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level: Level 1

Questions and Answers List

level questions: Level 1

QuestionAnswer
abscission zonearea at the base of the petiole where cellular breakdown leads to leaf and fruit drop
absorbing rootsfine, fibrous roots that take up water and minerals. Most absorbing roots are within the top 12" (30 cm) of soil.
aerial rootsaboveground roots. Usually adventitious in nature and sometimes having unique adaptive functions.
adventitious budbud arising from a place other than a leaf axil or shoot tip, usually as a result of hormonal triggers.
angiospermpolant with seeds borne in an ovary. Consists of two large groups: monocotyledons (grasses, palms, and related plants) and dicotyledons (most woody trees, shrubs, herbaceous plants, and related plants). Contrast with gymnosperms.
anthocyaninred or purple pigment responsible for those colors in some parts of trees and other plants. Compare to carotenoid.
antitranspirantsubstance applied to the foliage of plants to reduce water loss (transpiration).
apical budbud at the tip of a twig or shoot.
apical dominancecondition in which the terminal bud inhibits the growth and development of the lateral buds on the same stem formed during the same season.
apical meristemgrowing point at the tips of shoots and roots.
apoplasmfree spaces in plant tissue. Includes cell walls and intracellular spaces.
auxinplant hormone or substance that promotes or regulates the growth and development of plants. Produced at sites where cells are dividing, primarily in the shoot tips. Auxin-like compounds may be synthetically produced.
axial transportmovement of water, minerals, or photosynthates longitudinally within a tree.
axillary budbud in the axil of a leaf. Lateral bud.
branch bark ridgeraised strip of bark at the top of a branch union, where the growth and expansion of the trunk or parent stem and adjoining branch push the bark into a ridge.
branch collararea where a branch joins another branch or trunk that is created by the overlapping vascular tissues from both the branch and the trunk. Typically enlarged at the base of the branch
bud(1) small lateral or terminal protuberance on the stem of a plant that may develop into a flower or shoot. (2) undeveloped flower or shoot containing a meristematic growing point.
buttress rootroots at the trunk base that help support the tree and equalize mechanical stress.
cambiumthin layer(s) of meristematic cells that give rise (outward) to the phloem and (inward) to the xylem, increasing stem and root diameter.
carbohydratecompound, combining carbon, hydrogen, and oxygen, that is produced by plants as a result of photosynthesis. Sugars and starches.
carotenoidyellow, orange, or red pigment responsible for those colors in some parts of trees and other plants. Compare to anthocyanin.
cellulosecomplex carbohydrate found in the cellular walls of the majority of plants and algae and certain fungi.
chlorophyllgreen pigment of plants found in chloroplasts. Captures the energy of the sun and is essential in photosynthesis.
chloroplastspecialized organelle found in some cells. Site of photosynthesis.
CODITCompartmentalization of Decay in Trees
companion cellspecialized cell in the angiosperm phloem derived from the same parent cell as the closely associated, immediately adjacent sieve-tube member.
compartmentalizationnatural defense process in trees by which chemical and physical boundaries are created that act to limit the spread of disease and decay organisms.
cork cambiummeristematic tissue from which the corky, protective outer layer of bark is formed.
cuticlewaxy layer outside the epidermis of a leaf that reduces water loss and resists insect damage.
cytokininplant hormone involved in cell division, leaf expansion, and other physiological process. Compounds with cytokinin-like activity may be synthetically produced.
deciduoustree or other plant that sheds all of its leaves according to a genetically scheduled cycle as impacted by climate factors (usually during the cold season in temperate zones). Contrast evergreen.
decurrentrounded or spreading growth habit of the tree crown. Contrast with excurrent.
differentiationprocess in the development of cells in which they become specialized for various functions.
diffuse porouspattern of wood development in which the vessels and vessel sizes are distributed evenly throughout the annual ring. Contrast with ring porous.
dormantin a period of dormancy
ecologystudy of the relationships among organisms and other living and nonliving elements of their environment.
epicormicarising from a latent adventitious bud (growth point). Usually in reference to a shoot.
evergreentree or other plant that does NOT shed all of its foliage annually. Contrast with deciduous.
excurrenttree growth habit characterized by a central leader and pyramidal crown. Contrast with decurrent.
fiber(1) elongated, tapering, thick-walled cell that provides strength to wood. (2) smallest component of a rope.
frondlarge, divided leaf structures found in palms and ferns.
geotropismplant growth produced as a response to the force of gravity, either positive, as in the direction of gravity (roots) or negative, as in opposite the direction of gravity (shoots).
growth ringrings of xylem that are visible in a cross section of the stem, branches and roots of some trees. In temperate zones, the rings typically represent one year of growth and are sometimes referred to as annual rings.
guard cellpair of specialized cells that regulate the opening and closing of a stomate.
gymnospermplants with exposed seeds, usually within cones. Contrast with angiosperm.
heartwoodwood that is altered (inward) from sapwood and provides chemical defense against decay-causing organisms and continues to provide structural strength to the trunk. Trees may or may not have heartwood. Contrast with sapwood.
