plant nutrition igcse

7/26/2019 plant nutrition Igcse

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CHAPTER 6 IGCSE

PLANT NUTRITION


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THE EQUATION FORPHOTOSYNTHESIS

Photosynthesisis the fundamenta !"#$ess %&!ants manufa$tu"e f##d m#e$ues (carbohydrf"#m "a' mate"ias(CO2and H2O) usin* energyf"#m light+

The "a' mate"ias a"e Ci*ht ene"*&+

The !"#du$ts a"e *u$#s


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THE PROCESS OF PHOTOSYNTH

G"een !ants ta.e in CO2th"#u*h thei" ea/es (%& difusion H2Ois a%s#"%ed th"#u*h !ants0 "##ts (%& osmosis)- and

t"ans!#"ted t# the eaf th"#u*h xylem/esses+

Chlorophyll t"a!s light energyand a%s#"%s it+

This ene"*& is used t# %"ea. u! H,O m#e$ues- than t# %#nh&d"#*en and CO, t# f#"m glucose+

Gu$#se is usua& $han*ed t# sucrose f#" t"ans!#"t a"#un!ant- #" t# starchf#" st#"a*e+

O2is "eeased as a 'aste !"#du$t- #" used %& !ant f#" "es!

In this !"#$ess- light energy is $#n/e"ted t# chemical enthe f#"mati#n #f *u$#se and its su%se1uent st#"a*e+


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PHOTOSYNTHESIS IN2ESTIGATIOPRINCIPLE AN3 STARCH TEST

E4!e"iments $an %e used t# 5nd #ut 'hat fa$t#"i*ht- $h##"#!h&) a"e needed f#" !h#t#s&nthesthe !ant need t# %e destarch+ T# %e $e"tain thaeafs a"e th#"#u*h& desta"$hed- testa eaff#" starch %ef#"e %e*in the in/esti*ati#n+


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PRINCIPLE OF IN2ESTIGATION

1.Inestigations need controls Control!ant (#" ea/e) has a su%stan$es it needs+

!est!ant a$.s #ne su%stan$e (i*ht$h#"#!h&CO,)

2. Plants must be destarched

It is /e"& im!#"tant that the ea/es u a"e testin* sh#udan& starchin them at the %e*innin* #f the e4!e"iment+

S#- 5"st #f a- u must desta"$h the !ants+ Lea/e them inthe dar"f#" 78 h#u"s+ The !ants use u! a st#"es #f sta"$ea/es+


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#. $tarch test %ith Iodine solution

Afte" a fe' h#u"s- $a""& #ut the sta"$h test #n %#th!ants9Iodine solutionis used: a %ue;%a$. $##u" #

ea/e is !#siti/e+ &oil the lea' in %ater f#" %"ea. d#'n the mem%"ane > i#dine s#uti#n *eth"#u*h $e mem%"ane t# "ea$hstarchinside the $hand "ea$t 'ith them+


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&oil the lea' in alcohol (ethan#) in a 'ate"%ath9The green colour#f the eaf and the %"#'i#dine s#uti#n $an ##. %a$. t#*ethe"- s# u n

"em#/e chlorophyll%& dissolingit #ut 'ith aLea/e it unti a the $h#"#!h& has $#me #ut #f eaf+


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(inse the lea' in %ater9 ?#iin* the eaf in ethma.es it %"itte- the 'ate" s#ftens it+

S!"ead the eaf #ut #n a %hitetie > eas& t# see

"esut+ dd iodine solutiont# the eaf > %ue; %a$. $#

!#siti/e- sta"$h is !"esent+

A leaf before (on the left) and after (on the right) starch test


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PHOTOSYNTHESIS IN2ESTIGATIO(CH*O(OPH+**, CO2 AN3 *I-

TESTS)


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CHLOROPHYLL

ProcessTa.e a !#tted !ant 'ith ariegated (*"een and

ea/es+

estarch the !ant %& .ee!in* it in $#m!ete daf#" a%#ut 78 h#u"s+

E4!#se the !ant t# the sunlightf#" a fe' da&sTest #ne #f the ea/es f#" starch 'ith i#dine s#


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Obserations; A"eas 'ith !"e/i#us& green!at$hes test positi%ue %a$.)+

; A"eas 'ith !"e/i#us& !ae yello% !at$hestest negatie ("emain %"#'n)+ Conclusion

- Photosynthesis takes plapatches because of the preof chlorophyll.

