why do plants do this?
915434
Plant cells differentiate in many tissues, like leaf, xilem, phloem, root and many others. It's the same for us, an animal cell can differentiate into a liver cell, a brain cell, a skin cell....\nPlants, unlike us, have regions of undifferentiated cells, called meristems. The main meristem of the shoot is at the top, called the terminal bud. Theese cells divide and produce the elongation of the shoot, and as they become more and older they produce new shoot, leafs and stuff.\nOther meristems, axial buds, are kept right in the place where the leaf meets the shoot. When this buds start growing in the same way the terminal buds do, branches arise.\nOther regions of meristematic tissue are right between the phloem (where the sap flows) and the xilem (where the water flows) all along the shoot. This region is called the Vascular Cambium.\n\nNormally, the terminal bud secretes hormones to the sap that keep the other meristematic tissues at rest. This is to avoid a lot of branches beeing produced before the roots can cope with the water demand of a lot of leafs.\nWhen you cut the shoot, the terminal bud dissapears, so the axial buds and even the cambium start dividing and differentiating into new shoots. \nThe reason why this new growth happens near the cut is because this would be the youngest axial buds and cambium, and therefore the most active ones (or the ones that can more readily be activated).
862372
Because light is needed for photosynthesis which makes energy..since the seeds have no leaves and hence no photosyntheisis they get around by having enough energy material provided within the seed to allow for growth until plant is above ground and has the leaves needed for photosynthesis
712277
one of the characteristics of living things is respiration, which is the breakdown of glucose to release energy, so the same thing applies for plants...because plants do respire!!! They need energy for other physiological processes like photosynthesis or growth or reproduction etc..
878227
if you're talking about plant cells, then it is for photosynthesis, the plant's way of making food. This is how it works.\n\nthe plant takes in carbon dioxide, water, and light. These are processed in the cell's chloroplasts and food is produced. The by-products of photosynthesis are sucrose (sugar) and oxygen, which is why we depend on rain forests and plants to give us a continuous supply of oxygen. In goes CO2 and out comes Oxygen!!
1100760
Plants are living things, and like us, need noses to breathe.  The 'noses' of plants are tiny holes called stomata (s), stoma (p) at the underside of leaves.  These stoma help the plant exchange gases with its surrounding.  Oxygen is produced during the day as the byproduct of photosynthesis, when the plant takes in carbon dioxide in the presence of sunlight to make food.  At night, the plant rests and does not make any more food, thus consuming oxygen.  This whole process is called respiration.
40194
It is a good idea for plants to spread their seeds about (seed dispersal).\n\nSome plants use animals to do this for them. The plants make attractive bits which animals eat. The seeds are eaten too but are undigested and pass out with the animal's droppings.\n\nIt depends which bit of the flower develops to make the attractive bit - sometimes the seeds are inside, sometimes (like strawberries) they are on the outside.
1179455
Animals have a circulatory system that transports fluids, chemicals, and nutrients around within the animal body. Some plants have an analogous system: the vascular system in vascular plants; trumpet hyphae in bryophytes.\n\nRoot hairs are thin-walled extensions of the epidermal cells in roots. They provide increased surface area and thus more efficient absorption of water and minerals. Water and dissolved mineral nutrients enter the plant via two routes. \n\n\nWater and selected solutes pass through only the cell membrane of the epidermis of the root hair and then through plasmodesmata on every cell until they reach the xylem: intracellular route (apoplastic). Water and solutes enter the cell wall of the root hair and pass between the wall and plasma membrane until the encounter the endodermis, a layer of cells that they must pass through to enter the xylem: extracellular route (symplastic). \n\n\nThe endodermis has a strip of water-proof material (containing suberin) known as the Casparian strip that forces water through the endodermal cell and in such a way regulates the amount of water getting to the xylem. Only when water concentrations inside the endodermal cell fall below that of the cortex parenchyma cells does water flow into the endodermis and on into the xylem.\nXylem and Transport \nXylem is the water transporting tissue in plants that is dead when it reaches functional maturity. Tracheids are long, tapered cells of xylem that have end plates on the cells that contain a great many crossbars. Tracheid walls are festooned with pits. Vessels, an improved form of tracheid, have no (or very few) obstructions (crossbars) on the top or bottom of the cell. The functional diameter of vessels is greater than that of tracheids.