Net Photosynthetic Production Research Articles

INFLUENCE OF MORPHOLOGICAL AND PHYSIOLOGICAL CHARACTERISTICS OF LENTIL (LENS CULINARIS MEDIK) SAMPLES ON YIELD COMPONENTS AND CORRELATION ANALYSES OF SOME CHARACTERISTICS

The aim of the research is to study the correlation between crop capacity and physiological characteristics of Lentil (Lens culinaris Medik). Determination of correlation between physiological characteristics and crop indicators, and assessment of their influence on grain yield give an opportunity to select genotypes with high crop capacity. According to the results of the analysis, strong positive correlation was detected among the valuable economic characters of lentil genotypes, i.e. between indexes such as number of grains per plant with grain weight per plant r=0.88*** and grain productivity per plant r=0.71***; between grain weight per plant and grain productivity in 1m2 plot r=0.79***; among chlorophyll ‘a’, chlorophyll ‘b’ and carotenoid content in leaves (r=0.92***, r=0.81*** respectively); between net photosynthetic productivity and biomass in 1m2 plot (r=**0.67;). Moreover, moderate positive correlation was detected among the indicators of grain number per plant (r=*0.54) and grain weight (r=**0.57) and grain productivity (r=*0.62). Among the lentil genotypes, K-72015 genotype, which has a good result based on the analysis of morphological-physiological and productivity characteristics, gives the opportunity to grow it as a new promising variety in the republic and obtain a higher yield.

The impact of biologically enhanced fertilisation systems on sweet potato (Ipomoеa batаtas) productivity and quality

The relevance of this research lies in determining the potential use of microbial preparations with varying functionalities to optimise the nutrition and stimulate the growth processes of sweet potato plants, as well as the synergistic effects of different preparations. The developed nutrient optimisation systems are designed to restore soil fertility, reduce the anthropogenic load on vegetable agroecosystems, produce high-quality yields, and increase sweet potato productivity without relying on energy-intensive production methods. This study aimed to investigate the impact of biological fertilisation systems on the biometric parameters, yield, and quality of sweet potato tubers. The research programme was implemented through field, statistical, computational-analytical, and laboratory methods. An increase in the number (7.33-9.83 per plant) and length (175.55-184.89 cm) of shoots was observed with the application of the biological preparations “Groundfix” + “Humifriend”, “Help-Rost for vegetables”, and “Mycofriend”. The use of foliar fertilisations in three terms of “Help-Rost for vegetables”, both in combination with “Mycofriend” during fertigation and with the foliar fertilisation “Humifriend”, resulted in maximal leaf mass formation on the plant (2.41-2.56 m2 /ha in the third decade of June and 23.12-27.45 m2 /ha in the third decade of August). Microbial preparations significantly increased net photosynthetic productivity by 28.9-63.9% during the period from the third decade of June to the third decade of July, especially when “Groundfix” and “Humifriend”, or “Humifriend” and “Help-Rost for vegetables” were combined. A substantial commercial yield of tubers (17.4 t/ha) was achieved by applying the mycorrhizal preparation “Humifriend” (1.5 L/ha) in the first fertigation and conducting three foliar applications of “Help-Rost for vegetables” at 2.0 L/ha. Treatments involving biological preparations demonstrated improvements in key biochemical parameters. The use of “Groundfix” + “Humifriend” and “Humifriend” + “Help-Rost for vegetables” resulted in a decrease in nitrate levels in the produce. The authors hypothesise that the optimal supply of micronutrients, particularly iron, manganese, and molybdenum, enhances the transformation of nitrates into organic matter. This research provides valuable insights for the rational application of biologically enhanced fertilisation systems to achieve high yields and quality of sweet potato tubers in various agricultural settings

Фотосинтез, минеральное питание и продуктивность лиственных и хвойных видов дендрофлоры центральной части Русской равнины

