Qualification > Sciences
IGCSE BIOLOGY------>TRANSPORT IN PLANTS
SGVaibhav:
lol i can
haha
:D
i have one sort of textbook (not exactly textbook, someone prepared this book)
it is quite inaccurate and wrong at times also.
but the good thing about it that it is more like a summary, that helps in revision.
should i scan and attach those 2 to 3 pages? (but i cant gurantee if the content is right)
sweetsh:
No need ...wait for me about 3 hours from now...
And I'll tell you the name of my book as it is amazing concluding everything you need
SGVaibhav:
which book do u have?
emi:
as i know ,, the thing i posted is the only thing thats coming ,,
those things are not in the syllabus .
not in my textbooks neither my guides .
sweetsh:
Sorry but I was studying chemistry.... :(
OKay now...
My book is Complete Biology for IGCSE by Ron Pickering...
http://www.worldcat.org/oclc/162144426
About the transpiration thing...let me explain it in simple words...
First thing...you have to know how the uptake of water and minerals occur in roots...They enter root hair cells by osmosis...As the water in the soil has a high water potential gradient than the cytoplasm of the root hair cell...Thats how the water enters...:D Then,,,water crosses the living cells of the cortex by osmosis...It crosses the cell wall and cytoplasm of the endodermis...The cell wall of the endodermis contains a waxy material which makes them impermiable to water...So the membranes of endodermis cells select what sybstances can enter the xylem and to be distributed through the body of the plant... :D
Now part(2)...Transport in plants 8) You know that inside the plants there xylem tissue and phloem tissue...
Xylem tissue contains xylem vessels...to transport water and dissolved mineral ions...
Its walls are thickened by LIGNIN...its waterproof and prevent the cells collapsing inwards...
There is no cytoplasm or organelles inside..(which is a kind of adaptation) so there will be no obstruction to the flow of water and mineral ions...
NOW...the end walls are removed...cells join to form long hollow tunes calles xylem vessels...
**They have small holes in their sides called pits..When the water from the root hair cell arrive in the center of the root it goes into the xylem vessels through there pits...
Well the picture in mybook is very useful and I cant find a good picture to make you understand!!
Third thing...Phloem tissue...it contains sieve tubes and companion cells...Its adapted for transport of the organic products of photosynthesis(sugars as sucrose) and amino acids...This is called Translocation
Translocation is the movement of sugars and amino acids from source(where they were made)to the sink(where they are stored or used)
They have think cytoplasm-cell must remain alive or sugar transport stops..
There is no nucleus or organelles..so sugar flow is not impeded...
Pores in sieve plates allows sugars to pass from one cell to the next...
Companion cells doesnt transport sugars but carries out some life processes of the sieve tubes..... !!!
Now a little bit explanation about transpiration because im sure you got bored or maybe slept on the keyboard!!! :D
Transpiration stream is the flow of water through the plant to replace the losses by evaporation from the leaf...
As the water loss occur from the leaves...this reduces the pressure at the tops of the xylem vessels by transpiration.It becomes less than the pressure of the base,thats why water moves upwards..
1)Water uptake occur by osmosis(as I mentioned above)
2)water moves up the stem in the xylem due to the tension caused by water loss from the leaves.
3)water moves from xylem to enter the leaf tissue down the water potential in the leaf tissues///
4)water evaporates into internal air spaces from the surfaces of leaf cells
5)water diffuses through stomata dow water potential gradient....
You may also know the leaf structure and how its adapted to reduce transpiration...
And the atmospheric conditions that affect transpiration...I think those are included in your textbooks and can be easily understood...
Dont forget how some plants are adapted to reduce water loss in diff. environments...(such as cacti,aquatic plants, and maram grass)
I hope I benefited you from this huge article!!! But I really wish you understand!!
Note: I attached a silly photo which shows transpiration very simply just to help you in studying...
Good Luck for you and Me...
sweetsh
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