| 4. The extentions are made up of collenchyma and parenchyma cells.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n Question 13.
\nWhere do you find passage cells ? What are the functions ?
\nAnswer:
\nSome of the cells which are present in the endodermis of roots just opposite to the protoxylem vessels are called passage cells or transfusion cells. They have no casparian strips. These cells are thin walled and retain their living protoplasts. They provide a passage for water and solutes between the cortex and vascular tissues.<\/p>\n Question 14.
\nWhy are xylem and phloem called complex tissues?
\nAnswer:
\nAs they possess cells which are heterogeneous.<\/p>\n ![\"1st](\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2021\/06\/KSEEB-Solutions.png\") <\/p>\n
1st PUC Biology Anatomy of Flowering Plants Three Marks Questions and Answers<\/h3>\nQuestion 1.
\nName the three basic tissue systems in the flowering plants. Give the tissue names under each system.
\nAnswer:<\/p>\n The tissue system is a tissue along with its associated structures. Based on their structure and function they are of three types, namely:<\/p>\n (a) Epidemial Tissue System : The epidermal tissue system forms the outermost covering of the plant body. It comprises of epidermal cells, stomata, epidermal outgrowths like trichomes and hairs, secretory glands. The epidermis is the outermost layer of the primary plant body. It is made up of single row of rectangular parenchyma cells. It is protected by the outer layer of waxy cuticle which prevents loss of water.<\/p>\n Also stomatal pores are present along with guard cells and subsidiary cells to form stomatal apparatus. In roots, epidermal surface bears root hairs which are unicellular, and in the stem multicellular trichomes
\nare present.<\/p>\n (b) The Ground Tissue System : All the tissues except epidermis and vascular bundles constitute the ground tissue. It comprises of hypodermis, cortex or mesophyll, endodermis, pericycle and pith.<\/p>\n (c) The Vascular Tissue System : Vascular bundles cati be defined as a compact strand of xylem and phloem with or without cambium. Vascular tissues derived from the procambium, during primary growth of the plant, are called primary vascular tissues. They include primary xylem and primary phloern. Vascular tissues derived from vascular cambium, during secondary growth of the plants, are called second my vascular tissues. They include secondary xylem and secondary phloem.<\/p>\n 1st PUC Biology Anatomy of Flowering Plants Five Marks Questions and Answers<\/h3>\nQuestion 1.
\nWhat are meristems? With a neat labelled diagram, explain the different types of meristems based on their position in the plant body.
\nAnswer:
\nFormative tissue found in the growing regions of the plant body such as root tip, shoot tip and branch tip is referred to, as meristematic tissue.
\n![\"1st](\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2021\/06\/1st-PUC-Biology-Question-Bank-Chapter-6-Anatomy-of-Flowering-Plants.6.png\")
\nIt comprises of undifferentiated mass of rapidly dividing cells.
\nBased on the position in the plant body, meristems are classified into three types:
\n(a) Apical meristem.
\n(b) Intercalary meristem.
\n(c) Lateral meristem.<\/p>\n (a) Apical meristem : Meristematic tissue found at the apices of the root and stem is called Apical meristem. They cause linear increase of the plant body i.e, primary growth.<\/p>\n (b) Intercalary meristem : Meristematic tissue found in between the permanent tissues either at the base of the intemodes or at the leaves is referred to as intercalary meristem. It is responsible for the elongation of the plant body i.e., primary growth.<\/p>\n (c) Lateral meristem : These are found along the lateral sides of the stem and root. Vascular cambium and cork cambium are the examples for lateral meristem.<\/p>\n <\/p>\n Question 2.
\nExplain the structure and functions of Parenchyma.
\nAnswer:
\nParenchyma is defined as a living, simple, permanent and storage tissue. It is the basic and
\npacking tissue occur in all parts of the plant body such as cortex, pith, pericycle etc.
\nAs they possess cells which are heterogenoous.
\nCharacters:-
\n1. Cells appear usually oval or spherical.
\n2. Cells are loosely arranged with many intercellular spaces.
\n3. Cell wall is thin and made up and cellulose and hemicellulose.
\n4. Cells have cytoplasm and nucleus and have living tissue.
\n5. Cells have large and prominent vacuoles.<\/p>\n Types of Parenchyma:
\nThere are two types namely.
\n(a) Chlorenchyma – Parenchyma tissue in which cells contain chloroplast is called chlorechyma. It is present in green parts of the plant body and helps in photosynthesis.
