SOME FACTORS AFFECTIIW !lA.GNESIUH UPTAKE BY CITRUS LEAVES
A thasi s pr e;scnte:~ in l)r.;rtial fulfilment of the r oquircments for tho Deer oc of
Master of Horticultural Science at Massey University
Palmerston North New Zoalan0.
by
Shnli0re .. m Ku1:1ar Thapa
A B S T ,h A C T
Pineap~le sweet oran~e seedlings and rooted leaf bud
cuttings of Meyer lo~ons were used to investigate the effects of some cf the factors affecting mac:;nesium u1.:;take by leaves. Magnesiun was cteterrnined by thiazol e yellow nethot of Drosdoff and Nearpass ( 1948) anc1 u:,take was usually m0asured 24 hours after spray treat• ent.
It was shown that the addi t ion of wetting a5ents to
nacnesiuD nitr2.te sprays si t;nificant1.y increased the u1)tako of mac;nesiun '.)y l eaves. The nonionic wetter (Terrie GN9) at the very l ow (0.01% a.i.) anr~ high (0.08 - 0.1% a.i.) concentratio.ns di e~ not affect nc1.c;nesiu,:1 uptake, whereas at interi11ediate
con-centrations, ma5nesium uptake was increased.
Use of the humectant clycerine at 1 or 2 percent sie
nif-icantly increase,, the uptake of nagnesiu1a by leaves, compared
with sprays to which no: slycerine was added, but had no bene-ficial effect o,ver sprays which contained a nonionic wetter
(Te·rric GN9).
Magnosium uptake by leaves grown in 100% relative humidity
for two weeks was greater than the uptake by leaves grown in
Both morning ar.d tho evening sprays resulted in great er
uptake of magnesium by :!_oavos, compared with afternoon sprays.
A significant increase in l eaf magnesium concentration occurred after 2 hours of a magnosiur:1 nitrate spray appli ca-tion. Loaf magnesium concentration rose steeply for 24 hours after spraying, thereafter remaining constant. (Becaus;) it was not possible to measure the degr ee of magnesium transport out of the l eaf, it i s not cl ear whether m&gnesium uptake, in fact, stopped after 24 hours).
Of the three magnesium salts used, magnesium nitrate and magnof;ium c hloridG sprays rGsll.ll t ed in groa tor magnesium upta.i..:e by l 0aves, compar ed with magnesium sulphate sprays.
Uptake varied wi th tho cone entra.tion of magnesium in. the l eaves. The lower the concentration of ~agnesium in the leaves, the l oss the uptake of magnesiur:;i by loaves, and tho hie;hcr the cone entration o.f magnesium, the higher tho uptake of magnesium.
Thus the incroo.w in the % l eaf cone ontration · of i:lai:)1Gsium
in the high nitros2n ; lants waE dcubl o that of tho low nitrogen
pl ants. This may to a direct effect of the low l oaf nitroccn
or an inc1.irec t one .h1c to tho in•:uc cc'. low lce.f ;-1ac;nosim1 in
those plants.
-A C K N O W L E D G E M E N T S
I gratefully ecknc~lotl~G tho continuous
assistanc0 ant guidance of Hr D.A. Slaie of the
Dopartucnt of Horticulture, Massey University in
conplotinc this project. My sincere thanks also go to Professor J.A. Veale of the Department of Horticurlture for his nsGful sugiestions and ac1.vico.
This stutly was made possibl e by financial
assistance from t~e Ne~ Zoal anJ Department of
External Affairs under the Colonbo Plan. I ac very
1 •
2.
INTRODUCTION
.'f'ABLE OF CONTENTS
CHAFER 1
CHAPTER 2
FOLIAR APPLICATION OF NUTRIENTS
· CHAPTER 3
LITERATURE REVIEW
3.1. Pathways of ponetrc..tion of nutrients,
her:Jie.i.dos and other substances into the
leaf.
3.
1. 1.3.
1. 2.3
.1.3.
3. 1.5.
Entry through stomata
Structure of tho cuticle
3.1.2.1. 3.1.2.2. 3.1.2.3. St:r-ucturo wa.11 Structure Mechanisms
3.1.5.1.
3.1.5.2.
