, as wel as for the product safety.

A List of Important Honeybee Nectariferous and Polleniferous Plant Species in the West Bank Governorates, Palestine

The main goal of this study is to provide information about the foraging value of a number of specific plant species for honeybees in Palestine, since one of the limiting factors of Palestine＇s apiculture industry is the unpredicted seasonality in the blooming phenology of nectariferous and polleniferous plant species. This limiting factor can be overcome by increasing and diversifying the population of bee forage plant species throughout man made plantations. In this survey, a combination of literature and field surveys were used in order to identify and compile a list of plant species, which are of importance for fulfilling the honeybee＇s needs of nectar and pollen. The study was conducted through bi-weekly visit to a numbers of randomly selected sites located in some nature reserves and agricultural fields, within the West Bank Governorates. A total of 143 nectariferous and polleniferous plant species, belonging to 37 families, were identified through direct observation of foraging bees, and/or through literature survey. The dominant families are Compositae with 27 （18.8%） belonging species, followed by Lamiaceae family with 24 （16.7%） belonging species, then followed by Boraginaceae family with 8 （5.5%） belonging species and then followed by other families. The identified plant species was grouped into pollen, nectar and both pollen and nectar sources plant species. The polleniferous plant species group counted 17 which is equivalent to 11.8%; the nectariferous plant species group counted 29 which is equivalent to 20.2%; and the third groups of plant species that have been visited by bees for collecting both pollen and nectar counted 97, which is equivalent to 68%. The chronologies of the blooming plant species were also recorded. It was concluded that any of the studied locations can be profitably utilized for commercial and or large scale beekeeping, if the important limiting factor can be overcome by increasing and diversifying the population of bee forage plant species throughout man made plantations. The paper provides information on the wild and cultivated nectariferous and polleniferous plants that are important for the bees in the West Bank Governorates, Palestine.

Cytological Studies on the Development of Sieve Element and Floral Nectary Tissue in Arabidopsis thaliana

Ultrastructural changes in the sieve element and dense cells of nectariferous tissue during the development of floral nectary in Arabidopsis thaliana L. were investigated with transmission electron microscopy. Samples were prepared with high pressure freezing and freeze substitution techniques. The ultrastructure of dense cell was similar to that of sieve element at its early developmental stage. With the concurrent agglutination of chromatin in the nucleus, the abnormal location of organelles and the high density of cytoplasm, the ultrastructural characteristics in die dense cells of the nectariferous tissue and in the sieve element are matched with those of the programmed cell death in animal and plant reported in recent years. The disorganization of nucleus and most organelles in the differentiation of sieve elements and dense cells is closely associated with the transportation and modification of pre-nectar and the transference of nectar. This suggests that the cytological changes in sieve element and nectariferous tissue are closely associated with the nectary functional activities.