The influence of manganese on the growth of pineapples

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Title:
The influence of manganese on the growth of pineapples
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Press bulletin ;
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Kelley, W. P ( Walter Pearson ), b. 1878
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Hawaii Agricultural Experiment Station
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Honolulu
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Pineapple -- Effect of manganese on -- Hawaii   ( lcsh )
Pineapple industry -- Hawaii   ( lcsh )
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government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )

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by W.P. Kelley.
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Caption title.

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University of Florida
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Hawaii Agricultural Experintmi

Oi ONOLULU. J '

E. V. WILCOX, SPECIAL AGENT IN C&cE

PRESS BULLETIN NO. 2a


he Influence of Mangan

the Growth of Pineapples.


By W. P. KELLEY,


.a : '.
..:". : :: ."
':;;:" Chiemist, Hawaii Experiment Station, United States Department of
AI. Agriculture.

.. For a- number of years the pineapple growers in the Wahi-
..awa district have observed that on certain sections of their land
pineapples do not grow well. On these areas the young plants
beginn to. grow as on the best soils, but in the course of a few
S..: months theleaves 'begin- to show a reddish-purple color, which
*-,soon gives place to a yellowish-white appearance, and this color
persists throughout the. remaining life of the plant. Many of
these plants never bear fruit; that which is produced, however,
is. always of inferior size and quality. These areas are quite
definite and with the rapid expansion of the pineapple fields in
Recent years, the land thus affecting this crop has been found to
S :be much greater in extent than was formerly thought. All
efforts of the best growers, including the application of ferti-
,liers and lime, good tillage, drainage, etc., have failed effectually
to change the growth of the pines on these lands.

A number of investigators have from time to -time studied the effects
:. of anganese on plant growth. Such studies, however, have involved
:b 'me ely. the application of small amounts of manganese -to soils. The
u -.mallest amount of manganese found in our best pineapple soils is
Five. times greater than the heaviest artificial application made in pre-
S vious experiments, while in our black soils the amount is 120' times
gr&tert. Previous experiments with manganese have been concerned
SWith the possible stimulating effect of minute quantities. In our pine-
i .le diflricts, .manganese is an important element in the eoil. The
present bulletin is a preliminary report on the first investigation evir
I made of soils jn which manganese is a dominant and determining fac-
: i tor of plant growth.-E. V. Wilcok.
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'.n '*in aideration of the extent of such soil, and its unusual
characteirtil Hawaii Experiment Station has undertaken an
extended'Investigation of the question. This work is still in pro-
a: t grea p i I it thought that results of sufficient importance and
1. scientific jfterest have been obtained to warrant their publication
.. at this time, This 'bulletin should, therefore, be regarded as a
. '' '-preliminary report, rather than a complete discussion of the
*"',,'-^ct t.
'The pineapple growers 'have noticed for several years that
the soil which produces yellow pines in most instances is dark
in color, whereas that producing thrifty, green plants is usually
red. From this difference in color, it is common in Hawaii to
speak of pineapple soils as being red or black, meaning thereby
good or poor pineapple soil; and it is in this sense that the
terms red and black soils are used in this paper. In addition
to this difference in color, the black soils appear to have a
finer texture than the red soils. 'When reasonably dry and in
good tilth, the red soil usually has a granular or "s'hotty" tex-
ture, while the black soil, under similar conditions, is reduced to
a finer state of division. Upon thoroughly wetting, however,
either of these types1, may be crushed between the fingers to an
almost impalpable mass; and indeed, to such a fine state of
division that practically all of it will pass through a one hundred
mesh sieve. There is, therefore, very little true grit in this sec-
tion. It should be remembered in this connection that prac-
tically all soils of Hawaii are of volcanic origin, and it seems
that in this district, a very complete disintegration of the lava
has taken place, which, in some places, extends to a depth of
thirty feet or more.
In certain other pineapple sections of Oahu, particularly near
Pearl City and Pupukea, a similar condition exists, but since
there is a larger area devoted to this crop, and a greater extent
of black soil in the Wahiawa district than in other sections of
the Islands, it was decided to undertake this investigation at
Wahiawa. Accordingly, in September, 1908, two extensive se-
ries of fertilizer plot experiments were begun; one on red soil,
and one on -black. There was a twofold object in these experi-

