life11e_ch36

Plant growth is regulated

The development of a plant—the series of progressive changes that take place throughout its life—is regulated in many ways. Key factors involved in regulating plant growth and development are:

Environmental cues, such as day length, water availability, and various chemicals in the environment
Receptors that allow a plant to sense environmental cues, such as photoreceptors that absorb light, and chemoreceptors that signal the presence of pathogens
Hormones—chemical signals that mediate the effects of the environmental cues, including those sensed by receptors
Regulatory proteins and enzymes that catalyze the biochemical reactions that control development

We will explore these *regulatory mechanisms in more detail later in this chapter. But first let’s look at the initial steps of plant development—from seed to seedling—and the types of internal and external cues that guide them.

*connect the concepts Much of growth regulation occurs via signal transduction pathways. Review these mechanisms, mostly from animal cells, in Chapter 7.