STD IX – PLANT PHYSIOLOGY (Online)

Seed – Structure and its Classification

A seed is a fertilised, matured ovule of a flowering plant, containing an embryo. This tiny embryo enclosed within the seed devolves to form a new plant by the process of germination. Plant embryo in seeds have structures called cotyledons.

Dicot And Monocot Seeds

The structure of Dicot Seed:

A bean (dicot) seed is normally kidney shaped, flat and has a notch on one side.Dicots have two seed leaves inside the seed coat. They are usually rounded and fat because they contain the endosperm to feed the embryo plant.

Dicot seed consists of the following parts:

Hilum | Micropyle | Seed coats | Embryo

The structure of Monocot Seed:

The maize grain (monocot) is roughly oval in shape and normally flattened. The lower narrower portion shows a white triangular region, which is the embryo. The broader and more yellowish region is the endosperm.

Monocot seed consists of the following parts:

Endosperm | Embryo

Germination :

Germination is the development of a plant from a seed or spore under specific environmental conditions. In other words, Seed germination is a process in which dormant embryo of seed resumes metabolic activities and grows to produce a seedling.

There are 2 types of Germination, namely:

Epigeal Germination.

Hypogeal Germination.

Respiration In Plants

Respiration:

The process which helps in releasing of energy from cells of the body is Respiration It is a catabolic process

Glycolysis

Glycolysis is the metabolic process that serves as the foundation for both aerobic and anaerobic cellular respiration. In glycolysis, glucose is converted into pyruvate.

Aerobic Respiration

The breakdown of glucose in cells in the presence of oxygen is called aerobic respiration.

ATP (Adenosine triphosphate) undergoes hydrolysis to give adenosine diphosphate (ADP), inorganic phosphorus, and energy.

Kreb’s cycle or Citric acid cycle

It is a series of chemical reactions used by all aerobic organisms to release stored energy through the oxidation of acetyl-CoA derived from carbohydrates, fats and proteins into carbon dioxide and chemical energy in the form of adenosine triphosphate, (ATP.)

Anaerobic Respiration:

The breakdown of glucose in the absence of oxygen is called anaerobic respiration.

Sometimes, glucose undergoes incomplete oxidation to form ethanol and carbon dioxide and a lesser amount of energy is released. This is anaerobic respiration or fermentation. It may occur temporarily in plants and in our muscle cells when oxygen is not available.