STEMS

LEAF ARRANGEMENT

• ALTERNATE

LEAF ARRANGEMENT

• OPPOSITE

LEAF ARRANGEMENT

• WHORLED

REGIONS

• NODE

• WHERE LEAF OR STEM ATTACHES

• INTERNODE

• SPACE BETWEEN NODES

• AXIL

• WHERE LEAF PETIOLE AND STEM MEET

• PETIOLE IS A LEAF STEM

BUDS

• BUD

• DEVELOPMENT OF LEAF OR BRANCH

• BUD SCALES

• PROTECT LIVE TISSUE

• SOME BUD’S ARE NAKED

BUDS

• BUD SCALES

• PROTECT LIVE TISSUE

• APICAL MERISTEM

• LEAF PRIMORDIA

• SOME BUD’S ARE NAKED

BUDS

• LEAF SCARS

• DECIDUOUS SCAR LEFT AFTER LEAF DROP

BUDS

• TERMINAL BUD

• END OF BRANCH

• APICAL MERISTEM

• BRANCH GROWS LONGER

• GROWING POINT, OR MERISTEM

• HOW DOES A TREE GROW?

FIG. 6.1

BUDS

• AXILLARY BUD

• BRANCHES, FLOWERS OR LEAVES

BUDS

• LEAF PRIMORDIA

• TIP OF EACH BRANCH

• APICAL MERISTEM

• PROTECTED BY BUD SCALES

• TINY EMBRYONIC LEAVES

• DEVELOP INTO MATURE LEAVES

DEVELOPMENT OF STEM

3 PRIMARY MERISTEMS DEVELOP FROM BUD

• PROTODERM

• ALSO KNOWN AS THE EPIDERMIS

• ONE CELL THICK

• COATED WITH WAXY LAYER

• CUTICLE

DEVELOPMENT OF STEM

3 PRIMARY MERISTEMS DEVELOP FROM BUD

• PROCAMBIUM

• PRODUCES PRIMARY XYLEM AND PRIMARY PHLOEM

• FORM VASCULAR BUNDLES

DEVELOPMENT OF STEM

3 PRIMARY MERISTEMS DEVELOP FROM BUD

• GROUND MERISTEM

• FOOD STORAGE

DEVELOPMENT OF STEM

3 PRIMARY MERISTEMS DEVELOP FROM BUD

• GROUND MERISTEM

• PRODUCES 2 TYPES OF TISSUE

• CORTEX

• OUTER PORTION OF STEM

DEVELOPMENT OF STEM

3 PRIMARY MERISTEMS DEVELOP FROM BUD

• GROUND MERISTEM

• PRODUCES 2 TYPES OF TISSUE

• PITH

• CENTER OF STEM

• LARGER CELLS THAT CAN BREAK DOWN

• CAN BECOME HOLLOW

STELE

• THE CORE OF THE STEM

• PRIMARY XYLEM

• PRIMARY PHLOEM

• PITH

PRIMARY VERSUS SECONDARY

• ANNUAL PLANTS ONLY PRODUCE PRIMARY CAMBIUM

• PERENNIAL PLANTS PRODUCE SECONDARY CAMBIUM

• WOODY PLANTS

DICOTS

• DICOTYLEDONOUS

• DICOT

• TWO LEAVES EMERGE FROM SEED

• COTYLEDONS

• NOT TRUE LEAVES

DICOTS

• HERBACEOUS DICOTS

• ANNUAL DICOTS

• SOFT TISSUE

• GERMINATE AND DIE IN ONE SEASON

• WOODY DICOTS

• PERENNIAL DICOTS

• HARD (WOODY) TISSUE

• LIVE MULTIPLE SEASONS

DICOTS

• HERBACEOUS DICOTS

• ONLY CONTAIN VASCULAR BUNDLES

• PRIMARY XYLEM

• PRIMARY PHLOEM

• WOODY PERENNIAL DICOTS

• PROCAMBIUM GIVES RISE TO VASCULAR CAMBIUM

• SECONDARY XYLEM

• SECONDARY PHLOEM

VASCULAR CAMBIUM

VASCULAR CAMBIUM

• SECONDARY XYLEM CELLS PRODUCED INSIDE CAMBIUM

• TOWARD CENTER OF STEM

