Nectar production and floral characteristics of Tropaeolum majus L. grown in ambient and elevated carbon dioxide
1999
Lake, J.C. | Hughes, L.
Tropaeolum majus (nasturtiums) were grown from seed in growth cabinets, under 380 and 750 ppmv CO(2). Elevated CO(2) significantly increased nectar secretion rate, both in flowers milked of nectar daily and in once sampled, 3-d-old flowers. Elevated CO(2) did not affect time to flowering, total number of flowers produced, pollen to ovule ratio, or the total or individual concentrations of nectar amino acids. The dry weight and longevity of individual flowers was also unchanged. Nectar sugar content was unchanged by elevated CO(2) in a subset of flowers used to assess the 3-d-old nectar volume. This subset did not show the same increase in nectar volume under elevated CO(2) as the full set, resulting in the concentration of sugars remaining unchanged. Overall, the quantity rather than the quality of the nectar changed under elevated CO(2) while flower characteristics remained constant, implying that the identity of pollinators may remain the same while foraging behaviour (e.g. number of visits per plant, distance travelled) may change in the future.
显示更多 [+] 显示较少 [-]