Chapter 10, Problem 28A

Summary Introduction

To hypothesize:

The process of creating a polyploid plant by a plant breeder

Introduction:

Polyploidy cells have one or more extra sets of chromosomes. For example there could be a triploid organism with 3n number of chromosomes. Polyploidy is rare in animals except in earthworms and goldfish. It is lethal in humans but is very common in flowering plants. Polyploidy has been used in agriculture to increase the size of flowers.

Answer to Problem 28A

Plant breeders create polyploids by soaking the seeds or buds of certain plants in cochicine. The chemical inhibits chromosome separation during cell division. This creates diploid gametes which fertilize to produce polyploid plants.

Explanation of Solution

Plant geneticists develop new polyploidy species of plants that are more beneficial to humans. Such plants have larger and stronger, have better developed root system, and produce larger flowers and fruits. This feature of polyploidy is used by agriculture scientists to increase the size of flowers.

Plant breeders select some plants for polyploidy. They soak the seeds or buds of these plants in a chemical called colchicine. Colchicine is an alkaloid which interferes with cell division. It does not allow chromosome separation and so all the chromosomes remain in one cell. Gametes are formed with diploid chromosomes. During fertilization, the chromosomes get doubled in number leading to polyploidy.