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Anatomical alterations of P haseolus vulgaris L . mature leaves irradiated with X ‐rays
Author(s) -
De Micco V.,
Arena C.,
Aronne G.
Publication year - 2014
Publication title -
plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 1435-8603
DOI - 10.1111/plb.12125
Subject(s) - phaseolus , biology , chloroplast , photosynthesis , irradiation , ionizing radiation , radioresistance , biophysics , radiation , botany , horticulture , biochemistry , cell culture , optics , physics , genetics , nuclear physics , gene
Abstract The cultivation of higher plants in Space involves not only the development of new agro‐technologies for the design of ecologically closed Space greenhouses, but also understanding of the effects of Space factors on biological systems. Among Space factors, ionising radiation is one of the main constraints to the growth of organisms. In this paper, we analyse the effect of low‐ LET radiation on leaf histology and cytology in Phaseolus vulgaris L. plants subjected to increasing doses of X ‐rays (0.3, 10, 50, 100 Gy). Leaves irradiated at tissue maturity were compared with not‐irradiated controls. Semi‐thin sections of leaves were analysed through light and epi‐fluorescence microscopy. Digital image analysis was applied to quantify anatomical parameters, with a specific focus on the occurrence of signs of structural damage as well as alterations at subcellular level, such as the accumulation of phenolic compounds and chloroplast size. Results showed that even at high levels of radiation, general anatomical structure was not severely perturbed. Slight changes in mesophyll density and cell enlargement were detected at the highest level of radiation. However, at 100 Gy, higher levels of phenolic compounds accumulated along chloroplast membranes: this accompanied an increase in number of chloroplasts. The reduced content of chlorophylls at high levels of radiation was associated with reduced size of the chloroplasts. All data are discussed in terms of the possible role of cellular modifications in the maintenance of high radioresistance and photosynthetic efficiency.