Group Title: ARC-A research report - Agricultural Research Center-Apopka ; RH-81-16
Title: Effects of production shade level on postharvest decline of leatherleaf fern
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Permanent Link: http://ufdc.ufl.edu/UF00065976/00001
 Material Information
Title: Effects of production shade level on postharvest decline of leatherleaf fern
Series Title: ARC-Apopka research report
Physical Description: 4 leaves : ; 28 cm.
Language: English
Creator: Stamps, R. H ( Robert Huguenor ), 1948-
Agricultural Research Center (Apopka, Fla.)
Publisher: University of Florida, IFAS, Agricultural Research Center
Place of Publication: Apopka FL
Publication Date: 1981
 Subjects
Subject: Leatherleaf fern -- Effect of light on -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references (leaf 4).
Statement of Responsibility: R.H. Stamps.
General Note: Caption title.
 Record Information
Bibliographic ID: UF00065976
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 71061483

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Q V1L-


6 EFFECTS OF PRODUCTION SHADE LEVEL ON POSTHARLVEST
DECLINE OF LEATHERLEAF FERN f

R. H. Stamps L,, ,
IFAS, University of Florida
Agricultural Research Center-Apopka I
ARC-Apopka Research Report RH-81-16 S. v, of Foric

Postharvest decline continues to be a problem for producers and
users of leatherleaf fern (Rumohra adiantiformis [G. Forst] Ching).
Postharvest decline, as described herein, is comprised of two
phenomena, wilting and yellowing. Wilting of fern is characterized by
partial or complete folding of green pinna (leaflets) along the midvein
and/or loss of overall rigidity of the frond. Yellowing of fronds
begins along the midveins of pinna and spreads towards the margins.
Postharvest losses due to disease, insects, and mishandling are not
included in this discussion.

In 1976, 50% of the 32 fern growers who returned surveys reported
wilt problems and about one third of those reporting wilt estimated its
severity at 5 to 25% (4). Tests conducted in 1978 during the high wilt
months of July, August, September, and October indicated that by six
days postharvest 30% of the fern from commercial ferneries had wilted
under simulated household conditions and 67% of the fern wilted after 12
days (1). Fern wilt, therefore, is a problem of consequence. No mention
is made in either report (1,4) of frond yellowing but this phenomenon is
also a problem (Stamps, unpublished).
Research has shown increased frond size and number of fronds
produced under 60% as compared to 80% shade (3,5) but no attempt was made
to determine the effects of the two shade levels on postharvest decline of
leatherleaf fern. This study was designed to compare the postharvest
decline of leatherleaf fern produced under 63% and 73% shade'black
polypropylene fabric, since these two coverings are the main ones used
commercially (2).









Materials and Methods


Biweekly samples of 20 leatherleaf fern fronds were taken from
each of two sections of two commercial ferneries beginning March 1979.
Samples were taken for two years. One fernery was located in the
DeLeon Springs, Florida area on Astatula fine sand. The other fernery
was located in the Pierson, Florida area on Deland fine sand. Each
fernery had areas covered with 63% and 73% shade polypropylene fabric.
Other cultural factors were the same in both areas of each fernery.

After cutting, samples were transported by car to the Agricultural
Research Center, Apopka, Florida. Upon arrival 1.5-2,0 hours
postharvest, the ends of the fern stipes (stalks) were recut and placed
in 2000 ml beakers of deionized water, 20 fronds per beaker. The fern
were held under simulated household conditions. Cool white fluorescent
lamps supplied a light intensity of 2 watts per square meter (65 foot-
candles) 12 hours per day. Temperatures were maintained between
20-260C (65-780F) and relative humidity was 50 + 25%. Fern wilt and
yellowing were recorded every third day for 12 days. Wilcoxon's paired
sample signed rank test was employed to compare means.

Results and Discussion

Comparison of the relative severity of wilting and yellowing of
fern grown under the two shade levels in the DeLeon Springs fernery
indicate that shade level had no effect (Table 1). Wilting was the
predominant postharvest decline factor during the two year study period,
accounting for 99, 94, 79, and 72 percent of the postharvest decline 3,
6, 9, and 12 days postharvest, respectively.

