My Science School

As well as directly affecting the environment, trees supply homes and food for millions of other living creatures, including people. They are also the source of wood, which is used in buildings and for making such essential items as furniture and paper.

Trees are very important, valuable and necessary to our existence as they have furnished us with two important life essentials; food and oxygen. Apart from basically keeping us alive, there are many other little and big benefits we get from trees. So, trees are vital resources for the survival of all living beings. Therefore, Governments world over and many Organizations are taking steps to prevent deforestation and to tell the benefits of planting trees. Let us go through some important points about the Importance of trees for the existence of human life.

Trees play an especially important role in enhancing our quality of life in the urban environment and this is acknowledged in the Governments Sustainable Development Strategy. They screen unsightly structures and activities, give privacy and soften the hard lines of buildings. Trees also bring colour and contrasts into the urban environment.

Not only do trees have a visual quality, but they also enhance the environment in less obvious ways. Trees improve air quality by acting as natural air filters removing dust, smoke and fumes from the atmosphere by trapping them on their leaves, branches and trunks. Just 1 hectare of beech woodland can extract 4 tonnes of dust per year from the atmosphere. Trees reduce the 'Greenhouse' effect by removing carbon dioxide from the air and releasing oxygen. Each year a mature tree produces enough oxygen for 10 people.

Trees are also an effective sound barrier and can limit noise pollution. Recent research shows that trees also help reduce the stress of modern life. Trees in themselves benefit the environment and the landscape, but they are also an integral part of the ecosystem providing benefits to wildlife and biodiversity. Trees, especially older or veteran trees and those in groups or woodlands, provide habitats for native ground flora such as bluebells and fauna, particularly bats, red squirrels and invertebrates. The planting of trees and the care and preservation of mature trees can go a long way to making Trafford a great place to live, work learn and relax.

Trees are the largest plants on Earth and play a very important part on the planet. They cover almost a quarter of the Earth, helping to stabilize the atmosphere by taking in huge amounts of carbon dioxide from the air and giving off oxygen. In addition, tree roots help to retain fertile soil and stop the rain from washing it down hillsides, while the huge amount of water vapour given off by trees has an important effect on the weather.

The largest tree in the world is a giant sequoia (Sequoiadendron giganteum) in California's Sequoia National Park. Called General Sherman, the tree is about 52,500 cubic feet (1,487 cubic meters) in volume.

That's the equivalent of more than half the volume of an Olympic-size swimming pool, commonly considered to be 88,500 cubic feet (2,506 cubic meters).

General Sherman is estimated to be about 2,000 years old. That makes it only a middle-age giant sequoia, as other trees are believed to be more than 3,220 years old, based on tree ring counts.

The tree lost a huge branch in 2006, which shattered a new walkway and fence below. It didn't affect General Sherman's ranking as the largest tree, however, as that was calculated using trunk volume and not branches.

Flowers that are closely related often cross-pollinate in the wild, creating a variety of flower shades and shapes. Under controlled conditions, plant breeders ensure that their parent plants are not pollinated naturally. They then transfer pollen from a selected “father” plant to the stigma of the “mother” plant and wait for seeds to form. These are sown to see what kind of flowers result. It may be years before the results are known and even then only a few of the plants will prove to be different and attractive enough to be launched as new varieties.

The goal of flower breeding is the creation of new flowers that would not normally be found in nature. By selecting two flowers of the same species with different traits -- such as color, height or bloom type -- and cross-pollinating them, seeds that combine the traits of both plants will be produced. The seeds produced are F1 hybrids that will grow into new, different plants. Not all flowers are candidates for cross breeding, as some have natural inhibitors to prevent crossing.

Step 1

Select different varieties of the same species of parent flowers. Neither parent can be a hybrid, nor will unpredictable results occur. The parent flowers should always be the same, using the same variety to supply the ovules and the other variety to supply the pollen.

Step 2

Snip the filaments and anthers off the flower, which will supply the female parts. Hold the filament with a tweezers and cut the filament below the tweezers. Do not allow the anther to touch the center portion of the flower. Removal of the anthers ensures the flower will not self-pollinate and ruin the cross. Call this flower the female flower.

