Аномалії проростання насіння очерету звичайного з водойм Чорнобильської зони відчуження за умов додаткового гострого йонізувального опромінення

Abstract

В роботі представлено результати досліджень аномалій розвитку насіннєвого потомства очерету звичайного з водойм Чорнобильської зони відчуження, що отримало дозу додаткового гострого опромінення 25, 75 та 150 Гр. Аналіз показав, що у спектрі аномалій переважають некрози зародкових коренів. Збільшення дози гострого опромінення у градієнті хронічного дозового навантаження на батьківські рослини викликало збільшення загальної кількості аномалій у паростків насіння за рахунок порушень органогенезу. Досліджено кореляційний зв’язок різних груп аномалій з показниками життєздатності паростків насіння.

В работе представлены результаты экспериментальных исследований аномалий семенного потомства тростника обыкновенного с водоемов Чернобыльской зоны отчуждения после дополнительного острого облучения в дозах 25, 75 и 150 Гр. При увеличении дополнительной дозы острого облучения установлено существенное повышение аномальности жизнеспособных семян растений с водоема-охладителя ЧАЭС и оз. Вербного, где мощность дозы, полученной родительскими растениями соответственно составляет 1,5 и 0,03 мкГр/час, что в 10 и 1000 раз меньше в сравнении с мощностью дозы на семенное потомство растений оз. Глубокого (15 мкГр/час). Наблюдалась достоверная обратная корреляция жизнеспособности проростков зерновок тростника и доли аномальных проростков семян. Обнаруженные аномалии отнесли к трем группам: семена с хлорофильными аномалиями листьев, нарушениями геотропизма и аномалиями органогенеза. Наиболее многочисленной была группа аномалий органогенеза. Доля каждой группы в спектре аномалий проростков зависела от дозовой нагрузки, получаемой родительскими растениями в водоеме и от дозы дополнительного острого облучения.

The paper deals with the investigation of anomalies of the common reed (Phragmites australis) seed progeny from the water bodies of the Chernobyl Exclusion Zone (ChEZ) after receiving additional acute ionizing radiation dose of 25, 75 and 150 Gy. The range of seedling abnormalities included three groups: chlorophyll leaf anomalies, organogenesis disturbances, geotropizm disorders and root necroses. The ratio of each group in the range of seedling abnormalities depended on the dose received by the parent plant in the water body, as well as on the additional acute irradiation exposure. High number of various seedling anomalies was detected in case of the ChEZ water bodies. The group of germs with the organogenesis disturbances was predominating, its ratio reached up to 60 and 34% in case of seedlings from the Glyboke Lake and the Cooling Pond of the Chernobyl NPP respectively, where the average dose rate, absorbed by parent plants, is about 15 and 1.5 μGy hour-1. Less number of chlorophyll abnormalities and geotropism disorders of germinated seeds was indicated – not more than 6%. The number of seedling abnormalities decreased from 30 to 3-6% in conditions of 25-, 75- and 150-Gy additional acute irradiation. Insignificant ratios of organogenesis disturbances, geotropism disorders and chlorophyll anomalies of leafs – 20, up to 6.7 and 2% respectively, were indicated for seedlings from the water body with about 0.03 μGy hour-1 background absorbed dose rate (Verbne Lake). Additional acute irradiation caused the reliable reduce of seedling abnormalities – up to 2%, as well as to vitality loss. With the increase of additional acute irradiation dose, root necroses of seedlings from the Verbne Lake increased in up to 26%. In case of the Cooling Pond of the Chernobyl NPP, investigated index increased in up to 35%, like the Verbne Lake. The minimal number of seedling root necroses was indicated in sampling from the Glyboke Lake – 16%, however after additional acute irradiation increase up to 150 Gy, their number increased in more than 4 times. The reliable negative correlation between the vitality and majority of seedling abnormalities was detected in background sampling (r = -0,95 – -0,98), except of insignificant chlorophyll anomalies (r = -0,30). In normal conditions, the general tendency of vital seedling abnormalities increase took place, when the additional irradiation dose increased, as in case of background sampling. Additional acute irradiation caused significant discrepancies of occurrence of seedling abnormalities of plants from the water body, where the parent plants receive 1.5 μGy hour-1 total absorbed dose rate (the Cooling Pond of the Chernobyl NPP). Vitality did not correlated with organogenesis disturbances in this sampling (r = -0,05). However, the most of the vital germs had chlorophyll anomalies, which affected the vitality. Conversely, the increase of the geotropism disorders, is connected with the growth of vitality of seedlings from the Cooling Pond of the Chernobyl NPP. Vitality of seedlings of plants from the Glyboke Lake (1.5 μGy hour-1 total absorbed dose rate) reliably correlated with organogenesis disturbances (r = 0,96), it confirms that germs with similar disorders were vital. Correlation between vitality and chlorophyll anomalies of leaf and root necroses, was reliably negative (r = -0,73 and -0,77 respectively). Geotropism disorders in given sampling did not effect the vitality of seedlings (r = -0,26). Thus, additional acute irradiation of seed progeny of the common reed Phragmites australis, indicated significant variability in the occurrence of various types of seedling anomalies depending on the absorbed dose of long-term low-intensity ionizing radiation. Analysis of the occurrence of incompatible with life seedling anomalies –embryonic root necroses, proved that the seed progeny of plants that are exposed to long-term irradiation of absorbed dose rate of 15 μGy hour-1, is more resistant to radiation in comparison to seedlings of plants that grow in conditions of natural background radiation exposure and long-term exposure of 1.5 μGy hour-1. It is made up an assumption about radioadaptation of the plants of the common reed Phragmites australis, populations of which are exposed to 30-years long-term low-intensity irradiation in water bodies of ChEZ in the gradient of the total absorbed dose rate of 5-22 μGy hour-1.