An ecological and physiological retrospective transformation of the data from the dry mass tables obtained by V.A. Usoltsev has been carried out for 7 coniferous and deciduous species (Larix sukaczewii, Picea abies, Pinus sylvestris, Betula alba, Quercus robur, Tilia cordata and Fraxinus excelsior) in the central part of the Russian Plain. In the age range from 5–20 to 80–200 years, the indicators of net photosynthetic productivity, net mineral productivity, net primary production, carbon sequestration, free oxygen emission and biological productivity have been determined at the organism level. When establishing these parameters, plants have been considered from the standpoint of ecology and the structure of a modular organism. The calculation of net mineral productivity has been carried out according to I.A. Muromtsev and V.M. Lebedev, and the net productivity of photosynthesis has been calculated according to A.A. Nichiporovich. A decrease in all physiological parameters with age has been recorded at a simultaneous increase in the ratio of root to photosynthetic potential (as an adaptive response to a decrease in the availability of nutrients). In all species, upon reaching the age of 20–30 years, a sharp decrease in the absorption activity of the roots has been revealed, which has stabilized at an extremely low level by the age of 50–60 years. The relationship between the listed plant indicators and their age for the studied species has been negative, and the relationship between mineral and biological productivity has been characterized as highly positive. In comparable age periods (30, 60 and 90 years), the studied species differed in nitrogen absorption by the root system by 21.7–28.0 times, in net photosynthetic productivity – by 4.4–7.0 times, in the value of net primary production – by 1.8–6.2 times, in nitrogen absorption – by 3.2– 6.1 times, in carbon sequestration and free oxygen emission – by 1.8–6.2 times, and in the mass of the whole plant – by 2.4–3.9 times. According to the accumulated dry mass, tree species at 90 years of age have been arranged in the following descending order: oak, spruce, larch, pine, linden, ash and birch.

Photosynthetic productivity of soybean (Glycine max L.) crops under various fertilization options and pre-sowing seed treatment

The objective of the research is to determine the impact of basic fertilization options, foliar feeding with organo-mineral fertilizer during critical periods of soy plant development, pre-sowing seed treatment with mycorrhizal biofertilizer, and mycorrhizal inoculant in combination with a fungicide on the dynamics of dry matter accumulation by the plants and the net productivity of photosynthesis in the soy crop. Methods. Field (for studying the interaction of the research object with biotic and abiotic factors); morphophysiological (for biological monitoring of productivity elements development during organogenesis stages); statistical (statistical analysis of research results). Results. The article presents research findings on the accumulation of dry matter by soy plants and the net productivity of photosynthesis in the crop across different growth and development stages. Equations have been calculated to establish the relationship between soy seed yield and the indicators of dry mass accumulation by the plants during the pod-filling phase. Conclusions. In modern agricultural practices aimed at achieving maximum seed yield, cultivation technology should include agronomic measures directed towards meeting the biological needs of the plant throughout the vegetation period and reducing the influence of adverse external factors. The highest levels of dry matter accumulation by plants in the study — 26.8–29.2 g/plant, were noted during the pod filling phase in variants with the application of N15P45K60+N30 fertilization, sowing seeds treated with mycorrhizal biopreparation and fungicide, and foliar feeding with organo-mineral fertilizers during the budding and flowering phases. The maximum indicators of net photosynthetic productivity of the crop in the study (8.52–11.29 g/m2×day compared to 5.46 g/m2×day in the absolute control) were observed during the interphase period of flowering and pod filling in variants with N45P45K60 fertilization. For the optimal seed yield of soybean variety Muza observed in the study, the optimal conditions were provided by a cultivation technology involving the application of N15P45K60+N30 fertilizers, pre-sowing seed treatment with mycorrhizal inoculant in combination with fungicide, as well as foliar feeding with organo-mineral fertilizers during the branching or budding phases, when the plants are forming flowers, pods, and seeds within the pods. Through the combination of these agronomic measures, plants accumulate dry matter during the pod filling phase at 25.9–27.4 g/plant, ensuring the net photosynthetic productivity of the crop during this developmental period at 5.60–6.10 g/m2×day, compared to 20.8 g/plant and 5.46 g/m2×day observed in the absolute control, respectively.

Effect of fertilization and microbial preparations on productivity of chickpea (<i>Cicer arietinum</i> L.)