• TRANSPORTS WATER AND NUTRIENTS UP THE PLANT

SECONDARY XYLEM

SECONDARY XYLEM

• SECONDARY XYLEM EVENTUALLY BECOMES WOOD

• AS CELLS BECOME INACTIVE, THEY BECOME STRUCTURAL

SPRING WOOD

• ACTIVE GROWTH PRODUCES LARGE XYLEM CELLS

• LIGHTER COLORED BAND

SUMMER WOOD

• SMALLER AND FEWER XYLEM CELLS

• DARKER BAND

GROWTH RINGS

• THE ALTERNATION OF SPRING AND SUMMER GROWTH BANDS

• FIRE, DROUGHT, AND OTHER EVENTS

• INCREMENT BORER TO READ RINGS

VASCULAR RAYS

• PARENCHYMA CELLS

• RADIATE FROM THE PITH

• LATERAL TRANSPORT OF WATER AND NUTRIENTS

HEARTWOOD VERSUS SAPWOOD• HEARTWOOD

• INACTIVE XYLEM CELLS

• ACCUMULATION OF RESINS, GUMS, AND TANNINS

• DARKER COLOR OF WOOD

• SAPWOOD

• ACTIVE XYLEM (NEAR CAMBIUM)

• LIGHTER COLOR WOOD

HEARTWOOD VERSUS SAPWOOD

• HEARTWOOD CAN ROT BUT TREE CAN STILL FUNCTION

• PORTION OF HEARTWOOD AND SAPWOOD CAN BE REMOVED

SECONDARY PHLOEM

• SECONDARY PHLOEM CELLS PRODUCED OUTSIDE OF CAMBIUM

• UNDER BARK

• TRANSPORTS FOOD FROM PHOTOSYNTHESIS UP AND DOWN TO THE PLANT

GIRDLING PHLOEM

• PHLOEM NEAREST CAMBIUM TRANSPORT THE MOST SUGARS

• CAMBIUM STRIPPED FROM GRAPEVINES TO TRAP SUGARS

CORK CAMBIUM

• OUTER BARK OF WOODY PLANTS

• DEVELOPED FROM EPIDERMIS

• CORK CELLS

• ALSO CALLED PHELLOGEN

• IMPREGNATED WITH SUBERIN

• WAXY SUBSTANCE

CORK CAMBIUM

• LENTICELS ARE OPENINGS ALONG STEM

• GAS EXCHANGE

LATICIFERS• SPECIALIZED CELLS MOST COMMON IN PHLOEM

• 20 FAMILIES OF TREES

• TRANSPORT LATEX

• THICK FLUID

• MOST COMMONLY WHITE

• THOUGHT TO HELP SEAL WOUNDS

• RUBBER, CHEWING GUM, AND HEROIN (POPPIES)

MONOCOTS

• HERBACEOUS, GRASSY PLANTS

• ALWAYS NON-WOODY

• ONE COTYLEDON AT GERMINATION

MONOCOTS

• VASCULAR BUNDLES THROUGHOUT STEM

• XYLEM FACING CENTER

• PHLOEM FACING OUT

MONOCOTS

• NO TREE RINGS

• PALM TREES

• DO NOT SEAL WOUNDS

SPECIALIZED STEMS

• RHIZOMES

• HORIZONTAL GROWTH BELOW GROUND

SPECIALIZED STEMS

• RUNNERS AND STOLONS

• HORTIZONTAL GROWTH ABOVE GROUND

SPECIALIZED STEMS

• TUBERS

• SEVERAL INTERNODES AT THE TIPS OF STOLONS SWELL

• “EYES” DEVELOP A NEW PLANT

SPECIALIZED STEMS

• BULBS

• LARGE BUDS SURROUNDED BY FLESHY LEAVES

SPECIALIZED STEMS

• CORMS

• SIMILAR TO BULBS BUT COMPOSED ENTIRELY OF STEM TISSUE

SPECIALIZED STEMS

• THORNS

• MODIFIED STEM

• HONEYLOCUST

SPECIALIZED STEMS

• SPINES

• MODIFIED STIPULES

• BLACK LOCUST

SPECIALIZED STEMS

• TENDRILS

• VINE EXTENSIONS THAT WRAP OR STICK TO OBJECTS