anchor trees firmly in the soil, usually through an extensive branching network that constitutes about one third of the total dry weight of the plant.\; they also absorb water and minerals in solution, mostly through "feeder" roots found in the upper meter of soil. Some store water or food.
Roots that do not develop form another root but develop instead from a stem or leaf.
fibrous root system
have large numbers of fine roots of similar diameter develops from the adventitious roots.
The four regions of a developing root
the root cap, the region of cell division, the region of elongation, the region of maturation.
composed of a thimble shaped mass of parenchyma cells covering the tip of each root; it's quite large and obvious in some plants; it functions to protect the delicate tissues
plastids containing starch grains; act as gravity sensors, collecting on the sides of root cap cells facing the direction of gravitational force
region of cell division
is composed of an apical meristem which is a tissue of actively dividing cells, in the center of the root tip, produce the surrounding root cap.
appears as a solid cylinder in the center of the roots, produces primary xylem and primary phloem
parenchyma tissue; originates from ground meristem; generally present in stems but absent in most dicot roots.
region of elongation
merges with the apical meristem, usually extends about 1 centimeter or less from the tip of the root.
absorb water and minerals, adhere tightly to soil particles with the aid of microscopic fibers they produce and greatly increase the total absorptive surface of the root.
a tissue composed of parenchyma cells lying between the epidermis and inner tissues; mostly store food.
the inner boundary of the cortex; consists of a single layered cylinder of compactly arranged cells whose primary walls are impregnated with suberin
the suberin bands; on the radial and transverse walls; they prevent water from passing through the otherwise permeable cell walls.
some endodermal cells; may remain thin-walled and retain their Casparian strips, but may eventually tend to become suberized.
a core of tissues; lies to the inside of the endodermis; most of the cells conduct water or food in solution
grouth that stops after an organ such as a flower or leaf is fully expanded or after a plant has reached a certain size.
occurs in tress and other perennials where new tissues are added indefinitely, season after season.
special spongy roots which extend above the water's surface and enhance gas exchange between the atmosphere and the subsurface roots to which they are connected.
nonparasitic plants that grow suspended without direct contact with the ground like orchads.
appears as a solid cylinder n the center of the root; produces primary xylem and phloem
tiny embryonic leaves that will develop into mature leaves after the bud scales drop off and growth begins.
functions the same as primary counterparts; conducts, in soluble form, food manufactured by photosynthesis throughout the plant
one of usually numerous, slightly raised, somewhat spongy groups of cells in the bark of woody plants; they permit gas exchange between the interior of a pant and the external atmosphere.
herbaceous dicot stems retain these; patches of xylem and phloem; arranged in a cylinder that separates the cortex from the pith
only primary xylem and phloem, but later, a vascular cambium arises between these two primary tissues and adds secondary xylem and phloem to the vascular bundles.
When a typical tree first becomes active in the spring, it usually produces relatively large vessel elements of seconary xylem.
The xylem that is produced after the spring wood, and which has smaller or fewer vessel elements and larger numbers of tracheids
lighter streaks or lines can be seen radiating out from the center across the annual rings; consist of parenchyma cells that may remain alive for ten or more years.
Monocots do not...
have a vascular cambium nor a cork cambium and thus produce no secondary vascular tissues or cork.
Horizontal stems that grow below ground, often near the surface of the soil; superficially resemble roots but have scalelike leaves.
Horizontal stems that grow above ground, generally along the surface; they also have long internodes.
composed almost entirely of stem tissue, except for the few papery, scalelike leaves sparsely covering the outside.
the sum of all the interrelated biochemical processes that take place in a living organism which requires energy to occur.
proteins that speed up chemical reactions in cells without being used up in the reactions; regulate about every metabolic activity.
light dependent reactions
the first major steps in the conversion of light energy to biochemical energy; the reactions are initiated when units of light energy strike chlorophyll molecules embedded int he thylakoid membranes of chloroplasts.
reduced nicotinamide adenine dinucleotide phosphate; caries hydrogen and is used in the second phase of photosynthesis.
light independent reactions
utilizes ATP and NADPH to form sugars; also known as dark reactions because they don't directly require light; take place outisde of the grana in the stroma of the chloroplast
nicotin amide adenine dinucleotide phosphate; natural elecron acceptor in the light dependent reaction
During light dependent reactions...
water molecules are split apart, releasing electrons and hydrogen ions, and oxygen gas is released; the electrons from the split H2O molecules are passed along an electron transport system; energy-storing ATP molecules are produced; some hydrogen from the split H20 molecules is involved in the reduction of NADP to form NADPH.