Azerbaijan National Academy of Science

Doctor of Biological Sciences,prof. 

1.The qualitative and quantitative characteristics of radionuclides were studied both on individual soil profiles and in the horizontal distribution plane in one of the local pollution zones of the Absheron Peninsula (on the territory of the Ramani iodine plant). We studied both the migration of radionuclides polluting the territory along the earth-plant chain, and the features of their accumulation in individual plant organs. The biomorphological and reproductive features of herbaceous wild plants under the conditions of chronic exposure to ionizing radiation created by contaminating the territory with radionuclides, and the effect of this radiation on the photosynthesis process and the antioxidant system of plant protection were also studied.

2. The effect of ionizing radiation on the growth and development of both themselves and the first generations of beans, eggplant, cucumber and tomato, whose seeds were treated with different doses of gamma rays before sowing, the dynamics of dose-dependent changes in the amount of malonodialdehyde (MDA) - product lipid peroxidation formed in the leaves of plants under conditions of radiation stress, as well as the dynamics of dose-dependent changes in the amount of proline - an antioxidant that plays the role of a "trap" for reactive oxygen species. The effect of different doses of ionizing radiation on the antioxidant system of plant protection was studied on the basis of the determination of the activities of catalase (KAT) antioxidant enzymes, ascorbate peroxidase (APO), and superoxide dismutase (SOD). It is established that there are obvious differences in the biometric sizes of the fruits of the first generation of the studied plants in comparison with both parent and control fruits; as the radiation dose increases, membrane lipids undergo more “destruction”, and as a result, MDA content increases. The amount of proline varies depending on the dose, along with proline, antioxidant enzymes such as SOD, CAT and APO are also actively involved in protecting plants from the harmful effects of ionizing radiation. Damage caused by radioactive radiation is saved in the next generation only in special cases. Based on the results obtained, it was revealed that increasing the dose in the low-dose region enhances the formation of reactive oxygen species, as a result of which the cell membranes are even more destroyed. In such conditions, the antioxidant protection system of plants, along with the acceleration of the synthesis of antioxidants, such as proline, also causes the activation of antioxidant enzymes. In the field of large doses, the destructive effect, along with lipids, covers the biological macromolecules themselves.

3. Considering that plants grow under the influence of several extreme environmental factors, and that such effects can lead to a decrease in the productivity of cultivated plants and a decrease in the biodiversity of wild plants, the growth and development of certain grain crops (peas, beans, corn) in various concentrations of  NaCl are studied. , the seeds of which were treated with γ rays in different doses, and based on the synthesis of chlorophylls and quantitative changes in carotenoids, brought some clarity to the process of photosynthesis under the conditions of double stress. To assess the “destruction” caused by reactive oxygen species in cell membranes under double stress, the dynamics of quantitative changes in malonodialdehyde, the main product of membrane lipid peroxidation, as well as total protein from the radiation dose and NaCl concentration, were studied. Based on changes in the amount of low molecular weight antioxidants, such as proline, carotenoids, anthocyanins and flavonoids, and the activity of antioxidant enzymes, such as SOD, CAT, and APO, the functioning of the antioxidant defense system (AODS) under joint and separate radiation and salt stresses was evaluated. It is established that for peas and corn:

- both for seeds irradiated with different doses, and for seeds grown in different concentrations of NaCl, there is a clear dependence of plant growth and development on both the radiation dose and the salt concentration in stressful situations; - in such conditions, the antioxidant protection system of the plant is activated, while this activation includes both antioxidant enzymes of this system and low-molecular antioxidants;

- an increase in radiation dose causes changes in antioxidant enzymes. These changes at different concentrations of NaCl are different. Thus, a decrease in SOD activity in NaCl concentrations of 1, 5, and           10 mM, not counting minor deviations, occurs against the background of an increase in the activities of CAT and APO. However, at salt concentrations of 50 and     100 mM, on the contrary, a decrease in the activities of KAT and APO occurs against the background of an increase in SOD activity, i.e., under stressful conditions, antioxidant enzymes in some way show balanced activity;

- functioning of AODS in stressful conditions with an increase in radiation dose causes acceleration of synthesis of stress proteins. The observed tendency to increase the acceleration of protein synthesis is more large-scale with a high salt concentration;

