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Pollen Dispersal In Low-Density Populations Of Three Neotropical Tree Species, Jason D. Nason, E. A. Stacy, J. L. Hamrick, S. P. Hubbell, R. B. Foster, R. Condit
Pollen Dispersal In Low-Density Populations Of Three Neotropical Tree Species, Jason D. Nason, E. A. Stacy, J. L. Hamrick, S. P. Hubbell, R. B. Foster, R. Condit
Jason D Nason
Studies of mating patterns of tropical trees, typically involving common species, have revealed that most species are outcrossed and that, in some cases, a significant reaction of outcross pollen moves long distances. We evaluated mating systems and effective pollen dispersal for three hermaphroditic insect-pollinated Neotropical tree species, Calophyllum longifolium, Spondias mombin and Turpinia occidentalis, all of which occurred at low adult densities at the study site. Mating patterns were estimated for each maternal tree within 84-ha populations of C. Longifoliuman d S. mombin in 1992 and 1993 and within a 50-ha population of T. occidentalis in 1993. Each population was …
Non-Mycorrhizal Uptake Of Amino Acids By Roots Of The Alpine Sedge Kobresia Myosuroides: Implications For The Alpine Nitrogen Cycle, Ted K. Raab, David A. Lipson, Russ K. Monson
Non-Mycorrhizal Uptake Of Amino Acids By Roots Of The Alpine Sedge Kobresia Myosuroides: Implications For The Alpine Nitrogen Cycle, Ted K. Raab, David A. Lipson, Russ K. Monson
Ted K. Raab
Non-mycorrhizal plants of the alpine sedge, Kobresia myosuroides , take up the amino acid glycine from nutrient solutions at greater rates than NO3- or NH4+. The amino acids glutamate and proline were also taken up at high rates. Total plant biomass was twice as high after 4 months of growth on glycine, compared to NH4NO3, with significant increases in both root and leaf biomass. By taking advantage of differences in the d13C signature of air in the growth chamber and the glycine used for growth, a two-member mixing model was used to estimate that a significant amount of the glycine …