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METABOLIC INHIBITORS AND CHROMOSOME REJOINING
Author(s) -
Beatty Alvin V.,
Beatty Jeanne W.
Publication year - 1959
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1959.tb07018.x
Subject(s) - biology , anaerobic exercise , oxygen , botany , tradescantia , dicentric chromosome , chromosome , biophysics , biochemistry , chemistry , karyotype , physiology , organic chemistry , gene
B eatty , A lvin V., and J eanne W. B eatty . (Emory U., Atlanta, Ga.) Metabolic inhibitors and chromosome rejoining. Amer. Jour. Bot. 46(5): 317–323. 1959.—X ray‐induced chromosomal aberrations of the dicentric and ring types in the first microspore division in Tradescantia paludosa were used to study the effects of temperature and chemical substances acting as metabolic modifiers on rejoining under both aerobic and anaerobic conditions. A total dose of 400 r of x rays was administered at 50 r/min. at temperatures ranging from 0.3°C. to 45°C. In the aerobic temperature experiments, 5% oxygen was used in either helium or carbon monoxide and in the anaerobic ones helium was used. In 5% oxygen in helium, the highest number of aberrations was produced at the lowest temperature. When the amount of oxygen in solution was made constant at all temperatures by adjusting the positive pressure of gas in experiments carried out above zero degrees, there was a temperature effect at 0.3°C. and 10°C., but no effect from 20°C. to 45°C. Temperature was believed not to influence chromosome breakage but only rejoining, through its influence on oxidative metabolism, thereby removing the source of energy. In the anaerobic temperature experiments, a low aberration yield of 0.14 occurred at 0.3°C., while a high of 0.66 was recorded at 40°C. Cytochrome oxidase was found not to be involved in the energy supply for rejoining in anaerobic experiments, since exposures in alkaline pyrogallate‐washed carbon monoxide gas gave the same results as helium, indicating that both gases only provide anoxic conditions. Under anoxic conditions, pretreatment in M/1000 sodium iodoacetate or M/10,000 p‐chloromercuribenzoate solutions had no effect on non‐irradiated plants thus treated, but increased the average number of chromosome aberrations per cell produced by x rays at least 2‐fold over the irradiated controls. The effect of these 2 salts, as used in these experiments, is believed to have taken place through their inactivation of triosephosphate dehydrogenase, thus inhibiting glycolysis at an early stage before any energy was released.