|
objective:
the lens or combination of lenses that first receives the rays from an observed object, forming its image in an optical device, as a microscope micr
objective lens: the lower lens in a microscope that is closest to what is being looked at micr
obligate: restricted to a particular way of life phyt
obligate apomixis: seed apomixis with maternal offspring to 100 % bot
obligate parasite: an organism that cannot live in the absence of its host phyt
observation: a data collection strategy in which the activities of subjects are visually examined; the observer attempts to keep his presence from
interfering in or influencing any behaviors stat meth
observation tube >>> eyepiece
ocDNA: an open circular DNA molecule that has at least one nick; it cannot be supercoiled and has the same density as linear DNA in CsCl2/EB density gradients biot
ochre codon: UAA stop codon gene biot >>> nonsense mutation
octopine:
a rare derivate of an amino acid; it is produced in some crown galls of plants; the controlling genes are part of the T-DNA of Ti plasmids chem phys
octoploid: having eight chromosome sets of identical or different complements cyto
octovalent: chromosome configuration consisting of eight chromosomes cyto
ocular >>> eyepiece
OECD >>> Organization for Economic Cooperation and Development
off-grade:
postharvest removal of pathogen-infested or damaged fruit, seeds, or plants by screening procedures; the culled or off-graded material can later be individually analyzed or discarded meth
offset: a young plant produced by the parent, usually as its base (offshoot) or a small bulb at the base of a mother bulb bot
offspring >>> progeny
off-type:
an individual differing from the population norm in morphological or other traits; the term also includes escapes and contaminants (e.g., seeds that do not conform to the characteristics of a variety, uncontrolled self-pollination during production of hybrid seed, segregates from plants, etc.) gene agr
Ohio method >>> ear-to-row selection
oidium: the generic name given to the conidial stage of all >>> powdery mildews, the Erysiphales; the conidia are consistently
similar throughout this family, being unbranched and producing chains of hyaline, i. e., oval conidia phyt
oil crops:
plants that are grown for oil or oil-like products; main oil crops are: castor, peanut, rapeseed, safflower, sesame, soybean, sunflower, crambe, niger, jojoba, and poppy agr
oil immersion: the oil that is placed between the lens of a microscope and the coverslip above a microscopical preparation micr
oil legumes >>> oil crops
oil poppy >>> oil crops
oil-immersion objective:
the objective lens system used for highest resolution with the light microscope; the space between the coverslip over the object to be examined and the lens is filled with a drop of oil of the same refractive index as the glass micr
oilseed >>> oil crops
OKAYAMA-BERG procedure: a method of cDNA cloning using specialized vectors favoring the generation of full-size clones biot
olein: a colorless to yellowish, oily, water-insoluble liquid, C57H104O6, the triglyceride of oleic acid, present in many vegetable oils chem phys
oligocarpous - wenigfrüchtig adj: bearing less than the typical amount of fruit bot
oligogene: a gene that produces a pronounced phenotypic effect on characters that show normal inheritance gene
oligogenic: inheritance due to a small number of genes with discernible effects gene
oligogenic resistance: resistance controlled by one or a few genes phyt
oligomer: a protein composed of two or a few identical polypeptide subunits chem phys
oligonucleotide (oligos): a small piece of ssDNA or ssRNA; oligos are synthesized by chemically linking together a number of specific
nucleotides; they are used as synthetic genes and DNA probes or in site-directed mutagenesis biot
oligopeptide: a small protein composed of 5-20 amino acids chem phys
oligos >>> oligonucleotide
oligospermous: showing only few seeds bot
omnipotency >>> totipotency
omnivorous: of parasites, or attacking a number of different hosts phyt
once blooming: it refers to plants or varieties (e.g., in roses) that bloom once a year hort
one-gene-one-enzyme (polypeptide) hypothesis:
the hypothesis that a large class of structural genes exists in which each gene encodes a single polypeptide that may function either independently or as a subunit of a more complex protein; originally it was thought that each gene encoded the whole of a single enzyme, but it has since been found that some enzymes and other proteins derive from more than one polypeptide and hence from more than one gene gene bio
one-point crossover:
in genetic algorithms, a breeding technique using one randomly chosen point, interchanging the portions of the two breeding individuals to the right of that point stat
ontogenesis: the course of growth and development of an individual from zygote formation to maturity phys
http://www.plantontology.org
ontogeny >>> ontogenesis
oogonium: a primordial germ cell that gives rise, by mitosis, to oocytes, from which the ovum and polar bodies develop by meiosis bot
opal: a UAG stop codon biot >>> nonsense mutation
opaque: partially pervious to light bot
opaque (–2) maize (mutant): a mutant form that produces proteins rich in lysine and higher in content of calcium, magnesium, iron, zinc, and
manganese gene
open continuous culture: a cell culture in which inflow of fresh medium is balanced by outflow of a corresponding volume of culture biot >>> closed continuous culture >>> continuous culture
open pollination: natural, cross, or random pollination; a free gene flow bot
open storage: storage with free access to normal atmospheric conditions seed
open-pollinated crossing group >>> crossing group(s)
open-reading frame (ORF): the mRNA region between the start and stop codon gene
operator (gene): a region of DNA at one end of an operon that acts as the binding site for a specific repressor protein and so controls the
