Railway Science (Biology-Nutrition in Plant)

Many plant waste products are stored in cellular vacuoles. Plants can get rid of excess water by transpiration. Some waste products are stored as resins and gums in old xylem.
Plants need to excrete excess carbon dioxide and oxygen. Plants excrete these through stomatal pores on their leaves. It also excretes some waste substances into the soil around them.

Transpiration is the process of water movement through a plant and its evaporation from aerial parts, such as leaves, stems and flowers.
Guttation is the process of secretion of water droplets from the pores of some vascular plants like grass. Tropic movement is the movement of the plant in response to the stimulus present in the environment, this movement is in response to root and shoot growth.

Xylem Fibre - Dead cell with lignified walls and a central lumen. Involved in water transportation and providing mechanical support.
Xylem Parenchyma - Only living cells of xylem and store starch and fat.

Parasitic nutrition is a mode of heterotrophic nutrition where a parasitic organism lives on the body surface or inside the body of another type of organism (a host) and gets nutrition directly from the body of the host.
This type of parasitic nutritive strategy is used by a wide variety of organisms like cuscuta, lice, leeches and tapeworms.

It is the process by which plants use sunlight, water, and carbon dioxide to create oxygen and energy in the form of sugar.

It stores food material in the form of oil, fats, proteins, and starch. The parenchyma's cell properties : They have isodiametric shape, made of thin cellulose walls, and perform various functions such as photosynthesis, secretion, and storage.
Tracheid cells - To transport water and inorganic salts, and to provide structural support for trees.

Xylem - A type of vascular tissue in plants which transports water and nutrients from roots to stem and leaves, also provide mechanical strength to the plants. Different components of Xylem - Tracheids, Vessels, Xylem Fibre and Xylem Parenchyma.

Phloem - Transports food prepared in the leaves (during photosynthesis) to all the parts of the plant. In the diagram - ‘a’ is Sieve Pore, ‘b’ is Companion Cell, ‘c’ is Phloem Parenchyma, and ‘d’ is Sieve Tube Element.
Companion Cell - The companion of the sieve tube cells that help in carrying out the metabolic functioning of the sieve elements. They use transmembrane proteins to take up sugar and amino acids by active transport.

Photosynthesis converts carbon dioxide and water into oxygen and glucose in the presence of sunlight and chlorophyll.
Glucose is used as food by the plant and oxygen is a by-product. The process of photosynthesis is commonly written as : 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ .

The rate of transpiration increases when atmospheric pressure is low. During low atmospheric pressure, water will move out of the plant as a result of diffusion. At low pressure, the water vapour moves fast thus the rate of transpiration increases. At higher atmospheric pressure plants will lose water at a slow rate.