CAM Plants: Definition, Evolution, Photosynthesis, Examples

Definition Of Cam Photosynthesis

The Crassulacean acid metabolism is among the most unique photosynthetic pathways. It is a characteristic very unique and common among several specially adapted plants which gives excellent performance in dry and semi-arid habitats. Such a pathway confers to the plants' wonderful means through which they can afford and effectively capture and utilise carbon dioxide and still be in a position to conserve water efficiently, hence making them very good at surviving in dry environments. Carbon fixation takes place in CAM plants in a manner quite different from either C3 or C4 plants.

Cam Photosynthesis Mechanisms

Although all photosynthetic plants photosynthesize, CAMs go a step further and carry out a very strange photosynthetic activity by which they fix carbon dioxide at night rather than during the day. These adaptations greatly avoid the loss of water due to transpiration, especially in conditions when the atmosphere is hot and dry. The major steps are:

1. Nocturnal carbon fixation:

In plants with CAM, the stoma opens at night when it becomes cold and humid. Carbon dioxide will gain entry then through the opened stomata. This carbon dioxide is fixed into a 4-carbon compound, normally malate, which is then stored in vacuoles.The malate is thus stored in the vacuoles, and it is to be used at night. Thus, carbon dioxide is saved in a form that can be used both day and night.

2. Daytime Respiration:

During the day, after stomata have been closed to prevent the loss of water, the stored malate is again re-converted for use as carbon dioxide. This CO2 results in the production of sugar during the Calvin cycle.

Differences Between Cam Plants

Some Of These Features Of The Cam Plants That All Add To Survival In Adverse Conditions are those such as stomatal behaviour, in that the stomata are closed during the day and hence no water is lost, and they only open up at night to take in carbon dioxide. Water use efficiency is attained due to carbon dioxide fixing at night, hence reduced transpiration, and less water loss, which makes the plants thus perform better even in arid conditions.

Adaptation To Extreme Conditions:

Most CAM plants are succulent—for instance, cacti and some orchids—a characteristic that enables them to store water in their tissue to survive for a long time without water.

Examples Of Cam Plants

There are so many plants that are examples of CAM, but some common ones are stated below:

1. Cacti:

The symbolic plants since they can survive in the most dried environment, they fix CO2 through photosynthesis they carry with the use of CAM.

2. Pineapple:

The tropical fruit uses CAM photosynthesis to survive in environments that are warm and humid-tensed, and therefore conserved water.

3. Orchids:

Most orchids have their niches in variable water availability conditions. CAM affords them an advantage in maximizing their efficiency for carbon fixation.

Benefits Of Cam Photosynthesis

The following are some of the benefits that are imparted to plants, which live in dry environments, by the CAM pathway:

1. Less Loss of Water:

CAM plants can reduce the loss of water to a considerable degree during night carbon fixation, and hence survive in conditions where water is at a minimum.

2. Better Carbon Fixation:

This ability to store carbon dioxide as malate gives CAM plants the ability to fix a lot of carbon during the day even when the stomata becomes closed.

This may therefore make it possible for CAM plants in any other case uninhabitable to thrive, and this will increase the biodiversity in the arid ecosystems.

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