Step 3

Obtain pollen from the flower that is supplying the male parts. To store pollen, collect it from the anthers with a small camel hair brush and brush it in a vial. Label the vial with the flower species and type. Clean the brush with alcohol before using it to collect a different type of pollen. You can also gather pollen for immediate use by removing the filaments and anthers from the male flower as was done with the female flower.

Step 4

Fertilize the female flower with pollen. Dab the brush in the pollen grains in the vial and gently brush the pollen onto the emasculated female flower's stigma. For immediate use of pollen, simply collect the anthers from the male plant and use the anthers to brush pollen onto the stigma of the female plant. Immediately cover the female flower with a cellophane bag and tie it closed with a piece of string to prevent contamination with other pollen. Tag and label the female flower as a cross with the male by listing the variety of male and female.

Step 5

Collect the seeds from the female flower once they are ripe. Usually this occurs when the flowers is wilted and dry, although readiness varies by species. Label the seeds for storage as the cross of the two varieties selected. Good record keeping is a must when experimenting with flower breeding.

Step 6

Keep notes in a notebook about the results of the breeding experiments. Add pictures of flowers and detailed descriptions of the hybrid plants created. Experiment with crossing the male of one variety with the female of another and also the reverse to see if the results are different.

When the flower has been fertilized, the ovary swells to form a fruit, inside which one or more seeds will grow. These seeds may simply fall to the ground below, or the plant may have methods of ensuring that its offspring grow much further away.

Plants make seeds that can grow into new plants, but if the seeds just fall to the ground under the parent plant, they might not get enough sun, water or nutrients from the soil. Because plants cannot walk around and take their seeds to other places, they have developed other methods to disperse (move) their seeds. The most common methods are wind, water, animals, explosion and fire.

Wind dispersal

Have you ever blown on a dandelion head and watched the seeds float away? This is wind dispersal. Seeds from plants like dandelions, swan plants and cottonwood trees are light and have feathery bristles and can be carried long distances by the wind. Some plants, like kauri and maple trees, have ‘winged’ seeds. They don’t float away but flutter to the ground. With wind dispersal, the seeds are simply blown about and land in all kinds of places. To help their chances that at least some of the seeds land in a place suitable for growth, these plants have to produce lots of seeds.

Water dispersal

Many plants have seeds that use water as a means of dispersal. The seeds float away from the parent plant. Mangrove trees live in estuaries. If a mangrove seed falls during low tide, it can begin to root in the soil. If the seeds fall in the water, they are carried away by the tide to grow somewhere else. K?whai trees also use water dispersal. They have a hard seed coat that allows them to float down streams and rivers. That is one of the reasons k?whai trees are commonly found on stream banks.

Animal dispersal

Over 70% of plants in our woody forests in New Zealand have fleshy fruit that is eaten by birds. Chemicals in our native birds’ digestive systems help to weaken the tough coats around these seeds. Birds often fly far away from the parent plant and disperse the seeds in their droppings. The kerer?, t?? and bellbird play an important role in seed dispersal. Trees that produce the largest fruit – miro, p?riri, tawa and taraire – rely on the kerer? because it has such a large, wide beak to eat the fruit.

Some seeds have hooks or barbs that catch onto an animal’s fur, feathers or skin. Plants like pittosporum have sticky seeds that can be carried away by birds. Humans can also spread seeds if they get stuck to our clothing or shoes – and if we throw fruit pips and stones out of the car window!

Fire

Plants cannot run away from a fire so some plants have developed a way to help their seeds survive. There are some species of pine tree that require the heat from a fire before their cones will open and release seeds. Banksias, eucalypts and other Australian plants also rely on fire. The intensity and timing of the fire is important. It needs to be hot enough to trigger the cones to open, but if fires are too frequent, there is not enough time for the plants to grow big enough to make new seeds.

Adaptation and seed dispersal

Adaptation is an evolutionary process that helps an organism makes the most of its habitat. Seed dispersal is an example of adaptation. Fires are common in Australia, so some plants have adapted and become well suited to make the most of it. Mangrove trees have seeds that float, making the most of their watery environment.