Significant differences in the severity of wilting and yellowing of
fern grown under the two shade levels in the Pierson fernery did occur
(Table 2). Wilting was less severe with fern grown under the higher
shade level but yellowing was more severe. Wilting was again the greater
of the two postharvest decline factors, accounting for 92, 86, 66, and 56
percent of postharvest decline 3, 6, 9, and 12 days postharvest,
respectively. Wilting and yellowing were complementary so that total
postharvest decline except at 6 days, was no different under the two
shade levels.







Table 1. Comparison of postharvest decline of leatherleaf fern grown
under 63% and 73% polypropylene shade fabric in DeLeon Springs, FL.Z

(%) Days (%)
Shade level postharvest Wilt Yellow Combined
63 3 5.4 0.1 5.5
73 3 3.7NSD 0NSD 3.7NSD

63 6 14.8 0.6 15.4
73 6 13.2NSD 1.3NSD 14.5NSD

63 9 19.6 5.9 25.4
73 9 21.4NSD 4.9NSD 26.3NSD
63 12 23.0 10.5 33.5
73 12 24.4NSD 8.3NSD 32.7NSD

ZMeans compared using Wilcoxon's paired sample signed rank test. NSD
indicated pairedmeans not significantly different.



Table 2. Comparison of postharvest decline of leatherleaf fern grown
under 63% and 73% polypropylene shade fabric in Pierson, FL.z

(%) Days (%)
Shade level postharvest Wilt Yellow Combined

63 3 1.4y 0.0y 1.4
73 3 0.9 0.2 1.1NSD

63 6 5.6 0.5y 6.2
73 6 2.9.05 0.9 3.7.05

63 9 11.5 3.5 15.0
73 9 6.2.01 5.9'05 12.0NSD
63 12 15.5 7.3 22.7
73 12 9.1.02 12.102 21.3NSD
ZMeans compared using Wilcoxon's paired sample signed rank test. NSD
indicates paired means not significantly different. .05, .02', .01
indicate paired means significantly different at indicated probability
level.
YThere were not sufficient numbers of differences between pairs to allow
statistical analysis.









Comparison of the postharvest decline in the two ferneries shows
little difference in the incidence of yellowing but wilt was more severe
in the DeLeon Springs fernery than the Pierson fernery.

These data indicate there is no difference in total postharvest
decline of leatherleaf fern grown under 63% and 73% shade black
polypropylene fabric. Both wilting and yellowing occurred predominantly
during the warmer months, June through October, and therefore may be due
in part to high temperature stress. The more severe wilting of fern grown
under the higher light level (63% shade) at the Pierson fernery may be due
to higher leaf temperatures caused by greater radiant energy input.

Literature Cited

1. Conover, C. A., R. T. Poole and L. L. Loadholtz. 1979. Update on
leatherleaf fern wilt. IFAS, Univ. of Fla., Agric. Res. Ctr., Apopka
Res. Rept. RH-79-1.
2. Henley, R. W., B. Tjia, and L. L. Loadholtz. 1980. Commercial
Leatherleaf Fern Production in Florida. IFAS, Univ. of Fla. Ornamental
Horticulture Report. Coop. Ext. Serv. Bull. 191. p. 13.
3. Poole, R. T. and C. A. Conover. 1973. Influence of shade, nitrogen,
and potassium levels on production and elemental composition of
leatherleaf fern. Proc. Trop. Reg. Amer. Soc. Hort. Sci. 17:385-388.
4. Poole, R. T., C. A. Conover, and L. L. Loadholtz. 1976. Results of
survey on leatherleaf fern. IFAS, Univ. of Fla., Agric. Res. Ctr.,
Apopka Res. Rept. RH-76-5.
5. Poole, R. T., D. B. McConnell, and W. E. Waters. 1971. Production of
leatherleaf fern as influenced by several cultural practices. Proc.
Trop. Reg. Amer. Soc. Hort. Sci. 15:223-228.




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