Document: MAR-3-48-3

The effects of soil nitrogen on amino acid composition of floral nectar.

GARDENER, M.C.*, M.P.GILLMAN and J.SILVERTOWN

The Open University, Milton Keynes, United Kingdom ¹

Abstract:
Plants of the meadow annual Agrostemma githago (Carophyllaceae) were grown in one metre square field plots prepared with three fertilizer treatments as follows: a) 'low', no fertilizer, b) 'medium', 25 g of slow release fertilizer granules, and c) 'high', 75 g of granular treatment. After sowing in spring the plants were left until flowering in late summer. Nectar was extracted by using glass microcapillary tubes. The material was frozen and sampled at a later date. The samples were analyzed by high performance liquid chromatography (HPLC) using the AccQtag (Waters Corp.) system. Analysis showed that the total concentration of amino acids increased significantly with increasing soil nitrogen treatment (p<0.05). Of the amino acids present glutamine showed a large and significant increase (p<0.02) whilst the others showed no significant trend. Due to the large increase in glutamine the relative abundance of each amino acid in the nectar was altered. Glutamine showed a significant increase (p<0.01) in percentage of the total with most of the remaining amino acids declining in relative abundance. The results show that, in contradiction to earlier work, that environmental conditions can affect the amino acid complement of nectar. This may have implications for plant-insect interactions as local populations of pollinators may benefit in a variety of ways and visit plants preferentially.

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This abstract is being presented at: 8:45 AM in session:
Oral Session #6: Pollination Ecology.