Question

Protective tissue is an outer protective covering of (stems, leaves flowers, fruits and roots) of
plants. Protective tissue is of two types, epidermis and cork. Epidermis is the outermost
covering made up of single layer of cells. Bark is mostly made up of cork that consists of
several layers of compactly arranged dead rectangular cells. At places cork possesses small
aerating pores called lenticels. The cells are impermeable due to deposition of chemical
substance. They contain air, tannins, resins and alkaloids. Commercial cork is obtained from
the stem surface of Quercus suber ( Cork Oak).Cork provides protection against mechanical
injury, extremes of temperature, fire and browsing animals


1. Identify the chemical substance present in cork cells that makes it impermeable.
(a) Lignin (b) Pectin (c) Cellulose (d) Suberin

2. Tiny pores are found on the surface of the leaves of plants. These pores are called stomata.
These stomata surrounded by the kidney shaped guard cells provide many vital functions to the
plants.
Which of the following functions is not served by the stomata for the plants?
(a) Exchange of gases, particularly CO2 and O2, with atmosphere
(b) Loss of water in the form of vaspours during transpiration
(c) Helps to create pressure for the water to rise upward, by its process of transpiration
(d) Protect the inner parts of plant

3. External protective tissue of plants that are formed as a result of secondary growth are
(a) Cork and Cortex (b) Cortex and Epidermis
(c) Epidermis and Cork (d) Pericycle and Cortex

4The tissue X forms as the outer covering of plants and Y forms as an outermost covering on
leaf. Identify X and Y
(a)X- epidermis, Y- pectin (b) X- cuticle, Y-suberin
(c)X- cuticle, Y-lignin (d) X- epidermis , Y- cuticle

5. The bark of a tree comprises
(a) All the tissues outside the cork cambium (b) All the tissues outside the vascular cambium
(c)Only the cork (d) just inside the cork cambium

please help me i need to complete my assignment

Answer 1

1. The thin walls of those cells are saturated with a fatty waxy substance, called suberin, which makes cork almost impervious to water and air.

2. (d) Protect the inner parts of plant

3.Thus, the two types of external protective tissues are cork and epidermis. The correct option is (D) Cork and epidermis. Note:- Cortex is a layer of cells present below the epidermis.

4.epidermis, Y- pectin

5.The bark of the tree comprises all the tissues outside the vascular cambium. Various kinds of cell layers that constitute the bark are – Periderm (phellogen, phellem and phelloderm), primary cortex, pericycle, primary and secondary phloem. These all tissues are present outside the vascular cambium