\n(b) Aerenchyma – Parenchyma tissue in which intercellular spaces are filled with air is called aerenchyma. It is present in aquatic plants and helps in buoyancy.<\/p>\n Functions:
\n1. The main function of parenchyma is storage of food.
\n2. It forms the packing tissue.
\n3. Chlorenchyma helps in photosynthesis.
\n4. Aerenchyma helps in buoyancy in aquatic plants.
\n5. It becomes meristematic through de-differentiation and helps in secondary growth.
\n6. It helps in healing of wounds and takes part in regeneration.<\/p>\n Question 3.
\nWith the help of a neat labeled diagram, explain structure and any one function of collenchyma,
\nAnswer:
\nCollenchyma is defined as a simple, permanent and living mechanical tissue. It occurs in hypodermal regions of young dicot stem and bundle sheath extension of dicot leaf. It is a highly restricted tissue and totally absent in roots and monocot plants.
\nCharacters:
\n1. Cells appear usually oval or spherical.
\n2. Cells are compactly arranged without intercellular spaces except lacunar type.
\n3. The celL wall is made up of cellulose and pectin,
\n4. The cell walls show uneven thickening specially at corners.
\n5. Cells have cytoplasm and nucleus and hence are called living cells.
\n6. Cells have large and prominent vacuoles.<\/p>\n Types:
\nBased on the pectin deposition, collenchyma is of the following three types.
\n(a) Angular collenchyma – Here pectin is deposited in the angles or intercellular spaces of cells, eg: Datura, Ficus etc.
\n(b) Lamellar collenchyma – Here pectin is deposited in between the cellular layers in the form of sheets, eg: Radish, Sunflower etc.
\n(c) Lacunar collenchyma – Here pectin is deposited along the sidewalls around the\u00a0 intercellular space leaving a small space in the centre, eg: Malva, Althea etc.<\/p>\n Functions:
\n1. Collenchyma gives mechanical support.
\n2. Cells possess chloroplasts in young stems and help in photosynthesis.
\n3. Cells become meristematic and help in the secondary growth.
\n4. In young parts of dicot plants, it give resistance against the pulling and bending actions of wind.<\/p>\n Question 4.
\nDescribe a water conducting tissue?
\nAnswer:
\nXylem is water conducting complex permanent tissue and is also called wood. Earlier formed xylem elements are small in size and are referred to as \u2018Protoxylem\u2019. Later formed xylem elements are quite large in size and referred to as \u2018Metaxylem\u2019. Xylem comprises of four elements, namely.
\n(a) Tracheids
\n(b) Trachea \/ vessels
\n(c) Xylem fibres
\n(d) Xylem Parenchyma.<\/p>\n <\/p>\n (a) Tracheids These are elongated dead cells with tapering ends found in pteridophytes and gymnosperm. In cross section they may appear polygonal or rectangular in shape with lignified walls. Lignification may be annular, spiral, scalariform, reticulate and pitted type. Tracheids are comparatively longer than trachea and measure about 1 mm to 120 mm. in length. They are arranged one above the other to form canals in the plant body for water conduction. They are also mechanical in function.<\/p>\n (b) Trachea (X.vessels): They are found in most of the angiosperms. There are dead cells and are shorter and wider than tracheids. However xylem vessels in trees such as quercus and eucalyptus measure upto 2 mts in length respectively.<\/p>\n Xylem vessels are arranged one above the other similar to water pipes for conduction of water. As a consequence, end walls are absent or they may have perforated endwalls. Xylem vessels protoxylem, usually exhibits annual and spiral thickening. Among xylem vessels protoxylem usually exhibits annual and spiral thickening whereas metaxylem shows scalariform, reticulate and pitted thickenings. Because of lignification they are mechanical in function.<\/p>\n (c) Xylem fibres: These are similar to those of sclerenchyma fibres, but are associated with xylem. They provide mechanical support to the plant body.<\/p>\n (d) Xylem parenchyma: These are the parenchyma cells associated with xylem. They are also called a wood parenchyma. These are compactly arranged. Xylem parenchyma extend into xylem vessels and appear like balloons. These balloon like structures are called tyloses. They hinder the ascent of sap.<\/p>\n Question 5.
\nExplain the internal structure of dorsiventral leaf with an neat labelled diagram.
\nAnswer:
\nStudy of internal structure of parts of the plants is called plant anatomy.<\/p>\n Anatomy of leaves :
\nLeaves of angiosperms are of two types.