1. The word "type" is not used in this bulletin in its usual sense,
but rather for the sake of brevity.











ments,-first, to determine the fertilizer requirements of pine-
apples in Hawaii; second, to ascertain the cause of pineapple
yellowing on the black soil. This bulletin deals with the latter
of these only.
At the beginning of these experiments, a number of samples
of soil and sub-soil were taken from various arts of the dis-
trict. About one-half of these were from the black soil, where
the pines were very yellow; and one-half from red soil, produc-
ing good pines. The samples of soil were taken to a depth of
eight inches; and the sub-soil from eight inches to twenty inches
below the surface. Each of these samples represents a compo-
site, taken from not less than six different places; and, there-
fore, the average of the six samples of each type may be looked
upon as representing not less than thirty-six different places in
the red and black soils, respectively. In the following table
is given the average water-free composition of the two types as
determined by the methods of The Association of Official Agri-
cultural Chemists.


TABLE I.


Red
Average Composition of Soils
Insoluble matter .............. 42.82%
Potash (K 2 O)................ .59
Soda (Na 2 0)................ .27
Lime (CaO) .................. .36
Magnesia (MgO) ............. .39
Manganese oxide (Mn 3 0 4). .37
Ferric oxide (Fe 20 ) ........ 27.82
Alumina (Al 203) ........... 10.04
Phosphorus pentoxide (P 205) .08
Sulphur trioxide (S 3) ....... .11
Volatile matter ............... 15.14
Titanium oxide (TiO 2 ) ...... 2.01

Total ........................100.03
Nitrogen (N) ................ .32
Acidity (1) ................... 1235


Red
Sub-Soil
41.42%
.63
.25
.48
.38
.20
30.10
10.37
.12
.08
13.74
2.49

100.26
.24


Black
Soils
35.26%
.91
.31
.97
.47
5.61
22.58
15.39
.27
.17
17.61
.88

100.43
.37


Black
Sub-Soil
37.73
.87
.41
.58
.41
4.90
22.96
17.20
.16
.06
13.67
1.0S

100.03
.20


98


1. Calculated to pounds of CaO per


acre foot.







The growers at Wahiawa often refer to their black soils as
being sour, and many of them are inclined to attribute the yel-
low, dwarfed appearance of the crop on this land to this cause.
Investigations, in other countries have pointed out that the
pineapple plant is very sensitive to acidity'. But in view of the
fact that the determination of acidity in these soils shows the
presence of much less actual acidity in the black soil than in the
red soils, (see table above), it seems that, considering this factor-
only, the black soils should be the more productive of the two.
In fact, every sample of the black soil analyzed contained less
acidity than any of the red soils, and furthermore, some of the
black soils tested were found to be neutral. It, therefore,
seems reasonable that some cause other than acidity is bring-
ing about the unfavorable growth. By reference to the pre-
vious table, the black soils are shown to contain even more of
the so-called plant foods than the red soil, and in this connec-
tion, it is especially noteworthy to point out that the black soil
is well supplied with nitrogen, phosphoric acid and potash.
It is well known, however, that the usual chemical analysis
of a soil is not sufficient to determine its crop producing power;
that the chemist often fails to recognize certain conditions in
the soil, which have great influence on crops; and further, that
the usual chemical analysis fails to indicate the availability of
the elements in the soil; but without discussing this subject fur-
ther, it is sufficient at this time to say that the application of
liberal amounts of various high grade fertilirers. in conjunction
with good tillage, drainage, etc., has not resulted in overcoming
the yellowing of pines on this land.
The plots of black soil, to which the Station applied nitrogen,
phosphorus, potassium and calcium in various forms and
amounts do not indicate an effectual remedy for the yellow-
stunted growth of pines there. Some of the same applications
to red soil, on the other 'hand, are proving highly satisfactory.
What then is the cause of this phenomenon?
By again referring to the previous table, one striking differ-
ence in the composition of the two types is apparent, namely, in
their manganese content. In order to bring out this point more
forcibly, the following table is submitted, which shows the


1. Bul. 68, Florida Experiment Station, page 697.










complete analysis of the soils containing the maximum, mini-
mum and average percentages of manganese oxide found in each
type.

TABLE II.


