---
title: "From Seed to Plant"
book: "Primary & Middle School Biology"
subject: biology
language: en
chapter: 9
exercises: 10
source: https://one-course.com/books/biology/1/en/chapter/9-from-seed-to-plant
---

# Chapter 9 — From Seed to Plant

Shake a dried bean pod and little hard beans rattle out — dry, dull, apparently as lifeless as gravel. Yet [plant](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-plant) one in the earth and water it, and within days something extraordinary happens underground. A whole [plant](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-plant) was folded up inside, waiting for its signal.

## 9.1 What a seed is

**Definition 9.1 (Seed).**

A *seed* is the beginning of a new [plant](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-plant), made by the parent [plant](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-plant). Inside its protective coat, a seed holds:

- a tiny [plant](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-plant) already started — the *germ* of the [plant](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-plant) , with the beginnings of a [root](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-parts) and a shoot;
- a store of food to feed it until it can feed itself.

**Example 9.2 (Opening a soaked bean).**

Soak a big white bean overnight, and its coat slips off easily. The bean opens into two thick halves — the food store — and there, nestled at one edge, lies a tiny pale [plant](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-plant), [root](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-parts) tip and folded first [leaves](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-parts), small as a grain of rice. The new [plant](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-plant) was there all along.

![Inside the soaked, opened bean: a tiny plant — root tip and folded first leaves — lying against its food store.](https://one-course.com/images/onecourse/chapters/biology-1/g2-from-seed-to-plant/fig-acb13d467e4e.svg)

*Inside the soaked, opened bean: a tiny [plant](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-plant) — [root](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-parts) tip and folded first [leaves](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-parts) — lying against its food store.*

**Remark 9.3 (Seeds travel through our kitchens).**

Beans, peas, lentils, rice, sunflower [seeds](#def-g2-from-seed-to-plant-seed), the pips in the apple and the stone in the peach: the kitchen is full of [seeds](#def-g2-from-seed-to-plant-seed). Some are tiny, like poppy [seeds](#def-g2-from-seed-to-plant-seed); the coconut is a giant one. Each of them, given the chance, would try to become a [plant](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-plant).

## 9.2 Germination

**Definition 9.4 (Germination).**

*Germination* is the moment a [seed](#def-g2-from-seed-to-plant-seed) wakes and starts to grow: it swells with water, its coat splits, the little [root](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-parts) comes out first and dives downward, then the shoot rises, carrying the first green [leaves](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-parts) toward the light. We say the [seed](#def-g2-from-seed-to-plant-seed) *germinates*.

**Proposition 9.5 (What a seed needs to germinate).**

To [germinate](#def-g2-from-seed-to-plant-germination), a [seed](#def-g2-from-seed-to-plant-seed) needs *water* and *warmth*. It does not yet need light: the food store feeds the [seedling](#prop-g2-from-seed-to-plant-cycle) at first, even under the soil, in the dark. Without water, or in the cold, a good [seed](#def-g2-from-seed-to-plant-seed) simply waits.

**Proof.** *Admitted at this level.* ∎

**Example 9.6 (Why sowing waits for spring).**

Gardeners sow beans in spring, not in winter: the [seed](#def-g2-from-seed-to-plant-seed) in cold earth would wait — or rot — instead of germinating. Warm days and watered soil are exactly the two signals of [Proposition 9.5](#prop-g2-from-seed-to-plant-needs).

**Method 9.7 (Sowing a seed and watching it germinate).**

1. Line a glass jar with damp cotton or paper;
2. slide a bean between glass and cotton, so you can see it;
3. keep the jar in a warm room and the cotton damp;
4. look every day and note what you see: swelling, the coat splitting, [root](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-parts) down, shoot up.

The glass makes visible what usually happens under the soil.

![The jar experiment in mid-germination: root down, shoot up, and the emptying seed between them.](https://one-course.com/images/onecourse/chapters/biology-1/g2-from-seed-to-plant/img-847856335229.jpg)

*The jar experiment in [mid-germination](#def-g2-from-seed-to-plant-germination): [root](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-parts) down, shoot up, and the emptying [seed](#def-g2-from-seed-to-plant-seed) between them.*

**Remark 9.8 (Root down, shoot up — always).**

However the bean lies in the jar — on its side, upside down — the [root](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-parts) always turns downward and the shoot always turns upward. The [seedling](#prop-g2-from-seed-to-plant-cycle) cannot see, yet it knows which way is up. [Plants](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-plant) sense more than they show.

## 9.3 From seedling to plant with seeds

**Proposition 9.9 (The plant’s life cycle).**

The *seedling* grows into a [plant](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-plant) with [roots](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-parts), [stem](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-parts) and [leaves](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-parts); the [plant](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-plant) [flowers](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-parts); the [flowers](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-parts) make new *[seeds](#def-g2-from-seed-to-plant-seed)*; and the cycle can start again. A single bean [plant](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-plant) can make dozens of new beans in one summer.

**Proof.** *Admitted at this level.* ∎

**Example 9.10 (One bean, one summer).**

Sown in May, a bean [germinates](#def-g2-from-seed-to-plant-germination) in a week; by June it is a leafy [plant](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-plant) climbing its pole; in July come white [flowers](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-parts), then green pods; in August the pods hang heavy, each holding a row of new beans — next year’s [seeds](#def-g2-from-seed-to-plant-seed), made by this year’s [plant](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-plant).

## 9.4 Exercises

**Exercise 9.1 ★.**

What two things lie inside a [seed](#def-g2-from-seed-to-plant-seed)’s coat?

