Introduction to Plant Nutrition

All living things feed/need nourishment. In a previous lesson, you learnt that plants are producers, and producers make their own food. This food is in the form of a sugar (often glucose). Sugars are made during a process called photosynthesis from carbon dioxide and water. The end products, organic compounds, are composed from the simple inorganic compounds water and carbon dioxide. In order for the reaction to take place energy comes from light (usually the sun) and is stored within the sugar which is an energy-rich molecule.

 

The two raw materials required for photosynthesis are acquired by different means. Carbon dioxide is absorbed by the leaves while water is obtained by the roots from the soil.

 

Photosynthesis occurs inside special organelles called chloroplasts. This organelle is found in all green plants and is located mainly in the leaves; hence photosynthesis takes place mainly in the leaves. The conversion of light energy to chemical energy is done by the chloroplast.

 

Many different kinds of sugars may be made during photosynthesis, but glucose (C6H12O6) is the one that is usually made. The glucose is dissolved and transported throughout the plant via vascular tissues called phloem. This dissolved glucose may be stored for later use or converted into a myriad of products such as different sugars, starch, pectin, lignin and many more.

 

The whole process of photosynthesis involves two stages: the light dependent stage and the light independent stage.

 

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