Plant Structures and Plant Growth Flashcards
What do vascular plants for hydration and movement of products of photosynthesis?
hydration with water drawn from soil (xylem and roots)
bulk transport to move products of photosynthesis
What is the above ground and below ground anatomy of a vascular plant?
above ground: leaves, stems, and reproductive organs. collectively forming the shoot
below ground: roots
What is a leaf structure made up of?
blade, petiole (stalk), stipules
What are stipules?
scales or leaf-like appendages at the base of some leaves; protect the emerging leaf or bud
What are the 3 types of simple leaves?
undivided/entire, lobed, or toothed leaf blades
What are compound leaves?
blade divided into leaflets
each leaflet with own small ‘petiole’
What does it mean to be a palmately compound leaf?
leaflets attach at one point
What does it mean to be a pinnately compound leaf?
leaflets attach along a central axis = rachis
What is Phyllotaxy?
arrangement of leaves on stem
What are 3 types of phyllotaxy?
alternate arrangement
opposite arrangement
whorled arrangement
What is alternate arrangement of leaves?
one leaf per node, forming helical pattern around stem
what is opposite arrangement of leaves?
two leaves per node on opposite sides of stem
What is the function of leaves?
photosynthesis by chloroplasts - plants manufacture food (glucose) from carbon dioxide and water using energy from the sun
What are the 3 major tissues in a leaf?
the epidermis, mesophyll, and the veins
WHat is the epidermis?
sheets of cells that line the upper and lower surfaces
What is the mesophyll?
loosely packed or columnar photosynthetic cells
What is the veins?
system of vascular tubes or conduits that connects (transports water and glucose) the leaf to the rest of the plant
What do the upper and lower epidermal cells secrete on their surface?
a waxy cuticle
WHat does the waxy cuticle do?
limits water loss and CO2 diffusion into the cells
Where are stomata located? what is their function?
in the lower epidermis
allow CO2 and water to diffuse into and out of the leaf
What is the makeup of each stoma?
a pore on the lower surface of leaf formed by a pair of flanking guard cells
WHat do guard cells do?
allow stoma to function as valves that can open and close when they swell and shrink
what is the function of the lower spongy mesophyll?
when the air spaces surrounding are fiilled with CO2 they can use the CO2 for photosynthesis
What also occurs when stomata are open? (other than CO2 uptake)
transpiration - evaporative loss of water from leaves
What factors can contibute to opening anfd closing of stomata?
light, CO2 levels, and water loss
how do stomata cells open?
water moves into gurad cells by osmosis causing them to swell (dependent on K concentration in cells from active transport)
occuring when water is readily available and CO2 levels relatively low
how do stomata cells close?
potassium is actively transported out the cells, which causes water to move out by osmosis
causing guard cells to shrink closing off pores
occurs when water is limited and CO2 levels relatively high
What is the bundle sheath?
the photosynthetic cells arranged into a tightly packed sheath around the vascular tissue of a leaf; the sheath forms a protective layer around the vascular tissue
How do leaves begin to form?
as small bumps (leaf primordia), which from on the sides of the shoot apical meristem
what are the 4 types of tissue in plants?
meristematic tissue, dermal tissue, ground tissue, vascular tissue
What is meristematic tissue?
tissue regions or populations of cells which retain ability to divide throughout entire life of plant
What is the apical meristem?
are of primary growth - shoots and roots; increase plant length or height
what is the lateral meristem?
cambium - area of secondary growth : wood, bark; increases plant diameter
What is the shoot apical meristem?
tiny dome of cells at the very tip of each branch, totipotent cells that give rise to new tissues.
as new cells are added near the shoot tip, older cells stop to divide.
What does it mean to be a totipotent cell?
a cell capable of giving rise to any cell type
What did stem branching allow early plants to do?
to produce more sporangia (reproductive structures)
What did stem branching allow present-day plants to do?
support greater numbers of both reproductive structures (flowers and leaves)
In seed plants where do branches (stems) grow out from?
axillary buds
What are axillary buds?
meristems that from at the base of each leaf
What are the two layers of Dermal tissue?
Epidermis and Cuticle (functions earlier)