Transcript FoliarIndicators

Foliar Indicators of Age
in Louisiana Native
Dwarf Palmetto Plants
Jim Wandersee, Ph.D.
William LeBlanc Alumni Association Professor of Biology Education
LSU Department of Curriculum & Instruction &
LSU AgCtr Burden Research Center
Introduction
 Dwarf Palmetto (Sabal minor) is a native
Louisiana plant
 Understory palm found in the Southeast
in swamp forests and on floodplains
 Slow growing to hundreds of years of age
 First described in 1691 by Le Clercq in
an account of La Salle’s explorations of
the Mississippi River
Dwarf Palmetto
 Botanical
Classification
 Family: Palmae
 Genus: Sabal
 Specific epithet:
minor
The Palm Family
(Palmae)
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Found in sub-tropics and tropics
Third-largest monocot family
Contains >2,700 species in >200 genera
Greatest diversity in SE Asia &
Malaysia, Central America, African
Congo region, and N. Madagascar (Uhl &
Dransfield, 1987)
Range: Distribution of
Sabal minor
 Coastal plains of the
South Atlantic Seaboard
and the states bordering
the Gulf of Mexico
 Louisiana is the ONLY
state to be completely
included in its range
 States partially within its
range are NC, SC, GA,
FL, AL, MS, & TX
S. Minor Inflorescence
Structure & Fruit
Flowering season:
mid-June to July
Variablity in Stature
 Sabal minor data recorded in the botanical
literature suggest:
 Height MINIMA: ~40 centimeters (mature)
 Height MAXIMA: ~5.8 meters (mature)
 As a rule of thumb, height increases from east
to west (e.g., Panhandle of Florida to West
Texas).
 Caulescent populations have not been
observed in the eastern half of its range
(Ramp, 1989).
Research Program Goals
 To improve both
scientific
understanding and
public understanding
of one of Louisiana’s
most widespread and
“signature” native
plant species, Sabal
minor.
Research Target: Phase I
 To find the simplest way of estimating
the age of individual Sabal minor
plants—by investigating the predictive
value of selected foliar variables that
are supported by a review of relevant
research literature in plant ecology and
in horticulture.
Research Plots
 Phase I: Full Sun Specimens
 Will yield a conservative age estimate
 Plot #1: 3-acre Barton arboretum area of BRC
 ~40 individuals of varying pre-reproductive age
 Phase II: Forest Understory Specimens
 In full range of stages [#1-#12] of development
 3 native population plots within BRC’s 100-acre
forest
Methods
 Foliar Variables under study:
Leaf surface area for largest leaf
Maximum leaf thickness for largest leaf
Leaf oven dry mass (estimated by
regression equation via petiole bladebasal width for largest leaf)
Total number of leaves per plant
Total number of leaf scars per
plant, plus (see next slide)
Methods continued
 Foliar Variables under study:
Munsell Plant Tissue Color Chart ratings
for the largest and smallest leaves
Leaf nutrient analysis of 21 elements via
ICP spectroscopy for largest and
smallest leaves
These variables will be correlated to
historically established, age-benchmark
specimens, and to pre- and postreproductive features described by Ramp
(1989).
Researcher Memberships
 American Association for the
Advancement of Science
 Botanical Society of America
 Crosby Arboretum
 LSU 15º Laboratory
 National Association of Biology
Teachers
 National Tropical Botanic
Garden
 International Palm Society
 Royal Horticultural Society