Anatomy of Flowering Plants - Vocabulary Flashcards

Comprehensive vocabulary flashcards covering the key terms and definitions of plant anatomy as presented in the NCERT Biology curriculum.

Anatomy

The study of the internal structure of plants.

Tissue

A group of cells having a common origin and usually performing a common function.

Meristems

Specialised regions of active cell division in plants derived from the Greek word 'meristos', meaning divided.

Apical meristems

The meristems which occur at the tips of roots and shoots and produce primary tissues.

Root apical meristem

The meristematic tissue that occupies the tip of a root.

Shoot apical meristem

The meristematic tissue that occupies the distant most region of the stem axis.

Axillary bud

Buds present in the axils of leaves, composed of cells ‘left behind’ from the shoot apical meristem, which are capable of forming a branch or a flower.

Intercalary meristem

The meristem which occurs between mature tissues, such as in grasses where they regenerate parts removed by grazing herbivores.

Primary meristems

Meristems that appear early in the life of a plant and contribute to the formation of the primary plant body, including apical and intercalary meristems.

Secondary (Lateral) meristem

The cylindrical meristems that occur in the mature regions of roots and shoots and appear later than primary meristems, responsible for producing secondary tissues.

Fascicular vascular cambium

An example of a lateral meristem responsible for secondary growth in plants.

Interfascicular cambium

An example of a lateral meristem that forms between vascular bundles.

Cork-cambium

A lateral meristem also known as phellogen that replaces broken epidermal layers with new protective cork layers.

Permanent (Mature) cells

Newly formed cells from primary or secondary meristems that become structurally and functionally specialised and lose the ability to divide.

Simple tissues

Permanent tissues having all cells similar in structure and function.

Complex tissues

Permanent tissues made of more than one type of cells that work together as a unit.

Parenchyma

A simple tissue that forms the major component within organs, with isodiametric cells and thin walls made of cellulose.

Isodiametric

A term describing cells that are generally equal in diameter, found in parenchyma; shapes may be spherical, oval, round, polygonal, or elongated.

Collenchyma

A simple tissue occurring below the epidermis in most dicotyledonous plants, characterized by cells thickened at the corners due to cellulose, hemicellulose, and pectin.

Sclerenchyma

A simple tissue consisting of long, narrow, dead cells with thick and lignified cell walls and few or numerous pits; provides mechanical support.

Fibres

Thick-walled, elongated, and pointed sclerenchyma cells that generally occur in groups in various parts of the plant.

Sclereids

Spherical, oval, or cylindrical dead sclerenchyma cells with highly thickened walls and very narrow cavities (lumen), found in fruit walls of nuts and pulp of guava.

Xylem

A complex conducting tissue for water and minerals that also provides mechanical strength, composed of tracheids, vessels, xylem fibres, and xylem parenchyma.

Tracheids

Elongated or tube-like dead cells of the xylem with thick, lignified walls and tapering ends, devoid of protoplasm.

Vessels

Long cylindrical tube-like structures in the xylem of angiosperms made of vessel members with lignified walls and a large central cavity.

Xylem fibres

Xylem elements with highly thickened walls and obliterated central lumens; they may be septate or aseptate.

Xylem parenchyma

Living, thin-walled xylem cells made of cellulose that store food materials like starch or fat and substances like tannins.

Ray parenchymatous cells

Cells in the xylem responsible for the radial conduction of water.

Protoxylem

The first formed primary xylem elements.

Metaxylem

The later formed primary xylem elements.

Endarch

A primary xylem arrangement in stems where the protoxylem lies towards the centre (pith) and the metaxylem lies towards the periphery.

Exarch

A primary xylem arrangement in roots where the protoxylem lies towards the periphery and the metaxylem lies towards the centre.

Phloem

A complex tissue that transports food materials, usually from leaves to other parts of the plant.

Sieve tube elements

Long, tube-like phloem structures arranged longitudinally with perforated end walls called sieve plates; they lack a nucleus at maturity.

Companion cells

Specialised parenchymatous cells closely associated with sieve tube elements that help maintain the pressure gradient in the sieve tubes.

Phloem parenchyma

Elongated, tapering cylindrical cells in the phloem with dense cytoplasm and nucleus, absent in most monocotyledons.

Phloem fibres (Bast fibres)

Sclerenchymatous cells in the phloem that are elongated, unbranched, and dead at maturity; used commercially in jute, flax, and hemp.

Protophloem

The first formed primary phloem consisting of narrow sieve tubes.

Metaphloem

The later formed primary phloem consisting of bigger sieve tubes.

Epidermal tissue system

The outermost covering of the whole plant body comprising epidermal cells, stomata, and epidermal appendages like trichomes and hairs.

Cuticle

A waxy thick layer on the outside of the epidermis that prevents water loss; it is absent in roots.