The pollen that fertilizes the stigma may come from the same flower or from a nearby flower. Many flowers are fertilized (or pollinated) by insects. The flowers produce drops of sweet liquid called nectar at the base of their petals. When insects visit the flower to drink the nectar, pollen from the anthers rubs off onto their wings, bodies and legs. When the insect visits another flower, the pollen is deposited on its sticky stigma.

Fertilization is a process of sexual reproduction in plants, which occurs after pollination and germination. Fertilization can be defined as the fusion of the male gametes (pollen) with the female gametes (ovum) to form a diploid zygote. It is a physicochemical process which occurs after the pollination of the carpel. The complete series of this process takes place in the zygote to develop into a seed.

In the fertilization process, flowers play a significant role as they are the reproductive structures of angiosperms (flowering plants). The method of fertilization in plants occurs when gametes in haploid conditions fuse to produce a diploid zygote. In the course of fertilization, male gametes get transferred into the female reproductive organs through pollinators (honey bees, birds, bats, butterflies, flower beetles) and the final product will be the formation of the embryo in a seed.

In flowers, the pollen grain germinates after the pollination of the carpel and grows into the style by creating the pathway for the pollen grain to move down to the ovary. The pollen tube breaks into the ovule through the micropyle and bursts into the embryo sac. Here the male nucleus fuses with the nucleus of an egg inside the ovule forming a diploid zygote, which later swells up and develops into a fruit.

The different shapes of flowers help to ensure that they are fertilized. Flowers that rely on insects for pollination must make sure that the insect is carrying pollen from the same kind of plant. The shape of the flower ensures that only certain kinds of insect can pollinate it. Flat flowers, such as daisies and sunflowers, can be visited by hoverflies and some bees. Flowers that are formed into tubes only attract insects that have long tongues. As flowers bloom at different times of the year, there are usually only a few different species available to each insect at any one time, so the chances of pollination are increased.

The flowers of plants have evolved to permit the transmission of pollen and (hopefully) its eventual reception by an appropriate ovum of the same species. Many flowers have evolved to attract pollinators (mostly insects, bird and bats) with a nectar reward and are colored or structured to be attractive only to a few (or a single) pollinator to increase the odds of successful pollen transmission. For example, red flowers (and fruits) are attractive to birds, yellow to bees, blue to butterflies, and white to moths and bats.

In addition, the size and structure of the flower contributes to the type of fruiting bodies. Fruits can be a source of nutrients for some seeds, but they are also often a means of dispersing the seeds. Many fruits are palatable only to certain animals, and evolved to prevent damage to the seeds while the fruit is digested. Some plant species require that an animal erode the outside of the fruit or seed in its digestive tract, or else to break the fruit open. 

Flowering plants are known as angiosperms. Although there are plenty of plants that do not have flowers, such as mosses, ferns, algae and conifers, the majority of plants on Earth are flowering ones. That does not mean that they are what we generally think of as flowers — colourful blooms that can be presented in bouquets. Most trees and grasses, for example, are flowering plants, but their flowers may be so small that they usually go unnoticed.

No. Although most of the world's plants are flowering plants called angiosperms (from the Greek words for “vessel” and “seed”), there are hundreds of plants that do not make flowers. Seed plants that do not have flowers such as cycads, ginkgo, and conifers are called gymnosperms. Conifers, for example, are common gymnosperms; instead of flowers, conifers have cones that produce pollen or eggs. Well-known examples are cedars, cypresses, Douglas firs, junipers, pines, redwoods, and spruces. Male cones are small and soft, and female cones are large and hard. Wind carries pollen from the male cone to the female cone. As the eggs are pollinated and seeds develop, the scales of the cone open up to release the seeds. Once the seeds take root, a new plant grows. Other plants that do not have flowers are mosses; although they sometimes look like they are blooming, the flower-like part is a little capsule full of spores at the end of a small stem.

Flowers are the reproductive parts of a plant. Usually, one flower has both male and female parts. The male parts are the stamens, which consist of filaments and anthers. Filaments are like little stalks that support the anthers. Anthers produce tiny dust-like grains called pollen. The female part of a flower is called the carpel. This consists of an ovary, ovules, a style and a stigma. The ovary is hidden in a bulb-shaped receptacle at the base of the flower. Inside the ovary are one or more ovules, which become seeds if the flower is fertilized. Rising from the ovary is a small, sticky stem called the style, the tip of which is the stigma. In order for a flower to be fertilized, pollen must be transferred from the male stamen to the female stigma.