The aim of the study was to optimize the nutritional status and increase the productivity of chickpeas through the application of mineral and organic-mineral fertilizers as well as microbial preparations based on nitrogen–fixing, phosphorus–mobilizing, and potassium-mobilizing microorganisms. The research was conducted in 2019-2021 in the Poltava Research Agricultural Station (Ukraine). NPK fertilizers were applied at a dose, of 20, 80, and 80 kg ha<sup>-1</sup>, respectively. Before sowing, the seeds were inoculated with the microbial preparation BiNitro Chickpea (BN) and Biofosforyn (BF). Foliar feeding was carried out with the microfertilizer Freya–Aqua™ C(12) Legumes (F). The development of chickpea leaf area and the intensity of organic matter production were largely determined by the supply of the main macronutrients to the plants. The introduction of NPK significantly increased leaf area and net photosynthetic productivity, while the effect of BN, BF, and F on the values of these indices was not significant. Their effect was manifested during the accumulation of aboveground biomass and the formation of yield structure elements. An increase in the seed yield was shown in relation to the application of NPK, microbial preparations, and micronutrient fertilizers. Regardless of the NPK, the highest yield was shown in the variant of the combination of BN+BF+F.

Photosynthetic activity of safflower under the effect of the elements of cultivation technology

Purpose. To establish the peculiarities of the formation of photosynthetic indicators of safflower varieties as affected by the elements of cultivation technology, specifically row width, row spacing, and sowing rate, in the Right Bank Forest Steppe of Ukraine. Methods. The research was carried out in 2021–2023 at the Agronomic Research Station of National University of Life and Environmental Sciences of Ukraine. The soil type was typical low-humus chernozem. The design of the field experiment provided for the study of the influence of the following factors: factor A – varieties: ‘Dobrynia’ and ‘Soniachnyi’; factor B – row width: 19, 38 and 57 cm; factor C – sowing rate: 100, 200 and 300 thousand seeds/ha. Results. The leaf area of safflower increased as the row width and sowing rate increased, which emphasizes the importance of optimizing the location of plants in the field for reaching effective photosynthesis and subsequent crop formation. In particular, at the time of flowering, in the ‘Dobrynia’ variety, the leaf area was 32.7, and in ‘Soniachnyi’ 31.2 thousand m2/ha; the varieties in general differed by 1.5 thousand m2/ha, which exceeded the value of the smallest significant differences by experience. At the same time, it was determined that the average leaf area for a row spacing of 19 cm was 30.7 thousand m2/ha. Increasing the row width to 38 cm contributed to the leaf area formation of 31.4 thousand m2/ha, which is 0.6 thousand m2/ha more than in the previous treatment. At a row spacing of 57 cm, the crops had a leaf area of 33.8 thousand m2/ha, which was 3.1 thousand m2/ha more than at a row spacing of 19 cm. Sowing rate of 100 seeds/ha resulted in leaf area of 31.0 thousand m2/ha, while sowing rates 200 and 300 thousand seeds/ha ensured a leaf area increase of 1.50 and 1.53 thousand m2/ha, respectively. In the budding stage, the highest content of the chlorophylls a and b in safflower plants was noted for row width of 38 cm and sowing rates of 200 and 300 thousand seeds/ha. The content of chlorophylls was 5.21 and 5.24 5.19 and 5.22 mg/g of dry matter, respectively, in ‘Dobrynia’, and 5.19 and 5.22 mg/g of dry matter in ‘Soniachnyi’. Conclusions. The highest parameters of the photosynthetic potential were obtained for row width of 57 cm and sowing rates of 200 and 300 thousand units/ha: in ‘Dobrynia’, 0.89–90 million m2 × day/ha in the period of budding – flowering, and 1.21–1.23 million m2 × day/ha in the period flowering – full maturity; in ‘Soniachnyi’ 0.93–0.94 million m2 × day/ha and 1.35–1.36 million m2 × day/ha, respectively. The parameters of net photosynthetic productivity (NPF) of crops in the period from flowering to full maturity in ‘Dobrynia’ was 1.59 g/m2 per day, and 1.47 g/m2 per day in ‘Soniachnyi’. At the same time, for a row width of 19 cm, the NPP was 1.73, and at 38 cm 1.76 g/m2 per day, and for a row spacing of 57 cm it was 1.11 g/m2 per day, which is 0.6 g/m2 per day less than for a row spacing of 19 cm. At the sowing rates of 100, 200 and 300 thousand seeds/ha, the NPP was, respectively, 1.29, 1.65, and 1.65 g/m2 per day. In ‘Soniachnyi’, the highest NPP indicators were obtained for a row spacing of 38 cm and a sowing rate of 300,000 plants/ha: 2.02 g/m2 per day; in ‘Soniachnyi’ for a row spacing of 19 and 38 cm and a seeding rate of 300,000 seeds/ha: 1.86 g/m2 per day for both options.

