Plant Structure
Plants can be either herbaceous or woody. Herbaceous plants are plants with growth which dies back to the ground each year, in contrast with woody plants Most herbaceous plants have stems that are soft, green, and contain little woody tissue. Most annual and perennial flowers fall into this category along with vegetables and houseplants.
Life Cycle A plant's life cycle describes how long a plant lives or how long it takes to grow, flower, and set seed. Plants can be either an annual, perennial, or biennial.
Annual A plant that completes its life cycle in one growing season. It will grow, flower, set seed, and die.
Perennial A plant that lives for 3 or more years. It can grow, flower, and set seed for many years. Underground parts may regrow new stems as in the case of herbaceous plants, or the stems may live for many years like woody plants (trees).
Biennial A plant that needs two growing seasons to complete its life cycle It grows vegetatively (produces leaves) one season Then it goes dormant or rests over the winter In the spring, it will begin to grow again and grow flowers, set seed, and die The seed that is left behind on the ground germinates and the cycle begins again Examples: Sweet William, Canterbury bells, Foxglove
Basic Plant structure Plants are made up of different parts Each part has a certain job These parts can also help us to identify plants
Basic parts of most plants roots stems leaves flowers fruits seeds
Plant Parts - Roots Anchor plants into the ground Absorb water and nutrients from the soil needed for growth They can also store sugars and carbohydrates that the plant uses to carry out other functions Used to propagate new plants
Plant Parts - Stems Hold leaves, flowers, buds & fruit in the best position for them to carry out their functions Carry water & nutrients from the roots to the whole plant Carry sugars manufactured in the leaves to all parts of the plant Used to propagate new plants node - where the leaves join the stem the internode -the space between the leaves and the stem.
Plant Parts - Leaves Leaves are the food making factories of green plants Leaves are designed to capture sunlight which the plant uses to make food through a process called photosynthesis Leaves come in many different shapes and sizes Plants are classified according to their leaves Leaves can be simple or compound
Simple leaf Leaves can be simple. They are made of a single leaf blade connected by a petiole to the stem. An oak leaf or a maple leaf are examples
Compound leaf A compound leaf is a leaf made up of separate leaflets attached by a petiole to the stem like an ash or a locust.
Leaf Arrangement Leaves may be arranged on the stem either in: alternate arrangement leaves staggered or placed directly across from each other on the same twig or in opposite arrangement leaves that are directly across from each other on the same twig
Compound Leaves Pinnate Compound Palmate Compound Doubly-Compound
There are always three parts of a leaf to look for. Blade (or Lamina), which is the flat part of the leaf Petiole attached to stem it is the stalk of the leaves that supports the blade. The angle between the petiole and the stem is called axil, and a bud present in the axil is the axillary bud Apex- tip of the leaf At the base of the petiole as it attaches to the stem, there is a stipule. It is a small growth that resembles a leaf. It is not to be confused with an axillary bud.
Plant Parts- Flowers Flowers come in all shapes, sizes and colours
Flowers are the reproductive part of most plants Flowers contain pollen and tiny eggs called ovules After pollination of the flower and fertilization of the ovule, the ovule develops into a fruit
All flowers have some features in common Petals are used to attract insects/pollinators such as bees, butterflies and bats into the flower Stigma- Is covered in a sticky substance that the pollen grains will adhere to Style - raises the stigma away from the Ovary to decrease the likelihood of pollen contamination. It varies in length Ovary -this protects the ovule and once fertilisation has taken place it will become the fruit Ovule is like the egg in animals and once fertilisation has taken place will become the seed Receptacle- this is the flower's attachment to the stalk Flower stock - gives support to the flower and elevates the flower for the insects Sepals protect the flower whilst the flower is developing from a bud Filament - this is the stalk of the Anther Anther - The anther produces pollen (male reproductive cells
The stigma, style, ovary, and ovule are often known collectively as the Carpel or Pistil or female parts of the flower The filament and the Anthers are collectively known as the Stamen or the male parts of the plant
Fertilization The joining of pollen with an ovule to form a seed During the process of fertilization, pollen lands on the stigma, a tube grows down the style and enters the ovary. Male reproductive cells travel down the tube and join with the ovule, fertilizing it. The fertilized ovule becomes the seed, and the ovary becomes the fruit.
