title: The influence of the development of temperate fruit tree species on the potential for their uptake of radionuclides.
abstract: This paper reviews the published literature that describes the phenological development of above and below ground organs of temperate fruit trees (top fruit), particularly with respect to apple (Malus domestica). Critical information is presented which is considered appropriate in developing an understanding of the potential for top fruit species to take up radionuclide contaminants from the atmosphere and the soil. Information is cited on how climatic and edaphic factors influence the growth and development of temperate fruit trees, the phenological production of their leaf area and the development and growth of their fruit and hence the potential for foliar and fruit uptake of radionuclides from the atmosphere. The study also reports on the importance of the distribution and phenological development of roots in the soil and the potential for their uptake of radionuclides from the soil. The effects of above and below ground management procedures, within temperate fruit orchards, on potential radionuclide uptake are also considered. It is concluded that the potential for the uptake of radionuclides by temperate fruit tree species will depend on a number of phenological and physiological factors. For uptake from the soil these factors include; root distribution and density in the soil profile, seasonal changes in the production and distribution of roots, and the presence and amount of water in the soil. These factors are themselves influenced by rootstock type and its growth vigour, scion type and its growth vigour, tree age, spacing of trees in the orchard, orchard management practices (presence or absence of weeds or grass under the trees) and soil type and depth. Direct uptake by the shoot, however, will be influenced by the climatic conditions at the time of exposure and the presence of foliage. Deposition and uptake are likely to change with leaf area development and the ability of radionuclides to penetrate the cuticle of the leaf changes with seasonal development. Transport of radionuclides to the fruit may also depend on the time of season, as the importance of the xylem and phloem transport routes can change with the growth and development of the fruit.
authors.affiliation: Horticulture Research International, East Malling, Kent ME19 6BJ, UK. chris.atkinson@hri.ac.uk
authors.forename: C J
authors.initials: CJ
authors.lastname: Atkinson
authors.forename: A D
authors.initials: AD
authors.lastname: Webster
mesh_terms: D000383:Agriculture; D018517:Plant Roots / Q000737:chemistry; D011868:Radioisotopes / Q000493:pharmacokinetics*; D019685:Rosales / Q000254:growth & development* / Q000502:physiology; D012987:Soil; D012990:Soil Pollutants, Radioactive / Q000493:pharmacokinetics*; D014018:Tissue Distribution; D014197:Trees
chemical_list: D011868:Radioisotopes; D012987:Soil; D012990:Soil Pollutants, Radioactive