The roots, stem and leaves, which do the work a plant needs to stay alive, are called vegetative organs, while flowers, fruits and seeds, which handle reproduction, are grouped separately as reproductive organs.
Roots take up water and minerals from the soil, the water rises through xylem in the stem to the leaves, where it is used in photosynthesis, and the food made in the leaves is carried through phloem to wherever it is needed.
Water can climb to the top of a tall tree because transpiration, water escaping as vapor through stomata on the underside of leaves, pulls it upward.
In the first picture, choose the root, stem or leaf to see what each organ does; in the second, open and close the stoma and vapor escapes as far as the guard cells part.
What Roots, Stems and Leaves Do
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Vegetative organs: the jobs of roots, stems and leaves
Root
💡 Vegetative and Reproductive Organs
①Vegetative organs are the roots, stems and leaves that a plant needs to live.
②Reproductive organs are the flowers, fruits and seeds used to produce offspring.
③Root hairs near the root tips are thin and numerous, greatly enlarging the area touching the soil so water and minerals are absorbed well.
④The stem is a passage for materials and holds the plant up so the leaves get plenty of light.
⑤Leaves are broad and thin, well suited to catching light for photosynthesis.
Xylem and Phloem
Xylem and phloem
Xylem and phloem compared
Feature
Xylem
Phloem
Carries
Water, minerals
Food made in the leaves (sugars)
Direction
Roots → leaves (upward)
Leaves → roots, fruits, shoot tips (wherever food is needed)
Position in stem
Inside the cambium
Outside the cambium
Cells
Tubes of dead cells
Living cells
🔍 Telling Xylem from Phloem
①Xylem is the pipe for water, carrying water and minerals absorbed by the roots upward.
②Phloem sends food made in the leaves to where it is needed: roots, fruits and growing shoot tips.
③Strip a ring of bark from a tree trunk and the outer phloem is cut, so food piles up and the bark above the ring swells.
④A bundle of xylem and phloem is called a vascular bundle; in leaves, the veins are vascular bundles.
Transpiration
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Transpiration: a stoma on the underside of a leaf, magnified
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Transpiration
absorbed by roots → rises in xylem → leaves the stomata as vapor
As water leaves the leaf, more water is pulled up to take its place, so transpiration drives water upward.
🌿 What Transpiration Does
①It pulls water up from the roots to the leaves.
②Evaporating water takes heat with it and keeps the leaves from getting too hot.
③Stomata are mostly on the underside of leaves.
④Guard cells open and close the stomata, usually open during the day when there is light and closed at night.
⑤Transpiration is strongest when the sunlight is strong, the air is warm, the wind blows and the humidity is low.
The three vegetative organs share the work of moving water and food that keeps a plant alive.
🎯 Exam Points
①Xylem: water and minerals, roots → leaves, inside the cambium.
②Phloem: food made in the leaves, to where it is needed, outside the cambium.
③Transpiration: water escaping as vapor through the stomata of leaves; it drives water upward.
④Guard cells open and close the stomata, which are mostly on the underside of leaves.
⑤Root hairs enlarge the area touching the soil and help absorption.
Examples and Unit Test
Example 1
What carries the water and minerals absorbed by the roots up to the leaves, and what carries the food made in the leaves?
1
Xylem carries the water and minerals absorbed by the roots upward to the leaves.
2
Phloem carries the food made by photosynthesis in the leaves to where it is needed, such as the roots and fruits.
▸ Water and minerals = xylem / food made in the leaves = phloem
The difference: xylem moves one way (up), while phloem moves food up or down, wherever it is needed.
Example 2
What is the process by which water inside a plant escapes as vapor through the stomata of leaves, and what does it do?
1
Water escaping as vapor through the stomata of leaves is called transpiration.
2
Transpiration drives the water absorbed by the roots upward, and the evaporating water cools the leaves.
▸ Transpiration / it pulls water up and cools the leaves
Close the stoma in the picture and no vapor escapes; in a drought, plants close their stomata to save water.
Unit-test style
Which statement about plant vegetative organs is correct?
①The xylem carries organic nutrients from the leaves to the roots
②The phloem carries the organic nutrients made in the leaves
③The leaf is the organ that absorbs water and minerals
④Transpiration occurs in the roots
⑤Flowers and fruits are vegetative organs
▸ ② The phloem carries the organic nutrients made in the leaves
1
Phloem carries the food made by photosynthesis in the leaves all over the plant, so ② is correct.
2
Xylem carries water and minerals upward (①), the roots absorb water and minerals (③), transpiration happens at the stomata of leaves (④), and flowers and fruits are reproductive organs (⑤).