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ARS Home » Pacific West Area » Tucson, Arizona » Carl Hayden Bee Research Center » Research » Research Project #444736

Research Project: Nutritional Analysis of Pollen from Bee Pollinated Plants

Location: Carl Hayden Bee Research Center

Project Number: 2022-21000-022-058-I
Project Type: Interagency Reimbursable Agreement

Start Date: Aug 1, 2023
End Date: Sep 30, 2024

The goals of the project are to: 1) quantify concentrations of protein, lipid, amino and fatty acids in pollen from plants that are foraged by bees, and 2) provide the information to collaborators and NRCS PLANTS database for inclusion in the new Pollinators section. Pollen will be collected from plants grown in greenhouses, growth chambers and fields at the CHBRC and at field settings as provided by collaborators.

Pollen will be collected from anthers of flowers, and immediately frozen at -80oC. Protocols for shipping pollen have been developed and include overnight shipping of frozen samples on dry ice. Nutritional analyses will be conducted using previously published protocols (DeGrandi-Hoffman et al. 2015, 2018). Briefly, protein concentrations will be estimated using a BCA analysis, while fatty acid concentrations will be determined using a chromic acid oxidation assay. Amino acids (AAs) will be quantified after fluoroalkyl chloroformate derivatization using an EZFAAST amino acid hydrolysate kit (Hušek et al., 2008). All essential amino acids except tryptophan and cysteine will be characterized after acid hydrolysis. Glutamine and asparagine will be converted by acidic conditions to their acid equivalents glutamic acid and aspartic acid. Tryptophan will be extracted separately after base hydrolysis and characterized by fluoroalkyl chloroformate derivatization (Yust et al., 2004). Cysteine residues will be quantified after phenylisothiocyanate (PITC) derivatization adapted from Manneberg et al. (1995). Individual fatty acids will be analyzed by FAME (fatty acid methyl ester) analysis after conversion to their methyl ester equivalents (Seppänen-Laakso et al., 2002). FAME compounds will be quantified by comparison of characteristic mass fragments (m/z) with known amounts of authentic standards. The fraction of the total sample injected will be calculated from the amount of internal standard (pentadecanoic acid) detected in each injected sample.