CH:7 - Transport in Plants

Question 1

Vascular System

Answer 1

A system of fluid-filled tubes, vessels or spaces, most commonly used for long distance transport in living organisms; examples are the blood vascular system in animals and the vascular system of xylem and phloem in plants.

Question 2

Vascular

Answer 2

A term referring to tubes or vessels (from the Latin ‘vascul’, meaning vessel)

Question 3

Xylem

Answer 3

A tissue containing tubes called vessels and other types of cell, responsible for the transport of water and mineral salts through a plant and for support.

Question 4

Phloem

Answer 4

A tissue containing tubes called sieve tubes and other types of cell, responsible for the transport through the plant of organic solutes (assimilates) such as sucrose.

Question 5

Vascular Tissue

Answer 5

A tissue in plants consisting mainly of xylem and phloem but also containing sclerenchyma and parenchyma cells.

Question 6

Dicotyledon

Answer 6

Flowering plants can be classified as monocotyledons or dicotyledons; the seeds of dicotyledonous plants contain an embryo with two cotyledons (seed leaves) in their seeds and
the adult plant typically has leaves with a blade
(lamina) and a stalk (petiole).

Question 7

Eyepiece Graticule

Answer 7

Small scale that is placed in a microscope eyepiece.

Question 8

Stage Micrometer

Answer 8

Very small, accurately drawn scale of known dimensions, engraved on a microscope slide.

Question 9

Vascular Bundle

Answer 9

A strand of vascular tissue running longitudinally in a plant; within the bundle, the arrangement of tissues like xylem, phloem and sclerenchyma varies in different plants and organs.

Question 10

Parenchyma

Answer 10

A basic plant tissue typically used as packing tissue between more specialised structures; it is metabolically active and may have a variety of functions such as food storage and support; parenchyma cells also play an important role in the movement of water and food products in the xylem and phloem.

Question 11

Collenchyma

Answer 11

A modified form of parenchyma in which the corners of the cells have extra cellulose thickening, providing extra support, as in the midrib of leaves and at the corners of square
stems; in three dimensions the tissue occurs in strands (as in celery petioles).

Question 12

Epidermis

Answer 12

The outer layer of cells covering the body of a plant or animal; in plants it is usually one cell thick and may be covered with a cuticle which provides additional protection against loss of water and disease.

Question 13

Endodermis

Answer 13

The layer of cells surrounding the vascular tissue of plants; it is most clearly visible in roots.

Question 13

Sclerenchyma

Answer 13

A plant tissue consisting of thick-walled cells with a purely mechanical function (strength and support); the cell walls have usually become impregnated with lignin and the mature cells are dead with no visible contents; many sclerenchyma cells take the form of fibres.

Question 13

Lignin

Answer 13

A hard material made by plants and used to strengthen the cell walls of certain types of cell, particularly xylem vessel elements and sclerenchyma cells; it is the main material in wood.

Question 14

Transpiration

Answer 14

The loss of water vapour from a plant to its environment; it mostly takes place through the stomata in the leaves.

Question 15

Mesophyll

Answer 15

The region of a leaf between the upper and lower epidermis; in dicotyledonous plants the mesophyll has an upper palisade layer and a lower mesophyll layer; the palisade mesophyll cells are column-shaped and form the main photosynthetic layer, whereas the spongy
mesophyll has large air spaces between the cells for gas exchange.

Question 16

Stoma (Plural: Stomata)

Answer 16

A pore in the epidermis of a leaf, bounded by two guard cells and needed for efficient gas exchange.

Question 17

Xerophyte

Answer 17

A plant adapted to survive in conditions where water is in short supply.

Question 18

Cuticle

Answer 18

A layer covering, and secreted by, the epidermis; in plants it is made of a fatty substance called cutin, which helps to provide protection against water loss and infection.

Question 19

Symplast(ic) Pathway

Answer 19

The living system of interconnected protoplasts extending through a plant, used as a transport pathway for the movement of water and solutes; individual protoplasts are connected via plasmodesmata.

Question 20

Apoplast(ic) Pathway

Answer 20

The non-living system of interconnected cell walls extending throughout a plant, used as a transport pathway for the movement of water and mineral ions.

Question 21

Xylem Vessel ELEMENT

Answer 21

A dead, lignified cell found in xylem specialised for transporting water and for support; the ends of the cells break down and join with neighbouring elements to form long tubes called xylem vessels.

Question 22

Xylem Vessel

Answer 22

A dead, empty tube with lignified walls, through which water is transported in plants; it is formed by xylem vessel elements lined up end to end.

Question 23

Source

Answer 23

A site in a plant which provides food for another part of the plant, the sink.

Question 24

Sink

Answer 24

A site in a plant which receives food from another part of the plant, the source.

Question 25

Sieve Tube Element

Answer 25

A cell found in phloem tissue, with non-thickened cellulose walls, very little cytoplasm, no nucleus and end walls perforated to form sieve plates, through which sap containing sucrose is transported.

Question 26

Companion Cell

Answer 26

A cell with an unthickened cellulose wall and dense cytoplasm that is found in close association with a phloem sieve tube element to which it is directly linked via many plasmodesmata; the companion cell and the sieve tube element form a functional unit.

Question 27

Sieve Tube

Answer 27

Tube formed from sieve tube elements lined up end to end.