Premium
CHANGES IN SENSITIVITY OF MAIZE CHROMOSOMES TO X RAYS DURING SEED GERMINATION
Author(s) -
Latterell Richard L.,
Steffensen Dale M.
Publication year - 1962
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.1537-2197.1962.tb14967.x
Subject(s) - radiosensitivity , germination , biology , seedling , locus (genetics) , horticulture , somatic cell , zoology , irradiation , botany , genetics , gene , physics , nuclear physics
L atterell , R ichard L., and D ale M. S teffensen . (Brookhaven Natl. Lab., Upton, L. I.. N. Y.) Changes in sensitivity of maize chromosomes to X rays during seed germination. Amer. Jour. Bot. 49(5): 472–478. Illus. 1962.—Changes in the radiosensitivity of maize seeds during early stages of germination were studied by means of somatic‐mutation techniques. Seeds heterozygous for the yg 2 (yellow‐green) locus were irradiated with 800 r of X rays after soaking in running tap water up to 42 hr. Yellow‐green sectors, representing mutations affecting the dominant yg 2 locuss in leaves 4 and 5 of seedling plants were used as a criterion of radiosensitivity. The frequency of somatic sectors was virtually nil for dry seed and for seeds soaked up to 16 hr. Sector frequencies underwent a marked (9‐ to 15‐fold) rise from 16 to 28 hr, reached a plateau of sensitivity and subsequently declined. Manometric studies were conducted on seeds soaked under the same conditions as those irradiated. The rate of oxygen consumption rose rapidly from 0 to 7 hr, remained essentially constant from 7 to 16 hr, then underwent an approximately 2‐fold increase from 16 to 24 hr, after which the rate of progressive increase was retarded. The fact that the marked rise in frequency of X‐ray‐induced somatic sectors coincided with the major increase in oxygen consumption suggests that radiosensitivity of soaked seeds is conditioned by metabolic changes during seed development. Changes in radiosensitivity that followed attainment of peak sector frequencies were apparently governed by factors that influenced the rate of seed development.