\n(a) Dicot leaf or Dorsiventral leaf.
\n(b) Monocot leaf or Isobilateral leaf.<\/p>\n Anatomy of a Dicot leaf or Dorsiventral leaf:
\n![\"1st](\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2021\/06\/1st-PUC-Biology-Question-Bank-Chapter-6-Anatomy-of-Flowering-Plants.2.png\")
\nHelianthus leaf
\ne.g. Helianthus annus (Sunflower).
\nA thin transverse section of a dorsiventral leaf shows the following features.
\n(i) Epidermis
\n(ii) Mesophyll tissue
\n(iii) Vascular bundles.<\/p>\n (i) Epidermis:
\nThe epidermis covers the upper and Lower surface of a leaf and known respectively as .
\n(a) Upper epidermis: It consists of a single layer of parenchyma cells arranged without intercellular \u0161pace. The outer walls of epidermal cells bear a thick waxy layer called cuticle. Multicellular epidermal hairs are present. Stomata are usually absent on the upper epidermis.<\/p>\n (b) Lower epidermis : It is almost similar to upper epidermis but numerous stoma are found to be distributed throughout the lower surface ( Hypostomatic condition). These are pores concerned with gaseous exchange. Each stomatal pore is surrounded by two specialised cells called guard cells containing chloroplasts. The other epidermal cells do not possess chioroplasts. Epidermis protects internal tissues.<\/p>\n ii. Mesophyll : It is the portion between the upper and lower epidermis. It is the photosynthetic
\nregion and heterogenous. It is differentiated into two regions.
\n(a) Palisade parenchyma.
\n(b) Spongy parenchyma.<\/p>\n <\/p>\n (a) Palisade parenchyma: It occurs below the upper epidermis and composed of two to many layers of columnar elongated parenchyma cells. They are arranged at right angles
\nto the leaf surface. The cells contain abundant chloroplasts and hence form the chief photosynthetic tissues.<\/p>\n (b) Spongy parenchyma: It occurs below the lower epidermis composed of loosely arranged irregular cells with numerous large intercellular spaces. Some of the large intercellular spaces are found next to the stomatal pore forming substomatal cavities or respiratory cavities. The cells of spongy parenchyma also contain chioroplasts but less in number. This region is the main transpiring region, which allows exchange of gases.<\/p>\n iii. Vascular bundles : These are located in the midrib and the veins. Each bundle is conjoint collateral and closed. Each vascular bundles is covered by compact layers of thin walled parenchyma cells forming the bundle sheath or border parenchyma. In the midrib region space between the vascular bundle and the epidermis is filled with parenchyma and collenchyma cells. Collenchyma tissue provides strength. They form the bundle of sheath extensions. Xylem in the bundle is located towards the upper epidermis and phloem towards the lower epidermis.<\/p>\n Question 6.
\nState the location and function of different types of meristems.
\nAnswer:
\nThese are actively dividing cells found at all the growing regions of the plant. e.g: root tip, shoot tip, flower bud, leaf tip etc.<\/p>\n Characters:
\n1. Cells of the meristem may be spherical, oral, polygonal or rectangular in shape.
\n2. Cell wall is thin and made up of cellulose only.
\n3. Intercellular spaces are absent because of compact arrangement.
\n4. Each cell has a large nucleus and a dense cytoplasm usually without vacuoles.
\n5. Cells are highly active and exhibit rapid divisions.
\n6. Plastids are in proplastid state.
\n7. Mitochondria and endoplasmic reticulum are less complex in organisation.
\n8. Cells do not store food materials.
\n9. The cells lack ergastic substances.<\/p>\n Meristems are classified on the basis of their:
\n(A) Position.
\n(B) Function and
\n(C) Origin and development.<\/p>\n (A) Based on position, there are mainly three types:
\n(a) Apical Meristems – They are found at the tip of the stem and root. Activity of this, meristem leads to increase in length.
\n(b) Intercalary Meristems – These are found between permanent tissues, at the base of internode and leaf. Activity of this meristem leads to increase in the length of internode.
\n(c) Lateral Meristems – These are meristem is situated parallel to the sides of the organs and permanent tissues. Their activity leads to secondary growth.<\/p>\n (B) Based on function, there are three types:
\n(a) Protoderm – Gives rise to epidermis.
\n(b) Procambium – Gives rise to primary vascular tissues (xylem, phloem and intra fascicularcambium).