3.1.5.3.
Physical nature of tho
pl:mt cuticle
Chemical nature of tho
plant cuticle
Tho role of the cuticle
anc1.. na.ture of the. col l
of the plasma-mem :Jr ane
of foliar penetra.tion
Mechanism.s of po
netra-tio.n in tho cuticle
Mech2..nism.s· o,f pe
netra-tion in the cell wall
Mechanisms of
penetra-tion in the p
lasma-membrane
3.2 .. Fae tors .3.f f cc tinr 11011otr.:-, ti •_,n an'.l
3.2. 1. Pl.s.nt factors
3.2.1.1.
l.il.0Vornont 30 30
of tho ~lant cuticle 30
3.2. 1.2. AGO C• f the l oaf
3
.
2
.1.
3
.
Leaf surfaces andrJorpholocy
3.2.1.4. Mineral status of tho
lc:i.f
3.2.2 .. External factors
3
.
2
.
2
.1.
3
.
2
.
2
.
2
.
3
.
2
.
2
.
3
.
3.2.2.4.
3
.
2
.
2
.
5
.
3.2.2.6.
3
.
2
.
2
.7.
The citrus leaf U12tak.e of ma.c;nesium anr_~, other crops
3.4. 1. Glasshouse 3.4.1.1.
3
.
4
.1.
2
.
Licht
Temperature
Humidity
pH of the s~r~y so lu-tions
Surfactants Humectants
Solute characteristics
b;:t: 1-oaves of citrus
and luborator;:t: studios Tho effect of different magnesium s.:1.l ts on magnesium absorption The effect of differ-ant spreaders and hygroscopic aeonts on
ma.gnes ium abs ori)tion
ThG r~to of O~OGiULl
ahaorption
Tho effect of sprc.l.ying
at different hours of
the d~y
Tho effect of nitrogen
lovol
The effect of macncsiun 53
55
57
level 60
Plant responses to fi 81.d concU t ions 62
3
.
4
.
2
.
1
.
3.4.2
.
2.
3
.
4
.
2
.
3
.
Responses to citrus
Miscellaneous responses
The effect of nitrogen
level
Tho effect of magnesium
lovel
M~rne.sium nobility studies
Literature review Summary
62
66
69
71
CHAPTER 4
MATERIALS AND KCTH0DS
4. 1 • 'rhe experi1:1ents
4,2. Con11Josition an~l ;,reraration of concentratecl
nutrient stock solution for experiments
4
.
3
.
.
Techniques usorl_ in crowinc pinea;;ple sweetoranee seedlings
4
.
6
.
4
.
7.
Sowin5 of seeds
Planting out
Fcojin3 the ~lents
0rowi n,:; ?_!__!'1_eyer l oaon l eaf bud. cuttine;s
Exeerimontal ncthods
4.5,1.
4.5.2.
Spraying techniques
Ex1Jerimental desi gn
Leaf sampl es and analysis
4.6.1.
4.
6
.
2
.
4
.
6
.
3
.
4.6.4,
Sampling techniques
Cloanin
g-Ashing
Techniques of leaf magnesium
analysis
Statistics
CHAPTER
5
5. 1. Ex~eriment I
Tho effect of different wetting a~ents on the uptako of m~~nosiuw by l eaves.
5.2. Ex~erirnont II
Tho effect of :iiffercmt concentrations of a
noni onic wetter (Terrie GN9) on tho uptake of
magnesium by leaves.
5
.
3.
Ex]'cffirirnnt III93
93
96
Tho eff0ct of different concentrations of
cl ycorine on tho uptake of rna~nesius by l eaves. 101
5
.
4
.
Ex?erinont IVThe effect of hm-:1.idi ty on tho uptake o-f
magncsiu• by l eaves.
5
.
~
.
~xp~riment VThe effect of srraying at different times of the
d~y on the uptake of magnosiun by l eaves.
5
.
6
.
Exuerinent VI103
105
The rat e of uptake of ma[';nesium by l eaves. 107
5
.
7
.
~ _periment_~IIThe effect of different 3aGnesium salts on tho uptake o-f mac;nosiun by leaves.
5
.
8
.