BLACK SOILS RED SOILS
Max. Aver. Min. Max. Aver. Min.
Insoluble matter .......... 33.45% 35.26% 34.86% 39.07% 42.85% 44.00
Potash (K20)........... .83 .91 1.06 .76 .59 .59
Soda (Na20) ............. .40 .31 .29 .33 .27 .29
Lime (CaO) ............... 1.39 .97 .36 .29 .36 .24
Magnesia (MgO)........... .54 .47 .40 .35 .39 .41
Manganese oxide (Mn 04) 9.74 5.61 3.91 .91 .37 .15
Ferric oxide (Fe2 03)...... 19.65 22.58 26.39 24.98 27 82 27.94
Alumina (Al203) ......... 15.50 15.39 14.85 14.73 10.04 11.91
Phosphorus pentoxide
(P205).......... 21 .27 .18 .10 .08 .03
Sulphur trioxide (SO 3).. .16 .17 .13 .17 .11 .11
Volatile matter ........... 17.73 17.61 16.33 17.84 15 14 13.94
Titanium oxide (Ti 02) ... .73 .88 1.54 .23 2.01 .28
Total................100.33 100.43 100.30 99.76 100.03 99.89
Nitrogen (N) ............. .39 .37 .30 .34 .32 .29


Since the above analyses were made, numerous other samples
have been drawn both from red and black soil; and in every
instance, the samples drawn from sections where the pines are
yellow, have been found to contain large amounts of manga-
nese, whereas, those taken from the red soil, on which thrifty
pines grow, contain little of this element. In general, the black
soils contain from ten to fifty times as -much maganese as the
red soils'.
All the samples previously referred to were drawn from ex-
tremes, that is, either from sections which produce very yellow
plants, or from soils producing very thrifty, green pines. The
yellow and green areas are not separated by sharp lines of divi-
sion, however, -but rather gradually merge the one into the other.

1. It has been previously pointed out that some Hawaiian soils con-
tain large amounts of manganese (see Press Bulletin No. 18, this Sta-
tion); but no effort has been made to correlate yellowing of pine-
apples with the occurrence of manganese in the soil.







6

There is, therefore, an intermediate area surrounding the yel-
low spots on which the pines show the yellowing effect to a lesser
degree. With the view of determining whether the maganese
likewise decreases in passing from the black soil to the red,
several series of samples from different places, were drawn at
regular distances apart, in passing from the black to the red soil.
From the -analysis of these samples, a very close correlation
between the yellow color of the pineapples and the manganese
content of the soil was found to exist.
The following table will show the percentages of the oxide
of maganese in black, intermediate and red soils.

TABLE III.
Black. Intermediate. Red.
Manganese oxide (Mn 304) ........ 5.61 1.36 .37

It seems, therefore, that some correlation exists between the
yellowing of pineapples and the amount of manganese in the soil,
According to Leclerc1, manganese is an almost universal con-
stituent of soils, and it is often not determined in soil analysis
for the reason that it is not usually regarded as a necessary
element of plant food, and is thought to have little or no econo-
mic importance in crop production. Among all the analyses,
to which the author has had access, none have been reported
that contain more than a few tenths of one per cent of Mn3O4.
The solubility of a substance in the soil, however, determines
in a large measure its influence on plant growth. Sodium, for
instance, while not usually considered as an essential to plant
growth, when present in the form of a soluble salt, is known to
exert a marked influence on crops. Wheeler and Hartwell2, at
the Rhode Island Experiment Station, 'have shown that solu-
ble sodium compounds may even partially take the place of po-
tassium in the development of certain plants and in certain in-
stances sodium may perform a physiological function in the de-
velopment of these plants. The occurrence of large amounts
of soluble sodium compounds in the soil, 'however, is known to
be very detrimental to the growth of the plant. As is well

1. Cited by S'chreiber in Revue Generale Agronomique, January, 1906.
2. Nineteenth Ann. Rept. Of R. I. Experiment Station.







