Introduction

Some plants, like the banyan tree, keep growing for thousands of years, while others - especially annuals - complete their growth and die within a single season or year. What explains this difference? And at a more basic level, how does a single fertilised zygote give rise to an embryo, an embryo to a seedling, and eventually a whole new plant structure built from what came before? Growth is the answer this chapter explores: it is defined as an irreversible, permanent increase in an organ's size, shape, cell number, volume and dry weight, brought about by cell division, cell enlargement, differentiation and maturation acting together.