Experiment VIIIThe effect of l eaf magnesium l evel on the uptake of magnesium by leaves
110
6.
7.
5
.9.
Expcrirucnt IXTho ofL:c t of l eaf ni troGon l.evel on the
CHAFER 6
DISCUSSION OF THE DATA
CONCLUSION
APPENDICES
BIBLIOGRAPHY
CHAPTER
7.
115
117
TABLE
LIST OF TABLES
Sto~atal pore si zes of citrus l oaves
(Turrell,
1
94
7).
2 Th8 effect of tlifforent raacnosium salts
on na5nesium absorption
(Fi.sher anc Walker,
1
9
55).
3 Th~ effect of three spreaders an magnesium
atsorption from a 5 per cent Mgso
4.7H2o spray applic~tion (Fisher and Walker,
1955)
4 The effect of glycerine, carbowax and m2thyl
cel losolve on cagnesium atsorption fro• a
5 per cent Msso
4.?H2
o
spro.y applicati on (Fisher end Walker,(1955)
5 The rat o of e1acnosi.um al:sorpti.on over a 12
day period (Fi.sher and Walkeri
1955)
6 Tho effect of Mgso
4.?H2o solution applied at
different hours 6urinB the day
(OlGnd and Opiand,
19
56
).
7 Moan concentration of elements(% dry weight)
in l oaves (Ford,
196?).
8 Effects o-f mat;nesium treahi.ents on the
concentration of magnesiun in the l eaves of
PAGE
48
50
52
53
55
57
62
Valoncict orange (Embl eton anc1 Jones,
1959)
65
9 Magnesium concentration in grape leaves as
affected :.)y spray and soi l application of
Mgso
Ti1.:3LE
(ForE:hey,
1
95.9
)
.
7
0
1 1 ~-~0 an con contra t ion of clo:-:ieot:__: (% dYIY •-,;,,1· .',ht) Jo• L ' . . J . D
in l eovcs, stc1.TIE.i :--:nrJ root::. (Fora,
1966)
.
7.
3
t M ( ..,-,, ) ~r O 1 · t ·
cen . g ~u
3 2.b~2
•
pray•
pp 1ca 10n.9~
-12a Tho effect of different ~ctting agents usca~t 80~ wettability of th~ loaf area.
13 The effect of rJifferent concontro.t iono of D
nonionic wettorr (Torrie GN9) on the upta}:o of
i:nar;nosi um by l eaves from a 2.5 per cont
13a The visual nsscfJ;::iii1ent of the ,,ottine of tho
upper surface of the citrus leaves by
To rric GN9.
14
The effect of different concentrations of97
99
gl ycerine on ths uptako of ma~nasium by l eaves
from a
2
.
5
per centhl
g(No
3
)
2.
6E
20
spray application.15
The effect of humidity on the uptcko ofmari:nosium by leaves from n
2
.
5
per cent102
TABLE
1 6 The effect of s::raying at ,1iffcrent tiri1os of
the day on the u11take 0f ::1a1:.,nesiw,1 by leaves
frorn a 2.5 percent
Mg(No
3)2.6H2
o
sprayPAGE
a~plication. 106
17
The rate of uptake of ~asnesiu• by l eavesfrom a 2.5 percent Mc,(~m
3)2.6H20 srray
a~plication. 108
18 The effect of different TiaGnesiug salts on the
uptake of • aGnesium by l oavos.
19 Th(: effect of leaf ;:1aGnesiu::1 l ovel on the
uptake of ua~nesiuc by leavos frora a 2.5
por-cent
Mc
(
No
3)2.6H2
o
sprny application. 20 The effect of leaf nitroeen level on thouptake of nacnesium by leaves from a 2.5
per-1 per-1 per-1
113
LIS'I' OF FIGURES AND PLA'I1ES ...
-
~----
..FIGURE
rrjpothotical structure of tho functional
asject s nf the rlant cuticle (Foy et al; 1967) , 10
1 a A c1.i asrai7! showin:.c, the su~stances th2.t r1ny compose tho cell wall (Miller,
1
938)
.
