Влияние фотонов ближней ультрафиолетовой области на рост и развитие свеклы сахарной (Beta vulgaris L. ssp. vulgaris var. saccharifera Alef.) в условиях закрытой агробиотехносистемы

Relevance and methodology. In order to determine the effect of near-ultraviolet radiation with a wavelength of 380 nm on the growth and development of a sugar beet hybrid plant, Smena was grown for 82 days under LED lighting with phytolamps and under conditions of increased UV-A intensity of the light range (an increase in the UV/PPFD ratio (0.027) compared with the control (0.0075) while maintaining the ratio of the remaining sites spectrum). The study was carried out on the basis of the digital software package "Synergotron" with a controlled internal environment.Results. An increase in the share of UV-A in the illumination spectrum leads to a significant change in the biometric indicators of plants – the aboveground biomass increases by 2.2 times compared to the control, and the mass of the underground part (root crops), on the contrary, decreases by 86.9%. At the same time, the share of root crops in the total biomass of plants decreases from 60% in the control to 30%. The morphological structure of the leaf apparatus changes: the proportion of petioles increases significantly compared to leaf blades (64.8% of petioles in aboveground biomass, whereas in the control 30%). Probably, an increase in the share of UV-A in the spectrum can favorably affect the cultivation of leaf forms of beets and other root crops. UV-A radiation leads to a change in the chemical composition of root crops, in particular, a decrease in the accumulation of dry substances (by 1.58%) and a decrease in sugar content (by 1.8%). An increase in the proportion of UV-A in the irradiation spectrum changes the parameters of chlorophyll fluorescence and contributes to an increase in the maximum quantum yield of Fv/Fm, non-photosynthetic quenching of NPQ fluorescence and a decrease in the real quantum yield of photosynthesis Y(II), as well as the electron transport rate (ETR).Актуальность и методология. С целью определения влияния ближнего ультрафиолетового излучения длиной волны 380 нм на рост и развитие растения свеклы сахарной гибрида Смена выращивали в течение 82 суток при светодиодном освещении фотолампами и в условиях усиления интенсивности УФА диапазона света (повышение отношения UV/PPFD (0,027) по сравнению с контролем (0,0075) при сохранении соотношения остальных участков спектра). Исследование проводили на базе цифрового программного комплекса «Синерготрон» с регулируемой внутренней средой.Результаты. Увеличение доли УФ-А в спектре освещения приводит к существенному изменению биометрических показателей растений - надземная биомасса увеличивается в 2,2 раза по сравнению с контролем, а масса подземной части (корнеплоды), наоборот, снижается на 86,9%. При этом доля корнеплодов в общей биомассе растений снижается с 60% в контроле до 30%. Изменяется морфологическая структура листового аппарата: существенно возрастает доля черешков по сравнению с листовыми пластинками (64,8% черешков в надземной биомассе, тогда как в контроле 30%). УФ-А излучение приводит к изменению химического состава корнеплодов, в частности, понижению накопления сухих веществ (на 1,58%) и снижению сахаристости (на 1,8%). Повышение доли УФ-А в спектре облучения изменяет параметры флуоресценции хлорофилла и способствует повышению максимального квантового выхода Fv/Fm, нефотосинтетического тушения флуоресценции NPQ и снижению реального квантового выхода фотосинтеза Y(II), а также скорости электронного транспорта (ETR)

Effect of cryptochrome 1 deficiency and spectral composition of light on photosynthetic processes in A. thaliana under high-intensity light exposure

The role of cryptochrome 1 in photosynthetic processes and pro-/antioxidant balance in the Arabidopsis thaliana plants was studied. Wild type (WT) and hy4 mutant deficient in cryptochrome 1 grown for 20 d under red (RL, 660 nm) and blue (BL, 460 nm) light at an RL:BL = 4:1 ratio were kept for 3 d in different lights: RL:BL = 4:1, RL:BL:GL = 4:1:0.3 (GL - green light, 550 nm), and BL, then were exposed to high irradiance (4 h). Activity of PSII and the rate of photosynthesis in WT and hy4 decreased under the high irradiance in all spectral variants but under BL stronger decrease in the activity was found in the hy4 mutant than in WT. We assumed that lowered resistance of photosynthetic apparatus in the hy4 mutant may be associated with the low activity of the main antioxidant enzymes and reduced content of low-molecular-mass antioxidants in the mutant compared to the WT