functioning of adjacent cistrons gene
operon:
a set of adjacent structural genes whose mRNA is synthesized in one piece, together with the adjacent regulatory genes that affect the transcription of the structural genes; it is under the control of an operator gene, lying at one end of it gene
opine: a group of unusual amino acid derivatives produced by plant cells transformed by Agrobacterium inorder to feed the pathogen; opines include agropines, nopalines, octopines and are characteristic for individual strains of Agrobacterium biot
opposite: applied to the leaf arrangement in which leaves arise in pairs, one pair at each node bot
optic chiasma: it refers to a visible chiasma on meiotic chromosomes through the microscope cyto
optical density (OD): a logarithmic unit of transmission; OD = –logT (transmission), for example, a change of the optical density
from 1 to 2 represents a tenfold increase in absorption micr
optical mapping: an enabling technology for whole genome analysis, which involves the capture of individual DNA molecules, obtained directly from
genomic DNA, followed by digestion in situ by selected restriction endonucleases; the resulting fragments are then visualized directly to produce detailed optical restriction maps; this methodology allows
patterns of sequence variation to be detected across entire genomes, without the need for DNA amplification, and, unlike other genomewide scanning methods, provides detailed haplotype information by analyzing
individual DNA molecules meth biot cyto
optimal sampling strategy: a sampling strategy that ensures that the genetic diversity of a species is represented in the samples stat meth
opuntia: within the subtribe Opuntioideae there are several species used as crop and horticultural plants; edible fruits and fleshy parts
of the plant; special use for production of the stain “carmine red” by the ecto-parasite Cochenille (Dactylopius coccus) bot
orangery:
a sheltered place, especially a greenhouse, used for the cultivation of orange trees and other tropical or subtropical plants in cool climates meth hort
orcein: a dye used in cytology; it is dissolved in acetic acid and used for staining of squash preparations of chromosomes cyto meth prep
orchard: an area of land devoted to the cultivation of (fruit or nut) trees hort
ordinal scale:
a scale for scoring quantitative data using a series of predefined intervals arranged in a logical sequence (e.g., a typical ordinal scale may involve responses of “very good”, “good”, “satisfactory”, “poor”, or “very poor”) stat
ordinary least squares: the estimator that minimizes the sum of squared residuals stat
organ asymmetry: in many plants the left and right halves of their organs have distinct shapes (e.g., the leaves of Begonia, Tilia (lime tree), Ulmus (elm) and petals of Anhirrhinum (snapdragon) or Pisum (pea) flowers; they can occur in two mirror-image forms, left handed and right-handed; in many cases these two forms occur in equal numbers on the plant, either being located opposite each other or alternating along the stem; asymmetry of each organ traces back to a meristem with a single plane of symmetry (bilateral symmetry), such that mirror-image organs arise from opposite halves of the meristem bot
organ culture:
the growth in aseptic culture of plant organs, such as roots or shoots, beginning with organ primordia or segments and maintaining the characteristics of the organ biot
organelle:
within a cell, a persistent structure that has a specialized function; mostly separated from the rest of the cell by selective membranes bot
organic soil: a soil that is composed predominantly of organic matter; it usually refers to peat agr
Organization for Economic Cooperation and Development (OECD): an international agency which, among other things, has developed
specifications, procedures and standards for international seed certification among member countries seed org
organogenesis: the initiation and growth of an organ from cells or tissue phys
organogenetic: it refers to cells or tissue able to form organs biot
organogenic >>> organogenetic
organo-metallic complex: a general term referring to compounds in which metal ions have been complexed by organic compounds, e.g., chelates; while
all chelates are complexes, all complexes are not chelates agr chem. >>> siderophore
ornamental plant: a plant that is grown for visual display; it describesany plant cultivated for decorative purposes; plants classified as
ornamental are generally contrasted with those grown as food sources, though there are other, non-ornamental uses for plants hort
ornamentals >>> ornamental plant
ornithogamy >>> ornithophily
ornithophilous >>> ornithophily
ornithophily: pollination by birds bot
orphan crop(s):
those crops which are typically not traded internationally but which can play an important role in regional food security; many of these crops have received little attention from crop breeders or other research institutions agr >>> minor crop
orphan gene: a gene identified by sequencing; its function is unknown gene
ortet:
the original plant from which a clone is started through rooted cuttings, grafting, tissue culture, or other means of vegetative propagation (e.g., the original plus tree used to start a grafted clone for inclusion in a seed orchard) meth hort fore >>> cutting
orthodox seed: seed that can be dried and stored for long periods at reduced temperatures and under low humidity seed
orthogonal design: a design, where the various factors in the design are orthogonal in the sense of partitions stat
orthogonality: it is considered to be one of the most important features for design of experiment stat
orthologous genes:
homologous genes that have become differentiated in different species derived from a common ancestral species, as opposed paralogous genes gene
orthoploid >>> euploid