2 Tho level of P32 activity found in the ;otiol e
fol lowinc, a 4-hour l}ericc' of trn.nslocation fron tho blac'l,) as a function of pH of tho an-'lie,~
solutisn (Sv.r-.:i_nson am1. \'/hitney,
1
953
)
3
The rate of a~sorJt ion of nitrocen, ;hosfborus4
and macnosiu• from s}rays applieC to tho l ower sur fac '..: ,:: f McIntosh a~:_;_-·le leaves
(Fisher an~ Valker,
1
955
)
,
Standard wettins chart for citrus l oav0s
5
The standarf curve of wettability of tho uppersurface of the citrus l eaves fer different
vret tin~: at~onts .
6 The effect 8f different concontruticns of a nonionic wetter (Torrie GN9) on ~ho uptake of uagnesiura by l eaves.
6a The effect of different concentrations of a
nonionic wetter (Terrie
G
N9
)
on the wettinG 0£ the uprer surface of the citrus l e&ves.7
The rate of uptake of macnesium by l eaves.8
Tho effect of l oaf magnesium 1cvol on theuptake of m,:1,.enesiu1.1 by l oaves.
PLATE
Pinoappi o sweot orange seodlinG supflied with
hich and low lGvel of nitrocen.
1
8
38
5483
84
98
1001
09
11488
APPENDIX
LIST OF APPENDICES
Comi)ositio:n cf concentrated. nutric,nt stock solution for exJerirnonts I, II, III, V, VI, VII -?tlllt VIII.
2 Couposi tio,n of cone ontrated nutrient stock solution for experiment IX.
3 Quan ti tati ve r.iicro c.~eterminntion o,f ;nacnesium in plant tissue and soil extracts.
4
5
A rapid colorimetric method. Nitr'Jge:n analysis.
Analysis of vnriance of the eff0ct of diffo r-ont '!lotting agents on the uptake of magnosiur.1 by leaves.
6
Analysis of variance of the effect of differ-ent wettinc agents used on the uptake of
magnesium by l eaves, at
80%
wettability of tho l eaf area.7 Analysis of variance of tho effect of diffe
r-ent concentrations of a n,.,nionic (Terrie GN9)
on the uptake of magnesium by leaves.
7a Analysis of variance o·f the visual assessment
of the wettins of the upper surface of the citrus loaves hy Terrie GN9.
8 Analysis of variance of the effect of d
iffer-ent concentrations of vlycerino on the uptake
of magnesium by leaves.
PAGE
134
.
135
136
13
9
142
142
143
143
APPENDIX
9 Analysis of variance of tho effect of humid
-i ty on tho uptake ,::,f m?.cnesium ty l oaves.
10 Analysis cf varianc0 of the effect 0f spray
-ins at differunt times of the day.
11 Analysi s of varianc o of the r:1 te of uptake of
JQ[uosium by leaves.
12 Analysis 0f variance of th& effect of differ
-ent mnEnesium. salts on the uptake of me.cnesium
ty leaves.
1
3
Analysi s of variance of the effect of l eafrnagnosiu• lovol on the uptake of magnesium
l,y l0aves.
14
Analysis of variance of the effect of l oafnitrogen Level on the uptclrn of ma6nosium
cy leaves.
PAGE
14
6
1
4
6
1
47
148
CHAPTER 1
1. INTRODUCTION
Nutrient sprays, these days, are becoming increasingly
important to supplement the mineral requirements o:f the
crops to increase crop production.··
Nutrient sprays may be important in two directions.
(i) Where soil application of fertilizers is not responsive
or very slow.
(ii) To prevent the development of a deficiency symptom vary
sonn before the trouble is expected or immediately it
has app€ared.
1
But the responses of nutrient sprays are influenced by
environmental factors (both physical and chemical) and plant
!actors. Magnesium absorption is not an exception to these
factors. Leaves of same plant species do not sho,w responses
to magnesium sal.t sprays, while o.thers do • . Soil application
of magnesium salts on the other hand, has been slow. in action
or has not been effective or partially effective. Foliage
application of magnesium sal.ts appears to be superior to soil
application in increasing the concentration of magnesium in
the leaves and in reducing deficiency syptoms. But the
respoilS'es are not consistent.
The present study, therefore, was undertaken to
2
affect the magnesium absorption by citrus leaves. The