EFFECT OF ADDITIONAL LOW INTENSITY LUMINESCENCE RADIATION 625nm ON PLANT GROWTH AND PHOTOSYNTHESIS

Tomato (Licopersicon esculentum Mill.) and cabbage (Brassica oleracea L. var. Cymosa) plants were grown in a glass greenhouse under natural radiation in summer. A half of pots with plants were placed under an ordinary (control) and the other part under the \u22Redlight\u22 (experimental variant) polyethylene films, both 100μm thick. The Redlight film had the same transmittance but transformed 3.5% of ultraviolet light falling on a plant into fluorescent radiation with a main maximum of 625nm. Plants grown under modified solar radiation exhibited high intensity of photosynthesis at light saturation, a shift of saturation region to the higher level of radiation, as well as high efficiency of photosynthesis under low light intensity. An appreciable increase in the CO_2 assimilation rate and biological productivity under modified light irradiation of plants allows recommending the method of additional plant irradiation under controlled conditions. Under natural irradiation of plants this can be achieved by the use of Redlight film

EFFECT OF ADDITIONAL LOW INTENSITY LUMINESCENCE RADIATION 625nm ON PLANT GROWTH AND PHOTOSYNTHESIS

Tomato (Licopersicon esculentum Mill.) and cabbage (Brassica oleracea L. var. Cymosa) plants were grown in a glass greenhouse under natural radiation in summer. A half of pots with plants were placed under an ordinary (control) and the other part under the "Redlight" (experimental variant) polyethylene films, both 100μm thick. The Redlight film had the same transmittance but transformed 3.5% of ultraviolet light falling on a plant into fluorescent radiation with a main maximum of 625nm. Plants grown under modified solar radiation exhibited high intensity of photosynthesis at light saturation, a shift of saturation region to the higher level of radiation, as well as high efficiency of photosynthesis under low light intensity. An appreciable increase in the CO_2 assimilation rate and biological productivity under modified light irradiation of plants allows recommending the method of additional plant irradiation under controlled conditions. Under natural irradiation of plants this can be achieved by the use of Redlight film

The Effect of Short-Term Heating on Photosynthetic Activity, Pigment Content, and Pro-/Antioxidant Balance of <i>A. thaliana</i> Phytochrome Mutants

The effects of heating (40 °C, 1 and 2 h) in dark and light conditions on the photosynthetic activity (photosynthesis rate and photosystem II activity), content of photosynthetic pigments, activity of antioxidant enzymes, content of thiobarbituric acid reactive substances (TBARs), and expression of a number of key genes of antioxidant enzymes and photosynthetic proteins were studied. It was shown that, in darkness, heating reduced CO2 gas exchange, photosystem II activity, and the content of photosynthetic pigments to a greater extent in the phyB mutant than in the wild type (WT). The content of TBARs increased only in the phyB mutant, which is apparently associated with a sharp increase in the total peroxidase activity in WT and its decrease in the phyB mutant, which is consistent with a noticeable decrease in photosynthetic activity and the content of photosynthetic pigments in the mutant. No differences were indicated in all heated samples under light. It is assumed that the resistance of the photosynthetic apparatus to a short-term elevated temperature depends on the content of PHYB active form and is probably determined by the effect of phytochrome on the content of low-molecular weight antioxidants and the activity of antioxidant enzymes

Effects of Iron Oxide Nanoparticles (Fe₃O₄) on Growth, Photosynthesis, Antioxidant Activity and Distribution of Mineral Elements in Wheat (<i>Triticum aestivum</i>) Plants

Engineered nanoparticles (NPs) are considered potential agents for agriculture as fertilizers and growth enhancers. However, their action spectrum differs strongly, depending on the type of NP, its concentrations, and plant species per se, ranging from growth stimulation to toxicity. This work aimed to investigate effects of iron oxide (Fe3O4) NPs on growth, photosynthesis, respiration, antioxidant activity, and leaf mineral content of wheat plants. Wheat seeds were treated with NP for 3 h and plants were grown in the soil at two light intensities, 120 and 300 μmol (photons) m−2·s−1, followed by physiological assessment at several time points. High NP treatment (200 and 500 mg·L−1) enhanced plant growth, photosynthesis and respiration, as well as increasing the content of photosynthetic pigments in leaves. This effect depended on both the light intensity during plant growth and the age of the plants. Regardless of concentration and light intensity, an effect of NPs on the primary photochemical processes was not observed. Seed treatment with NP also led to increased activity of ascorbate peroxidase and reduced malondialdehyde (MDA) content in roots and leaves. Treatment with Fe3O4 also led to noticeable increases in the leaf Fe, P, and K content. It is concluded that iron oxide (Fe3O4)-based NP could enhance plant growth by improving photosynthetic performance and the availability of Fe and P