explain these correctly
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Answer:
Tissue system
Sachs (1875) classified tissue system in plants into three types i) Dermal or Epidermal tissue system ii) Ground tissue system iii) Vascular tissue system
Dermal or Epidermal Tissue System: It consists of epidermis, stomata and epidermal outgrowths. Epidermis is the outer most layer. It has many minute pores called stomata.Cuticle is present on the outer wall of epidermis to check evaporation of water. Trichomes and root hairs are the epidermal outgrowths.
Functions:
1) Epidermis protects the inner tissues. ii) Stomata helps in transpiration. iii) Root hairs help in absorption of water and minerals.
Ground Tissue System:
It includes all the tissues of the plant body except epidermal and vascular tissues like (i) Cortex (ii) Endodermis (iii) Pericycle (iv) Pith Vascular Tissue System :
It consists of xylem and phloem tissues. They are present in the form of bundles called vascular bundles. Xylem conducts water and minerals to different parts of the plant. Phloem conducts food materials to different parts of the plant.
There are three different types of vascular bundles namely (i) Radial (ii) Conjoint (iii) Concentric
(i) Radial Bundles Xylem and phloem are present in different radii alternating with each other. e.g. roots
ii) Conjoint bundles Xylem and phloem lie on the same radius There are two types of conjoint bundles.
a) Collateral Xylem lies towards the centre and phloem lies towards the periphery. When cambium is present in collateral bundles, it is called open. e.g. dicot stem and collateral bundle without cambium is called closed. e.g. monocot stem.
b) Bicollateral In this type of bundle, the phloem present on both outer and inner side of xyle e.g. Cucurbita
(iii) Concentric Bundles
Vascular bundle in which xylem completely surrounds the phloem or viceversa is called concentric vascular bundle. It is of two types:
1. Amphivasal: Xylem surrounds phloem. e.g. Dracaena
2. Amphicribral: Phloem surrounds xylem. e.g. Ferns
Endarch: Protoxylem lies towards the centre and metaxylem lies towards the periphery. e.g. stem.
Exarch : Protoxylem lies towards the periphery and metaxylem lies towards the centre. e.g. roots.
Explanation:
Dermal tissue: It is the external tissue responsible for protecting the soft tissue inside the plant body
Ground tissue: It contains the cell produced by ground meristem . And these cells include with parenchyma , collenchyma, and sclerenchyma. Main function of these tissue is to fill the space between vascular and dermal tissue
vascular tissue: It is a complex conducting tissue the primary component of these tissue is xylem and phloem . these two tissues contain fluid and Nutrients internally.