The effects of nutrient addition on floral characters and pollination in two subalpine plants, <Emphasis Type="Italic">Ipomopsis aggregata</Emphasis> and <Emphasis Type="Italic">Linum lewisii</Emphasis> |
| |
Authors: | Laura A Burkle Rebecca E Irwin |
| |
Institution: | (1) Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA;(2) Rocky Mountain Biological Laboratory, Crested Butte, CO 81224, USA |
| |
Abstract: | The availability of soil and pollination resources are main determinants of fitness in many flowering plants, but the degree
to which each is limiting and how they interact to affect plant fitness is unknown for many species. We performed resource
(water and nutrients) and pollination (open and supplemental) treatments on two species of flowering plants, Ipomopsis aggregata and Linum lewisii, that differed in life-history, and we measured how resource addition affected floral characters, pollination, and reproduction
(both male and female function). We separated the direct effects of resources versus indirect effects on female function via
changes in pollination using a factorial experiment and path analysis. Resource addition affected I. aggregata and L. lewisii differently. Ipomopsis aggregata, a monocarp, responded to fertilization in the year of treatment application, increasing flower production, bloom duration,
corolla width, nectar production, aboveground biomass, and pollen receipt relative to control plants. Fertilization also increased
total seed production per plant, and hand-pollination increased seeds per fruit in I. aggregata, indicating some degree of pollen limitation of seed production. In contrast, fertilization had no effect on growth or reproductive
output in the year of treatment on L. lewisii, a perennial, except that fertilization lengthened bloom duration. However, delayed effects of fertilization were seen in
the year following treatment, with fertilized plants having greater aboveground biomass, seeds per fruit, and seeds per plant
than control plants. In both species, there were no effects of resource addition on male function, and the direct effects
of fertilization on female function were relatively stronger than the indirect effects via changes in pollination. Although
we studied only two plant species, our results suggest that life-history traits may play an important role in determining
the reproductive responses of plants to soil nutrient and pollen additions. |
| |
Keywords: | Floral traits Life-history Nutrient limitation Plant reproduction Pollen limitation Water addition |
本文献已被 SpringerLink 等数据库收录! |
|