known, sodium and potassium are closely related elements and
have many properties in common. Maganese and iron are like-
wise closely related. It has been shown that when certain plants
are grown in culture solutions containing very small amounts
of iron, the application of a small amount of soluble manganese
brings about new vigor and increased chlorophyi production
and in this connection the solubility of the maganese and iron
in the black soil becomes a matter of interest. The chief func-
tion of iron in plants seems to be connected with the produc-
tion of chlorophyl, and since the general appearance of the yel-
low pines indicates that the cholorphyl has been affected the
possibility of some influence on the part of the manganese at
once suggests itself. In this connection, Loew and Sawa in
commenting on the work of Birner and Lucanus say: "In re-
gard to the behavior of plants toward manganese compounds
but few experiments have been made and these show that man-
ganese cannot replace the related iron in regard to the produc-
tion of chlorophyl; and that the manganous and manganic phos-
phate suspended in culture solution can exert an injurious ef-
fect." 1
* With the view of determining the solubility of the manganese
and iron, a number of samples of both red and black soils were
extracted with a one-per cent solution of citric acid. In this
determination, 200 grams of air-dried soil, were treated with
200ooo cc of one per cent citric acid for forty-eight hours, with occa-
sional shaking. At the end of this time the solution was filter-
ed, and the iron and manganese determined in the filtrate. The
following table will show the results, expressed in percentages
of air-dried soil : 2
TABLE IV.

Black Soil. Red Soil.
Mn304 ...................... .733% .028%
Fe203 ......................... .243 .379
Estimating that an acre foot of this soil weighs about 3,500,-
ooo pounds, we find that the black soil contains, on an average,
about 23,755 pounds of citrate soluble mangano-manganic oxide

1. Bul. of the College of Agric. Tokio Imp. Univ., Vol. 5, No. 2, p. 162.
2. Average of the determination in six samples.









per acre foot, while the red soil is found to contain only 980
pounds in the same area. It would, therefore, be extremely
surprising if this large amount of soluble manganese were with-
out influence in the soil. It is sufficient here to point out the
relations between the citrate soluble iron and manganese in the
soil. From the table it is shown that these stand in inverse
proportions.
In the strong acid digestion of the black soils, it was noticed
that considerable frothing or effervescence developed upon
slightly heating the same, and subsequently, this was found to
be due to the escape of chlorine gas. Numerous samples have
been treated with hydrochloric acid, and in every instance, the
black soils have been found to liberate large quantities of chlor-
ine; the red soils -do not possess this power.
In the determination of volatile combustible matter, it was also
observed that after heating the black soil just below redness for
some hours the sample still retained some of its dark color; but
upon subsequent stronger heating, further loss in weight oc-
curred and the soil took on a dark brown color. From these
facts, it seems likely that at least a part of the manganese in
the black soil exists in the form of higher oxides. The. black
color and the liberation of chlorine gas suggest the presence of
manganese dioxide, or of sesquioxide of manganese.1 It is, of
course, likely that the dark color is caused in part, at least by
organic matter.
It is reported that in some of these fields the first crop of
pines, on virgin soil, showed but little yellow color during the
first twelve months of their growth. Later, however, these
plants became very yellow and almost ceased to grow. With
the continued growth of pines on this soil, its color also seems
to become darker. A number of the yellow plants were pulled
up and it was found that the soil adhering to the larger roots
was darker in color than the general soil. Aso reports that
wheat grown in solutions containing a small amount of man-
ganous sulphate was found to contain manganese dioxide ad-
hering to the roots.2 These facts, together with the observation
that the cultivation of pines on this soil renders it less adapted

1. See "Soils" by Hilgard, p. 283.
2. Bulletin of the College of Agriculture, Tokio Imperial University,
Vol. V, No. 2, page 188.









to the crop, indicates that there is some change brought about
in the soil. by the crop itself; and since the soil of this entire
section has arisen from the disintegration of lava, which, in its
original state could not have contained either of the black oxides
of manganese, it seems reasonable that in the growth of pines
a change in the state of oxidation of the manganese takes place.
In connection with the investigation of the soil, a study of
the yellow plants has also been undertaken. It was formerly
-believed that the etiolated appearance of the pines was caused
by some pathological or entomological infestation; but as yet all
efforts to determine such infestation have proven fruitless. No
insect or fungus, which is known to produce this phenomenon,
has been found on these plants The root system of the yellow
plants was found to be dwarfed and much less extensive than
that of vigorous, green plants. In many instances, the roots
are covered with a black coat, and have but little indication of
life. The yellow plants possess but few root hairs. The healthy
green pines on the contrary have a very extensive root system,
sometimes reaching out to a distance of several feet from the
plant.
Some analyses of the ash from both the green and yellow plants
'have been made, and while a sufficiently large number of plants
have not been analyzed to warrant positive conclusions, it seems
that the entire metabolism of the yellow plants has been dis-
turbed. A number of young plants, about four months old, taken
from both red and black soils, and also an equal number of
plants two years old, were examined. A composite sample,
made up of an equal number of leaves from the same portion of
these plants, was analyzed. In the following table the percen-
tages of manganese oxide in the ash of these plants is given:

TABLE V.

