Chapter 35.5, Problem 3CC

Summary Introduction

To explain: “Tepals” on the basis of ABC hypothesis.

Concept introduction: In plants, transition from vegetative to reproductive phase is marked by production of flowers. Flowering is induced by day length and certain chemicals called hormones. “Floral meristem identity genes” play an important role in flowering.

The development of floral pattern is regulated by various organ identity genes. These genes belong to the MADS-box family. These genes encode transcription factors that regulate the expression of other genes and thereby produce a peculiar floral pattern. The floral pattern consists of four whorls that appears as concentric circles when viewed from the top.