\n(c) Ground meristem – Gives rise to cortex, hypodermis, pith and medullary rays.<\/p>\n (C) Based on Origin, there are three types:
\n(a) Primordial meristerns: Small groups of young embryonic cells existing in early stages of development. They give rise to Primary meristem. They are present in stem tip and roottip.
\n(b) Primary meristems: They are directly derived from the promeristems and divide rapidly. They are responsible for the primary growth.<\/p>\n <\/p>\n Question 7.
\nWith a neat labelled diagram, explain phloem tissue.
\n![\"1st](\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2021\/06\/1st-PUC-Biology-Question-Bank-Chapter-6-Anatomy-of-Flowering-Plants.7.png\")
\nAnswer:
\nPhloem is a food conducting tissue and is also called bast. Phloem is composed of four elements:
\n(a) Sieve elements
\n(b) Companion cells
\n(c) Phloem parenchyma
\n(d) Phloem fibres.<\/p>\n (a) Sieve elements: Sieve elements in lower vascular plants (Pteridophytes and gymnosperms) are referred to as \u2018sieve cells\u2019 whereas in higher plants (Angiosperms) they are referred to as \u2018sieve tubes\u2019. Sieve cells are elongated, thin walled, and arranged one above the other, and show thin protoplasmic layer within. Sieve cells posses perforated lateral walls and they are not associated with companion cells, but with the cells called albuminous cells.<\/p>\n Sieve tubes are much longer than sieve cells and are arranged one above the other longitudinally with perforated transverse end walls, called \u2018sieve plates\u2019. Protoplasmic strands maintain the continuity through these perforations with the adjoining sieve tubes, sieve tubes are living cells but they are enucleate.
\nAt the end of the growing season, sieve pores are covered by deposits of callose.<\/p>\n (b) Companion cells: These are thin walled living and narrow cells running parallel to sieve tubes in angiosperms. Sieve tubes and companion cells are sister cells derived from the same mother cell. These are known to regulate the functions of sieve tubes.<\/p>\n (c) Phloem parenchyma: Parenchyma cells associated with phloem are referred to as phloem parenchyma. They are storage in function. Phloem parenchyma is absent in monocot stem.<\/p>\n (d) Phloem fibres: These are sclerenchyma fibres associated with phloem. They are also called bast fibres. They provide mechanical support to the plant body.<\/p>\n 1st PUC Biology Anatomy of Flowering Plants Text Book Questions and Answers<\/h3>\n* The branch of botany that deals with the study of tissues is called plant histology.
\n* A tissue can be defined as a group of cells which are similar in their structure, have a common origin and function.<\/p>\n Classification of Tissues<\/strong>
\n* Tissues are broadly classified into two types based on the ability of the cells to divide or not.
\n(1) Meristematic tissues.
\n(2) Permanent tissues.<\/p>\n![\"1st](\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2021\/06\/1st-PUC-Biology-Question-Bank-Chapter-6-Anatomy-of-Flowering-Plants.1.png\") <\/p>\n
To describe the nature of apical meristem, various theories were proposed by scientists.
\n(1) Apical cell theory : This theory was proposed by Nageli. According to this theory a single cell found at the apex is responsible for the formation of the complete plant body.<\/p>\n (2) Histogen theory : This theory was proposed Hanstein. According to this theory, tips of the plants are composed of three histogen layers namely central pleurome, outer dermatogen and middle periblem.
\nHistogen forms the epidermal tissues, periblem forms the stele and pleurome forms the ground tissue.<\/p>\n (3) Tunica corpus theory : This theory was proposed by schmidt. According to this theory’, tips of the plant body comprises of only two zones namely outer tunica which forms the epiderms and inner corpus which forms the plant body.<\/p>\n 1. Meristematic Tissues:<\/strong><\/p>\nThese are actively dividing cells found at all the growing regions of the plant. e.g: root tip, shoot tip, flower bud, leaf tip etc.
\nCharacters:-
\n1. Cells of the meristem may be spherical, oral, polygonal or rectangular in shape.
\n2. Cell wall is thin and made up of cellulose only.
\n3. Intercellular spaces are absent because of compact arrangement.
\n4. Each cell has a large nucleus and a dense cytoplasm usually without vacuoies.
\n5. Cells are highly active and exhibit rapid divisions.
\n6. Plastids are in proplastid state.
\n7. Mitochondria and endoplasmic reticulum are less complex in organisation.
\n8. Cells do not store food materials.