Yellow Pines. Yellow Pines. Green Pines Green Pines.
(4 months old) (2 years old) (4 months old) (2 years old)
Mn3 04..... 2.12% 1.15% 1.65% 1.68%

In consideration of the very large percentage of easily solu-
ble manganese in this soil it is rather surprising that a higher
percentage of this element is not found in the pineapples grown
thereon, especially, since it is generally considered, that, in the







I0

presence of soluble substances, plants have the power of taking
up these substances in considerable amounts. It is interesting
here to note the smaller percentage of manganese in the ash
of the yellow plants two years old, than is found in the younger
pines. In the case of green plants, the ash is found to contain
about the same percentage of manganese in each of the two
stages. In this connection, other investigators have found that
many other plants contain notable amounts of manganese.
Schroder, for instance, found in the ash of the leaves of the
Norway spruce 35.53% Mn304.
The fact that the ash of other plants, such as wheat, barley,
etc., grown under normal conditions, contains not only a higher
percentage of nitrogen and potash, but also more of these sub-
stances in actual pounds, during the advanced growing period,
than at maturity, has been pointed out by several investigators.
In a very exhaustive investigation of this subject, Wilfarth and
Romer' at the Ducal Experiment Station, have shown that the
decrease of the actual total nitrogen and potash in wheat and
barley, as they pass from the growing stage into maturity, can
be explained in no other way than that these substances
are actually returned to the soil. These inevstigators found
that of the potash in wheat and barley at the time of flowering.
only 58.87% of that in the former, and 64.97% in the latter
remained at maturity; and while it is true that potash is neces-
sary to plant growth, and manganese is not usually so consid-
ered, the suggested analogy in the two cases is none the less
interesting.
Manganese, when applied in small quantities, has been shown
by several workers to produce the effect of stimulation. Nagaoka3
at the Tokio Imperial University, effected an increase in the
yield of rice to the extent of 370% by the application of 77 kilos
of manganous sulphate per hectar. At the Woburn Experi-
ment station, the stimulating power of manganese on wheat and

1. Cited from the Bul., College of Agric., Tokio Imp. Uni., Vol. V,
No. 2, p. 161.
2. Researches of the Ducal Agric. Expt. 'Station, on The Assimilation
of the Elements of Nutrition by Plants During Different Periods of
Their Growth. Die landwirtschschaftlichen, Versuchsstationen, Vol. 63,
1905.
3. Bul., College of Agric., Tokio Imp. University, Vol. VII, No. 1.









other crops has also been determined; and other investigators
have found that small amounts of various manganese com-
pounds produce the same effect. The fact, however, that small
quantities of a substance exert a stimulating effect does not
necessarily imply that larger quantities would be beneficial. In
the animal organism, for instance, a small amount of alcohol is
known to produce the effect of stimulation, whereas larger
amounts have a depressing effect. The same may be said of
ether and chloroform. With plants, there are several well known
examples of the same condition. Katayama 1 and others have
shown that ferrous sulphate in small quantities produces a sti-
mulation of certain plants; and whether or not this is 'brought
about by bringing into solution some of the dormant bases of
the soil, larger quantities of the same substance are often referred
to as actually poisonous to the plants. 2 Sutherst3 has shown that
the application of small amounts of various manganese com-
pounds, including the dioxide, has a stimulating effect on maize,
but he points to the work of Salamone as indicating that larger
amounts of these substances are detrimental.
The question of how these substances produce stimulation, in
small quantities, and a depressing effect, when present in large
quantities, is not thoroughly understood; but that such is the
case, is generally accepted. Aso 4 for instance, has shown that
a given amount of manganese may produce stimulation of rice,
whereas the same amount of this element, when applied to
wheat and 'barley, may, under certain conditions, result in de-
creased vigor and the development of a yellow color in the plant.
This author has further pointed out that the depressing effect
of such applications of manganese is usually more marked in
cold weather than in warm; and with the return of warm wea-
ther, in some instances, these plants were able to entirely over-
come the stunted growth and yellow color.


1. Bul. College of Agric., Tokio Imperial University, Vol. VII, No. I.
2. "Agriculture" by Storer, Vol. I, p. 216.
3. "Manganese Compounds as Fertilizers for Maize," The Transvaal
Agric. Journal. Vol. VI, No. 23.
4. Bul. College of Agric., Tokio Imperial University, Vol. V, No. 2,
pp. 177-185.







