by K. G. Sharma
One and the same substance may be both a poison and a medicine, depending upon the dose. A similar situation is in radiobiology. Under its influence any living organism produces various chemical compounds, some of them are inhibitors they suppress vital processes others are effectors they act as stimulants. The ratio between the two groups largely determines the overall effect of radiation on the organism.
In radiation biology technology, the stimulating action of ionizing radiation is used to promote the growth of many agricultural crops, Genetic effect of radiations are employed to produce new plant varieties and increase their yields. The ability of ionizing radiation to suppress certain biochemical processes is utilized to lengthen the shelf life of foods.
Pre-sowing treatment of seeds with gamma radiation, for instance, raises the yielding capacity of cereals by 10 to 15 percent and that of vegetables by 20 to 30 percent, while exposure to radiation of the seeds of radish, cucumbers and tomatoes grown in hothouses, guarantees their early ripening (5 to 10 days ahead of schedule). Besides, seed treatment improves the biochemical properties of the plants. For example, the green mass of maize grown for silage has a higher fat and protein content, while cabbage contains more vitamin C. Sugar beets increase their sugar content, and sunflower seeds, their oil content. The stimulating effects of low doses of ionizing radiation may be used not only in crop farming. In particular, a good promise is held out by experiments in which hen’s eggs are exposed to gamma radiation before being placed in an incubator. The new technology increases the yield of chickens from treated eggs. Hens that develop from exposed eggs have a good egg laying ability. Ionizing radiation can be successfully used to ‘treat fish embryos to increase the production of fingerlings. Different having organisms and farm crops absorb afferent quanta of lionizing radiation pre-sowing treatment of carrot seeds involves 2,500 to 4,000 rad, cucumber seeds 300 rad, and pre incubator exposure of eggs mere 3 10 5 rad, (One rad is equivalent to 100 ergs of energy absorbed by one gramme of substance).
Way back in 1925, Soviet scientists Nadson and Fitippoy discovered that ionizing radiation could also be applied to effect induced mutation plant and animal organisms for selection. Today’s tasks of the selectionists is not only to produce high yielding cereals but also to guarantee the required biochemical content of the grain. Using the proximate method developed to determine the amount and composition of proteins and changing the inherited forms of me tabolism by ionizing radiation, it is possible to conduct a purposeful search for new varieties with pretailored properties.
It has been found out that certain doses of gamma radiation are capable ‘of suppressing the immune ability of the plant. But this is only part of the solution; The point is that before inoculation of graft has to be deprived Of all its eyes. This is an extremely Labour consuming operation and is at present carried out mainly by hand. As eyes are removed, injuries are inflicted, with bacteria and parasitic fungi penetrating into vegetable tissues, Correctly chosen doses of gamma radiation can suppress eye sprouting and inflict no damage on the graft tissues. The high penetrating ability of gamma rays fully mechanizes the operation, with labour productivity rising 20 fold.
Radiations can also be used to control the activity of microorganisms and food pests. In particular, exposure of prepared meat to ionizing radiation allows it to be stored at room temperature for 10 days. The taste, smell and quality remain unchanged. Sterilization of foodstuffs and medical products is very effective, too. For the first time it is possible to sterilize products in any package form and thus to preclude secondary infection in packaging, In addition, radiation methods alone can sterilize polymer made injection syringes and parts of heart and lung and kidney machines, ‘Chemical and heat techniques are inapplicable in sterilization of biological tissues, such as blood vessels and cardiac valves. Only ionizing radiation can destroy bacteria without injuring the living cells of the tissue. Radiation biology methods are effective in neutralizing effluent waters. Only recently the problem was to reduce the harm done to nature by effluents, while now we take a different look. Effluent sediments are a nutrient for various microorganisms. Following radiation treatment, they may become a source of fertilizers and feed biomass. Radiation methods today are becoming indispensable for ‘many branches of the economy, their further introduction will help to intensify production.
Article extracted from this publication >> July 7, 1995