included barkbark that becomes embedded in a crotch (union) between branch and trunk or between codominant stems. Causes a weak structure.
inflorescencecluster of flowers
internoderegion of the stem between two successive nodes. Contrast with node.
lateral budvegetative bud on the side of a stem. Contrast with terminal bud.
lateral rootroot that arises by cell division in the pericycle of the parent root and then penetrates the cortex and epidermis.
leaf axilpoint of attachment of a leaf petiole to a stem.
lenticelsmall opening in the bark that permits the exchange of gases.
ligninorganic substance that impregnates certain cell walls to thicken and strengthen the cell to reduce susceptibility to decay and pest damage.
meristemundifferentiated tissue in which active cell division takes place. Found in the root tips, buds, cambium, cork cambium and latent buds.
monocotsee monocotyledon
monocotyledonplant with an embryo that has on seed leaf (cotyledon). Examples are grasses and palms. Contrast with dicotyledon.
mycorrhizaesymbiotic association between certain fungi and the roots of a plant.
nodeslightly enlarged portion of a stem where leaves and buds arise. Contrast with internode.
osmosisdiffusion of water through a semi-permeable membrane from a region of higher water potential (lower salt concentration) to a region of lower water potential (higher salt concentration).
parenchyma cellthin-walled, living cells essential in photosynthesis, radial transport, energy storage and production of protective compounds
peridermthe outer layers of tissue of woody roots and stems, consisting of the cork cambium and the tissues produced by it, such as bark.
petiolestalk or support axis of a leaf.
phloemplant vascular tissue that transport photosynthates and growth regulators. Situated on the inside of the bark, just outside the cambium. Is bidirectional (transports up and down). Contrast with xylem.
photosynthategeneral term for the sugars and other carbohydrates produced during photosynthesis.
photosynthesisprocess in green plants (and in algae and some bacteria) by which light energy is used to form glucose (chemical energy) from water and carbon dioxide.
phototropisminfluence of light on the direction of plant growth. Tendency of plants to grow toward light
plant growth regulatorcompound effective in small quantities that affects the growth and/or development of plants. May be naturally produced (hormone) or synthetic. See plant hormone.
plant hormonesubstance produced by a plant that, in low concentrations, affects physiological processes such as growth and development, often at a distance from the substance point of origin. See plant growth regulator.
primary growthroot and stem growth in length. Occurs at the apical meristems and lateral meristems of all vascular plants
propagationprocess of increasing plant numbers, both sexually and asexually.
radial transportlateral movement of substances, perpendicular to the longitudinal axis of the tree or stem.
rayparenchyma tissues that extend radially across the xylem and phloem of a tree and function in transport, storage, structural strength and defense.
reaction zonenatural boundary formed chemically within a tree to separate damaged wood from existing healthy wood. Important in the process of compartmentalization.
respirationin plants, process by which carbohydrates are converted into energy by using oxygen.
ring porouspattern of wood development in which the large-diameter vessels are concentrated in the earlywood. Contrast with diffuse porous.
root crownarea where the main roots join the plant stem, usually at or near ground level. Root collar.
root initiation zoneregion at the base of a palm stem where lateral roots emerge.
root matdense network of roots near the base of a palm.
sapwoodouter wood (xylem)that is active in longitudinal transport of water and minerals. Contrast with heartwood.
secondary growthincrease in root and stem girth or diameter. Occurs at lateral meristems in some vascular plants such as dicots.
sieve celllong, slender phloem cell in gymnosperms.
specialized phloem cells involved in photosynthate transport. Exist only in angiosperms.sieve tube element
sinkplant part that uses or stores more energy than it produces.
sinker rootdownward-growing roots that provide anchorage and take up water and minerals. Especially useful during periods of drought.
sourcein physiology, plant part that produces carbohydrates. Mature leaves are sources.
stomatasmall pores, between two guard cells on the undersides of leaves and other green plant parts, through which gasses are exchanged and water loss is regulated.
symbiosisassociation of two different types of living organisms that is often, but not always, beneficial to each.
symplasmentire mass of protoplasm of all the cells in a plant, interconnected by plasmodesmata. Symplast. Contrast with apoplasm.
tap rootcentral, vertical root growing directly below the main stem or trunk that may or may not persist into plant maturity.
temperateregion lying between the tropics and the poles that has relatively moderate temperatures.
terminal budbud at the tip of a twig or shoot.
tracheidelongated, tapering xylem cell adapted for the support and transport of water and elements.
transpirationwater vapor loss through the stomata of leaves.
tropismtendency of growth or variation of a plant in response to an external stimulus such as gravity (geotropism) or light (phototropism).
vesselend-to-end, tubelike, water-conducting cells in the xylem of angiosperms.
xylemmain water-and mineral-conducting (unidirectional, up only) tissue in trees and other plants. Provides structural support. Arises (inward) from the cambium and becomes wood after lignifying. Contrast with phloem.