Formation of the photoassimilation apparatus of pea (Pisum sativum L.) crops under biostimulants in arid conditions of the Southern Steppe of Ukraine

The Southern Steppe of Ukraine is characterised by a range of unfavourable agro-climatic conditions, which leads to inhibition of growth processes, disruption of physiological processes and loss of crop yields. The use of environmentally safe bioregulators stimulates growth processes, optimises nitrogen nutrition, increases the adaptability of legumes to adverse conditions and increases yields. The purpose of this study was to find out the specific features of the influence of biostimulants on the formation of the photoassimilation apparatus of pea of the Oplot variety in the Southern Steppe of Ukraine. A 3-year small-plot study was conducted to determine the leaf area index, total chlorophyll content, and net photosynthetic productivity in pea crops. The biostimulants were used for pre-sowing and foliar treatment of pea crops in the budding phase at concentrations described in the methodology. It was found that Stimpo (25 ml/t + 20 ml/ha) increased the leaf surface index in different stages of vegetation of pea variety Oplot by 1.12-1.54 times and Regoplant (250 ml/t + 50 ml/ha) increased the leaf surface index by 1.18-1.38 times compared to the control. A significant increase in the chlorophyll content in pea stipules was recorded after foliar treatment of crops with biostimulants and exceeded the value of control plants by 9.0-10.4% in the BBCH stages 61(65) – 75(79). Based on 3-year results, the positive impact of biostimulants on net photosynthetic productivity was proven. Thus, Stimpo and Regoplant increased the net photosynthetic productivity of pea crops by 35% and 22%, respectively, in the budding (BBCH 51-61) and flowering (BBCH 55-65) phases. The obtained scientific results contribute to the widespread use of the studied biostimulants in the technology of pea cultivation in the Southern Steppe zone of Ukraine to increase crop productivity and obtain a high-quality crop

The influence of fungicidal protection on the formation of photosynthetic parameters of soybean crops

