Plant Anatomy AP Biology 2006 2007 Plant TISSUES
Plant Anatomy AP Biology 2006 -2007
Plant TISSUES § Dermal u u epidermis (“skin” of plant) single layer of tightly packed cells that covers & protects plant § Ground u u bulk of plant tissue photosynthetic mesophyll, storage § Vascular u u AP Biology transport system in shoots & roots xylem & phloem
vessel elements § Xylem u vessel element u Vascular tissue move water & minerals up from roots dead cells at functional maturity § only cell walls remain § need empty pipes to efficiently move H 2 O § transpirational pull dead cells Aaaah… Structure–Function again! tracheids AP Biology
Phloem: food-conducting cells § carry sugars & nutrients throughout plant sieve tube companion cell sieve plate plasmodesmata AP Biology living cells
Phloem: food-conducting cells § sieve tube elements & companion cells AP Biology
Phloem Aaaah… Structure–Function again! § Living cells at functional maturity u cell membrane, cytoplasm § control of diffusion u lose their nucleus, ribosomes & vacuole § more room for specialized transport of liquid food (sucrose) § Cells u sieve tubes § sieve plates — end walls — have pores to facilitate flow of fluid between cells u AP Biology companion cells § nucleated cells connected to the sieve-tube § help sieve tubes
Phloem sieve tubes AP Biology sieve plate
Vascular tissue in stems dicot trees & shrubs AP Biology collect annual rings monocot grasses & lilies
Vascular tissue in roots: dicot phloem AP Biology xylem
Vascular tissue in roots: monocot xylem phloem AP Biology
Putting it all together § Obtaining raw materials u sunlight § leaves = solar collectors u CO 2 § stomates = gas exchange u H 2 O § uptake from roots u nutrients § uptake from roots AP Biology
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