Flowers do much more than just provide beauty and lovely scents. Their primary purpose is reproduction. During the reproductive process, flowers make use of their colorful petals to attract pollinators such as insects and animals. These creatures are also lured by the nectar that flowers produce in their nectarines, glands that are often found at the base of their petals. By producing nectar, flowers are able to provide food for the insects that help to pollinate the plants. After a flower is pollinated, its fertilized ovule develops into a seed that can create a new plant; and the ovary that formed the ovule becomes a fruit. The process of plant reproduction, then, also generates food for people and animals to eat.

In addition to reproduction, flowers also serve important roles in gardens in particular. Some flowers possess an unparalleled ability to attract insects that are beneficial for the fertilization of other garden plants. On the other hand, certain other flowers can repel unwanted insects that are harmful to garden vegetables and fruits. Employing flowers as "garden guardians" can allow gardeners to decrease the amount of pesticides they use on their crops, which in turn leads to an increased number of beneficial insects in the garden. For instance, lavender is great for repelling fleas, moths, and whiteflies. Japanese beetles, those garden pests, can be attracted and killed by Four O’clock flowers planted near vegetable gardens (though these plants are poisonous to animals and humans). Furthermore, the act of planting flowers in itself is beneficial to humans, allowing the planter to burn calories and increase elasticity in certain muscles.

About 9000 years ago, human beings invented farming. Since then, they have carefully selected the crops that give the best harvests under different conditions. Particularly in the last two hundred years, selective plant breeding has developed the characteristics that farmers and consumers require. Now that machines are used to pick most crops, and large stores prefer to package fruits and vegetables in regular sizes, many commercial varieties have been bred to produce even fruits that ripen together.

For most of history, humans have been hunter-gatherers. Adopting a more nomadic lifestyle, we moved with the changing seasons, with livestock migration patterns and adapted as climate change impacted crops and the surrounding environment. Today, we embrace technologies that our ancestors likely could never have dreamed of, but the incorporation of modern capabilities into agricultural practices took time and didn’t entirely abandon early advancements. In other words: our ability to grow and sustain life on a billboard didn’t come to us overnight.

The first true shift in agriculture came nearly 12,000 years ago at the start of the Neolithic Revolution (a.k.a. the Agricultural Revolution), which marked the first instances of a more permanent, settled lifestyle. Humans found a practical, long-term solution for food in the Fertile Crescent, an area located across what is now the Middle East, with ready access to major bodies of water such as the Mediterranean Sea. Humans began cultivating plants, domesticating such crops as wheat, barley, peas, and flax, and livestock, breeding domestic pigs from wild boars, goats from Persian ibex, and the sheep and cows commonly found on today’s farms.

For centuries, very little changed — a settled life with access to high-quality land and domesticated animals didn’t lend itself to transition. Then came the Middle Ages, a period marked by selective cross-breeding of plants and animals for optimal quality and a technique known as ridge and furrow farming, a plowing technique employing oxen (and later, horses) that inspired similar methods used today.

The development of crop rotation, or the growing and harvesting of different crops on the same land during different seasons, in the 16th century drove the modernization of farming practices, but it was the Industrial Revolution in the 18th century that really took humans from the past into the present. With crops that required fewer workers, better soil replenishment and improved livestock care, more people could work in urban industries as a result of agricultural productivity.

The 20th century introduced widespread use of machinery, fertilizer and pesticide technology, which coincided with huge population growth. As a result, food largely became an affordable and accessible commodity in developed countries.

Today, we find ourselves at yet another turning point in which we must balance sustainability and increased food production for the 9.6 billion people expected in the world by 2050. At Bayer, we strive to continually advance attach innovation to help tackle agricultural challenges such as these. Through digital farming, we’re leveraging improved data collection methods and GPS systems, and other innovative technologies like airborne photosynthesis sensors to drought resistant seeds.

Some plants do gain extra minerals and other nutrients by trapping and “eating” insects. They are usually found in areas where there are not enough nutrients in the soil for healthy growth.

