Investigating Pollination of Astragalus spp. Species in Karsanak rangelands, Chaharmahal and Bakhtiari Province

In this study, pollination of 6 herbaceous astragalus species including three rare herbaceous vegetative forms (As. Caraganae, As. Heterophyllus and As. Holopsilus) and three common herbaceous vegetative forms (As. Angustiflorus, As. Curvirostris and As. Effusus) and 6 shrub astragalus species includes three rare shrub vegetative forms (As. Cephalanthus, As. Camphylanthus and As. Cemerinus) and three common shrub vegetative forms (As. Verus, As. Susianus and As. Rhodosemius) based on comparison of phenological characteristics of the plant including maximum plant height, flowering time, total number of flowers produced, flower life and seed set produced between rare and common astragalus species were studied. For each plant studied, twenty stands were selected for sampling and the number of pollinating insect visits was recorded for 15 minutes for each. Sampling of rare and common astragalus species led to the identification of a total of 9 species of pollinating bees (Apis melifera, Megachili sp, Osmia sp, Eucera sp, Andrena sp, Anthophora sp, Xylocopa sp, Bombus zonatus and Bombus armeniacus) belonging to three family (Apidae, Megachilidae and Andrenidae). The results of herbaceous astragalus species showed the highest number of flowers and the highest number of pollinators (As. Effusus species), maximum plant height (As. Angustiflorus species), the highest seed mass (As. Angustiflorus and As. Effusus species) and the lowest plant height and the lowest number of flowers (As. Curvirostris) belonged to common astragalus species. Herbaceous astragalus species (rare and common) were not different in terms of flowering season, but flower life was longer in rare astragalus species (As. Heterophyllus). The results of shrub astragalus species showed that the highest number of flowers and the highest number of pollinators (As. Rhodosemius species), the maximum plant height (As. Susianus species) and the highest seed mass (As. Verus species) belonged to the common astragalus species. The lowest number of flowers, pollinators and plant height (As. Cemerinus) belonged to rare astragalus species. In terms of flowering season, rare (spring) and common (summer) species were different and flower life was longer in rare species (As. Camphylanthus and As. Cephalanthus).