Biosynthesis and Storage of Organic Substances in Plants
Photosynthesis event, some of the sugars and starch synthesized at the end are used by the plant during respiration. The remaining substances are stored in various tissues and organs of the plant.
Storage of Sugar
Some plants can directly store the organic matter they make as sugar. In this respect, sugar beet, sugar cane are important plants that store sugar. In some plants, sugar is stored, mostly by conversion from disaccharides to sucrose. The best example of this is grapes.
Storage of Starch
Starch made in leaves as a result of photosynthesis is first converted into soluble substances by enzymes. It is then stored in leucoplasts, turning back into starch. This starch in the storage organs is called reserve starch. Spare starch is stored for reuse when needed. In general, starch is stored in underground tubers and seeds.
Fat Metabolism and Fat Storage
Unlike fats, starch and sugar, it is a substance that can be synthesized by both plants and animals. Fats are special substances that appear as small droplets in plant cells and appear dispersed in the cytoplasm, as they do not dissolve in water.
Fats are formed as a result of chemical changes of carbohydrates formed as a result of photosynthesis. These oils are also stored in some plants. It is stored especially in seeds (walnut, hazelnut, sesame) and fruits (olive, sunflower) of plants. However, oils can be found in other parts of the plants, albeit to a lesser extent.
Some plants contain essential oils. These are commonly known as fragrance secretions. For example, rose oil, thyme oil can be given.
Storage of Nitrogen in Plants
A product that is very much added to the structure of plants and in many cases stored as a reserve food is protein. A large amount of protein is stored in solidified form in plants such as beans, broad beans, peas and wheat. Proteins are nitrogenous compounds.
Plants take nitrogen compounds dissolved in water with their roots. During photosynthesis, it uses these compounds to make protein foods necessary for the plant. Proteins are stored in plants, usually in seeds.
Utilizing the Nitrogen of the Air
There is plenty of nitrogen in the air. However, plants cannot benefit from air nitrogen. In order for plants to benefit from air nitrogen, air nitrogen must descend into the soil and turn into nitrogenous compounds.
Air nitrogen mixes with the soil with rain and lightning. Nitrogen-fixing bacteria in the soil convert this nitrogen into nitrogenous compounds. Plants take these compounds dissolved in water and use them. They synthesize the necessary protein for themselves.
Some plants can directly benefit from air nitrogen. Some bacteria in the roots of these plants fix the nitrogen in the air, allowing the plant to benefit from it.
Other Nutrition Forms in Plants
Plants usually make their own food. Plants capable of photosynthesis or chemosynthesis are called autotrophic plants. Some plants, however, lack this ability. These plants that cannot make their own food are called heterotrophic plants. Heterotrophic plants are of three types:
– Saprophytic plants (rotten)
They are plants that obtain their nutrients from the decomposition of organic materials in the environment. Some bacteria, mold fungi can be given as examples of this diet.
– Parasitic plants
Plants that obtain their food from another living thing. Parasitic plants are of two types:
– Complete parasite:
These plants get all their nutrients from the living thing on which they live. Disease-causing bacteria and fungi are parasitic. There is also parasitism in some higher plants. For example, tuberculosis and spoilage are fully parasitic plants. These plants absorb and use the products of photosynthesis by sending their roots to the stem pipes of the plant on which they live. The host also damages the plant.
– Semi-parasitic:
Plants in this state only take water and dissolved substances from the host plant. They are green in color and can photosynthesize. An example of this is mistletoe.
– common life
Sometimes two living things live together as if they were a single organism. This is called symbiosis feeding. Lichens are a good example of this situation. Lichen is a plant species formed by the symbiosis of algae and fungi. The algae produces food for the fungus by photosynthesis. The fungus, on the other hand, creates a raw material for algae with the carbon dioxide it releases at the end of respiration.
Insect-Eating Plants
There are some plants in the plant world that have special nutritional status. One of them is insect-eating plants. Plants mostly get the nitrogen necessary for their life from the soil. However, some soils are poor in nitrogen. Some plants living in these soils meet their nitrogen needs from insects they catch. In these plants, changes have occurred in their structures to catch insects. In particular, the leaves have turned into structures that allow the insect to be caught on them. This is how these plants meet their nitrogen needs. Other requirements are met by photosynthesis.
These plants have acquired special and different types of structures in order to catch insects. These:
Drosera type:
There are copious amounts of sticky head-shaped glands located at the tip of a long stem and corresponding to the palm of the leaf. The insect placed on the sticky part stays stuck there. As it flutters, the leaf begins to close with shaking. Enzymes on the insect allow the insect to be digested.
Dianea type:
The edges of the part corresponding to the palm of the leaf are toothed. When the insect is placed here, the leaf closes like a book and traps the insect.
Nepenthes type:
The leaf blade has taken the form of a pitcher. There is also a cover at the tip of the pitcher. If the insect accidentally enters the ewer, the cap at the end of the ewer is closed. Nitrogen is obtained from the insect digested by the enzymes in the ewer.
Bubble type:
This type is seen in plants living in nitrogen-poor waters. The stemmed leaves of this plant are segmented. Some of the leaf fragments are in the form of balloons. Some animals living in water enter the bubble with the movement of water.