- the same dynamics of changes in the content is characteristic of carotenoids. So, as increasing the dose of radiation, and salt concentration leads to an increase in the number of these pigments. It is believed that an increase in the number of carotenoids under the combined effect of radiation and salt stress is an adaptive response of plant cells to stressful conditions;

- unlike carotenoids, anthocyanins in the area of lower doses are characterized by a tendency to increase and, conversely, in the area of higher doses, a tendency to decrease. Such a dynamics of changes persists at practically all concentrations of NaCl, only at low salt concentrations, this change is of a sharply resonant nature;

- among the results of the study of green pigments is interesting that the studied plants have a higher level of Xl a than Xl b. With regard to the dose-dependent and concentration-dependent changes in the content of chlorophylls, it becomes clear that increasing the dose of radiation at low concentrations of NaCl leads to a noticeable increase in the content of Xl a, and a slight increase in Xl b. And at high salt concentrations, an increase in the radiation dose does not cause noticeable changes in the amount of green pigments. Considering the fact that plant growth and development is organically linked to the synthesis of green pigments, the combined effect of two stress factors causes a more inhibitory than stimulating effect;

- well-coordinated work of antioxidant enzymes and low molecular weight antioxidants ensures effective protection of plants against stress factors;

- in such conditions, depending on the intensity of stress factors, the antioxidant enzymes of the plant ASCP function in a balanced and coordinated manner both among themselves and with low molecular weight antioxidants, which protects the plants from the harmful effects of stress factors. It is believed that the study of details of adaptive mechanisms to such conditions in plants, will allow you to choose as plant varieties that are more resistant to stressful conditions, and resistant to stress factors of plants. These mechanisms will also allow to manage these processes 4. The effect of presowing treatment with high sterilization doses of 0.3, 0.5, 1, 1.5 and 2 kGy on the growth and development of potato plants, beans, eggplants, cucumbers and tomatoes was studied on the basis of changes in the content of photosynthetic pigments and changes in the dynamics of low molecular weight and high molecular weight antioxidants, evaluated the effect of high-dose radioactive radiation on photosynthesis and on AODS functioning. It is determined that:

- the lethal dose for seed potatoes treated with pre-sowing irradiation is 0.3 - 2 kGy, for beans, cucumber and tomatoes 0.5 - 2 kGy, for eggplant 1-2 kGy. It is believed that although an irradiation dose of 0.3 kGy and more destroying microorganisms, makes potatoes suitable for long-term storage and use, but potatoes irradiated at such doses are not suitable for subsequent sowing;

- a dose of 0.3 kGy accelerates the synthesis of chlorophyll a and b in eggplant, these doses have virtually no effect on the synthesis of green pigments in beans and tomatoes, and in cucumbers, inhibiting the synthesis of chlorophyll a, accelerate the synthesis of chlorophyll b; - the amount of MDA in plants, seeds, which were subjected to pre-sowing irradiation in sterilization doses, increases, respectively, in a row - beans, cucumber, tomato, eggplants;

- beans and eggplants in which the seeds were not treated with γ rays before sowing contain the same amount of protein, and seed treatment with γ rays before sowing can not significantly change the protein content;

- in the control sample of tomato the amount of carotenoids is higher than in the control sample of beans. Presowing treatment of tomato and pea seeds with γ-rays leads to an increase in the number of carotenoids and cannot change the amount of these pigments in cucumbers, and in eggplant an increase in the irradiation dose results in an imperceptible, then a sharp decrease in yellow pigments;

- treatment of seeds with radioactive rays at a dose of 0.3 kGy stimulates the synthesis of anthocyanins and proline in all plants;

- the control sample of cucumber has high APO and KAT activity, and the irradiation of seeds in all the studied plants reduces the activity of these enzymes;

- both control and test samples of the studied plants demonstrate similar activity in APO and CAT, in other words, these enzymes play a similar role in the functioning of the antioxidant defense system;

- beans, tomatoes and eggplants, which have low APO and CAT activity, show high SOD activity, and cucumbers, which, on the contrary, have high APO and CAT activity, have low SOD activity. In other words, the action of antioxidant enzymes in plants is balanced in a certain sense.