Growing Plants - There are seven basic requirements that plants need in order to grow properly: room to grow the right temperature light water air nutrients time
Room to grow. All plants like to have room to grow. The above ground portions of the plant need space so leaves can expand and carry out the job of making food. Roots also need room to grow. Plants growing in small spaces will have their roots crowded, and that results in smaller amounts of growth.
Temperature Most plants like temperatures that most humans like. Some may like warmer temperatures while others may prefer cooler temperatures for best growth. It is always good to know where plants come from so you can make them feel at home. Most plants like to have cooler temperatures at night and don't like to be in a drafty spot.
Light Plants grown indoors like bright light. Windows facing the south or west have the best light. Try to place the plants close to the window to take advantage of all the light. The further away from the window, the darker it becomes. A plant will tell you when it isn't getting enough light, because its stems will be thin and it will lean toward the light. If you don't have a bright window, try using grow lights. Remember to have the light about six inches above the plants and leave it on for 14-16 hours each day.
Water Water is important in the plant's ability to make and move nutrients. Without water or with too much water, a plant dies. Most plants like to be watered when the soil is slightly dry to the touch. When watering, moisten the soil by using enough water so that it starts to come out of the hole in the bottom of the container. How often you water depends on a lot of things. Plant size, time of the year, and type of plant are a few. Your best guide, though, is to feel the soil. If you stick your finger one inch into the soil and it is dry, then water your plant.
Plants use carbon dioxide in the air and return oxygen Smoke, gases, and other air pollutants can damage plants
Nutrients Most of the nutrients that a plant needs are dissolved in water and then taken up by the plant through its roots Fertilizers will help to keep the soil supplied with nutrients a plant needs Don't apply too much too often. Fertilizer won't solve all of your plant problems, so make sure your plants have good light, good soil, and good drainage The three most important nutrients are nitrogen, phosphorous, and potassium
The three most important nutrients Nitrogen is used for above ground growth. This is what gives plants a dark green colour. Phosphorous helps plant cell division. It aids in flower and seed production and in the development of a strong root system. Potassium helps fight off disease and provides for strong stems.
Time It takes time to grow and care for plants. Some plants require more time to grow than others. Getting plants to flower or fruit at a certain time can be challenging. Plants that normally grow outdoors need a certain number of days to flower or fruit.
In plants,the basic processes leading to growth and reproduction are: : Photosynthesis Respiration Transpiration
Plants are self-sufficient. They make their own food thru the process of photosynthesis using light energy to make sugars from carbon dioxide (C02) and water (H20).
Photosynthesis Leaves are the site of the food making process called photosynthesis. In this process, carbon dioxide and water in the presence of chlorophyll (the green pigment) and light energy are changed into glucose (a sugar). This energy rich sugar is the source of food used by most plants Oxygen is also released in this reaction
Respiration Respiration reverses the process of photosynthesis, releasing the stored chemical energy. Takes place in all living things Is a step by step process
Transpiration The loss of water from a plant by evaporation is known as transpiration. Most of the water is lost through the surface openings, or stomata, on the leaves.
Environmental factors that affect the rate of transpiration 1. Light Plants transpire more rapidly in the light than in the dark. This is largely because light stimulates the opening of the stomata (mechanism). Light also speeds up transpiration by warming the leaf. 2. Temperature Plants transpire more rapidly at higher temperatures because water evaporates more rapidly as the temperature rises. At 30 C, a leaf may transpire three times as fast as it does at 20 C. 3. Humidity The rate of diffusion of any substance increases as the difference in concentration of the substances in the two regions increases.when the surrounding air is dry, diffusion of water out of the leaf goes on more rapidly. 4. Wind When there is no breeze, the air surrounding a leaf becomes increasingly humid thus reducing the rate of transpiration. When a breeze is present, the humid air is carried away and replaced by drier air. 5. Soil water A plant cannot continue to transpire rapidly if its water loss is not made up by replacement from the soil.