oryzalin: an agent that is efficient for chromosome doubling of haploid apple shoots in vitro; also shoot tips of diploid roses can be
treated in vitro at concentrations of 5 to 15 µM; tetraploid shoots can be obtained in highest frequencies after exposure to 5 µM oryzalin for 14 days; thin (1 mm) nodal sections can be treated with 5 µM oryzalin for only 1 day meth cyto
oryzinin >>> glutenin
osmolarity: the total molar concentration of the solutes affecting the osmotic potential of a solution or nutrient medium phys
osmolyte:
osmolytes are osmolytic active, neutral organic compounds, such as sugars (polyols), certain amino acids, and quaternary ammonium compounds; proline is the most widely distributed compatible osmolyte; there is a strong correlation between increased cellular proline levels and the capacity to survive both water deficit and the effects of high environmental salinity phys
osmosis:
the net movement of water or of another solvent from a region of low solute concentration to one of higher concentration through a semipermeable membrane phys
other crop seed:
one of the four components of a purity test; the total percentage (by weight) of seed of all crop species, each comprising less than 5 % of the seed lot seed
O-type:
a maintainer plant in sugarbeet breeding; it carries the same sterility genes as the male sterile plants but having the normal cytoplasm—(N)xxzz; this genotype exists at low frequencies (3-5 %) in most sugarbeet populations; it can be identified only by test-crossing prospective O-types with CMS plants; if all the offspring from a test cross are male sterile, the test-crossed pollinator plant is of the O-type genotype; by repeated selfing of an identified O-type, and simultaneous repeated backcrossing to a CMS line, inbred O-type lines and their equivalent inbred CMS lines can be developed seed
ounce (oz): equals 31.1030 g
outbreeding:
the crossing of plants that are not closely related genetically, in contrast to inbreeding, in which the individuals are closely related bot
outclassed: it refers to a crop variety that is taken away from registration seed
outcrossing: cross pollination between plants of different genotypes bot gene; in biotechnology, the transfer of a given gene or genes
(e.g., one synthesized by humans and inserted into a plant via genetic engineering) from a domesticated organism (e.g., crop plant) to wild type (relative of crop) biot eco
outgrades (in potato): outgrades are tubers considered unmarketable because of size, disease, greening, second growth, or slug or mechanical
damage seed
outlier:
an individual that occurs naturally some distance away from the principal area in which its population is found; they are anomalous values in the data and can be due to recording errors, which may be correctable or they may be due to the sample not being entirely from the same population stat
outplant: a seedling, transplant, or cutting ready to be established on a certain site agr fore hort
ovary: the part of the flower that develops into the grain in grasses; the ovary has one or more ovules, each containing an embryo sac bot >>> Figure 35 >>> Table 8
ovary wall >>> pericarp
ovate: egg-shaped; having an outline like that of an egg, with the broader end basal bot >>> ovoid
overall resistance: resistance to disease expressed at all plant growth stages phyt
overdominance:
the phenomenon in which the character of the heterozygotes is expressed more markedly in the phenotype than in that of either homozygote; usually the heterozygote is fitter than the two homozygotes; this can give rise to monohybrid heterosis when the hybrid vigor obtained by crossing parents differing in a single specified pair of allelic genes gene >>> Tables 20, 21
overhang: 3' and 5' ssDNA overhangs of dsDNA; overhangs may also be called extensions or sticky ends biot
overlapping code >>> overlapping DNA (segments)
overlapping DNA (segments): a special type of gene organization; one DNA sequence may code for different proteins; it is performed by two open
reading frames, which subsequently act gene
overseeding: seeding into an existing crop stand or turf agr
overstocked:
the situation in which trees are so closely spaced that they are competing for resources, resulting in less than full-growth potential for individual trees fore
overstored seeds >>> method of overstored seeds
overstory:
the canopy in a stand of trees; in contrast to the understory which is low growing woody or herbaceous vegetation forming a layer beneath the overstory fore
oversummering: the survival through the summer and/or to keep alive through summer agr
overwintering: the survival through the winter and/or to keep alive through winter agr
ovoid: egg-shaped bot >>> ovate
ovule: a structure in angiosperms and gymnosperms that, after fertilization, develops into a seed bot
ovule primordium: meristematic tissue of the ovary wall from which the seeds of angiosperms originate bot
ovum >>> egg
oxalate oxidase:
an enzyme detected in, for example, barley seedling roots soon after germination and in the leaves of mature plants, and in response to powdery mildew infection; the enzyme contains manganese; the enzyme shows almost identical structure to the wheat protein germin phys
oxalic acid: a white, crystalline, water-soluble, poisonous acid, H2C2O4·2H2O, used for bleaching and as a laboratory reagent chem
phys
oxidase: an enzyme that catalyzes reactions involving the oxidation of a substrate using molecular oxygen as an electron acceptor chem phys
oxidation: a reaction in which atoms or molecules gain oxygen or lose hydrogen or electrons chem phys
oxidative burst an early defence response against pathogens where 10-14 mol H2O2 per cell per second is
generated; the early oxidative burst (phase I) is common for compatible and incompatible interactions, the later, but sustained (phase II) is associated with hypersensitive response/reaction phyt
|