- The pale yellow patches d

photosynthesis because of chlorophyll.


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*I-H!ProcessTa.e a !#tted !ant+

estarch the !ant %& .ee!in* it in $#m!ete da"a%#ut 78 h#u"s+Test #ne #f it ea/es f#" sta"$h- t# $he$. that is d#$#ntain an&+Fi4 a eaf #f this !ant in %et'een t'# st"i!s #f a t

#n eaf+Pa$e the !ant in i*ht f#" a fe' da&s+Rem#/e the $#/e" f"#m the eaf and test it f#" sta


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ObserationsP#siti/e sta"$h test 'i %e #%tained #n& in the !#"the eaf e4!#sed t# i*ht and ne*ati/e test in !a"ts!a!e" st"i!+

Conclusion

Light is necessary fophotosynthesis.


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C(&O/ IO0IProcessTa.e t'# desta"$hed !#tted !ants+C#/e" %#th the !ants 'ith %e @a"s and a%e them

and ?+Inside Set;u! A- .ee! /aHCO#(s#dium %i$a"%#na

!"#du$es CO,+

Inside Set;u! ?- .ee! /aOH(S#dium h&d"#4ide)+

a%s#"%s CO,+ee! %#th the set;u!s in the suni*ht at east f#" 6h#u"s+Pe"f#"m the sta"$h test #n %#th #f the !ants+


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Obserations

Leaf f"#m the !ant in 'hi$h /aHCO#has %een !a$ed*i/es positietest+Leaf f"#m the !ant in 'hi$h /aOH has %een .e!t*i/e negati' test+ConclusionPant in Set u! A *ets CO

,'he"eas !ant in Set;u! ? d#e

n#t *et CO,+


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C! O *I-H! I/!/$I!+ O/ !H (! OPHO!O$+/!H$I$

Pants need i*ht ene"*&

t# ma.e the $hemi$aene"*& needed t# $"eate$a"%#h&d"ates+

In$"easin* the i*htintensit& 'i %##st thes!eed #f !h#t#s&nthesis+

H#'e/e"- at hi*h i*htintensities the "ate%e$#mes $#nstant+


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xplanation

*ight energy absorbed by chlorophyll is conerted to

At /e"& #' i*ht e/es the !ant 'i %e "es!i"in* #n& n#t!h#t#s&nthesiBin*+

As the light intensity increases, the rate o' !h#t#s&ntheincreases.

Ho%eer, the rate %ill not increase beyond a $e"tain e/intensit&+

At hi*h i*ht intensities the "ate %e$#mes constant, een %in$"eases in i*ht intensit&- the"e a"e n# in$"eases in the "ate

The !ant is una%e t# ha"/est the i*ht at these hi*h intensit$h#"#!h& s&stem $an %e dama*ed %& /e"& intense i*ht e/


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EFFECT OF !4P(!5(ON THE RATE OFPHOTOSYNTHESIS

hen the temperaturerises the rate o'photosynthesis risesalso. !here is

an optimumtemperature at %hichthe rate o'photosynthesis ismaximum.

?end this tem!e"atu"e-the "ea$ti#n 1ui$.&$#mes t# a hat+


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xplanation

! *O6 !4P(!5(- the enB&me does not have enouenergyt# meet man& su%st"ate m#e$ues- s# the "ea$ti#n

hen the tem!e"atu"e "ises- the !a"ti$es in the "ea$ti#n moquicker and collide more- s# the "ate #f !h#t#s&nthesis "is


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! !H OP!I454 !4P(!5(- the enB&meefcient and the "ate if ma4imum+


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t !4P(!5($ &O7 89:C the rate slo%do%n.

