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LEAVES. The primary PHOTOSYNTHETIC ORGAN I will be able to label the parts of a leaf by completing a leaf lab. FUNCTIONS of LEAVES. PHOTOSYNTHESIS Conversion of LIGHT ENERGY into SUGARS CARBON DIOXIDE (CO 2 ) and WATER (H 2 O ) needed RESPIRATION (leaves, stems and roots)
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LEAVES The primary PHOTOSYNTHETIC ORGAN I will be able to label the parts of a leaf by completing a leaf lab.
FUNCTIONS of LEAVES • PHOTOSYNTHESIS • Conversion of LIGHT ENERGY into SUGARS • CARBON DIOXIDE (CO2) and WATER (H2O) needed • RESPIRATION (leaves, stems and roots) • Breakdown of SUGAR into ENERGY • ENERGY is needed for GROWTH and to MANUFACTURE other compounds • OXYGEN (O2) needed
FUNCTIONS of LEAVES • TRANSPIRATION • DIFFUSION of WATER VAPOR out of leaves through STOMATA • GAS EXCHANGE • TRANSPIRATIONAL PULL • COOLING
BLADE • Thin, flattened portion
Midrib • Large vein running down the center
Veins • The framework of the leaf
PETIOLE • STALK that attaches leaf to stem • ROTATES blade for maximum sunlight • Greater FLEXIBILITY in wind and rain
SESSILE- NO PETIOLE • When BLADES attached DIRECTLY to stem
STIPULE • Leaf-like or scale-like APPENDAGE at base of PETIOLE
AXIL • ANGLE between leaf and stem • AXILLARY bud located here
NODE • Area on stem where leaf arises
Assignment • You will go outside and find 3 different types of leaves. • Tape your leaves to a sheet of notebook paper • Label the following parts on your leaf: • Blade • Petiole or Sessile • Midrib • Veins • When done turn in on front table in the wire basket
CLASSIFICATION and ANATOMY of LEAVES I will be able to classify different leaves and identify if they have any modifications by completing a chart.
SIMPLE One blade per petiole COMPOUND Many leaflets per petiole DECIDUOUS LEAVES
TYPES of COMPOUND LEAVES • PINNATELY COMPOUND • Leaflets arranged on stem like a FEATHER • PALMATELY COMPOUND • Leaflets arranged on stem to RADIATE like the PALM of HAND
VENATION of LEAVES • Pattern of VEINS in a leaf • PARALLEL - monocots • NETTED - dicots • PINNATE- feather • PALMATE- palm
LEAF ARRANGEMENT • MUST have STEM to determine leaf ARRANGEMENT • ALTERNATE – one leaf per node • OPPOSITE – two leaves per node • WHORLED – three or more leaves per node, each leaf is the SAME SIZE
EVERGREEN LEAVES • BROADLEAF • Tree or plant with WIDE FLAT leaves • NEEDLED • Tree or plant with THIN POINTED leaves • SCALED • Small and tightly pressed to the stem
EPIDERMIS One cell layer thick, top and bottom of leaf NO CHLOROPLASTS present Cuticle- waxy layer for protection Stomata- gas exchange and transpiration Guard Cells- surrounds stoma and contains chloroplast ANATOMY of LEAVES
LEAF MODIFICATIONS • SUPPORT • Thick Petioles • Rhubarb and celery • Captured Gas • Aquatic plants
LEAF MODIFICATIONS • WATER STORAGE • Succulents • FOOD STORAGE • Scales on Bulbs • Cabbage and Brussel sprouts
LEAF MODIFICATIONS • CLIMBING • Tendrils (right) on peas • Leaf petioles (below) on Clematis
LEAF MODIFICATIONS • PROTECTION • Spines (right) • Cacti • Bracts (below) • Poinsettia
INGESTION Carnivorous plants Venus Fly Trap (above) Sundew (left) LEAF MODIFICATIONS
Assignment • Leaf sort worksheet