Would you believe that there are some plants that eat insects and even small animals from time to time? It’s true! We call these exotic things carnivorous plants. Although most carnivorous plants eat small insects, larger carnivorous plants in tropical areas have been known to capture rats, birds, and frogs.

One carnivorous plant that many students are familiar with is the Venus flytrap. Its unique “jaws” can be triggered by flies and other small insects. Once its jaws close on its prey, the Venus flytrap secretes enzymes that break down the insect into a goo that can be absorbed for its nutrients.

There are several other examples of carnivorous plants. The pitcher plant, for example, has leaves like champagne flutes, which can capture insects. Sundews, on the other hand, trap their victims with sticky tentacles. Bladderworts grow in ponds and streams, where they suck in their prey like underwater vacuum cleaners.

Carnivorous plants tend to grow in areas where the soil is very thin and lacks necessary nutrients. To survive, these plants must find other sources for the nutrients they need. Trapping and digesting insects allows these unique plants to survive. Unfortunately, human and environmental factors continue to threaten the limited environments where you can find wild carnivorous plants.

For many people, the thought of a plant eating an animal seems very strange. In fact, more than one person has turned the idea into a scary story or movie. Don’t worry, though, carnivorous plants don’t pose any danger to humans. Unless you’re the size of a tiny insect, you don't have to worry about falling prey to a Venus flytrap or a pitcher plant.

There are two main ways in which plants reproduce. In sexual reproduction, pollen is transferred by insects or the wind from one part of a flower to another, in such a way that fertilization can take place. Seeds are then formed. These seeds in turn are distributed in different ways to a spot where they can germinate and grow. In asexual reproduction, a plant can reproduce without fertilization taking place. It may, for example, reproduce by sending out runners from its roots or by growing new plants on the tips of its leaves or branches. Plants reproduce sexually through the fusion of male and female gametes in the flower. Asexual reproduction is through stems, roots and leaves.

Plant reproduction comes in two types: sexual and asexual. Sexual reproduction is similar to human reproduction, which involves the fusion of the male (pollen) and female (ovule) gametes to form a new organism that inherits the genes of both the parents. The sexually reproductive part of a plant is the flower. Asexual reproduction, on the other hand, involves vegetative reproduction through stems, roots and leaves. Essentially, the parent plant regenerates itself by using one of its parts (roots, stems or leaves).

Both sexual and asexual methods of reproduction have their own set of advantages. In sexual reproduction, the new plant formed is a combination of genes, giving it an advantage in new ways concerning adaptation in changing environments. It can also avoid the transmission of certain diseases, due to some genes being dominant and others being recessive. Asexual reproduction is faster and perhaps the only manner of reproduction in species that do not bear flowers. Since asexual reproduction is basically the cloning of the parent plant, farmers can ensure that there is no genetic abnormality by selecting a healthy plant for reproduction.

The flower consists of four whorls or parts (calyx, corolla, androecium and gynoecium). The first whorl is the calyx, which contains the green sepals. The second whorl is the corolla, which contains the petals. The petals are brightly colored to attract the agents of pollination (bees and other insects) that aid in reproduction. The petals also protect the inner two whorls, which are directly involved in reproduction. The third whorl is the Androecium—the male reproductive part of the plant. The innermost whorl is the gynoecium—the female reproductive part of a plant.

The androecium contains a bundle of stamens that consist of a tube called a filament and the swollen end called the anther. The anther contains the pollen grains. Once matured, the pollen grains burst out in order to reach the female reproductive part of the flower.

The gynoecium contains the pistil, which is composed of the tube (style) that reaches the ovary. The swollen tip of the style is the stigma, which receives the pollen grains. The ovary contains the ovules, which turn into the seeds.

If there were no Plants, there could not be animal life on Earth. All animals either eat plants or eat other animals that in turn eat plants themselves. In this way, every living thing on Earth indirectly gets its energy from the Sun, although only plants can convert the Sun’s light into a usable form.

Why plants are valuable and important. Every day, we encounter plants whether it is in parks, the wild outbacks of nature, or in the simple pleasure of plants aping the inside and outside of our homes. But do we truly understand the vital role plants have in this world? The very thought should cause us to pay more attention to the beautiful botany that surrounds us.

