Rbe of Monoenergetic Fast Neutrons: Cytogenetic Effects in Maize

RELATIVE BIOLOGICAL EFFICIENCY OF 14.1MeV FAST NEUTRONS AND ¹³⁷Cs GAMMA RAYS IN THE STAMEN HAIRS OF <i>TRADESCANTIA REFLEXA</i> RAFIN

“…The main reason why this study was carried out is that extremely high RBE values of 10 to 50 sometimes more than 100 have been reported in plant materials for fast neutrons or other heavy particles by many authors (Matsumura et al 1963;Neary et al 1963;Smith et al 1964;Matsumura 1966 and many others, see Discussion). The RBE values reported in animals and microorganisms are generally much closer to 1 (at most 5) (see Kondo 1964).…”

“…Each stamen hair is composed of a single chain of cells, and its development depends principally on the repeated division of the terminal cell. Thus the stamen hairs of this genus can be regarded as an essentially single-meristematic-cell system as demonstrated by Ichikawa and Sparrow (1967b), and can be used as an excellent plant material for radiobiological studies at the single-cell level (Davies 1963; Alvarez and Sparrow 1965;Nayar and Sparrow 1967; Ichikawa and Sparrow 1967a, 1967b, 1968, 1969 Ichikawa 1968; Ichikawa et al 1969).The present study was undertaken to determine the relative biological efficiency (RBE) of 14.1 MeV fast neutrons as compared with 137Cs gamma rays in causing loss of reproductive integrity and in inducing somatic mutations in Tyadescantia stamen hairs.The main reason why this study was carried out is that extremely high RBE values of 10 to 50 sometimes more than 100 have been reported in plant materials for fast neutrons or other heavy particles by many authors (Matsumura et al 1963;Neary et al 1963;Smith et al 1964; Matsumura 1966 and many others, see Discussion). The RBE values reported in animals and microorganisms are generally much closer to 1 (at most 5) (see Kondo 1964).…”

EFFECTS OF 14MeV NEUTRONS IN HETEROZYGOTIC EINKORN WHEAT

“…The dose-square term tends to predominate in radiations of low LET, such as r-rays and most X-rays, and high dose or dose rates ; the linear term dominates in high LET tracks in general and at low doses or dose rates (Smith et al 1964). When somatic mutation rates in Y-ray lots are represented by a curve the relation of higher dosages to higher mutation rates is exponential .…”

“…Recently Smith et al (1964) He observed that the RBE increases with the increase of DNA content per nucleus, and he assumed that RBE is influenced by the size of the genetic target. Further study is necessary for the elucidation of these discrepancies.…”

Somatic mutations induced by furylfuramide (AF-2) in maize and soybean.

“…The average number of yellow-green stripes per leaf at the fourth leaf stage, considered to be the most useful criterion for the check of striping was used for scoring of the mutation frequency (Smith et al 1964(Smith et al , 1974Fujii 1978 The most likely origins of these spots are due to the process of somatic crossing over (twin spot), back mutation and forward mutation (single spot) (Vig 1975). Twenty five g in dry weight or about 130 seeds of this strain were soaked in 30 ml solution of different concentrations of AF-2 for 24 h at 20°C, under the dark.…”