Download Vascular Plants.pptx

Mary Lou Wood
BIOL490 – Senior Seminar
Dr. P. Smith
Spring 2010
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What Are Vascular Plants?
◦ Characteristics
◦ Plant Nutrition
 Macronutrients and Micronutrients
 The Nitrogen Cycle
◦ Structure and Function
 Roots
 Stems
 Leaves
 Movement of Water and Minerals in Xylem
 Movement of Food Through the Phloem
Divisions
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Macronutrients –
mineral elements
(inorganic elements)
that are required in
relatively large
amounts.
Micronutrients –
minerals found in
relatively smaller
amounts
N2
N2
N2
NH4+
NO2NO3-
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Mycorrhizae – mutualistic associations of fungi and plant roots in the soil
that facilitate in the uptake of nutrients by the roots.
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Increase biomass due to better use of nutrients and
water
Improved resistance to stress conditions (biotic and
abiotic)
Protective effect against contaminants - heavy metals
and other pollutants - by blocking them before absorbed
by the plant
Protective effect against root diseases (soil pathogens)
and nematodes
The principal functions of
roots are to:
◦Anchor the plant in the soil
◦Absorb nutrients and
moisture
◦Can serve as food storage
organs
◦Provide a means of
propagation
Course textured
sandy soils with
large pores can
hold the least
amounts of
available plant
water.
Fine textured soils
with small pores
can hold the
greatest amounts
of available plant
water.
Adventitious roots
Taproots
Passage cells
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The principal function of
stems are to:
◦Form the framework that
supports leaves, buds,
flowers and fruit
◦Be a major part of the
plant's transport system
◦Serve as food storage
organs (asparagus)
◦Provide a means of
propagation
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Annuals
◦Completes entire
life cycle in a single
growing season
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Biennials
◦Takes 2 years to
complete life cycle
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Perennials
◦Lives for more than
2 years
Lenticels on bark
a. dicot stem
b. monocot stem
stolon
tubers
bulb
tendrils
stem
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leaves
corm
Cladode – a flattened stem resembling and functioning as a leaf.
Leaves are reduced to spines to prevent water loss in transpiration.
The stem is enlarged for the storage of water.
The stem carries out photosynthesis.
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Thin, flattened
structures that
amplify the
photosynthetic
capacity of plant
Come in variety of
shape/size
Parallel venation
Netted venation
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Vascular tissues
◦Vascular tissues make up the water/food conducting
system of a plant. They consist of the xylem and phloem.
 Xylem
 The xylem tubes are the water/mineral conducting channels and
are made up of cells that are shaped into columns that can
effectively move water through even the largest tree.
 Phloem
 Phloem tubes move food produced by photosynthesis to other
parts of the plant.
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Water moves into the root by
osmosis, and then into xylem
Water forms a cohesive
column in root/stem xylem
Tension pulls the water
column up and out in the
xylem of veins in the leaves
Water evaporates from
mesophyll cells
Water vapor diffuses out of
stomates
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Psilophyta
◦No differentiation of cells into
true roots and leaves and has
simple kind of conducting
system
◦Whisk ferns
Lycophyta
◦Club mosses, with cells
differentiated into roots,
stems, and leaves
Sphenophyta
◦horsetails
Ferns, 12,000+
species
Flattened leaves –
broad expanse of
photosynthetic
surface
Extensively branched
Produce seeds
Posses a cambium layer, meristematic
Make up the bulk of the botanical world today
Gymnosperm – naked seed
Angiosperm – enclosed seed
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Fried, George and Hademos, George. Schaum’s Outline
of Biology. New York: McGraw Hill, 2009.
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