Question

The concept of four distinct Zone of tissue builders on the root apex is called as:
A. Tunica-corpus theory
B. Dermatogen theory
C. Meristem theory
D. Histogen theory

Answer 1

Hint: The aspect of the root where development and improvement begins is the root summit. Near the tip is the place the creation of new cells and the lengthening of the as of late made cells occur. Such development in cell length and cell numbers is the means by which roots can advance towards the dirt and quest for undiscovered water and minerals. The extended organization of roots can likewise give safe haven to the plant.

Complete step by step answer:
-The Tunica-Corpus hypothesis is proposed by Schmidt for the association of shoot summits. As per this hypothesis, shoot zenith can be separated into two locales as a focal center and a tunica which encompasses the focal center. Focal centers contain enormous cells and separate unpredictably and bring about volume development. Nonetheless, tunica cells are littler which partition to shape the surface layer. So, option A is correct.
-Dermatogen is a layer, not a hypothesis. So, option B is incorrect.
-Meristem is a layer, not a hypothesis. So, option C is incorrect.
-Histogen hypothesis is proposed by Hanstein. As per histogen hypothesis, there are three zones as dermatogen, periblem, and pleurome in shoot and root apical meristem. These three zones are considered as histogens or tissue manufacturers. Each zone performs unmistakable capacities and has a gathering of starting cells. So, option D is incorrect.
Hence, the right answer is option D.

Note: Tunica is the fringe tissue zone of shoot summit. It comprises at least one fringe layer of cells. Dicotyledons display one to five layers of cells in tunica; two layers of cells are spoken to by the biggest number of species. Monocotyledons have one to four layers of cells in tunica; one and two-layered tunica prevails in it. One single-layered tunica is named monostratose. Many layered tunica are named as multistratose. Xanthorrhoea media shows eighteen layered tunica.