EVERYDAY SCIENCE

Detailed explanation-1: -stelar theory, put forward by van Tieghem and Douliot (1886). It postulated that the primary structure of the stem and root were fundamentally similar because each consisted of a central core, the stele, enclosed within the cortex.

Detailed explanation-2: -Van Tieghem and Douliot (1886) introduced this term and put forward the stelar theory. The theory suggests that the cortex and the stele are the two fundamental parts of a shoot system. Both these components (stele and cortex) are separated by endodermis.

Detailed explanation-3: -Stelar theory was proposed by Van Tiegham and Douliot in 1886. According to this theory the primary structure of the stem and root are basically similar and the fundamental parts of each are the cortex, a central column, the stele, and that the two are separated from each other by the endodermis.

Detailed explanation-4: -Stele is the central cylinder or core of vascular tissue in higher plants and Pteridophytes. It consists of xylem, phloem, pericycle and medullary rays and pith if present. The term stele has been derived from a Greek word meaning rod or column.

Detailed explanation-5: -Stellar evolution is the process by which a star changes over the course of time. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe.