Question

a)Why oil added over water in test tubes ? b) What would happen if we placed this in dark room c) if we add eosin dye in the water? d) On observing the T. S of stem & root, where you find the xylem in centre or periphery?​

Answer 1

A. when you add oil to a cup of water the two don't mix with each other. Because oil is less dense than water, it will always float on top of water, creating a surface layer of oil.

B. Plants will eventually die in the dark. The first thing that will happen will be that the cells will extend and the plant will stretch out reaching for light. Next, it will probably turn yellow without any light, and it will die.

C. . The use of one or the other is possibly just a matter of preference or tradition. Eosin can be used to stain cytoplasm, red blood cells, collagen, and muscle fibers for histological examination. It is most often used as a counterstain to hematoxylin in H&E staining.

D. The xylem consists of protoxylem which lies towards periphery and metaxylem which lies towards the centre or pith. This type of arrangement of xylem is called exarch (protoxylem is exarch in root and endarch in shoot).