Crystalline inclusions have been found in chloroplasts of the outer hypo- dermal cells of the peel of the banana fruit. Their structure has been observed at varying stages of ripeness of the fruit and, in line with earlier suggestions, a possible storage function is ascribed to them.

Root cells do not contain chloroplasts because in most plants the roots are underground and not exposed to light. Chloroplasts are needed for photosynthesis, which needs light to occur. The function of the roots is to absorb and store water and nutrients from the soil and to support the plant.

Plant chloroplasts are large organelles (5 to 10 μm long) that, like mitochondria, are bounded by a double membrane called the chloroplast envelope (Figure 10.13). In addition to the inner and outer membranes of the envelope, chloroplasts have a third internal membrane system, called the thylakoid membrane.

They have a double membrane on their outside, and are specilized for the storage of starch (amyloplasts), storage of lipids (elaioplasts), photosynthesis (chloroplasts), or other functions.

Plants take carbon dioxide (CO2) out of the atmosphere to do photosynthesis, and thus help reduce the greenhouse gases warming the planet. This increased warming results from plant leaves’ natural reaction to high CO2 environments.

In Photosynthesis, the temperature continues to increase but with limits. In this process, plants and other organisms convert the light energy from the sun into a chemical energy then released to fuel the organisms’ activities. The rate of carbon assimilation increases as the temperature increases.

light intensity

The rate of photosynthesis increases as carbon dioxide levels increase. However, the rate will not increase beyond a certain concentration of carbon dioxide. Temperature, light intensity and carbon dioxide levels vary at different times of the day and have an effect on each other, hence the photosynthesis rate.

As you rise from low light intensity to higher light intensity, the rate of photosynthesis will increase because there is more light available to drive the reactions of photosynthesis. At a very high intensity of light, the rate of photosynthesis would drop quickly as the light starts to damage the plant.

The effect of oxygen on photosynthesis depends on plant species and on some internal and environmental conditions. Oxygen inhibits the photosynthesis of C3 plants at atmospheric CO2 concentration (Varburg effect). Inhibition of photosynthesis by oxygen is reduced by increase of the C02 concentration.