FOOD: The sun is provider of all energy. We eat plants to gather the energy stored in their cells. And we are here because our ancestors foraged plants for food. They learned the ways of agriculture to make it easier and grew plants that produced products such as wheat and corn to eat. Approximately 7,000 different plant species have been cultivated and used as food for people. Though humans can live on the consumption of animal products, it is just a step away from plants since cows, pigs, sheep, chickens, rabbits and other animals eat plants to live.

AIR: The air we breathe mainly consists of 78% nitrogen and 21% oxygen. But it is oxygen that is vital for our cells to produce energy, energy that originated with the sun. When the sun shines down, plants absorb the sunlight to produce energy and end up releasing oxygen into the air as a by-product of their metabolism.  We in turn inhale the oxygen for our survival and exhale the carbon dioxides plants require. Breathe deeply and drink in the oxygen-laden air and realize it’s because of plants we are alive.

WATER: Where there is water, there is life. Plants regulate the water cycle by distributing and purifying the planet’s water supply. Through the act of transpiration, plants move the water from the soil up their roots and out into the atmosphere. Moisture accumulates into clouds and eventually the water droplets are returned back down as rain to revitalize life on earth.

MEDICINE: Many of prescription medicines come from plant extracts or synthesized plant compounds. Aspirin comes from the bark of the willow. Mint leaves have menthe that is used in throat lozenges, muscle creams and nasal medicine. The malaria drug ingredient quinine is from the bark of the Cinchona tree. About 65% – 80% of the world’s population use holistic plant-based medicine as their primary form of healthcare according to the World Health Organization.

HABITAT and CLOTHING: Plants make up the backbone of earth’s diverse landscape that provides hundreds of unique habitats necessary for life. Flowers dance in the fields while grasses on a hill sway in the wind. Trees strut tall in their habitat and act as the earth’s dynamic lungs, powering life everywhere. Birds pick up straw, leaves, bark, along with feathers, hairs and other items to make a comfy nest in a tree, bush or even tall grasses. Our ancestors used thatched roofs made of grasses or palm fronds, and wood to secure their homes. Industrial hemp was one of the first plants to be spun into usable fiber 10,000 years ago. Plants in all their diversity keep the cycle of life moving.

CLIMATE: Excessive carbon released into the environment has been blamed for the current climate change we are experiencing. But rarely is it explained that plants store carbon by pulling it from the air. Plants help keep much of the carbon dioxide produced from our burning of fossils fuels out of the atmosphere. We owe our temperate climate to the perpetual landscape of green that blankets our world.

Over thousands of years, human beings have found many uses for plants. Some of the most common ones are shown here.

Plants also provide us with fibres for making cloth, rope, paper etc. There are numerous dyes obtained from plants with which to colour our fabrics. Many plants have oil-rich seeds and these oils can be extracted when they have a variety of uses. Many of them are edible and they can also be used as lubricants, fuel, for lighting, in paints and varnishes, as a wood preservative, waterproofing etc.

The articles below highlight some of these uses.

• Alternative Lighting: Plant Oils Waxes


• Fibre Plants


• Soap Plants


• Vegetable Oil

Building Materials

• Insulation: Providing insulation against extremes of temperature, sound or electricity.


• Pipes: For carrying water etc.


• Pitch: Used for waterproofing, in paints etc.


• Plaster: Used for covering walls.


• Roofing: Used to give a waterproof roof to buildings. See also Thatching.


• Thatching Used for making thatched roofs.

Clothing

 

• Buttons: Plants that can be used as buttons. Not including making buttons from wood.


• Darning ball 


• Fibre: Used for making cloth, rope, paper etc.


• Latex: A source of rubber.


• Leather: Substitutes, that is.


• Needles: Used for sewing, darning etc.


• Pins: Used as needles and pins in sewing etc. Also used to lance boils, extract splinters from the skin etc.


• Raffia: A substitute for that material.


• Starch: Used as a fabric stiffener.


• Stuffing: Used in making soft toys, mattresses, pillows etc.


• Tannin: An astringent substance obtained from plants, it is used medicinally, as a dye and mordant, stabilizer in pesticide etc.


