Parts of a Plant
FoundationLeaves make food, roots absorb water and hold the plant firm, stems support and carry water — with sunlight, air and water, plants grow healthy and strong.
- Roots absorb water and nutrients and anchor the plant in the soil.
- The stem supports the plant and carries water and nutrients.
- Leaves make food in the sunlight — the plant's food factory.
文體小知識：說明文把知識講得清清楚楚。這一篇逐部分介紹植物的身體，看看根、莖、葉怎樣分工合作。
§Text Passage
1In the school planter, morning glories climb the railings and sunflowers open to the sky. Plants seem still, but every part of their body is busy at work. A plant has three main parts — roots, stem and leaves — and some also flower, bear fruit and make seeds. Each part has its own job, and none can be missing.
2Roots hide in the soil like many thin whiskers. They have two important jobs: first, to grip the soil and hold the plant firm so wind cannot blow it over; second, like straws, to absorb water and nutrients from the soil and pass them to the whole plant. Without roots, a plant would be thirsty and hungry and could not stand steady.
3The stem is the plant's pillar, growing upward from the roots, holding up the branches and leaves so they reach the sunlight. Inside the stem are many tiny channels, like the water pipes of an estate, carrying the water and nutrients from the roots up to every leaf. A melon seedling has a soft stem; a big tree has a thick trunk — different shapes, same job.
4Green leaves are the plant's food factory. The leaf surface has tiny holes for breathing in air; the leaf catches sunlight and, together with water from the roots, makes nutrients. With nutrients, a plant has energy to grow tall, flower and bear fruit. In autumn some trees drop their leaves — the factory takes a rest and saves water.
5So plants need sunlight, air and water, and none of the three can be missing. Shut a pot plant inside a dark cupboard and even with daily watering its leaves will turn yellow and wither in a few days, because without sunlight leaves cannot make food. Remember: roots, stem and leaves work as a team, and with sunlight, air and water the plant grows healthy and lush.
1Summary 重點摘要
Leaves make food, roots absorb water and hold the plant firm, stems support and carry water — with sunlight, air and water, plants grow healthy and strong.
2Vocabulary cards Vocabulary
The part in the soil; it absorbs water and nutrients and holds the plant firm.
The plant's pillar; it supports the plant and carries water and nutrients.
The plant's food factory; it catches sunlight to make nutrients.
To take in water and nutrients, like roots taking in water from soil.
To hold up and keep steady, like the stem holding the plant up.
To carry water and nutrients from one place to another.
Light from the sun; leaves use it to make food.
Nourishing substances in soil that help plants grow.
Where plants root; it holds water and nutrients.
The part that reproduces a plant; in soil it can grow into a new plant.
3Step by step Steps
- Step 1: Know the three main parts of a plantLook carefully at a pot plant or a small tree in the school garden: under the soil are the roots, rising straight up is the stem, and on the stem are the green leaves. Plants that flower also have flowers, fruit and seeds. The three main parts work like a team: the roots absorb and anchor, the stem supports and transports, and the leaves make food. Learning each part's name and position is the first step — observe with your eyes, and never pick the leaves.
- Step 2: Roots — the experts at absorbing and anchoringRoots grow in the soil and have two great skills. First, anchoring: roots reach deeper and wider and wider, like countless little hands gripping the soil, so wind and rain cannot easily knock the plant over. Second, absorbing: the root tips carry many tiny root hairs, like little straws, drawing in water and nutrients from the soil. If you pull up a small weed by the roots, it soon withers, because without roots it cannot drink — that shows how vital roots are.
- Step 3: Stems — the backbone of support and transportThe stem grows upward from the roots like the plant's pillar, holding up the branches, leaves, flowers and fruit so the leaves stand high and catch more sunlight. Inside the stem are many invisible tiny channels, like the water pipes of an estate, carrying the water and nutrients from the roots upward to every leaf and flower. Try a little experiment: stand a white flower in water dyed with red ink, and after a few hours the petals turn reddish — proof that the stem really carries water upward.
- Step 4: Leaves — the factory that makes foodMost leaves are green because they hold chlorophyll, which catches sunlight. The leaf surface also has many tiny holes for breathing in air. Using sunlight, together with water from the roots and gases from the air, the leaf makes nutrients — the plant's own food — to grow taller and to flower and fruit. Leaves are the plant's most important factory, so never pick them for fun: every leaf taken is one little factory lost, and the plant grows more slowly.
- Step 5: Plants need sunlight, air and waterThree things a plant can never do without: sunlight, air and water. Leaves need sunlight to make food; leaves need air to breathe, and roots need air in the soil; water must be absorbed by the roots every day. Run a comparison experiment: water two pots of bean sprouts the same, keep one on the windowsill and shut one inside a dark cupboard. After a few days the windowsill pot is green and strong while the cupboard one is yellow and weak — proof that without sunlight a plant cannot grow well.
- Step 6: Observe and care for plantsNow that you know what each part does, care for the plants around you: water pot plants in suitable amounts — when the soil is dry, water until a little seeps from the bottom; keep them where sunlight is gentle and bright; loosen the soil now and then so the roots can breathe. Observe with your eyes and touch the leaf veins gently; never pick leaves or pull up roots. Be a little green gardener: care, observe and record, and you will witness the miracle of growing life.
5Worked example Example
Example: Yi plants a bean in a pot on the windowsill and waters it every day. How do the bean's roots, stem and leaves help it grow into a seedling?
- The bean sprouts and grows a young root: it digs into the soil, anchoring the seedling and absorbing water and nutrients.
- Next a tender stem stretches upward: it holds the seedling upright and carries the water and nutrients to every part.
- Then young leaves grow on the stem: in the sunlight they make nutrients, giving the seedling energy to grow taller and sprout more leaves.
- The windowsill offers sunlight, Yi waters daily, and the soil holds air — with sunlight, air and water all present, the seedling grows healthily.
- Answer: Roots absorb water and nutrients and anchor the seedling; the stem supports it and carries water and nutrients; leaves make food in the sunlight. With sunlight, air and water, the bean slowly grows into a strong seedling.
6Common mistakes Mistakes
7Quick check Quick check
Q1Which part of a plant absorbs water?
Q2What are the two main jobs of the stem?
Q3Which part is the plant's food factory?
Q4What three things do plants need to grow?
Q5What happens to leaves kept in the dark?
8Recap Recap
- Roots absorb water and nutrients and anchor the plant in the soil.
- The stem supports the plant and carries water and nutrients.
- Leaves make food in the sunlight — the plant's food factory.
- Plants need sunlight, air and water, and none can be missing.
- Observe plants without picking; take good care of them.