EFFECTS OF RADIATION AND SUPRAGRAVITATIONAL FORCES ON GROWTH. Thesis

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1963

OSTI ID:4120915

Edwards, B F

The combined effects on growth of supranormal gravity and x radiation were studied. Germinating wheat seedlings and 10-day chick-embryo muscle tissue were used. Both were subjected to varying doses of x radiation, followed in some cases by continuous centrifugation to produce a force of 150 times normal gravity. Wheat seedlings were remarkably resistant to radiation. They were slightly stimulated by a 600-r dose and relatively unaffected by doses below 2400 r. Wheat coleoptile growth was depressed to approximates 50% by radiation doses of approximates 40,000 r and also by the continuous gravitational force of 150 g. Root length was more readily affected, being reduced to 50% by 10,000 r of x radiation and to 25% by the force of 150 g. Above 40,000 r there was little further change in growth response of either coleoptile or root. When irradiated plants were centrifuged, the growth depression resulting from radiation did not begin until larger doses were administered than those which affect non- centrifuged plants. The total inhibition of growth obtained was much less than the sum of the depression effects produced by each factor acting alone. The influence of hydration of seeds on their radiosensitivity was studied. Generally, seeds irradiated dry were less affected than seeds irradiated after soaking for more than 3 hours. A reversal phenomenon at higher radiation doses was not altered in centrifuged plants. Chick-embryo muscle cultures responded to both radiation and centrifugation by a decrease in the number of fibroblasts which grow out from the initial explant. The growing striated muscle was not grossly affected by either factor at the levels employed in these experiments. Cultures centrifuged at 150 g following irradiation at 200, 400, and 800 r showed little evidence of additional inhibition of fibroblast outgrowth, even at 800 r, although giant cells and nuclear abnormalities were increased. This study indicates that growth of both wheat seedlings and chick-muscle cultures are less radiosensitive under the influence of higher-than-normal gravitational force than at normal gravity. (M.P.G.)

• Research Organization: Originating Research Org. not identified
• NSA Number: NSA-18-011801
• OSTI ID: 4120915
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ANIMAL CELLS
BIOLOGY AND MEDICINE
BIRDS
CENTRIFUGATION
CEREALS
CHICKENS
EMBRYOS
GRAVITATION
HUMIDITY
MUSCLES
RADIATION DOSES
RADIATION EFFECTS
RADIOSENSITIVITY
ROOTS
SEEDS
TISSUES
WHEAT
X RADIATION