Environmental factors affecting photosynthesis and respiration rates

By Tamta, Natalya and Amelia

How the differences in light affect the rate of photosynthesis

Increasing the light intensity on the plant will increase the rate of photosynthesis.Bright light is a basic element of photosynthesis, but variations in the colour of light have an effect on plants. The entire spectrum of light hits the plant's leaves at the same time, but there are some colours that are known to cause higher amounts of photosynthesis than others. Chlorophyll is the cause of each plant's individual colouring and there are four kinds of pigments that create the chlorophyll. The colour that has the highest influence on photosynthesis is blue, which is why many plant growers use blue lights to grow indoor plants. Red light is next best for photosynthesis and yellow light creates the lowest amount of light absorption.If a plant does not receive adequate light it will attempt to reach the light by growing taller.

How the differences in light affect the rate of respirationRespiration is the opposite of photosynthesis. When the lights are out, the photosynthesis process ceases but the respiration continues. The plant will use oxygen to break down food substances, which is released as energy in the form of heat. Carbon dioxide is produced and expelled as a result of this process. When the lights are on the plants absorb carbon dioxide and expel oxygen. So the levels of light does not affect the rate of respiration.

How the levels of oxygen and carbon dioxide affect the

ratePhotosynthesisThe amount of oxygen:Plants release oxygen (O2) once they have photosynthesized; they do not need oxygen levels to be high in order to have photosynthesis occurring. Plants have no use for oxygen so no matter the oxygen levels, it does not affect the plant, as long as there is carbon dioxide available.Chemical equation: 6CO2+6H2O C6H1206+6O2

The amount of carbon dioxide:Plants need carbon dioxide (CO2) in order to photosynthesize. By increasing the amount of carbon dioxide, the rate of photosynthesis will generally increase. Carbon dioxide levels determine the maximum rate of photosynthesis. It does not seem to matter how much carbon dioxide there is in the air for plants to live. However, we need plants as they take in the carbon dioxide and release oxygen. Word equation for photosynthesis:Carbon dioxide+water+sunlight glucose+oxygen

RespirationThe amount of oxygen:In order for plants to respire, they need high levels of oxygen. Oxygen is needed to burn the glucose made from photosynthesis. They use the oxygen and the glucose to move; they burn it off as their energy, like a car burns off petrol to move. The higher the levels of oxygen, the higher the rate of respiration and the more the plant can move. They burn the glucose in the plant cells so that it is slow and gradual. If a plant was to burn glucose in the air, the reaction would be rapid and uncontrolled.

The amount of carbon dioxide:Plants only need oxygen and glucose in order to respire. These materials are the products of photosynthesis. They do not need carbon dioxide as they release CO2 in respiration. The more carbon dioxide there is, the plant would absorb it through photosynthesis and release it through respiration.

CO2

CO2

Which part of the day does…Photosynthesis occur in:Photosynthesis occurs during the day when sun is out so as to absorb as much sunlight as possible. It does not occur at night as there is no sunlight available to supply energy.

Photosynthesis is occurring

Photosynthesis is not occurring

Respiration occur in:A plant is always respiring. Plants are continuously taking in oxygen and giving off carbon dioxide and water. A plant relies on oxygen levels in order to respire so it does not affect the plant whether it is day or night to respire.

Respiration occurs day and night

How the water availability affects the stomata opening during photosynthesisTranspiration rates go up as the temperature goes up, especially during the growing season, when air is warm due to stronger sunlight and warm air. Water levels can affect the opening and closing of a plants stomata. A plant needs water in order to photosynthesize. If the plant does not have enough water available, the plant's stomata will shut so as to hold water and not dry out. However, this is a tricky process as the plant will be unable to take in carbon dioxide so the photosynthesis will cease. If the water levels are high, a plants stomata will open to absorb water and to expel used and unneeded water.

How the water availability affects the

stomata opening during respiration

Water also affects the stomata during respiration. A plants does not need water in order to respire, so if there are high levels of water, a plant will not take in any water so the stomata will close. However, a plants stomata will open during respiration so as to take in oxygen and expel carbon dioxide.A plants stomata will open and close during respiration and photosynthesis depending on the water levels.

What does a plant need to achieve maximum photosynthesis rate

The rate of photosynthesis depends on the availability of carbon dioxide, the amount of light available and the temperature. Increasing any of these factors increases the rate of photosynthesis. Carbon dioxide levels determine the maximum rate of photosynthesis. Plants in their natural surrounding seldom reach their maximum rate of photosynthesis. On a bright sunny day, carbon dioxide is he limiting factor since air only contains 0.04% of the gas. In the early morning and late afternoon, temperature and light are most likely to be limiting factors. At night there is no photosynthesis. In order for a plant to achieve the maximum photosynthesis rate, carbon dioxide, water and sunlight need to be available in high levels.