This is %e$ause the enB&mes in/#/ed in the $he"ea$ti#ns #f !h#t#s&nthesis a"e tem!e"atu"e sen

and destroyed (denatured) at higher


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fect o' Carbon Dioxide on the (ate o'Photosynthesis

hen the $#n$ent"ati#n #fCO, is #' the "ate #f!h#t#s&nthesis is as# #'+(the !ant has t# s!end time'aitin* f#" m#"e CO, t#

a""i/e)+ In$"easin* the $#n$ent"ati#n#f CO in$"eases the "ate #f!h#t#s&nthesis+


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xplanation

The "ate #f !h#t#s&nthesis

increases linearly %ithin$"easin* CO,$#n$ent"ati#n (f"#m !#int At# ? )+

The "ate fas *"adua&-

and at a $e"tain CO,$#n$ent"ati#n it sta&s$#nstant (f"#m !#int ? t#C)+

He"e a "ise in CO, e/es

has no efect as the


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Limitin* fa$t#"s in !h#t#s&nthes

*imiting 'actoris s#methin* !"esent in the

en/i"#nment in su$h short supply that it "est"i$t!"#$esses+


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$unlight

O/e" the 5"st !a"t #f the $u"/e(between A and )- i*ht is alimiting 'actor+ The !ant isimited in h#' fast it $an!h#t#s&nthesise %e$ause it

d#es n#t ha/e en#u*h i*ht+ etween and C- i*ht is n#t

a imitin* fa$t#"+ E/en if m#"ei*ht is sh#ne #n the !ant- itsti $ann#t !h#t#s&nthesise

an& faste"+


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Carbon dioxide

In !h#t#s&nthesis CO,is a .e&imitin* fa$t#"+ The usuaatm#s!he"i$ e/e #f CO,is =+=


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Tem!e"atu"e

The $hemi$a "ea$ti#ns #f !h#ts&nthe$an #n& ta.e !a$e /e"& s#'& at #'tem!e"atu"e- s# a !ant $an!h#t#s&nthesise faste" #n a 'a"m dan a $#d #ne+

i di i f h h i


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O!timum $#nditi#ns f#" !h#t#s&nthesis G"een h#use

if $"#!s a"e *"#'n in*assh#uses- it is !#ssi%et# $#nt"# $#nditi#ns s# thatthe& a"e !h#t#s&nthesisin*as fast as !#ssi%e+

CO i h t


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CO2enrichment

In a $#sed *assh#use- it is !#ssi%e t# !"#/ide CO,f#" the !ants- e+*+ %& %u"nin* f#ssi fues #""eeasin* !u"e CO,f"#m a *as $&inde"+

Optimum light

In $#ud& #" da". $#nditi#ns- e4t"a a"ti5$ia i*ht%e !"#/ided- s# that i*ht is n#t imitin* the "ate !h#t#s&nthesis+

Optimum temperature

The tem!e"atu"e $an %e "aised %& usin* a heatis&stem+ If f#ssi fues a"e %u"ned- the"e is as# a f"#m the CO2!"#du$ed+


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Leaf st"u$tu"e

The eaf $#nsist #f a%"#ad- at !a"t $aedthe lamina- 'hi$h is

@#ined t# the "est #f the!ant %& a eaf sta.#" petiole+ Runnin*th"#u*h the !eti#e

a"e ascular bundles-'hi$h then f#"mthe einsin the eaf+

Ath#u*h a eaf ##.s thin its is made u! #f see


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Ath#u*h a eaf ##.s thin- its is made u! #f seelayers#f $es+ Y#u $an see these if u ##. at at"ans/e"se se$ti#n ($"#ss;se$ti#n) #f a eaf unde"mi$"#s$#!e+


