7.3 Structure If Stems, roots And Leaves And The Distribution Of Xylem And Phloem Flashcards
What are the main organs involved in the transport of plants?
Stems roots and leaves
How is the structure of stems roots and leaves studied?
Using prepared slides of photomicrographs transverse sections (TS) of these organs
What is a useful way of understanding the structure of the organs and the distribution of xylem and phloem ?
Drawing low power plants and high power detail of representative groups of cells as seen with the microscope
Flowering plants can be classified as
Monocotyledons or dicotyledons
What is the difference between the leaves of monocotyledonous plants and dicotyledonous plants
Monocotyledonous plants typically have long narrow leaves while dicotyledonous plants have leaves with wide blades and narrow stalks (petioles)
What is the difference in monocotyledons and dicotyledons related to transport systems
The mechanism of transport through both types of plants as the same, but there are differences in the distribution of xylem and phloem in their roots
What is a dicotyledon?
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(laminated) and a stalk(petiole)
What does phloem look like through a microscope?
Phloem is usually stained green and has small cells
What does xylene look like through a microscope?
Xylem is usually stained red and usually contains a few large vessels
In stems and leaves the xylem and phloem are found in structures called
Vascular bundles which also contain other types of cell
In roots, the xylem and phloem are found at
The centre of the root
The epidermis is________ thick and covers
One cell, the outside of the plant
Most of the cells outside the vascular tissue are
Parenchyma cells
What are parenchyma cells?
A basic plant tissue typically used as packing tissue between more specialised structures; it is metabolically active
What functions are there for parenchyma cells?
It may have a variety of functions such as food storage and support ; also play an important role in the movement of water and food products in xylem and phloem
Parenchyma have_______ cell walls and ______ in size
Thin, vary
You may see _________ in some of parenchyma cells
Nuclear
The outer region of stem and roots is called
Cortex
What is cortex mainly made of?
Parenchyma
Secondarily collenchyma tissue
No what is epidermis?
The outer layer of cell covering the body of a plant or animal
No what is epidermis?
The outer layer of cell covering the body of a plant or animal
Why might the epidermis be covered with cuticle?
To provide additional protection against loss of water and disease
What is collenchyma?
A modified form of parenchyma in which the corner of the cell have cellulose thickening providing extra support
In three dimension, the collenchyma occurs in
Strands(as in celery petioles)
Where is collenchyma found?
The midrib of leaves
Around the outside of the stems just below the epidermis
What is endodermis?
The layer of cells surrounding the vascular tissue of plants
What is endodermis?
The layer of cells surrounding the vascular tissue of plants
The endodermis is ______ thick
One cell
The endodermis is most clearly visible in
Roots
Vascular bundles in stems have a cap of fibres called_______ for extra strength
Sclerenchyms
What is sclerenchyma?
A plant tissue consisting of thick walled cells with a purely mechanical function(strength and support)
Give more information about schlerenchyms
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 fibre
Give more information about schlerenchyms
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 fibre
Why are sclerenchyma usually stained red like xylem?
Because their cell walls contain lignin
What is lignin?
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
