of Medium Temperature and Magnesium Application Rate on Growth of
Philodendron scandens oxycardium r
;r.1sto n Sr-ien;'
Ik. i. ruuicl
P 3 0 1994
University of Florida, IFAS
Central Florida Research and Education Center ApopMversity of Florid,
CFREC Apopka Research Report, RH-91-18
Magnesium, one of the macroelements utilized by plants during photosynthesis, is
most frequently supplied by incorporation of dolomite or magnesium sulfate into potting
mixtures during the manufacturing process. Philodendron scandens oxycardium (Heart-leaf
philodendron) sometimes develops magnesium deficiency symptoms, also called bronzing
disease, during production. Plant growth slows and stems are unusually thin with short
interodes. The leaves of affected plants are smaller than normal, with yellowish green
markings appearing on older leaves first, in the inverted "v" shape which are typical
magnesium deficiency symptoms for many foliage plants. These symptoms seem to appear
more frequently in the winter months when medium temperatures are lower. As medium
temperature affects the plant's ability to extract essential nutrients, most foliage plants grow
best when medium temperatures are between 70 and 80F. The following research was
conducted to examine the effects of medium temperature and magnesium application rate on
growth of heart-leaf philodendron plants and growth of cuttings harvested from treated
Materials and Methods
Experiment 1, a 3 x 4 factorial experiment with 8 replications, was initiated on 22
February 1991 when heart-leaf philodendron plugs obtained from a local grower were
transplanted into 6 inch plastic pots containing Florida sedge peat amended with 3.5 lbs/yd3
CaNO,. Maximum medium temperature was maintained at 60 65 70 and 750F bv nlacing
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ix A (Verlite Co., Tampa, FL 33680). Cuttings were placed under intermittent mist, on a
)pagation bench, in a greenhouse where air temperatures ranged from 60 to 90F and
iximum light intensity was 2200 ft-c. On 15 July, cuttings were moved to a bench in a
henhousee where temperatures ranged from 60 to 90F and maximum light intensity was
D00 ft-c. Fertilizer was surface applied to medium on 16 July, when each pot received 2.5
i inch pot 19-6-12 Osmocote. Total vine length (cm) and number of nodes per plant were
:ermined on 17 September 1991, the day the experiment was terminated.
Results and Discussion
Vine length of stock plants was significantly affected by medium temperature, with
gth increasing as medium temperature increased (Table 1). The magnesium application
es tested did not affect plant growth. Plants subjected to the highest medium temperature
ted, 75F, produced longer vines regardless of magnesium rates. All plants were watered
th central Florida ground water containing approximately 15 ppm Mg. Theoretically, these
; levels could have been enough to prevent magnesium deficiency symptoms from
reloping on the plants which did not receive Mg(SO4).
The electrical conductivity of leachate from the medium generally tended to decrease
medium temperatures rose and increase as magnesium application rates increased (Table
The pH (not shown) of media from all treatments was about 4.4 at the start of research,
: had increased to around 5.4 by the time the experiment was terminated on 25 May 1991.
Growth of cuttings was not affected by medium temperature or magnesium levels
ck plants received. Total vine length averaged 204 cm and number of nodes averaged 43
the four longest vines of cuttings grown from plants receiving the 3 magnesium levels and
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,te from pots containing heart-leaf philodendron were determined initially and
als until 25 May.
x t /'1%l l+nn tf rav a xx+iyiv 4,a 4-ha lh,- -f _l , I ;ln,..an4-A ,-.1, 1.j-1n*
2. Conover, C.A. and R.T. Poole. 1974. Influence of shade and fertilizer source and
level on growth, quality and foliar content of Philodendron oxycardiwn Schott. J.
Amer. Soc. Hort. Sci. 99(2):150-152.
3. Conover, C.A. and R.T. Poole. 1981. Guide for fertilizing tropical foliage plant
crops. Univ. of Fla., IFAS, CFREC-Apopka Res. Rpt. RH-81-1.
4. Conover, C.A. and R.T. Poole. 1987. Growth of Dieffenbachia maculata
'Perfection' as affected by air and soil temperatures and fertilization. HortScience
5. Dicky, R.D. and J.N. Joiner. 1966. Identifying elemental deficiencies in foliage
plants. Fla. Foliage Grower 3(5):1-2.
6. Ingram, D.L., C. Ramcharan and T.A. Nell. 1986. Response of container-grown
banana, ixora, citrus and dracaena to elevated root temperatures. HortScience
7. Joiner, J.N., C.A. Conover and R.T. Poole. 1981. Nutrition and fertilization.
p.229-268. In: J.N. Joiner (ed.). Foliage Plant Production. Prentice-Hall,
Englewood Cliffs, NJ.
8. Koller, D.C., L.K. Hiller and R.W. Van Denburgh. 1980. A forced-air system for
controlling soil temperatures in plastic pots. HortScience 152):189-190.
9. Poole, R.T. and C.A. Conover. 1976. Chemical composition of good quality
tropical foliage plants. Proc. Fla, State Hort. Soc. 89:307-308.
nts receiving Mg(SO4) applied at rates of 0, 0.05 and 1.0 g/6" pot and soil
nperatures of 60, 65 70 and 750P, grown from 22 February until 23 May
(F) 22 Feb 23 May
60 5.3 49.0
65 4.6 48.2
70 5.0 51.8
75 5.6 56.5
linear ns **
quadratic ns ns
g Mg(SO4)/6" pot
0.0 5.1 51.3
0.5 5.1 51.6
1.0 5.2 51.2
linear ns ns
quadratic ns ns
**; Results nonsignificant or significant at P = 0.01, respectively.
table 2. Electrical conductivity (jtmhos/cm) of medium leachate from 6" pots
containing Philodendron scandens oxycardium treated with 0, 0.5 and 1.0 g/
pot Mg(SO4) and soil temperatures of 60, 65, 70 and 75F, grown from 22
February until 23 May 1991.
Medium temp. (F) 26 Feb 11 Mar 23 May
60 2567 3008 2467
65 2568 3058 2717
70 2495 2677 2698
75 2653 2682 2120