\n9. The cells lack ergastic substances.<\/p>\n <\/p>\n Meristems are classified on the basis of their:
\n(A) Position.
\n(B) Function and
\n(C) Origin and development.<\/p>\n (A) Based on position, there are mainly three types:
\n(a) Apical Meristems – They are found at the tip of the stem and root. Activity of this, meristem leads to increase in length.
\n(b) Intercalary Meristems – These are found between permanent tissues, at the base of internode and leaf. Activity of this meristem leads to increase in the length of intemode.
\n(c) Lateral Meristems – These are meristem is situated parallel to the sides of the organs and permanent tissues. Their activity leads to secondary growth.<\/p>\n (B) Based on function, there are three types:
\n(a) Protoderm – Gives rise to epidermis.
\n(b) Procambium – Gives rise to primary vascular tissues (xylem, phloem and intra fascicular cambium).
\n(c) Ground meristem -“Gives rise to cortex, hypodermis, pith and medullary rays.<\/p>\n (C) Based on Origin, there are three types:
\n(a) Primordial meristems: Small groups of young embryonic cells existing in early stages of development. They give rise to Primary meristem. They are present in stem tip and root tip.
\n(b) Primary meristems: They are directly derived from the promeristems and divide rap\u00acidly. They are responsible for the primary growth.
\n(c) Secondary meristems: These arise secondarily from permanent tissues by a process of dedifferentiation. Hence they appear much later in the life of a plant. They result in later growth of plants.<\/p>\n <\/p>\n Permanent Tissues:<\/strong><\/p>\nPermanent tissues can be defined as a group of well differentiated cells which have lost their capacity of undergoing division. These are usually present in the non growing regions.
\nClassification of permanent tissues:
\nPermanent tissues are broadly classified into two types namely,
\n(A) Simple Permanent tissue.
\n(B) Complex Permanent tissue.<\/p>\n (A) Simple permanent tissue: A homogenous tissue having only one type of cells which performs the same function, eg: Parenchyma, Collenchyma and Sclerenchyma.<\/p>\n 1. Parenchyma:
\nIt can be defined as a living, simple, permanent and storage tissue. It is the basic and packing tissue occurring in all parts of the plant body such as cortex, pith, pericycle etc.<\/p>\n Characters:-
\n1. Cells appear usually oval, spherical or rectangular.
\n2. Cells are loosely arranged with many intercellular spaces.
\n3. Cell wall is thin and made up of cellulose and hemi cellulose.
\n4. Cells have cytoplasm and nucleus.
\n5. Presence of reserve food materials and ergastic substances.
\n6. Presence of membrane bound cell organelles.<\/p>\n Types:-
\n1. Chlorenchyma : Parenchymatous cells containing chloroplasts and are photosynthetic in function.
\n2. Aerenchyma : Parenchyma with plenty of air filled intercellular spaces. It helps to maintain buoyancy.<\/p>\n Functions:-
\n1. The main functions of parenchyma is storage of food.
\n2. It forms the packing tissue. .
\n3. It stores water in succufent plants.
\n4. Helps in healing of wounds and takes part in regeneration.
\n5. Chlorenchyma helps in photosynthesis.
\n6. Aerenchyma helps in buoyancy in aquatic plants.
\n7. It becomes meristematic through dedifferentiation and helps in secondary growth.<\/p>\n 2. Collenchyma:<\/strong><\/p>\nIt is defined as a simple, permanent, living mechanical tissue. It occurs in hypodermal regions of young dicot stem and bundle sheath extension of dicot leaf. It is totally absent in roots and monocot plants.
\nCharacters:-
\n1. Cells appear usually oval, spherical or rectangular. .
\n2. Cells are compactly arranged without intercellular spaces, except in the lacunar types.
\n3. The cell wall is made up of cellulose and pectin.
\n4. The cell walls show uneven thickening specially at comers.
\n5. Cells have cytoplasm and nucleus.
\n6. Cells have large and prominent vacuoles.<\/p>\n Types: 1
\nBased on the pectin deposition, collenchyma is of three types:
\n(1) Angular collenchyma: Here pectin is deposited in the angles or intercellular spaces of cells, eg: Datura, Tomato, Ficus etc.
\n(2) Lamellar collenchyma: Here pectin is deposited in between the cellular layers in the form of sheets, eg: Radish, Sunflower etc.
\n(3) Lacunar collenchyma: Here p&ctin is deposited along the sidewalls around the inter\u00accellular space leaving a small space in the centre, eg: Malva, Althea etc.
