No abstract

Aim. To study the adaptive reactions of common wheat (Triticum aestivum L.) and emmer (T. dicoccum Schrank ex Schübl.) seedlings using the parameters of oxidative homeostasis under polyethylene glycol (PEG)-induced osmotic stress and metal (Fe, Cu, Mn, Zn) mixture nanoparticles treatment. Methods. Biochemical assays: spectrophotometric measurements of the activity of antioxidant enzymes (SOD, CAT), the content of proline and products of lipid peroxidation; mathematical statistics. Results. The state of oxidative homeostasis of common wheat (cv. Favorytka, cv. Trypilska) and emmer (cv. Holikovska) seedlings under PEG-induced osmotic stress conditions was investigated and analyzed. The development of lipid peroxidation processes under stress conditions was observed only in the cv. Trypilska seedlings. It was established that proline content in common wheat seedlings of both cultivars under stress had signifi cant (10 : 1) predominance in roots, while in roots and shoots of emmer seedlings proline content increased equally. SOD activity in the leaves of the studied cultivars under stress conditions was not changed. At the same time, an increase of SOD activity by 30 % under osmotic stress was shown in the roots of common wheat of cv. Favorytka, while it decreased by 25 % in the roots of cv. Trypilska. It was established that CAT activity in the roots of both cultivars of common wheat decreased by 25 and 38 %, respectively, whereas in emmer of cv. Holikovska this parameter increased by 35 % under osmotic stress. Presowing treatment using a colloidal solution of a mixture of biogenic metal nanoparticles contributed to the induction of SOD activity in the roots of cv. Favorytka, CAT activity in the leaves of cv. Trypilska, and CAT activity in the roots and leaves of cv. Holikovska compared to non-treated plants. It should be noted that the treatment of plants with metal nanoparticles promoted the restoration of CAT activity in the roots under osmotic stress conditions to the level of the control plants in both wheat varieties. Conclusions. It was established that osmotic stress provoked the development of oxidative processes and inhibition of the activities of antioxidant enzymes, in particular, SOD and CAT, in the seedling roots of common wheat cultivars. It was shown that emmer wheat seedlings of cv. Holikovska can maintain redox homeostasis and avoid oxidative damage under osmotic stress conditions. It was found that the seedlings of common wheat and emmer demonstrated different strategies of osmotic regulation under osmotic stress, which is confi rmed, in particular, at the level of proline accumulation. It was shown that the application of colloidal solutions of metal nanoparticles induced an antioxidant protection system and reduced the oxidative processes, which are inevitable effects of drought. The obtained results indicate that common wheat cultivars are more susceptible to drought compared to emmer wheat of cv. Holikovska.

Metal-and metal oxide-based nanoscales of titanium dioxide, silver, zinc oxide, cerium dioxide, copper, copper oxide, aluminum, aluminum oxide, nickel, and iron are most commonly used in industries and, therefore, are mostly studied for their influence on different biological objects including plants [1]. Al nanoscales characterized by a high wear-resistance, have good thermal conductivity, resist to strong acids and alkali-containing materials, are easily shaped, and have high strength and stiffness. This makes them a prime material to use in making products that include high-temperature electrical insulators, high-voltage insulators, thermometry sensors, wear pads, ballistic armor, and grinding media [2]. There is no single opinion on the influence of Al nanoscales on physiological and biochemical processes in plants in the literature available: positive and negative effects are noted. The direct exposure of Al nanoscales leads to phytotoxic and enhancement alterations in different plants at morphological, cellular, biochemical, and molecular levels [3].

Потенційний вплив нанопрепаратів на рослини потребує ретельного вивчення, оскільки дані щодо їхньої екотоксичності дуже суперечливі [1, 2]. Безпосередню токсичність наночастинок металів та їхніх оксидів пов'язують із хімічним складом сировини для їхнього виготовлення (наприклад, за рахунок вивільнення токсичних іонів), фізичними характеристиками наночастинок (розмір, форма, структура поверхні) або/та генерацією ними активних форм кисню в тканинах організму [3]. Крім того, опосередкована фітотоксичність наночастинок пов'язана із порушенням поглинання поживних речовин коренями внаслідок зміни хімічного складу ризосфери за наявності наночастинок [4]. Наноколоїди есенціальних металів, фітотоксичність яких досліджується в даній роботі, вже знайшли широке застосування в рослинництві у складі протимікробних препаратів (наночастинки Cu, CuO) або ж як добрива (наночастинки Mn) на противагу традиційним солям (MnSO 4) [5]. Проте пошуки способів покращення фізико-хімічних властивостей наноматеріалів тривають. Відомо, що поверхня наночастинок багатьох металів має підвищену хімічну активність і миттєво взаємодіє з киснем, водою та органічними сполуками. Тому на