PLANTS AND PEOPLE - Botany 328 - LECTURE NOTES
Hugh D. Wilson

REVIEW PHOTOSYNTHESIS: WATER + LIGHT --- CHLOROPLAST PRODUCES O2 + ENERGY [LIGHT REACTION], THEN ADD CO2 WHICH IS FIXED - USING ENERGY OBTAINED IN THE LIGHT REACTION - IN THE CALVIN CYCLE = TO PRODUCE A WIDE ARRAY OF CARBON COMPOUNDS  - Maasai, gourds (Lagenaria siceraria - Cucurbitaceae) - Ethnobotany of the Loita Maasai (detail/PDF file)



Classification overview:  FLOWERING PLANTS:  ALL PLANTS CLASSIFIED INTO 15-20 MAJOR UNITS OR DIVISIONS [=PHYLA].  CAN ALSO BE BROKEN DOWN INTO:

NON-VASCULAR [ALGAE, MOSSES]

VASCULAR:  NON-SEED [FERNS AND ALLIED] AND SEED [GYMNOSPERMS AND ANGIOSPERMS] -

DIVISIONAL NAME FOR THE FLOWERING PLANTS OR ANGIOSPERMS IS THE MAGNOLIOPHYTA [CA. 230,000 SPECIES DISTRIBUTED WORLDWIDE IN ESSENTIALLY EVERY HABITAT].  THIS GROUP IS CLASSIFIED INTO TWO CLASSES:  LILIOPSIDA [MONOCOTS] AND MAGNOLIOPSIDA [DICOTS].  BASIC WORKING UNITS WITHIN THE CLASSES ARE SUBCLASSES [GROUPS OF ORDERS] AND FAMILIES (ca. 440 with ca. 12,600 genera).



PLANTS VS. ANIMALS - or PLANTS AS ALIENS -  DETERMINATE VS. INDETERMINATE GROWTH AND DEVELOPMENT [CONTRAST 'US' WITH 'THEM'] -  [ANIMAL MODEL - CELLULAR [TISSUE] SPECIALIZATION - liver, brain, ect - juvenile, adolescent, sexual maturity, mid-life, old age, death

LARGEST ORGANISM ON EARTH - Sequoiadendron giganteum - Giant Redwood - GERMINATION - SHOOT VS. ROOT - TERMINAL MERISTEMS - CAPABILITY FOR CONTINUOUS GROWTH - SPECIFIC 'NODES' OF DEVELOPMENT AS IN ANIMALS NOT DEFINED IN THE GENETIC CODE of plants, I.E., CELLS CAN BE PRODUCED AS LONG AS THE HABITAT SUPPORTS PLANT LIFE.  THUS, THE LARGEST AND LONGEST-LIVING ORGANISMS [Used to be gymnosperm - bristle-cone pine - now looking at large woody perennial clones - Creosote bush, aspen] ARE PLANTS.  TWO PRIMARY MERISTEMS IN THE ANGIOSPERM EMBRYO:

1.  RADICLE - ROOT - SECONDARY - HAIRS - ABSORB, ANCHOR, SUPPORT [PROP , BUTTRESS, ADVENTITIOUS (MONOCOTS)], CONNECT [HAUSTORIA, VELLUM OR VELAMEN OF ORCHIDS] AND STORE [TAP OR TUBEROUS ROOT]

2.  HYPOCOTYL - SHOOT - TERMINAL VS. LATERIAL MERISTEM

NODES VS. INTERNODES - 'PLUMBING SYSTEM' OF XYLEM (Economic importance? - wood) AND PHLOEM  (Economic importance - Sugar Maple - phloem exudate [PITH - 'RING IN DICOTS WITH PITH [PARENCHYMA TISSUE] IN CENTER, SCATTERED IN MONOCOTS IN MATRIX OF PITH].  NODE - JUNCTION IN THE PLUMBING SYSTEM TO THE LEAF [PETIOLE, BLADE - SIMPLE VS. COMPOUND - USUALLY PHOTOSYNTHETIC [THE SITE OF ENERGY CONVERSION AND GAS FLOW - STOMATES], SOMETIMES ABSENT [CACTI - STEM IS THE SITE OF CONVERSION - WHY?], SOMETIMES STORAGE OF BOTH WATER AND PHOTOSYNTHATE].

SHOOT PROVIDES A PLATFORM FOR PHOTOSYNTHESIS AND A MATRIX FOR THE INTERNAL PLUMBING SYSTEM; SOMETIMES DISPERSAL [STOLON], SOMETIMES PHOTOSYNTHETIC [CACTI AND SUCCULENTS], OFTEN NOT ERECT [VINES - USING OTHER SHOOTS], SOMETIMES WITHOUT EVIDENT NODES [CONDENSATION - ACAULESCENT].

TRANSFER OF ENERGY - CONVERSION TO USABLE CELLULOSE

WOODY PERENNIALS - ESSENTIALLY CONTINUOUS PRODUCTION: [ca. 12,000 YR. OLD DESERT SHRUBS [CREOSOTE BUSH - Larrea divaricata] OF THE SOUTHWESTERN U.S., 4,000 YR. OLD BRISTLE-CONE PINE OF NEVADA MOUNTAINS] - VASCULAR CAMBIUM [COLUMN OF MERISTEMATIC TISSUE PRODUING ANNUAL RINGS OF XYLEM [WOOD-VESSEL ELEMENTS] AND PHLOEM [SIEVE TUBE ELEMENTS].  NOTE LIGNIN - ACCUMULATES IN CELL WALLS OF 'PROTECTIVE CELLS' [FIBERS - LONG, NARROW - AND SCLERIDS (SPHERICAL-SCLERENCHYMA TISSUE)

HERBACEOUS PERENNIALS:  SHOOT STOPS FUNCTION DURING COLD OR DRY SEASON, ACTIVE MERISTEM RETAINED UNDERGROUND AND FUELED BY PHOTOSYNTHATE IN EITHER STORAGE ROOT [TUBEROUS OR TAP - SWEET POTATO, DIAKON, PARSNIP] OR MODIFIED SHOOT:

RHIZOME - HORIZONTAL, UNDERGROUND, ELONGATE
TUBER - TUBEROUS OFF-SHOOT OF A RHIZOME, CONDENSED
CORM - VERTICAL, CONDENSED

BIENNIALS:  PHOTOSYNTHESIZE ONE YEAR, ACCUMULATE PHOTOSYNTHATE TO FULE PHOTOSYNTHATE FOR THE NEXT YEAR'S REPRODUCTIVE EFFORT: [HUMAN INTERVENTION]

CARROT, RADISH - TAP ROOT
ONION - BULB [CONDENSED SHOOT SURROUNDED BY LEAF BASES THAT HAVE ACCUMULATED PHOTOSYNTHATE

ANNUAL - SHUNT PHOTOSYNTHATE TO SEED AT END OF GROWING SEASON

HUMAN INTERVENTION USUALLY SEED, BUT ALSO VEGETATIVE TISSUE (BRUSSELS SPROUTS, BROCCOLI, ETC)


Return to Course syllabus
20 Jan 2011