Auxins


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Related to Auxins: callus, Plant hormones, Cytokinins
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Auxins

 

substances produced in plant cells that stimulate the growth processes (growth of roots in cuttings, elongation of cells in stem segments, cell division in plant tissue culture); a group of plant hormones. At low concentrations auxins accelerate plant growth, but at high concentrations they inhibit it. Judging by their structure, auxins are probably monobasic hydroxy acids. Beta-indolylacetic acid (called heteroauxin), which is most widespread in plants, and some of its derivatives which are formed in plants during oxidative deamination of tryptophan are similar to auxins. Auxins are formed in young, vigorously growing parts of higher plants—growing points in stems, in root tips, in young leaves and buds, in fungi, and so on. The high content of auxins in growing organs stimulates the inflow of nutrients from other parts of the plant. Auxins are capable of moving down the stem and up the root. Growth movements in the plant and various tropisms are due to the uneven distribution of auxins in the axial organs. Auxins are found in free or bound states in plant tissues; only free auxins are biologically active. Auxins interact both with other plant hormones (gibberellins and kinins) and with metabolic products. Their mechanism of action is varied and still not completely elucidated. Auxins are assumed to stimulate the biosynthesis of some protein-enzymes involved in the formation of the structural components of cell walls or to form unstable complexes with ribonucleic acid, thereby regulating cell division. Many synthetic organic substances (for example, betaindolebutyric acid) have the same action as auxins. Auxins are used in plant-growing to hasten the rooting of cuttings and the like.

REFERENCES

Boysen-Jensen, P. Rostovye gormony rastenii. Moscow-Leningrad, 1938. (Translated from English).
Kholodnyi, N. G. Fitogormony. Kiev, 1939.
Zöding, H. Rostovye veshchestva rastenii. Moscow, 1955. (Translated from German.)
Reguliatory rosta rastenii v sel’skom khoziaistve. Moscow, 1958. (Translated from English.)
Mel’nikov, N. N., and Iu. A. Baskakov. Khimiia gerbitsidov i regu-liatorov rosta rastenii. Moscow, 1962.
Leopold, A. Rost i razvitie rastenii. Moscow, 1968. (Translated from English.)
Went, F. W., and K. V. Thimann. Phytohormones. New York, 1937.
Pilet, P. E. Les phytohormones de croissance. Paris, 1961.

R. KH. TURETSKAIA and V. I. KEFELI

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Effect of bacterial inoculations on biochemical parameters including pigment content, auxin content and protein content of Helianthus annuus L.
Auxin is a central player in the hormone cross-talks that control adventitious rooting.
The effects of sub-lethal rate of synthetic auxin in off-target crops are reported to cause substantial injury and yield loss.
In this sense, the objective of this work was to evaluate the use of auxin, calcium and Azospririllum brasilense on rooting of semihardwood olive cuttings.
The largest numbers of rooted shoots occurred in those originated from cotyledon segments, not differing significantly (p [less than or equal to] 0.05) among shoots derived from apical segments, and there was no need for an exogenous source of auxin for the induction of adventitious roots.
The cuttings usually respond to concentrations of auxin in a typical way, showing a progressive increase in the number and quality of roots formed with each increase in concentration auxin reaching a peak, from which a descent begins in response due to toxicity (Mesen, 1998).
Experimental results showed the potential of clonal propagation of guava through soft wood cuttings treated with auxin under simpler and cheaper low-plastic tunnel.
Balko et al., "The discovery of Arylex[TM] active and Rinskor[TM] active: Two novel auxin herbicides," Bioorganic & Medicinal Chemistry, vol.
The results on response of shoot bud induction attributed to auxins were recorded after 60 days of planting in the soil mixture.
Thereafter, the calli were transferred to the PGR-free medium for excluding of auxin effect and further stimulation of somatic embryogenesis.
Synthetic auxin (2,4-D and NAA) at 5 mg/L treatment during the flowering also reduced the fruit drop and enhanced the quality.C and V-shaped girdling 3 weeks before flowering increased number of flowers and reduced the premature fruit drop of wax apple fruits.