The purpose of the research was to determine the effect of fungicidal protection on the formation of the leaf surface area and photosynthetic indicators of soybean crops. The research was conducted in 2021– 2023 in the conditions of LLC «Savarske» Obukhiv district Kyiv region. The scheme of the experiment: Factor A. Varieties «Amadea», «Aurelina». Factor B. Fungicides. Control (treatment of seeds and plants with water), «Maxim Advance 195 FS» (1.25 l/t) (treatment of seeds before sowing), «Vibrance RFC» (1 l/t) (seed treatment before sowing), «Selest top 312.5 FS» (1 l/t) (seed treatment before sowing), «Standak Top» (2 l/t) (seed treatment before sowing), «Abacus» (2 l/ha) (during the growing season), «Maxim Advance 195 FS» (1.25 l/t) + «Abacus» (2 l/ha), «Vibrance RFC» (1 l/t) +»Abacus» (2 l/ha), «Selest top 312.5 FS» (1 l/t) + «Abacus» (2 l/ha), «Standak Top» (2 l/t) + «Abacus» (2 l/ha). The maximum indicators of the leaf surface area of soybean plants of the varieties «Aurelina» and «Amadea» were obtained in the phase of grain formation – 44.85 and 45.91 thousand m2 /ha. The smallest assimilation surface of crops was in the budding phase – 15.10 and 15.07 thousand m2 /ha. Under the influence of fungicidal protection the leaf surface area of varieties «Amadea» and «Aurelina» increased by 0.90 and 0.94 thousand m2 /ha in the flowering phase and by 3.11 and 3.46 thousand m2 /ha in the phase of grain formation, compared to control variants. The greatest increase in leaf surface area was noted for the combined use of fungicides «Standak Top» (2 l/t) for pre-sowing seed treatment and «Abacus» (2 l/ha) during the growing season. According to the results of dispersion analysis varietal characteristics (37.7 %) and fungicidal protection (35.4 %) had the greatest influence on the formation of the leaf surface area of soybean plants and the interaction of these factors was 12.3 %. The highest photosynthetic potential of the varieties «Amadea» and «Aurelina» was on the variants of fungicides application «Standak Top» (2 l/t) + «Abacus» (2 l/ha) – 3.09 and 3.16 million m2 × days/ha, «Selest top» (1 l/ t) + «Abacus» (2 l/ha) – 3.08 and 3.14 million m2 × days/ha and «Vibrance» (1 l/t) + «Abacus» (2 l/ha) – 3.06 and 3.13 million m2 × days/ha. The maximum values of the net productivity of photosynthesis in the varieties «Amadea» and «Aurelina» were obtained in the budding phase – 3.88–4.16 and 3.89–4.27 g/m2 × day. The use of fungicidal protection provided an increase of this indicator by 0.07–0.28 and 0.06– 0.38 g/m2 × day, compared to the control options. Depending on the accounting periods, the variety «Aurelina» was superior to the variety «Amadea» in leaf surface area by 1.6–3.8 % in photosynthetic potential by 1.2–2.5 % and in net photosynthetic productivity by 0.8–1.7 %. Key words: soybean, varieties, fungicides, crop protection, leaf surface area, photosynthetic potential, net photosynthetic productivity.

Fungal symbionts impact cyanobacterial biofilm durability and photosynthetic efficiency

Cyanobacteria contribute to over 25% of the world's net primary photosynthetic production and are pivotal in mitigating greenhouse gas emissions.1 This study unveils a previously unobserved symbiotic relationship between benthic cyanobacteria and fungi that have also adapted to life as a plant endophyte. The interaction suggests an initial phase of lichenization. We isolated Leptolyngbya frigida from the Naracauli stream, which emanates from abandoned Zn industrial waste in Sardinia. Seasonally, L.frigida participates in a biomineralization processes, mitigating the Zn transfer to rivers and, subsequently, the sea.2,3,4L.frigida is a benthic cyanobacterium that establishes a biofilm on the stream bed. Notably, the area predominantly features Juncus acutus. From these roots, endophytic fungi were predominantly isolated as Clonostachys rosea, a fungus recognized for its biocontrol capabilities against plant pathogens. An intriguing observation was made when L.frigida was cultured with C.rosea on a low-carbohydrate agar medium: the fungal mycelium transformed into wall-less forms, a phenomenon not documented previously. In liquid environments, the resulting biofilm first settled at the container's bottom. Even upon rising to the surface, this biofilm remained pigment rich. Concurrently, a secondary biofilm began its formation at the bottom. These fungal-integrated biofilms displayed enhanced resilience and superior photosynthetic performance compared to those without fungal presence. Moreover, the symbiotic relationship significantly amplified O2 emission and CO2 sequestration by the biofilm.