Stomata

Structures in the epidermis of leaves that regulate transpiration and gaseous exchange.

Guard cells

Two bean-shaped (or dumb-bell shaped in grasses) cells that possess chloroplasts and enclose the stomatal pore to regulate its opening and closing.

Subsidiary cells

Specialised epidermal cells in the vicinity of guard cells that differ in shape and size.

Stomatal apparatus

The collective name for the stomatal aperture, guard cells, and the surrounding subsidiary cells.

Root hairs

Unicellular elongations of the epidermal cells that help absorb water and minerals from the soil.

Trichomes

Epidermal hairs on the shoot system that are usually multicellular and help in preventing water loss due to transpiration.

Ground tissue system

All plant tissues except the epidermis and vascular bundles; it consists of parenchyma, collenchyma, and sclerenchyma.

Mesophyll

The ground tissue in leaves, consisting of thin-walled chloroplast-containing cells.

Vascular tissue system

The system consisting of complex tissues, the phloem and xylem, which together constitute vascular bundles.

Open vascular bundles

Vascular bundles in dicot stems that possess cambium between phloem and xylem, allowing for secondary growth.

Closed vascular bundles

Vascular bundles, typically in monocotyledons, that lack cambium and cannot form secondary tissues.

Radial arrangement

A vascular bundle arrangement where xylem and phloem are situated along different radii, common in roots.

Conjoint arrangement

A vascular bundle arrangement where xylem and phloem are situated along the same radius, common in stems and leaves.

Epiblema

The outermost layer of the dicotyledonous root.

Endodermis

The innermost layer of the cortex, consisting of barrel-shaped cells, including casparian strips in roots.

Casparian strips

Water-impermeable, waxy suberin depositions on the tangential and radial walls of endodermal cells.

Pericycle

Layers of thick-walled parenchymatous cells next to the endodermis where lateral roots and vascular cambium initiate during secondary growth.

Conjunctive tissue

Parenchymatous cells lying between the xylem and phloem in roots.

Stele

All tissues on the inner side of the endodermis, including pericycle, vascular bundles, and pith.

Polyarch

An arrangement in monocot roots where there are usually more than $6$ xylem bundles.

Hypodermis

A few layers of collenchymatous cells below the epidermis in dicot stems that provide mechanical strength.

Starch sheath

The endodermis in dicot stems where cells are notably rich in starch grains.

Medullary rays

Radially placed parenchymatous cells located between vascular bundles in dicot stems.

Bundle sheath

A layer of thick-walled cells surrounding vascular bundles in leaves.

Dorsiventral leaf

A dicotyledonous leaf with distinct upper (adaxial) and lower (abaxial) epidermis and differentiated mesophyll.

Palisade parenchyma

Adaxially placed, elongated mesophyll cells arranged vertically and parallel to each other in a dicot leaf.

Spongy parenchyma

Loosely arranged, oval or round mesophyll cells situated below the palisade cells in a leaf.

Isobilateral leaf

A monocotyledonous leaf where stomata are on both surfaces and the mesophyll is not differentiated into palisade and spongy parenchyma.

Bulliform cells

Large, empty, colourless adaxial epidermal cells in grasses that cause leaf curling when flaccid to minimize water loss.

Primary growth

The growth of roots and stems in length with the help of the apical meristem.

Secondary growth

An increase in the girth of a plant due to the activity of lateral meristems like vascular cambium and cork cambium.

Intrafascicular cambium

The cells of cambium present between primary xylem and primary phloem in a dicot stem.

Secondary medullary rays

A narrow band of parenchyma formed by the cambium that passes through secondary xylem and secondary phloem in radial directions.

Spring wood (Early wood)

Wood formed during the spring when cambium is active, containing large numbers of xylary elements with wider cavities; it is lighter and less dense.

Autumn wood (Late wood)

Wood formed during winter when cambium is less active, containing fewer xylary elements with narrow vessels; it is darker and more dense.

Annual ring

Concentric rings formed by spring wood and autumn wood that give an estimate of the age of an old tree.

Heartwood

Hard, durable, dark brown central secondary xylem made of dead elements with highly lignified walls, resistant to pests.

Sapwood

The peripheral region of secondary xylem that is lighter in colour and involved in the conduction of water and minerals.

Phellem

Also known as cork, it is the water-impervious tissue cut off by the phellogen toward the outer side.

Phelloderm

Also known as secondary cortex, it is the parenchymatous tissue cut off by the phellogen toward the inner side.

Periderm

The collective term for phellogen (cork cambium), phellem (cork), and phelloderm (secondary cortex).

Bark

A non-technical term for all tissues exterior to the vascular cambium, including periderm and secondary phloem.

Lenticels

Lens-shaped openings in the stem produced by phellogen that permit gas exchange between the atmosphere and internal tissues.