12

We find a parallel condition at Wahiawa, where the pine-
apples on soils which contain an intermediate quantity of man-
ganese, have been repeatedly observed to become decidedly yel-.
low during the winter months; but such plants sometimes en-
tirely overcome this condition with the return of warm weather.
It should be mentioned in this .connection that sugar-cane grows
exceedingly well on these manganese soils, where the pineapples
refuse to grow.
Bertrand I some years ago, found that the ash of oxidizing
enzymes contains considerable amounts of manganese, and that
the addition of soluble manganese salts to the oxidase greatly
accelerated their oxygen carrying power. Woods 2 has shown
that- the yellow spots, which sometimes occur on leaves of cer-
tain plants, have a greater oxidizing power than the green parts
of the same plant. In seeking an explanation of the yellow
color produced by the appli-cation of manganese sulphate to bar-
ley, Loew and Sawa found that such plants are -more vigorous
oxidizing agents than those not treated with manganese. Sum-
marizing these effects, they say: "Manganese exerts, in mod-
erate quantity, an injurious action on plants, consisting in the
bleaching out of the chlorophyl. The juices of such plants show
more.intense reactions for oxidase and peroxidase than the
healthy control plants. Manganese exerts further a promoting
effect on the development, still observable in high dilution, while
the injurious effects disappear under this condition. It is prob-
ably that soils of great natural fertility contain manganese in
an easily absorbable condition, and this forms one of the char-
acteristies of such -soils." 3
With the view of ascertaining whether yellow pineapple plants
are more vigorous oxidizing agents than the green plants, a
small portion of both yellow and green leaves were macerated
with crushed- glass, allowed to stand about an hour, and the ex-


1. Compt. rend. Vol. 124, Page 1032.
2. Abstracted in E. S. R. Vol. XII, p. 216.
3. Bulletin, College of Agriculture, Tokio Imperial University, Vol.
V, No. 2, p. 172.









tract was tested for oxidase, using the guiacum and aloin tests;
the following table will show the results:

TABLE VI.

Guiacum Aloin.
Yellow leaves Deep blue. Rose red.
Green leaves Pale blue. Faint red.

It is thus shown that the plants grown on the soil containing
high percentages of manganese, contain a mo e active oxidase
than plants from soil containing little manganese; and whether
the increased activity of the oxidase in the yellow plants brings
about their etiolated appearance, by the actual oxidation of the
chlorophyl, or for other reasons, cannot be positively stated at
this time. An examination under the high power microscope
of the cross-section of the yellow leaves, shows, however, that
for the most part the chlorophyl bodies have been entirely de-
stroyed. Further investigation it is hoped will throw more light
on this subject.

SUMMARY AND CONCLUSIONS.

I. Some of the pineapple soils of Hawaii contain black spots
on which pineapples do not grow successfully.
2. The application of fertilizers and lime in conjunction with
good tillage and drainage, has not resulted in effectually overcom-
ing the yellow appearance of the pines on black soil.
3. The black soils contain less acidity than the red soils.
4. There is but one important difference in the chemical
composition of these soils, viz., in regard to the 'manganese
content. The black soils contains many times as much man-
ganese as the red soil.
5. The black color of these areas may in part be attributed
to the presence of higher oxides of manganese.
6 There is a close correlation between the degree of yellow-
ing of the pines and the percentage of manganese in the soil.







14

7. Yellow pines from soils containing a high percentage of
manganese are more active oxidizing agents than green plants
from red soil.
8. The yellow pines have a poor root system and contain but
little chlorophyl.
9. As yet no positive remedy for this condition has been
worked out. It seems wise to try other crops on the black soil,
especially since sugar-cane grows well on the black soil.
This investigation is being continued along the lines suggest-
ed in the body of this bulletin. Acknowledgments are due Miss
Alice R. Thompson, Assistant chemist, for assistance in this
work. A large part of the analytical work was done by her,
and many valuable suggestions were offered from time to time.
Also to Doctor E. V. Wilcox for the microscopic examination
of these plants, and for many very valuable suggestions. Thanks
are also due the pineapple growers at Wahiawa for cooperation
in this work.







*,," UNIVERSITY OF FLORIDA





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