FUNDAMENTALS OF PLANT PHYSIOLOGY for degree, post graduate and various competitive examinations

• Main Author: Jain, V.K. Dr (Author)
• Format: Book
• Language: English
• Published: New Delhi S.Chand & Company Limited 2008; ©2009
• Subjects: Plant physiology
• Online Access: Click Here to View Status and Holdings.

 The discovery of the cell dates back to later half of the 17th century when in 1665 Robert Hooke cut thin slices of cork and examined them under his own crude microscope. He found the slice of cork to be made up of small chambers which reminded him of the cells or compart ments of honey comb and he gave the same name i.e., the cells to them. He could not observe the details of the cell because the material which he examined was dead and consisted of only cell walls. Later on, other scientists experimented with living materials and concluded that all the plants and animals are made up of cells which are filled with a semi-solid, jelly-like sub stance. Robert Brown in 1831 observed a dense, spherical body in the cell which was subsequently termed as nucleus. In 1839 when the above facts became well established. M.J. Schleiden (a lawyer turned botanist) and Theodor Schwann (a zoologist) put forward their well known cell theory according to which "the cell is structural and functional unit of all the plants and animals". A second proposition was added to the cell theory later on as a result of observa tions made by other scientists especially Robert Remak (1841) and others including a German pathologist Rudolf Virchow (1958) according to which "the new cells arise from the division of the pre-existing cells". LAW JUD (A) (Robert Remak (1841) studied the frog egg and followed the early developmental stages and discovered that cells came from pre-existing cells. Virchow developed the concept of genetic continuity from cell to cell. To quote from his famous "Cellular Pathology (1858) where a cell exists there must have been a pre-existing cell, just as the animal arises only from an animal and the plant only from a plant":)) Albrecht Kölliker in 1843 recognised the jelly-like substance in the cell as cytoplasm while Hugo von Mohl in 1846 suggested that the cytoplasm and nucleus together should be called as protoplasm.