by admin on Tuesday, March 16, 2010 17:52 under Interesting Facts.
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- The first plants to appear on land were simple plants such as liverworts, ferns. They grow from tiny cells called spores.
- Today, most plants grow not from spores but from seeds. Unlike primitive plants, seed-making plants have stems, leaves and often roots and flowers.
- The stem of a plant supports the leaves and flowers. It also carries water, minerals and food up and down between the plant’s leaves and roots.
- A terminal bud forms the tip of each stem. The plant grows taller here.
- Lateral buds grow further back down the stem at places called nodes.
- Some lateral buds develop into new branches. Others develop into leaves or flowers.
- The leaves are the plant’s green surfaces for catching sunlight. They use the sun’s energy for joining water with carbon dioxide from the air to make the sugar the plant needs to grow (see photosynthesis).
- The roots are the parts of the plant that grow down into soil or water. They anchor the plant in the ground and soak up all the water and minerals it needs to grow.
- The flowers are the plant’s reproductive organs. In gymnosperms – conifers, cycads and gingkos – the flowers are often small and hidden. In angiosperms (flowering plants) they are usually much more obvious.
- The world’s longest plant is the rattan vine which can snake 150 m through tropical tree tops. 14
- Plants that trap insects for food are called carnivorous plants. They live in places where they cannot get enough nitrogen from the soil and so the insects provide the nitrogen.
- There are 550 species living in places from the high peaks of New Zealand to the swamps of Carolina.
- The butterwort gets its name because its leaves ooze drops that make them glisten like butter. These drops contain the plant’s digestive juices.
- The sundew can tell the difference between flesh and other substances and only reacts to flesh.
- The sundew’s leaves are covered in tentacles that ooze a sticky substance called mucilage.
- The sundew wraps up its victims in its tentacles and suffocates them in slime in less than ten seconds.
- A Venus fly-trap’s trap will only shut if touched at least twice in 20 seconds.
- Insects are lured on to many carnivorous plants by sweet-tasting nectar – or the smell of rotting meat.
- The juice of a pitcher plant will dissolve a chunk of steak to nothing in a few days.
- The bladders of bladderworts were once thought to be air sacs to keep the plant afloat. In fact, they are tiny traps for water insects.
- Plants such as lupins grow on the base of an old stem. As the plant ages, the stem widens and the centre dies, leaving a ring of separate plants around the outside.
- Flowers like crocuses and gladioli have a bulbous base to their stem. This is called a corm.
- Plants cannot survive without water. If they are deprived of water, most plants will wilt and die very quickly — although some desert plants manage to get by on very little.
- Nearly all plants are almost 70% water, and some algae are 98% water.
- In plants, water fills up the tiny cells from which they are made and keeps them rigid, in the same way as air in a balloon.
- For a plant, water also serves the same function as blood in the human body. It carries dissolved gases, minerals and nutrients to where they are needed.
- Some water oozes from cell to cell through the cell walls in a process called osmosis.
- If a plant isn’t watered enough, its leaves will soon start wilting and losing color. Eventually the leaves will drop off completely and the plant will die.
- Some water is piped through tubes called xylem. These are the fine veins that you can often see on leaves.
- Water in xylem is called sap and contains many dissolved substances besides water.
- Plants lose water by transpiration. This is evaporation through the leaf pores or stomata.
- As water evaporates through the stomata, water is drawn up to replace it through the xylem.
- If there is too little water coming up from the roots through the xylem, then the cells collapse and the plant wilts.
- Plants need regular watering to beep them fresh and healthy.
- Bulbs like those of tulips, daffodils and onions look like corms, but they are actually made of leaf parts rather than the stem. This is why they have layers.
- Garlic bulbs are separated into four or five segments called cloves.
- In winter, rhizomes, tubers, corms and bulbs act as food stores, so that in spring they are able to provide the energy to grow new leaves.
- Plants can also propagate (grow new plants) by sending out Bulb long stems, called runners, that creep over the ground or suckers, which grow under the ground.
- Annuals and biennials only grow once, from a seed. Many perennials die back and grow again and again from parts of the root or stem. This is called vegetative propagation.
- Plants such as irises sprout from thick stems called rhizomes. These rhizomes grow sideways under the ground.
- If the end of a rhizome swells up it forms a lump called a tuber.
- Potatoes are the tubers of the potato plant.