Влияние сроков посева на фотосинтез тритикале в условиях Приамурья

Abstract. In the Amur region the share of soybean in the structure of sown areas has reached 73.7 % over the last decade, the phytosanitary condition of agrocenoses has deteriorated, pesticide load on fields has significantly increased, which causes new ecological risks. Some reduction of this load may be caused by increasing the proportion of grain crops, including triticale. The purpose of the study was to establish the effective sowing date of spring triticale varieties providing optimal photosynthetic activity of agrocenoses in the conditions of Amur region. The method of field experiment by B. A. Dospekhov and determination of photosynthetic activity of crops by A. A. Nichyparovich were used. Scientific novelty. The photosynthetic activity of spring triticale varieties at different sowing dates in years with different meteorological conditions has been evaluated. Results. The greatest area of leaf apparatus is formed at sowing in April, 29 reaching maximum values in a phase of flowering in sort Ukro – 37,2 thousand m2/ha, in sort Yarilo – 30,4 thousand m2/ha, in sort Karmen – 33,0 thousand m2/ha. The correlation analysis revealed direct and strong influence of sowing dates on formation of the assimilative apparatus of plants and yield of spring triticale rxy = 0,833. Statistically significant differences were obtained p = 0.016. In the regression equation with increasing leaf area by 1 m2/ha the grain yield of triticale is expected to increase by 0.056 t/ha. Photosynthetic potential of the varieties differed in the years of research and depended on the value of the assimilating surface and the duration of the leaves. A regular decrease in net photosynthetic productivity from early to late sowing was established. The highest value of net photosynthetic productivity was obtained at sowing 15.04 – 2.03 g/m2 per day. The constituent elements of photosynthesis resulted in grain yields of the variety Yarilo – 2.26 t/ha, Ukro – 2.61 t/ha and Karmen – 2.23 t/ha.

Photosynthetic productivity of sorghum (Sorghum bicolor L. (Moenh) in the conditions of the Right-Bank Forest-Steppe of Ukraine

Sorghum (Sorghum bicolor L. (Moenh) is a technical, food, and fodder crop and can be used for various purposes, given its value, the acreage should be substantially expanded in Ukraine, and the elements of cultivation technology should be thoroughly examined. The purpose of the study was to determine the effect of the growth regulator on the photosynthetic productivity of sorghum in the conditions of the Right-Bank Forest-Steppe of Ukraine. The following methods were used in the study: field, measuring and weighing, mathematical, and statistical. The study was conducted in conditions of unstable moisture in the Right-Bank Forest-Steppe of Ukraine in 2016-2019. Based on the results of the study, it was determined that the use of a plant growth regulator affected photosynthetic productivity, namely, the leaf surface area, photosynthetic potential and net photosynthesis productivity. The indicators for the content of chlorophylls changed. Thus, the assimilation area of leaves reached a maximum with seed treatment and spraying of crops and amounted to 8.56 thousand m2 /ha during the tillering period, during the period of stem elongation – 29.6 thousand m2 /ha, during flowering and full ripeness – 40.32 and 4.97 thousand m2 /ha. Net photosynthetic productivity in the control was the lowest – 4.67 g/m2 , the use of a growth regulator on seeds and crops contributed to its increase by 0.27 and 0.79 g/m2 . With the treatment of seeds and crops, the net photosynthetic productivity was the highest and amounted to 6.12 g/m2 . The sum of chlorophylls a+b had the highest rates during the tasselling period and, depending on the experiment options, ranged from 4.36 to 5.35. The yield of grain and biomass also varied depending on the use of the preparation, and was the highest in the version with seed treatment and spraying of crops (7.1 and 35.9 t/ha). The close relationship between photosynthetic productivity and the yield of sorghum is also determined. The study can contribute to the widespread use of growth regulators in sorghum crops, ensure the full development of plants, and increase grain yields and biomass

Digital Database of Absorption Spectra of Diverse Flavonoids Enables Structural Comparisons and Quantitative Evaluations.

