The effect of light intensity on the rate of photosynthesis

Furthermore, I predict that if the light intensity increases, the rate of photosynthesis will increase at a proportional rate and more oxygen will be produced and therefore the oxygen levels will increase.

Aim: To see if raising the light intensity increases the rate of photosynthesis.

As we can see, there is a close relationship between the action spectrum and absorption spectrum of photosynthesis. There are many different types of photosynthetic pigments which will absorb light best at different wavelengths. However the most abundant photosynthetic pigment in plants is chlorophyll and therefore the rate of photosynthesis will be the greatest at wavelengths of light best absorbed by chlorophyll (400nm-525nm corresponding to violet-blue light). Very little light is absorbed by chlorophyll at wavelengths of light between 525nm and 625 (green-yellow light) so the rate of photosynthesis will be the least within this range. However, there are other pigments that are able to absorb green-yellow light such as carotene. Even though these are present in small amounts they allow a low rate of photosynthesis to occur at wavelengths of light that chlorophyll cannot absorb.


Low light intensity lowers the rate of photosynthesis

A limiting factor is a factor that controls a process. Light intensity, temperature and carbon dioxide concentration are all factors which can control the rate of photosynthesis. Usually, only one of these factors will be the limiting factor in a plant at a certain time. This is the factor which is the furthest from its optimum level at a particular point in time. If we change the limiting factor the rate of photosynthesis will change but changes to the other factors will have no effect on the rate. If the levels of the limiting factor increase so that this factor is no longer the furthest from its optimum level, the limiting factor will change to the factor which is at that point in time, the furthest from its optimum level. For example, at night the limiting factor is likely to be the light intensity as this will be the furthest from its optimum level. During the day, the limiting factor is likely to switch to the temperature or the carbon dioxide concentration as the light intensity increases.


BBC - GCSE Bitesize: Factors limiting photosynthesis

A) sunlight concentration B) temperature C) chlorophyll concentration D) carbon dioxide availability Effects of the variables and there concentrations: The amount of sunlight will decide the rate of photosynthesis as there will be a an increased rate of photosynthesis due to the increased availability of photons of light....

photosynthesis notes - Biology Junction

Effect of different colors of light on the rate of photosynthesisThe effect of different lights on plant growth: incandescent light, fluorescent light, sunlight and black light.

Primary Productivity & Dissolved Oxygen Lab - …

So by level of light you probably mean lightintensity which is something that can be measured.Light intensity is usually defined as theenergy hitting an area over some time period.So in the case of a plant, a higher lightintensity means more packets of light called“photons” are hitting the leaves. As you rise fromlow light intensity to higher light intensity, therate of photosynthesis will increase because thereis more light available to drive the reactions ofphotosynthesis. However, once the light intensitygets high enough, the rate won’t increase anymorebecause there will other factors that are limitingthe rate of photosynthesis. A limiting factorcould be the amount of chlorophyll molecules thatare absorbing the light. At a very high intensityof light, the rate of photosynthesis would dropquickly as the light starts to damage the plant.

LabBench Activity Dissolved Oxygen and Aquatic Primary Productivity

6CO + 6H O ® C H O + 12O (in the presence of light energy and chlorophyll) Aim- The aim of the experiment is to determine what effect light intensity has upon the rate of photosynthesis of Canadian Pondweed (Elodea)....