(n.) A disposition to turn or incline towards the earth; the influence of gravity in determining the direction of growth of an organ.
(1) On the basis of analysis of theoretical proposals and experimental investigations of the molecular mechanism of perception and realization of the gravity stimulus, a hypothesis was developed that the key factor in the development of geotropic reaction is an interaction of cell organelles with membranes of the endoplasmic reticulum as a result of their sensing the gravity stimulus.
(2) The conspicuous negative geotropism in the leaves of A. mexicana causes the formation of basal deposits of water, which play an important functional role in survival.
(3) The substances (Tables I leads to III) prepared by fusion of the required anhydride and amine were tested to evaluate the negative geotropic effect on germinating roots of Lens esculenta Moench s.1.
(4) Twenty-four cases (77.4%) showed more than two of the following four types which are listed in serial order of occurrence: spontaneous (or direction-fixed positional) nystagmus toward the involved ear; geotropic direction-changing positional nystagmus; spontaneous (or direction-fixed positional) nystagmus toward the opposite ear; and apogeotropic direction-changing positional nystagmus.
(5) In many biological systems mechanical forces regulate gene expression: in bacteria changes in turgor pressure cause a deformation of the membrane and induce the expression of osmoregulatory genes; in plants gravity regulates cell growth ('geotropism'); in mammals stretching a muscle induces hypertrophy which is accompanied by qualitative changes in protein synthesis.
(6) Rolling the patient onto the other side provokes a left intense geotropic nystagmus.
(7) Typical hairy root traits, high growth rate, branching and, most noticeably, absence of geotropism, were shown by roots containing rolB alone, while roots with rolA + B + C were geotropic as normal carrot roots.
(8) The authors take into account two different types of stationary, persistent and direction-changing nystagmus (ny): 1) the horizontal bidirectional ny (nyOB), apogeotropic (nyOBA) and geotropic (nyOBG); 2) the tridirectional apogeotropic ny (nyAT).
(9) Henry), depleted of amyloplast starch by incubation at 30 degrees C with gibberellin plus kinetin, retained their geotropic responsiveness.
(10) Basic work carried out recently on the role of the structural-functional condition of cell organelles in the development of geotropic reaction in higher plants is reviewed.
(11) The radicles of both plant species treated with these compounds at concentrations higher than 1.0 x 10(-4) M showed negative geotropism, even though germination occurred.
(12) In the early period after its administration, geotropic type positional nystagmus was induced.
(13) Plants containing the left T-DNA (TL) of Agrobacterium rhizogenes show a variety of developmental abnormalities that include severely wrinkled leaves, loss of apical dominance, reduced geotropism of roots, reduced internode distances, and floral hyperstyly.
(14) It was found that substances (I), (VII), (VIII) and (IX) showed negative geotropic effect of the same order of magnitude as that of the reference substance (alpha-naphthylphthalamic acid).
(15) The simultaneous appearance of geotropic and pre-emergence phytotoxic activity seems to be connected with the presence of an 8-quinoline residue on the amide nitrogen.
(16) Results of a neuromuscular screen indicated changes in gait, righting reflex, grip strength and performance of the negative geotropism test.
(17) The nyOB was present in 177 patients as follows: apogeotropic ny in 128 and geotropic in 49.
(18) Rapid rolling onto one side in recumbent position provokes a paroxysmal, purely horizontal and geotropic nystagmus which nearly always spontaneously inverts direction.
(19) N-Quinolinphthalamic acids and allied substances have been prepared and studied for negative geotropic effect and phytotoxic activity.
(20) Three patients with complete sudden unilateral hearing loss suffered from delayed vertigo and presented a strong geotropic positional nystagmus during the evolution of their disease.
(1) Cellulose terminal complex clustering and its role in gravitropic response is covered.
(2) Complementation and segregation ratio analyses were carried out on these mutants, which indicate that a single gene may mutate to switch the polarity of gravitropism.
(3) These findings suggest that the high concentration of calmodulin in the root cap may be important in relation to gravitropism and growth development.
(4) Although the concentration of exogenous indole-3-acetic acid (IAA) required to reduce root growth by 50% (GR50) was 12 times greater for the agravitropic mutant, agravitropic and gravitropic roots were equally sensitive to exogenous applications of 2,4-dichlorophenoxyacetic acid (2,4-D) and naphthalene acetic acid (NAA).
(5) Merit) which require light to develop gravitropic sensitivity.
(6) In the moss Physcomitrella patens, single-cell protonemata and multicellular gametophores respond to reorientation relative to the gravity vector by growing negatively gravitropically.
(7) Defects include decreases in plant height, root gravitropism, hypocotyl elongation, and fertility.
(8) Plants carrying the axr2 mutation are severe dwarfs and display defects in growth orientation of both the shoot and root suggesting that the mutation affects some aspect of gravitropic growth.
(9) The chemically induced barley (Hordeum vulgare L.) mutation, agr, was found to be a simple recessive trait resulting in agravitropic roots and normal gravitropic shoots.
(10) They aso provide another explanation for biological gravitropism.
(11) After lengthy exploration of structure-activity correlations, phytotropins were defined as compounds that inhibit plant gravitropic and phototropic responses and the polar transport of the hormone auxin.
(12) Root IAA contents, determined by high-pressure liquid chromatography (HPLC), were not different for gravitropes and agravitropes.
(13) SAUR transcripts became more abundant on the bottom side of hypocotyls that were undergoing gravitropic curvature.