Flavonoids play diverse roles in plants, comprise a non-negligible fraction of net primary photosynthetic production, and impart beneficial effects in human health from a plant-based diet. Absorption spectroscopy is an essential tool for quantitation of flavonoids isolated from complex plant extracts. The absorption spectra of flavonoids typically consist of two major bands, band I (300-380 nm) and band II (240-295 nm), where the former engenders a yellow color; in some flavonoids the absorption tails to 400-450 nm. The absorption spectra of 177 flavonoids and analogues of natural or synthetic origin have been assembled, including molar absorption coefficients (109 from the literature, 68 measured here). The spectral data are in digital form and can be viewed and accessed at http://www.photochemcad.com. The database enables comparison of the absorption spectral features of 12 distinct types of flavonoids including flavan-3-ols (e.g., catechin, epigallocatechin), flavanones (e.g., hesperidin, naringin), 3-hydroxyflavanones (e.g., taxifolin, silybin), isoflavones (e.g., daidzein, genistein), flavones (e.g., diosmin, luteolin), and flavonols (e.g., fisetin, myricetin). The structural features that give rise to shifts in wavelength and intensity are delineated. The availability of digital absorption spectra for diverse flavonoids facilitates analysis and quantitation of these valuable plant secondary metabolites. Four examples are provided of calculations─multicomponent analysis, solar ultraviolet photoprotection, sun protection factor (SPF), and Förster resonance energy transfer (FRET)─for which the spectra and accompanying molar absorption coefficients are sine qua non.

Photosynthetic activity of winter wheat depending on fertilization and lime application on sod-podzolic soil in the conditions of Western Polissia

Topicality. Increasing the productivity of crop photosynthesis, i.e. the amount of organic matter synthesised per unit of leaf surface in a day, is an essential condition for high crop yields. The area of the leaf surface depends on the biometric parameters of the plant, the nutritional regime, as well as the duration of leaf activity, which significantly affects the accumulation of organic matter. Purpose. To identify the influence of mineral nutrition optimization and chemical amelioration on the formation of leaf surface area, photosynthetic potential, and net photosynthetic productivity in the main development stages of winter wheat grown on sod-podzolic soil in the conditions of the Western Polissia. Methods. Field experiment, calculation and statistical methods. Results. In particular, with the application of dolomite powder at a dose of 1.0 Hh and different fertilisation variants, the leaf surface area of plants increased from 1.5 ths. m2/ha to 4.12– 6.99 ths. m2/ha in the tillering stage, from 4.07 ths. m2/ha to 14.16–21.34 ths. m2/ha in the stem elongation stage, and from 2.59 ths. m2/ha to 5.33–9.49 ths. m2/ha in the heading stage, respectively, compared to the control (without fertilisation). It is noted over the years of research that the application of mineral fertilisers on the background of liming increased the indicator of photosynthetic potential by 2.6–3.5 times compared to non-fertilised one, and the net productivity of photosynthesis increased by 15.4–21.3 % compared to the control. Conclusions. The largest indicators of leaf surface area, photosynthetic potential, and net photosynthetic productivity in the tillering, stem elongation and heading stages were formed by application of N150Р50К125 + S40 + microfertilizer (two applications). The highest photosynthetic activity of winter wheat plants were noted in the stem elongation stage. Key words: winter wheat, fertilization, amelioration, leaf surface area, photosynthetic potential, net photosynthetic productivity

Application of Siliplant in the technology of growing potato minitubers in protected soil conditions

Under greenhouse conditions the effect of silicon-containing preparation with complex action, capable of simultaneously stimulating plant ontogenesis, photosynthetic processes and increasing the productivity and quality of plants was studied. The purpose of this study was to study the effect of the silicon-containing preparation Siliplant on the productivity and quality of minitubers of early maturity potato varieties Vineta in the system of virus-free (original) potato seed production. Results demonstrated that Siliplant causes an increase in biometric and physiological parameters such as plant height (by 5.7%), the number of stems in the bush (by 30%), weight of roots (by 16.7%), leaf area (by 23.7%), net photosynthetic productivity (by 37%) compared with the control variant.Root treatments with the preparation increased the yield by 19.3 % and the multiplication factor by 20.0 % compared to the control. Also, the use of Siliplant contributed to a slight increase in quality indicators (17.7 - 2.5 %), respectively, compared to the control. Thus, the use of Siliplant in the double root treatment of potato microplants in protected soil conditions is a promising agricultural technique in the conditions of Nizhny Novgorod region, allowing to increase the productivity of photosynthesis, yields and its quality.