• Weaving: Items such as grass and palm leaves that are woven together for making mats, baskets etc. See also Basket making and Fibre.

Dyes, paints, inks and paper

• Blotting paper: Plant that can be used to make blotting paper.


• Dye: Plants that provide dyes.


• Ink: Plants that can be used as an ink.


• Mordant: Used for making a dye more permanent, it also affects the colour of the dye.


• Paint: Plants used directly as paint. Does not include oil plants and dyes that can be used as ingredients in paints.


• Paper: Related to the entry for Fibre, these plants have been specifically mentioned for paper making.


• Pencil: A couple of plants especially mentioned for making the tubes that pencil leads fit into.


• Size: Used on materials, paper etc to give a surface that will take ink, dyes etc. 

A Plant’s leaves contain a green substance called chlorophyll. The chlorophyll energy enables chemical reactions to take place. These use energy from the Sun and carbon dioxide gas from the air to make food for the plant to live and grow. As photosynthesis happens, oxygen is given off into the air.

Green plants use photosynthesis to create energy from carbon dioxide and sunlight. This energy, in the form of glucose, is used by the plant to grow and fuel the necessary reproductive activities of the plant. Excess glucose is stored in the leaves, stem and roots of the plant. The stored glucose provides food for higher organisms that eat the plants. A byproduct of the process of photosynthesis is oxygen, which is released into the atmosphere in exchange for the carbon dioxide used during the chemical reaction of photosynthesis.

Photosynthesis in plants requires a combination of carbon dioxide, water and light energy. The light energy used in photosynthesis is typically derived from the sun but is also effective when provided by artificial lighting. The leaves of a plant have the primary burden of creating food for the plant through the process of photosynthesis. The leaves of a plant are spread flat to catch as many of the sun's rays as possible, in order to facilitate the absorption of light energy.

Within the leaves are mesophyll cells which contain chloroplasts. Photosynthesis occurs within these structures, which contain the substance chlorophyll. Chlorophyll, along with other pigments present in the chloroplast, absorbs the light energy of all colors but green for use in the photosynthesis process. The remaining green light is reflected back off of the plant, resulting in green color characteristic of a plant using photosynthesis for energy. Once the light has been absorbed, it must be stored as ATP, or adenosine triphosphate, in order to be used in the next phase of photosynthesis.

During the final stage of photosynthesis, which is considered to be light-independent, carbon dioxide is converted into glucose. This chemical change requires the ATP that was stored in the first part of the photosynthesis cycle. The ATP is combined with carbon dioxide in what is known as the Calvin cycle. This combination creates a compound called glyceraldehyde 3-phosphate, which combines with another glyceraldehyde 3-phosphate compound as it is produced, to produce one glucose molecule.

Like animals, plants need food for energy to survive and grow, but while animals can move about to catch their food or find new areas of vegetation, plants are usually rooted to one spot. But plants can do something that no animal can do. They can make energy from sunlight. This process is called photosynthesis. As well as light, plants also need water and nutrients.

          A plant may not look lively and active. But inside its millions of microscopic cells, thousands of chemical changes take place as part of the plant’s life processes. Like an animal’s body, a plant’s body has many specialized parts for different jobs. The roots take in water, minerals, salts and other substances from the soil in which the plant grows. The stiff stem holds the main parts of the plant above the surface, away from animals on the ground that might eat it, and above other plants so that the leaves can catch more sunlight. 

          A plant’s leaves are “light-powered food factories”. They are broad and flat so that as much light as possible falls on them. A green substance called chlorophyll in the leaves catches or absorbs the energy in light. It uses this energy to make a chemical reaction. Water, taken up from the soil, and carbon dioxide, taken in from the air, join together to form sugar, which contains lots of energy in chemical form. The plant then uses the sugar to power its life activities. The process is called photosynthesis —a word meaning “making with light”.

          The carbon dioxide for photosynthesis comes from the air. It seeps into the leaf through tiny holes in its lower surface, known as stomata. In addition to sugar, photosynthesis also produces oxygen, which seeps out into the air. Living things including ourselves need oxygen to survive. Plants help to top up its level in the air.