why does plant require water?
400548
1-For terminal oxidation of Water and release of oxygen.\n2-As a solvent for many metabolic reactions.\n3-For cellular osmotic pressure.\n4-For transpiration.\n5-For seed imbibition.
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.
697611
Yes, plant cells need mitchondria to survive.
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.
309468
Water travels through a network of 'veins' through out the plant. The cells are re-hydrated which causes them to expand like a balloon. Once the cells are all filled to capacity, they rest on each other. The cell membranes contain cellulose that helps them stand erect when fully hydrated.
896536
Plants must have light to grow.  It doesn't necessarily have to be sunlight. Artificial light is a great to grow most plants too.  Photosynthesis is what causes plants to exchange necessary nutrients to create growth but each have unique abilities to utilize whatever light source is available.
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.
925453
well photosynthesis is a good way to start. the water from the roots are pulled by cohesion and then it leaves from the stroma in the plant leaves.
53458
Plants take in oxygen, carbon dioxide and water, and produce sugar which contains carbon, oxygen and hydrogen atoms from all three. So they use more water than they put out. In fact, I don't believe they "exhale" water the way we do at all,
487819
twigs usually have water. Its possible to dry them out.\n\nRocks can be porous enough to trap water inside them.
593033
cell walls keep the cell rigid, so they can stay upright.\n\ncuticles reduce water loss through evaporation, preventing the plant from being dehydrated
607027
Yeah plants can grow without sun. those plants are called are non-photosynthetic plants. as they do not have photosynthetic pigments. They are also termed as chemosynthetic plants as they prepare their food by chemicals and not by sun light. As far as water is concrned then no plant on earth gorws without it. Water is essential for every livig animal. Its basic requirement for solutes and solvents to get transported from one cell to another. without it plants will DIe. try growing plants without water, they will shrink and eventually die.
883000
Yes humidity does affect the growth of plants but the effect is greater in conditions of low humidity (dry).  When it is dry many plants will minimise opening of their stomata to reduce water loss this also has the effect of slowing gas exchange.  Plants need to take in CO2 for photosynthesis, if the stomata are closed this decreses the rate of photosynthesis and therefore the plant has less sugars created.  When the plant has less sugars (food) it can't grow as much.  \nSwamps can have the effect of flooding the root systems of plants so they don't work properly.  There are specially adapted plants that can survive in swamps, most can't.\nHope this helps
317241
http://www.biologyreference.com/Ve-Z/Water-Movement-in-Plants.html\n\nThe Cohesion-Tension Theory\nThe major mechanism for long-distance water transport is described by the cohesion-tension theory, whereby the driving force of transport is transpiration, that is, the evaporation of water from the leaf surfaces. Water molecules cohere (stick together), and are pulled up the plant by the tension, or pulling force, exerted by evaporation at the leaf surface.\n\nWater will always move toward a site with lower water potential, which is a measure of the chemical free energy of water. By definition, pure water has a water potential of 0 MegaPascals (MPa). In contrast, at 20 percent relative humidity, the water potential of the atmosphere is -500 MPa. This difference signifies that water will tend to evaporate into the atmosphere. The water within plants also has a negative potential, indicating water will tend to evaporate into the air from the leaf. The leaves of crop plants often function at -1 MPa, and some desert plants can tolerate leaf water potentials as low as -10 MPa. The water in plants can exist at such low water potentials due to the cohesive forces of water molecules. The chemical structure of water molecules is such that they cohere very strongly. By the cohesion-tension theory, when sunlight strikes a leaf, the resultant evaporation first causes a drop in leaf water potential. This causes water to move from stem to leaf, lowering the water potential in the stem, which in turn causes water to move from root to stem, and soil to root. This serves to pull water up through the xylem tissue of the plant.\nFrom Root to Leaf\nPlants have root hairs and often mycorrhizal fungi at the root surface, both of which serve to filter the soil water as it enters the plant. Mycorrhizae are symbiotic associations between plant roots and fungi. The root cells and mycorrhizal fungi both actively uptake certain mineral nutrients. Mycorrhizae can be particularly important for the uptake of phosphate. The active uptake of minerals by living cells of the root and the subsequent transfer of minerals to the xylem can result in positive root pressures, with water potentials above 0 MPa. This occurs only under certain conditions, such as at night or during rainstorms, when water loss from the leaves is minimal. Such positive root pressures disappear with the onset of leaf transpiration.\n\nWater molecules move from the soil into living cells of the root, and eventually into the transport cells of the xylem, known as tracheids and vessels. These xylem cells are dead and hollow, allowing rapid water transport. They also have hardened cell walls to help them resist the tendency to collapse as water is sucked through them. Both tracheids and vessels \n\n \nA drop of guttation, water extruded by a plant's root pressure, on a blade of grass. have pits on the sides of their walls, which include porous areas for side-to-side transport. Unlike tracheids, a vessel is composed of many cells stacked end to end, with perforations between cells, allowing for more efficient transport.\n\nThe long-distance transport of the water molecule occurs first within the xylem cells of the root, then the xylem of the stem and branch, and then into the xylem of a leaf midrib and vein. Driven by transpiration, the water molecule is pulled from the nonliving tracheids and vessels of the xylem in the living cells of the leaf mesophyll (middle layer) and to the surface of mesophyll cell walls. The water molecule then evaporates into a leaf inter-cellular air space and finally out of a stomatal pore and into the atmosphere. Though photosynthetic action consumes some water, only a small fraction of the water that travels through the plant is used directly for the photo-synthetic reaction, which occurs in leaf mesophyll cells. Instead, most water is lost by transpiration through the stomates.\nThe Role of Stomates\nLeaves of land plants are covered with a waxy cuticle that pr
389541
Their roots are actually specialized branches (rhizoids) that grow in the ground or into tree bark, on rock, etc. so the whole plant is actually living sideways.  The branches absorb water just like roots would. They have a great capacity for storing water, and most are pretty small, so they don't need as much rain as most plants, just humidity/moistness.  Most surfaces are wet with dew in the morning, and they absorb this.
584296
because without it they wouldn't be alive. It is necessary for plants and animals to live. There wouldn't be rain, and oceans, and lakes without it. There are thousands of reasons for why people worship water, because it's WATER!
61042
Yes. It does. Since there is more sugar in the water outside of the plant than there is in the water in the plant, the sugar solution will be hypertonic (higher concentration of solutes). This will cause osmosis to occur, causing water to flow out of the plant and into the sugar water to equilize the content. This will drain the vacuoles in the plant cells, and cause them to shrivel up inside of the cell wall.