- Garlic bulbs are made up of small segments called cloves. According to folklore, garlic is effective at keeping vampires away.
- The Arctic Circle is icy cold and dark for nine months of the year, but for a few months in summer it is daylight almost all the time.
- Over 900 species of plants cope with the Arctic climate.
- Full-size trees are rare in the Arctic; but grasses and sedges, mosses and
- Willow trees grow in the Arctic, but because of the cold and fierce wind, they grow less than 10 cm tall, spreading out along the ground instead.
- Many Arctic plants are evergreen so they are ready to make the most of the brief summer.
- Many small flowers are specially adapted to survive Arctic conditions, such as saxifrages, avens, stonecrops, snowbells and willowherbs.
- The Arctic poppy is the flower that blooms nearest the North Pole.
- Butterflies and bees are rare in the Arctic, so many plants, like mustard; rely on the wind for pollination.
- The soil is so poor in the Arctic that seeds make the most of any animal corpse, such as that of a musk ox. Arctic flowers often spring up inside skulls and near bones.
- Some plants have dark leaves and stems to soak up the sun’s warmth quickly and so melt the snow.
- Plants that grow on coasts must be able to cope with exposure to wind and salt spray, and thin, salty soils.
- Plants that can tolerate salt are called halophytes.
- Spray halophytes can tolerate occasional salt water splashing.
- True halophytes can tolerate regular immersion when the tide comes in.
- The annual seablite is a true halophyte that lives in between the tides. The word ‘seablite’ comes from an old English word for spinach.
- The rock samphire’s name comes from St Pierre (St Peter) who was known as `the rock’. The plant clings to bare rock faces. It was once a popular vegetable and poor people risked their lives to collect it from cliffs.
- The ice plant is native to South Africa but has acclimatized to growing on Cornish cliff tops.
- The droppings of sea birds can fertilize the soil and produce dense growths of algae and weeds such as dock.
- Lichens on rock coasts grow in three color bands in each tidal zone, depending on their exposure to salt.
- Grey ‘sea ivory’ lichen grows above the tide; orange lichens survive constant splashing by waves; black lichens grow down to the low water mark.
- On pebble and shingle beaches salt-tolerant plants like sea holly, sea kale and sea campion can be found.
- Epiphytes are plants that mostly grow above the ground in tropical rainforests, high up on tree branches.
- Epiphytes are often known as air plants because they seem to live purely on air, being attached neither to the ground nor to any obvious source of nutrients.
- Epiphytes get their water and minerals from rain water, and from debris growing on the branch.
- Various orchids, ferns and bromeliads are epiphytes in tropical forests.
- There are also epiphytes found in cooler places, including lichens, mosses, liverworts and algae.
- Pineapples belong to a big family of plants called the bromeliad family. At least half of them are epiphytes.
- The pineapple fruit is the most well known bromeliad.
- The pineapple plant, a bromeliad epiphyte, grows on the ground and takes its food from the air or from decaying plant matter near its roots. How plants live A Orchids, such as this cattleya orchid, are amongst the most common epiphytes. They survive best by clinging on to large branches, where their roots can more easily absorb the water and minerals from the tree.
- All but one bromeliad come from America, but they live in a huge range of habitats, living on cacti in deserts to moist forests high up in the mountains.
- The smallest bromeliads are moss-like Tillandsia bryoides, just a few centimeters long.
- The biggest bromeliad is Puya raimondii, with a stem up to 4 m long and a flower over 4 m tall.
by admin on Saturday, March 13, 2010 13:07 under Interesting Facts.
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- Annuals are plants that grow from seed, flower, disperse their seeds and die in a single season.
- Some annuals’ seeds lie dormant in the ground before conditions are right for germination.
- With an annual, producing flowers, fruits and seeds exhausts the plant’s food reserves, so once the seeds are dispersed the green parts of the plant die.
- Many crops are annuals, including peas and beans, squashes, and cereals such as maize and wheat.
- Annual flowers include petunias, lobelias, buttercups and delphiniums.
- Biennials live for two years.
- In the first year the young plant grows a ring of leaves and builds up an underground food store such as a bulb or taproot like beetroots and carrots. The food store sustains the plant through the winter.
- In the second year the plant sends up a stem in spring. It flowers in summer.
- Many vegetables are biennials, including beetroot, carrots and turnips.
- Biennial flowers include wallflowers, carnations, sweet williams and evening primroses.
