Plant Organs Leaves Flashcards
broad, flat part of a leaf
blade
part of a leaf that attaches blade to stem
petiole
biological process that includes the capture of light energy and its transformation into chemical energy of organic molecules which are manufactured from carbon dioxide and water
photosynthesis
transparent _______ allows light to penetrate into the mesophyll, where photosynthesis occurs
epidermis
waxy covering epidermis of aerial parts (leaves and stems) of a plant
enables plant to survive in dry conditions of a terrestrial environment
cuticle
specialized epidermal cells located on aerial parts of plants and are associated with a wide array of biological processes
protected plants from adverse conditions including UV light and herbivore attack and are also an important source of a number of phytochemicals
trichomes
• small pores in epidermis of stem or leaf
• permit gas exchange for photosynthesis and transpiration
• flanked by guard cells
stoma
typically opens during the day, when photosynthesis takes place, and close at night
stomata
2 guard cells from a pore (stoma)
guard cell
photosynthetic ground tissue in the interior of a leaf
contains air spaces for rapid diffusion of carbon dioxide and water into, and oxygen out of, ________ cells
mesophyll
conducts water and essential materials to the leaf
xylem
conducts sugar produced by photosynthesis to rest of the plants
phloem
one or more layers of nonvascular cells (parenchyma or sclerenchyma) surrounding the vascular bundle in leaf
bundle sheath
large, thin walled cells on upper epidermises of leaves of certain monocot
located on both sided of the midvein
help in leaf roll or fold inward during drought
bulliform cells
guard cells are associated with special epidermal cells called
subsidiary cells
activates proton pumps
in guard-cell plasma membrane
blue light
difference in concentration of protons on the 2 sides of a cell membrane
contains potential energy that can be used to form ATP or do work in the cell
Proton Gradient
diffusion of materials from a region of higher concentration to a region of lower concentration through special passageways in the membrane
facilitated diffusion
• loss of water vapor from a plant’s aerial parts
• occurs primarily through stomata
• rate of transpiration is affected by environmental factors
• temperature, wind, relative humidity
• both beneficial and harmful to the plant
transpiration
helps reduce the surface area from which transpiration occurs
wilting
normal falling off of leaves or other plant parts, such as fruits or flowers
abscission
in temperate climates, most woody plants with broad leaves shed leaves in fall
helps them survive low temperatures of winter
involves physiological and anatomical changes
leaf abscission
types of modified leaves
• bud scale
• spine
• bract
• tendril
• bulb
modified leaf that covers and protects delicate meristematic tissue of winter buds
bud scale
leaf modified for protection, such as a cactus spine
spine
modified leaf associated with a flower or inflorescence but not part of the flower itself
bract
modified leaf associated with a flower or inflorescence but not part of the flower itself
bract
leaf or stem that is modified for holding on or attaching to objects
support weak stems
tendril
rounded, fleshy, underground bud that consists of a short stem with fleshy leaves
specialized for storage
bulb
plant or plant-like organism that grows on the surface of another plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it.
epiphytes
