Palynological Investigations on Some Selected Bee Forage Plants of Family Fabaceae Using Light and Scanning Electron Microscopy From Himachal Pradesh, India

Abstract

The study aimed to investigate and describe the pollen morphology of six nectariferous and polleniferous members of family fabaceae by using light and scanning electron microscope. Pollen grains of Albizia lebbeck, Bauhinia variegata, Caesalpinia decalpetala, Cassia fistula, Dalbergia sissoo and Robinia pseudoacacia were examined for the morphological characterization. The pollen grains were analysed in terms of aggregation, shape, shape class, size, aperture, polarity, symmetry, surface pattern and exine complexity. All the pollen had solitary grains, except Albizzia lebbeck having compound grains. The shape of pollen grains varies from circular-ovoid in Albizia lebbeck, triangular in Bauhinia variegata, oval in Caesalpinia decapetala, oval / round in Cassia fistula and triangular/round in Dalbergia sissoo and triangular/elongated oval Robinia pseudoacacia. The pollens were either prolate-spheroidal or oblate spheroidal. The size of pollen grains studied ranged from small, medium to large sized among different members of family fabaceae. Most of pollens observed were tricolporate, except pollens of Dalbergia sissoo which were tricolpate and triporate. Exine ornamentation include psilate/faveolate in Albizzia lebbeck, psilate in Dalbergia sissoo and Robinia pseudoacacia, straite –reticulate in Bauhinia variegata, reticulate-rugulate in Cassia fistula and Caesalpinia decapetala. All the pollens observed were isopolar and radially symmetrical. The purpose of this study is to increase knowledge of the aspects related to the variability and to characterize the pollen morphology of some members of family fabaceae and to evaluate the utility of pollen features in order to develop an additional alternative plant material identification tool. Moreover, such studies can be of utmost important to students, researchers, and beekeeping industry, horticulture and forest departments.

Pollen morphology of Uraria Desv. and Christia Moench (Fabaceae) in China

“…However, variation of pollen exine ornamentation can be used as a reference to evaluate the degree of plant evolution and species diversity in Fabaceae (Zhang & Dai, 2022). Scanning and observing the exine ornamentation of pollen grains by high-resolution SEM can be used as a basis for identifying legume pollen and evaluating species diversity in future studies (Jamwal et al, 2021;Oliveira, Restrepo, Santos, Queiroz, & Santos, 2022)…”

“…The morphology of pollen gains is controlled by the genotype of the species, with strong genetic conservation and a lot of evolutionary information (Doyle, 1969;Erdtman, 1952;Martin, 1978;Solomon, 1983;Walker, 1974). Numerous studies have suggested that pollen morphology could provide evidence for plant taxonomy and evolution (Atasagun, Aksoy, & Martin, 2018;Bahadur, Taj, Long, & Hanif, 2022;El Kholy, Mohamed, & Khafagi, 2023;Jamwal et al, 2021;Khan et al, 2022). Palynological analyses have been sporadically performed in Fabaceae at a range of different taxonomic levels, such as in the Astragalus sect.…”