الفهرس 
Effect on growth, and fruit yieldOnly 14 pages are availabe for public view
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Abstract
Radiation results from a radioisotope undergoing nuclear decay. During the decay process the radioisotope changes from one isotope to another and emits one or more forms of radiation. Radioisotopes affect the environment in two ways: by emitting radiation that affects other materials, and by entering the normal pathway of mineral cycling and ecological food chains. There are three major kinds of radiation: alpha particles, beta particles and gamma rays. Alpha particles consist of two protons and two neutrons (a helium nucleus). Because of their relatively high mass, alpha particles do not travel far. In terms of humans health or other organisms, alpha radiation is most toxic or dangerous when inhaled or ingested since much of the radiation is absorbed by the tissue because alpha radiation is stopped within a very short distance by living tissue. Beta particles are electrons. Beta decay occurs when a proton or neutron spontaneously changes. Beta particles travel farther than alpha particles. Beta radiation is intermediate in its toxicity, although most beta radiation is absorbed by the body when a beta emitter is ingested. The third and most penetrating type of radiation is called gamma decay. During this type of decay, the radioisotope emits a gamma ray, a type of electromagnetic radiation similar to an x-ray but much more energetic and penetrating. All types of radiation and are toxic and dangerous inside or outside the body. Gamma radiations have been used in storage, mutation, induction, stimulation, and other purposes. Sodjan (1962) reported that the material and energy necessary for initial growth are already available in the seed, and so the young embryo has no need to form new substances, but only to activate those already stored in the cotyledons. The role of low doses of γ- radiation may be the increasing in enzymatic activation and awakening of the young embryo, which affects not only germination, but also vegetation growth and flowering. Exposing the dry seeds to low γ-irradiation doses resulted in increasing yield of some plants such as safflower (Abo-Hegazi et al., 1988), and Ammi visnaga (El shafie et al., 1993). Plant hormones play an important role in cell division, elongation, differentiation, and influence the biosynthesis of essential oils in aromatic plants. Hegazy et al., (1990) observed that.