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!"omework

3"a' $"#ss se$ti#n #f eaf 'ith a%La%e 'ith fun$ti#n (use #C$)/ame- Cha"a$te"isti$- un$ti#n+

E4!ain %"ie& theADA%&A&'#s#finte"na st"u$tu"e #f eaf f#" !h#t#s&n

E4am!e


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E4am!e

5PP( PI(4I$ thin and transparent ;

allo%s light to passthrough

no chloroplasts arepresent

act as a barrier todisease organisms

Cuticle


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Lower

epiderm

Upper

epiderm

Cuticle

Palisade

mesophyll

Vascular

bundle

Xylem

Phloem

Spong

mesoph

Airspace

stoma

CUTICLE


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CUTICLE

eatures !

characteristics Co"ersthe

epidermis

A transparent layer

o# cutin $a%yco"ering&

waterproo#

unction

'( Protectthe lea#)( Allow lightto enter the lea#

*( Pre"ente%cessi"e water loss

UPPE+ EPI,E+-IS


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UPPE+ EPI,E+-IS

eatures !

characteristics A single layero#

#lattenedcells

,oes notcontain

chloroplast Transparent

unction

'( Allow lightto penetrate the lea# andthe mesophyll layer

PALISA,E -ES.P/0LL


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PALISA,E -ES.P/0LL

eatures !

characteristics .ne or #ew rows o#

"erticallyorientedclosely pac1edcolumn2shapedcells

/a"e a highdensity o#chloroplast

unction

'( Trap most o# the incoming light


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SP.340 -ES.P/0L


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SP.340 -ES.P/0L

eatures !

characteristics Loosely pac1ed

irregularly shapedcells

/a"e#ewerchloroplast

unction

'( Increase the internal sur#acearea #gaseous e%change

)( Trape%cessi"e light #rom palisademesophyll

VASCULA+ 5U3,LE


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VASCULA+ 5U3,LE

eatures !

characteristics Consists o#%ylem

and phloem

unction

'( Xylem 6 transports mineral ions a

waterto the lea#)( Phloem2 transport products o#

photosynthesisaway #rom the lea#

AI+ SPACE


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AI+ SPACE

eatures !

characteristics Spaces between

spongy mesophyll

unction

'( Allowdi##usion o# gases betweentatmosphere and the mesophyll(

L.$E+ EPI,E+-IS


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L.$E+ EPI,E+-IS

eatures !

characteristics Layer o# epidermal

cells

,oes not contain

chloroplast e%cept#or the guard cells

unction

'( Protectthe lea#)( Allow gaseous e%change through

stomata

4UA+, CELLS !ST.-A


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4UA+, CELLS !ST.-A

eatures !

characteristics Thinner outerwalls

Thic1er innerwalls

-odi#iedlower

epidermis

7 Each stomata is

#lan1ed by two guard

cells which regulate

the si8e o# the pores

unction'( +egulatethe

opening and clos

o# the stomatal po

Pants mine"a "e1ui"ements an


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fe"tiiBe"s Pant is in need f#" mineral ions t# $#nt"# $hem

a$ti/ities- *"#'- and !"#du$e mate"ias+ The m#s

im!#"tant mine"as a"e 4agnesiumi#ns and /

+Im!#"tan$e #f nit"ate andi i


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ma*nesium i#ns

. /itrates


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. /itrates

plants absorb nitrate ions from the

soil, through their root hairs nitrate ions combine with glucose

----- amino acids

amino acids bond together----- protein

deficiencycauses poor growth,especially of lea!es. The stembecomes weak, lower lea!es becomeyellow and die, while upper lea!esturn pale green

% a*nesium


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%+a*nesium

plants absorb magnesium ions

from the soil solution used for the manufacture

of chlorophyll

each chlorophyll contains onemagnesium atom

deficiencymakes lea!es turnyellow from the bottom of the stem

upwards and e!entually stopsphotosynthesis

plant nutrition igcse

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