**Solution of Exercise 9.1.**

A tiny [plant](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-plant) already started (the germ of the [plant](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-plant), with the beginnings of a [root](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-parts) and a shoot) and a store of food to feed it.

**Exercise 9.2 ★.**

What does *[germinate](#def-g2-from-seed-to-plant-germination)* mean? What comes out of the [seed](#def-g2-from-seed-to-plant-seed) first: the [root](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-parts), or the shoot?

**Solution of Exercise 9.2.**

To [germinate](#def-g2-from-seed-to-plant-germination) is to wake and start growing: the [seed](#def-g2-from-seed-to-plant-seed) swells, its coat splits, and it begins to become a [plant](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-plant). The [root](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-parts) comes out first, and dives downward.

**Exercise 9.3 ★.**

Name the two things a [seed](#def-g2-from-seed-to-plant-seed) needs to [germinate](#def-g2-from-seed-to-plant-germination). Which famous need of grown [plants](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-plant) is *not* on the list?

**Solution of Exercise 9.3.**

Water and warmth. Light is not on the list — the [seed](#def-g2-from-seed-to-plant-seed) [germinates](#def-g2-from-seed-to-plant-germination) happily in the dark, under the soil.

**Exercise 9.4 ★.**

How can a buried [seedling](#prop-g2-from-seed-to-plant-cycle) grow in the dark, before reaching the light? Where does its food come from at first?

**Solution of Exercise 9.4.**

It lives off the food store packed inside the [seed](#def-g2-from-seed-to-plant-seed) — the two thick halves of the bean. That store feeds the [seedling](#prop-g2-from-seed-to-plant-cycle) until its green [leaves](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-parts) reach the light and it can feed itself.

**Exercise 9.5 ★.**

Name four [seeds](#def-g2-from-seed-to-plant-seed) you could find in a kitchen.

**Solution of Exercise 9.5.**

For example: beans, peas, lentils, rice, sunflower [seeds](#def-g2-from-seed-to-plant-seed), apple pips, a peach stone.

**Exercise 9.6 ★.**

Why do gardeners sow in spring rather than in winter?

**Solution of Exercise 9.6.**

Because a [seed](#def-g2-from-seed-to-plant-seed) needs warmth as well as water: in cold winter earth it would wait, or rot, instead of germinating. Spring brings the warm soil the [seed](#def-g2-from-seed-to-plant-seed) is waiting for.

**Exercise 9.7 ★.**

Put in order: pod with new beans — [seed](#def-g2-from-seed-to-plant-seed) — flowering [plant](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-plant) — [seedling](#prop-g2-from-seed-to-plant-cycle) — leafy [plant](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-plant).

**Solution of Exercise 9.7.**

[Seed](#def-g2-from-seed-to-plant-seed), [seedling](#prop-g2-from-seed-to-plant-cycle), leafy [plant](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-plant), flowering [plant](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-plant), pod with new beans.

**Exercise 9.8 ★.**

Try it: set up the glass jar of [Method 9.7](#met-g2-from-seed-to-plant-sow) with two beans — one lying sideways, one upside down. After [germination](#def-g2-from-seed-to-plant-germination), compare their [roots](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-parts) and their shoots. What does [Remark 9.8](#rem-g2-from-seed-to-plant-updown) predict?

**Solution of Exercise 9.8.**

Both [roots](https://one-course.com/books/biology/1/en/chapter/3-plants-around-us#def-g1-plants-around-us-parts) grow downward and both shoots grow upward, whichever way the beans were lying. The [seedling](#prop-g2-from-seed-to-plant-cycle) always finds up and down — exactly what the remark predicts.

**Exercise 9.9 ★★.**

Nina keeps a packet of bean [seeds](#def-g2-from-seed-to-plant-seed) in a dry drawer for a whole year, and they still [germinate](#def-g2-from-seed-to-plant-germination) when she finally sows them. Why did they neither grow nor die in the drawer? Use [Proposition 9.5](#prop-g2-from-seed-to-plant-needs).

**Solution of Exercise 9.9.**

In the drawer the [seeds](#def-g2-from-seed-to-plant-seed) had no water, so they could not [germinate](#def-g2-from-seed-to-plant-germination); but a good [seed](#def-g2-from-seed-to-plant-seed) without water does not die — it waits. A year later, given water and warmth, the waiting [seeds](#def-g2-from-seed-to-plant-seed) woke normally.

**Exercise 9.10 ★★.**

The chick of [Chapter 8](https://one-course.com/books/biology/1/en/chapter/8-how-animals-grow-up#ch-g2-animals-grow-up) grows inside its [egg](https://one-course.com/books/biology/1/en/chapter/8-how-animals-grow-up#def-g2-animals-grow-up-born), fed by the yolk. What plays the yolk’s part inside a bean? What do an [egg](https://one-course.com/books/biology/1/en/chapter/8-how-animals-grow-up#def-g2-animals-grow-up-born) and a [seed](#def-g2-from-seed-to-plant-seed) have in common?

**Solution of Exercise 9.10.**

The [seed](#def-g2-from-seed-to-plant-seed)’s food store — the bean’s two thick halves — plays the yolk’s part. [Egg](https://one-course.com/books/biology/1/en/chapter/8-how-animals-grow-up#def-g2-animals-grow-up-born) and [seed](#def-g2-from-seed-to-plant-seed) are both beginnings of a new [living thing](https://one-course.com/books/biology/1/en/chapter/1-living-or-not-living#def-g1-living-or-not-living), packed with the food the young one needs before it can feed itself.