Dissertation Research : Ecological Factors in Tetraploid Speciation

University Of California-Davis, Davis CA

Investigators

Abstract

Stanton 0105116 Unlike humans, plant species often have more than two sets of chromosomes. These polyploid plants, 30 to 70% of all plant species, are usually unable to mate with diploid individuals with two sets of chromosomes, and so they are considered different species. When a polyploid plant originates from diploid progenitors, how does it succeed, if the surrounding plants interfere with reproduction? One possibility is that the two types of plants have different habitat requirements. If so, their spatial separation may prevent reproductive interference. This project will examine whether the plant species, Ranunculus adoneus, with 16 or 32 chromosomes have different requirements for their survival, growth, and reproduction. Populations with different chromosome counts grow in separate places in the Colorado Rockies. This experiment will monitor survival and growth of seedlings transplanted between locations. Reproductive interference will be demonstrated if adding pollen from the other plant type reduces the number of seeds produced. Understanding the forces generating and maintaining biological diversity is one of the fundamental goals of biology. Polyploid speciation has been an important process leading to new plant species, but is not well understood. This study asks how new plant species originate, and so seeks to understand a major source of plant diversity.