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Pak. J. Bot., 45(6): 2079-2084, 2013.

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FLORAL NECTAR COMPOSITION OF AN OUTCROSSING BEAN SPECIES  MUCUNA SEMPERVIRENS HEMSL (FABACEAE)

TAO LIU^1, AMIN SHAH², HONG-GUANG ZHA^3*, MUHAMMAD MOHSIN⁴ AND MUHAMMAD ISHTIAQ⁵

Abstract: Mucuna sempervirens is a perennial woody climber belonging to family Fabaceae. Hand pollination experiments have proved it to be an out crossing species. In the present study, the chemical composition of M. sempervirens’s floral nectar was analysed. Concentrations of sugars, proteins, phenolics, and hydrogen peroxide were determined through spectrophotometry. Free amino acids were identified and quantified, among which aspartic acid was the most abundant. GC-MS analysis showed that aromatic compounds were responsible for the nectar scent which lacked sulphur compounds. ICP-AES analysis determined calcium to be the nectar’s major inorganic ion. The presence of high levels of hydrogen peroxide in the nectar might serve as defence against invading microorganisms. Phenolics may act as to repel nectar thieves repeller or serve a defensive function. Our findings show that M. sempervirens’s pollination system is different from other neotropical Mucuna species. Analysis of these differences may help to better understand how Asian Mucuna species adapted and coevolved with pollinators.

¹Faculty of Agronomy and Biotechnology, Yunnan Agricultural University, Kunming, Yunnan 650201, China

²Department of Biological Sciences, University of Sargodha, Sargodha

³Key Laboratory of Biodiversity and Biogeography, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, China

⁴Department of Textile Engineering, UET Lahore, Faisalabad Campus, Pakistan

⁵Department of Botany, Mirpur University of Science & Technology (MUST). Bhimber Campus, Azad Kashmir, Pakistan

*Corresponding author’s email: arctos725@gmail.com