Question

visit a greenhouse. Observe how plants are raised.How is light, water and carbon dioxide regulated there?

Answer 1

Greenhouses Provide Light and Heat

Plants need light, warm temperatures, air, water, and nutrients to survive and grow; different plants have different requirements for each of these necessities. A greenhouse works by providing the first two requirements for your plants, but the last three are up to you.

Providing Light

Greenhouses are made mostly of translucent materials, usually in the form of either glass or clear plastic. This gives the plants inside maximum access to sunlight, which they use for photosynthesis: combining carbon dioxide from the air and energy from sunlight to make simple sugars, which the plant then uses as food. On average, plants need about six hours of sunlight per day, although this varies depending on the type of plant; placing your greenhouse where it will get full sun all day will ensure that the plants inside get enough light.

Providing Heat

Greenhouses are warmer than the great outdoors because all that sunlight coming in through the clear glass or plastic walls turns into heat when it hits a solid surface, such as the ground or the plants inside the greenhouse. Light is really a form of energy, which is why plants can use it to fuel photosynthesis.

How a greenhouse provides heat When light hits a solid surface, the surface absorbs some of this energy, converting it to infrared energy (aka heat) in the process - the darker the surface, the more energy it can absorb and turn into heat. Infrared energy has a different "shape" than light energy - what scientists refer to as wavelength - so while light can easily pass though a greenhouse's glass walls, this heat takes longer to escape. The trapped heat warms the air inside the greenhouse and because a greenhouse is relatively air-tight, the warmer air stays inside, raising the entire building's temperature. This is the same effect that you've no doubt experienced when getting into a car after it's been sitting in a sunny parking space for a few hours.

With sufficient sunlight, the temperature inside a greenhouse may become much higher than the outdoor temperature; in fact, on a hot sunny day you may need to ventilate the greenhouse all day to keep from literally cooking the plants inside. On overcast days, less sunlight means that the greenhouse will heat up more slowly, if at all. For that reason, greenhouses are most useful in areas that have plenty of sun.

When There's No Sun

The plastic or glass that makes up most of a greenhouse's exterior is great for letting in the maximum amount of light, but it's a poor insulator; heat energy travels though it eventually to escape to the outside world. As long as the sun is shining this doesn't matter because light energy comes in faster than the heat can get out. At night, however, all that heat energy will quickly depart, leaving your plants at the mercy of lower nighttime temperatures. In order to protect your tender plants, you need either to store excess heat during the day or use an artificial heat source at night.

Answer 2

ANSWER :

The mechanism by which the plants are provided with light, water and CO2 is explained below -

Light : The greenhouse is constructed in such a way that it reflects large amount of light inside it. For this, they are made of glass which makes the light enter inside it.

Water : Capillary mats are introduced in the greenhouse. These mats oozes water and this water is taken to the roots of plants.

Carbon Dioxide : A system called movement of indoor air supplies the plants inside the greenhouse with carbon dioxide.