The role of photorespiratory homeostatic mechanism in adaptation of plants to the radioactive polluted environment

Full text: It is known, that radiostability of the plants growing in conditions of intensive action of the certain stress - factor of environment, basically it is determined by adaptive changes their antioxidant and genetic systems. In the given work we investigated germination ability of seeds, dynamics of growth and development of sprouts on an example of A.pseudoalhagi, Zygophyllum, Juncus, E.angustifolia and P.harmala in conditions of chronic action of the increased radiation background. Was it is found out, that germination ability of seeds the parameter determining ability of an output of seeds from rest, and also the seed peel interconnected to mechanical properties, changes from a site 10 μR/h to a site 400μR/h. At different kinds character of these changes had various number. But it was revealed that viability of seeds and sprouts is increased in process of increase of values of the increased radiation background of growth up to 300 VR/h then it is reduced. Observably effect, we connect to character of activation of fermental systems, including enzymes of antioxidant systems and of photosynthesis under influence of the radiating stress - factor. So, in earlier spent works (Juravskaya, 2001) it is shown, that maxima of activity of enzymes SOD and peroxidase are observed at capacity of an exposition doze 110-250 μR/h, or at the total absorbed doze 2,38-5,4 mZv for the period of maturing of seeds. At higher values of a radiation background activity of enzymes antioxidant systems is reduced, and it should be result in increase of radiosensitivity of plants, as we observably at values of a radiation background > 250-300 μR/h. Also it was shown, that carboxilase activity of RBPK/O (Rubisko) is reduced at increase of a radiation background > 120-150 μR/h. The last testifies to increase of oxigenase activity of RBPC/O which serves as alternative photosynthesis in conditions of lack NI2. But increase of oxigenaze functions of RBPK/O so, strengthening photorespiratory glicolate ways is observed under the most various stressful conditions resulting in formation of active oxygen forms. In conditions of the increased radiation background we connect universal character of changes of development of plants observably by us to nonspecific activation of photorespiration. Results of ours EPR researches of processes of electronic transport in the irradiated leaves also have confirmed our assumptions. Thus, we have the basis to consider, that the photorespiratory glicolate way plays the big role in adaptation of plants to the radioactive polluted environment. Various levels of radiosensitivity different kinds are determined by genetically determined level of photorespiration. Not casually, that between efficiency and a level of photorespiration of plants there is positive correlation