PLANTS

By: Allison, Brittney, Cord, and William

Chapter 1 Lesson 2

Roots And Stems

A stem is a structure that holds the plant up and supports itsleaves. There are soft and woody leaves. Woody leaves are tough and strong with protective bark. A soft stem is bendable and easy to break. Some plants store food in their stems, other plants use their stems to store water.

Roots are parts that anchor a plant into the ground. Roots can store the plants food and get water and nutrients from the soil. As roots absorb water, pressure pushes water through the stem and toward the leaves. In transpiration, plants release water into the atmosphere through their leaves. Some plants do not have roots like mosses.

Leaves And Photosynthesis A leaf stores the water for the plants. The outermost

layer of the leaf is the epidermis. The epidermis is covered by a waxy coating called the cuticle. The cuticle prevents the leaves from losing to much water, especially during cold or dry weather. A petiole is a stalk attaching a leaf blade to the stem.

Plants use sunlight to make their own food in a process called Photosynthesis. Photosynthesis occurs within the leaves of the plants and in structures called chloroplasts. Chloroplasts are found mainly in plant cells. Chloroplasts use carbon dioxide, water, and solar energy to produce food in the form of glucose. Glucose is a food molecule that results from digestion. Chloroplasts use carbon dioxide, water, and solar energy to form glucose.

Plant Reproduction

All living things carry out reproduction, which is the production of more individuals of the same species. A seed is a structure that contains a young developing plant and stored food. A new plant can grow under the right conditions. Plants that have seeds often reproduce by sexual reproduction. The male sex cell is the sperm. The sperm come together with the female sex cell called the egg.

Some plants are seedless. These plants grow from spores instead of seeds. A spore is a cell that can develop into a new organism. Unlike seeds, spores do not contain food for the young, developing plants.

Plant life cycles & angiosperms and gymnosperms

The life cycles of mosses and ferns have two separate stages. During one stage, asexual reproduction, the plant produces spores. This stage is called the sporophyte stage. The plants needs only one type of cell-the spore-to reproduce. The other stage in the cycle is sexual reproduction. This stage is called the gametophyte stage. In this stage the plant needs male sex cells and female sex cells in order to reproduce. The fertilized egg will develop into a sporophyte.

Angiosperms and gymnosperms are two types of vascular seed plants. Angiosperms reproduce using flowers, but gymnosperms do not. Instead, the seeds of gymnosperms are produced in cones, such as those on pine trees. Gymnosperms are the oldest seed plants. During the time when dinosaurs roamed Earth, gymnosperms were the dominant land plants. They first appeared on Earth about 250 millions years ago.

Storing food All fruits and vegetables come from plants that

capture energy from the Sun and store it as food. Sweet potatoes, beets, parsnips, and carrots come from plants that store food in their roots. Potatoes, sugar, and ginger come from plants that store food in their stems. When people drink a cup of tea or eat vegetables such as spinach, cabbage, lettuce, and oregano (spice), they are using plant leaves for food. Cauliflower and broccoli are flowers that are commonly eaten. Seeds people eat include beans, corn, rice, peanuts, and even chocolate. Plant seeds are usually very nutritious because they contain the developing plant and its stored food.

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