\n\nWater is pulled up the xylem by the force of transpiration, water loss from leaves. Mature corn plants can each transpire four gallons of water per week. Transpiration rates in arid-region plants can be even higher. Water molecules are hydrogen bonded to each other. Water lost from the leaves causes diffusion of additional water molecules out of the leaf vein xylem, creating a tug on water molecules along the water columns within the xylem. This "tug" causes water molecules to rise up from the roots to eventually the leaves. The loss of water from the root xylem allows additional water to pass throught the endodermis into the root xylem.\n\nCohesion is the ability of molecules of the same kind to stick together. Water molecules are polar, having slight positive and negative sides, which causes their cohesion. Inside the xylem, water molecules are in a long chain extending from the roots to the leaves. \n\nAdhesion is the tendency of molecules of different kinds to stick together. Water sticks to the cellulose molecules in the walls of the xylem, counteracting the force of gravity and aiding the rise of water within the xylem. \n\nCohesion-Adhesion Theory\nTranspiration exerts a pull on the water column within the xylem. The lost water molecules are replaced by water from the xylem of the leaf veins, causing a tug on water in the xylem. Adhesion of water to the cell walls of the xylem facilitates movement of water upward within the xylem. This combination of cohesive and adhesive forces is referred to as the Cohesion-Adhesion Theory.\n\n\nGuard Cells Regulate Transpiration\nIn most environments, the water concentration outside the leaf is less than that inside the leaf, causing a loss of water through openings in the leaf known as stomata (singular = stoma). Guard cells are crescent-shaped cells of the epidermis that flank the stoma and regulate the size of the opening. Together, the guard cells and stoma comprise the stomatal apparatus. The inner wall of the guard cell is thicker than the rest of the wall. When a guard cell takes up potassium ions, water moves into the cell, causing the cell to become turgid and swell, opening the stoma. When the potassium leaves the guard cell, the water
1144744
Excellent question.  \n\nThis is due to a process called osmosis.  Osmosis is the net movement of water molecules in and out of a partially permeable membrane (a kind of barrier that only allows certain molecules to pass through), from a region of their higher concentration to a region of their lower concentration.\n\nIts pretty self-explanatory here.  Since the concentration of water is higher inside than outside of the plant, water moves out of the plant, resulting in the plant dehydrating and dying.
184028
Not all plants have roots. The ones that do are the vascular plants which need to take in nutrients passively by means of capillary action and concentration gradients. The plants need their roots to reach down far enough into the vadose zone to get water during times of the year when there isn't much rain and the water table is dropping.\n\nAs already mentioned, roots also stabilize the plant to allow it to grow tall and get sunlight. In many places, competition for sunlight is intense so plants have to grow tall and hold themselves up. Thus, the need for roots.
104653
the sun flowers. they are used exactly for that purpose, in order to remove theese elements from the soil!
619674
Why is this in Biology?
427248
plants on land have a harder time spreading out their young, look at pollen and seeds.  water plants just release their gametes and they float away
533016
plants use the sunlight to turn nutrients into sugars to feed the plant they also take the toxins away from the plant when they go brown and drop off. Carbon dioxide and oxygen are released from them.
729914
There is a reason why plants only grow so high in nature.  They have to be able to still pump nutrients from the roots to the farthest limb.\n\nBesides, you would be providing a home for rats.
322754
i would assume that water would work best since a plant doesnt need any other ingredients excpet for the water to grow, other things that might affect the way a plant grows is the amount of sunlight and water it recieves.  This is just my guess from what i have learned in Biology.
200563
When plants take in H2O and minerals, the concentration changes from that of the surrounding soil. The concentration difference causes the plant to absorb more water and nutrients(including salt). For plants exposed to large amounts of salt in a short time, this means they absorb more than they need. As they have no way to get rid of it(with the exception of the mangrove), the plants end up dying.
95501
It is because of a plant hormone and also becasue plants are sensitive to light moisture and gravity.  shoots or stamp grow towards light and against the force if gravity.  roots grow towards moisture and in the direction of gravity.\n\nIn the shoot, hormone collects on the lower side and stimualtes the growth of the cells on this side.  therefore the shoot grows upwards and away from the force of gravity.\n\nin the root, the hormone also collects on the lower side buts slows down the growth of the the cells on this side.  therefore the roots grows downwards and towards the force of gravity.