Qualitative analysis of amino acids in pollen and nectar of onion (Allium cepa L.) cv. Bhima Super

The present investigation was carried out to qualitatively identify amino acids present in the nectar and pollen of onion (Allium cepa L.) cv. Bhima Super, using paper chromatography and to evaluate their potential ecological role in pollination. Onion is a cross-pollinated crop that depends heavily on insect pollinators, particularly honey bees (Apis mellifera), for effective seed production. Floral extracts were prepared from fresh nectar and pollen samples collected during peak flowering and subjected to paper chromatography using Whatman No. 1 filter paper and a solvent system of n-butanol:acetic acid:water (4:1:5 v/v). After solvent migration, the paper strips were sprayed with 0.2 % ninhydrin and heated at 60 °C for spot development. Amino acids were identified by comparing the Retention factor (Rf) values of the samples with those of standard amino acids. A total of 9 amino acids were identified: valine, leucine, isoleucine, threonine, glycine, serine, alanine, glutamic acid and aspartic acid. Proline and phenylalanine were additionally detected in nectar, both known to influence pollinator attraction, energy metabolism and floral scent production. The results confirm the biochemical richness of Bhima Super onion nectar and pollen, suggesting their potential role in enhancing pollinator visitation and ultimately improving pollination efficiency and seed yield. Paper chromatography proved to be a simple and cost-effective method for preliminary amino acid profiling in floral components. However, further quantitative analysis using advanced chromatographic techniques is recommended to determine the precise ecological relevance of individual amino acids in pollination biology.