\nFunctions:
\n1. Collenchyma gives mechanical support to the plant.
\n2. Cells posses chloroplasts in young stem and help in photosynthesis.
\n3. Cells can dedifferentiate and help in secondary growth.
\n4. It protects the vascular bundles of dicot leaves by forming bundle sheath extensions.
\n5. In young parts of dicot plants, it gives resistance against the pulling and bending actions of wind.<\/p>\n 3. Sclerenchyma :-<\/strong><\/p>\nIt can be defined as a simple, permanent and dead mechanical tissue.
\nIt occurs in hypodermal regions of monocot stem and bundle sheath extensions of monocot leaves.
\nCharacters:
\n1. Cells appear angular or polygonal in T.S.
\n2. Cells are compactly arranged without intercellular spaces.
\n3. Cell wall is uniformly thickened by the deposition of lignin.
\n4. Cell wall is made up of cellulose of lignin.
\n5. Cells loose their cytoplasm and nucleus as they mature and become dead. This results in an empty space in the cell called lumen.<\/p>\n Sclerenchyma cells can occur in two forms namely fibres and sclereids.
\n(i) Fibres: These are elongated, spindle shaped and highly lignified dead cells of sclerenchyma. These are produced from cambium. These are found in groups of completely arranged without intercellular spaces.
\nBased on their position in the plant body, fibres are classified into the following two types:
\n(i) Xylary fibres: Sclerenchyma fibres present in the xylem tissue are xylaiy fibres.
\n(ii) Extra xylary fibres: Sclerenchyma fibres present in any other part of the plant body other than xylem, are called extra xylary fibres, eg: Phloem, bundle sheath of monocot stem, pericarp etc.
\n(ii) Sclereids: These all small, short and lignified dead cells of sclerenchyma. They originate from parenchyma cells. These occur in seed coats, nuts, endocarp of stony fruits and pulp of custard apple, sapota etc.<\/p>\n Types:
\nThey are four types:
\n(a) Brachy sclereids (stone cells] – Small spherical or oval shaped sclereids.
\n(b) Macro sclereids – Elongated and rodlike sclereids.
\n(c) Osteo sclereids – Bone shaped.
\n(d) Astero sclereids – Star shaped.<\/p>\n <\/p>\n Functions:
\n(1) This give mechanical strength.
\n(2) Sclereids found in seed coat and endocarp of fruits provide a hard texture.
\n(B) Complex permanent Tissue: A heterogeneous tissue which possesses different types of cells performing a common function, is said to be complex permanent tissue, eg: xylem and phloem.<\/p>\n 1. Xylem [Hadrome]:<\/p>\n \n- It is a complex, permanent, dead arid water conducting tissue.<\/li>\n
- It consists of four different types of cells namely,<\/li>\n<\/ul>\n
(a) Tracheids.
\n(b) Tracheae \/ vessels,
\n(c) Xylem fibres.
\n(d) Xylem parenchyma.<\/p>\n (a) Tracheids: These are the main water conducting elements in pteridophytes and gymnosperms. Each tracheid is unicellular and spindle shaped. These are dead cells at maturity. The cells have narrow lumen and are arranged one over the other.<\/p>\n (b) Tracheae \/ Vessels: Vessels are the main water conducting elements in angiosperms but are absent in gymnosperms. Each vessel is cylindrical in shape with open ends. Lumen is broad. They are dead cells at maturity.<\/p>\n Based on the type of lignin deposition, tracheids and vessels are of following types:
\n(a) Annular – lignin is deposited on the primary wall in the form of rings.
\n(b) Spiral – lignin is deposited in the form of a spring.
\n(c) Scalariform: lignin is deposited in the form of inter connected ladder.
\n(d) Reticulate: lignin is deposited in the form of a network.
\n(e) Pitted: lignin is uniformly deposited except at pits.<\/p>\n (c) Xylem fibres:<\/p>\n | ![\"1st](\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2021\/06\/1st-PUC-Biology-Question-Bank-Chapter-6-Anatomy-of-Flowering-Plants.4.png\")
<\/p>\n![\"1st](\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2021\/06\/1st-PUC-Biology-Question-Bank-Chapter-6-Anatomy-of-Flowering-Plants.5.png\")
<\/p>\n![\"1st](\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2021\/06\/1st-PUC-Biology-Question-Bank-Chapter-6-Anatomy-of-Flowering-Plants.3.png\")