Photosynthetic parameters of winter pea sowings under the effect of nitrogen fertilization and seed inoculation in the Right Bank Forest-Steppe of Ukraine

Purpose. To evaluate the photosynthetic parameters of winter pea sowings under the effect of seed inoculation and nitrogen fertilization in the Right Bank Forest-Steppe of Ukraine. Methods. The research was carried out in the years 2019–2021 in the fields of the Agronomic Research Station (a division of NULES of Ukraine, Kyiv region). Winter pea ‘NS Moroz’ was sown in the second half of September at the rate of 1.2 million seeds/ha. The width of the rows was 15 cm, and the seed sowing depth was 4–4.5 cm. The design of the experiment provided for the combined use of such technological factors as seed inoculation (without inoculation; Optimize Pulse, 3.3 l/t) and nitrogen fertilizer [main application + early spring top dressing (N0; N15 + N15; N15 + N30; N15 + N45; N30 + N0; N30 + N15; N30 + N30; N45 + N0; N45 + N15; N60 + N0)]. P45K45 was also applied in the primary fertilization as a background. Results. Seed inoculation and nitrogen fertilizers positively affect the photosynthetic activity of winter pea; however, the efficiency of their action largely depends on the application doses and timing, as well as the stage of crop development. It was established that in the autumn period of winter pea vegetation (complete sprouting–stalking), the influence of the studied agrotechnical measures on the leaf area index (LAI), photosynthetic potential (PP), and net photosynthetic productivity (NPP) was mostly insignificant. In the period of spring-summer vegetation, the effect of the factor of seed inoculation, as well as early spring fertilization with nitrogen, increased significantly, while the main fertilization decreased. The highest LAI (on average according to the experiment 31.4 thousand m2/ha) was formed in the flowering stage, PP during the stages of bean formation – ripening of seeds (0.75 million m²/ha per day). The use of seed inoculation compared to options without it contributed to the increase of these indicators by 5.33 and 0.17 million m2/ha per day, respectively. In the experiment, the maximum values of both LAI (35.77–36.45 thousand m²/ha) and PP (0.91–0.93 million m2/ha per day) were obtained when applying N15 + N30–45 and N30 + N30 on the background of seed inoculation, while the minimal in control treatments (N0). The regularities of the formation of the NPP were radically different. Its highest indicators during the period of the beginning of vegetation – budding (as well as in the following interphase stages) were observed primarily with the minimal application of fertilizers (N30 + N0, N15 + N15) or in the control treatments (N0), 8.1–9.2 g/m2 per day. Seed inoculation had no significant effect on the formation of NPP. The maximum content of chlorophyll a in plants (5.90 mg/g) was formed in the budding stage, gradually decreasing to 5.74 and 5.05 mg/g in the flowering and bean formation stages, respectively. Instead, the content of chlorophyll b was the lowest in the budding stage (12.37 mg/g), reaching its maximum in the flowering stage (19.71 mg/g) and slightly decreasing in the stage of bean formation – 16.37 mg/g of raw mass. Seed inoculation helped to increase the content of chlorophyll a by an average of 0.9–1.0 mg/g over growth stages and chlorophyll b by 1.4–2.2 mg/g. The best fertilization treatment was N15 + N30–45. Conclusions. Seed inoculation and nitrogen fertilization are significant and effective factors to intensify the photosynthetic activity of winter pea sowings. The patterns of the parameters of leaf s area, photosynthetic potential, net productivity of photosynthesis, and the content of photosynthetic pigments revealed in the study may be used to improve the cultivation technology to fully realize the crop potential productivity under the conditions of the Right Bank Forest‑Steppe of Ukraine.

Продукционный процесс райграса пастбищного в зависимости от предпосевной обработки семян и нормы высева

Perennial ryegrass (Lolium perenne L.) in modern fodder production is one of the valuable fodder plants for pasture and hay use. An important condition for the formation of herbage is to ensure the friendliness of seedlings and the safety of plants, which is achieved through the preparation of seeds before sowing and the optimal feeding area, by determining the seeding rate of crops. The aim of the research is the formation of perennial ryegrass agrocenosis, which ensures a high production process of plants in the conditions of the Middle Urals. Studies on the study of pre-sowing seed treatment and the seeding rate of perennial ryegrass were carried out in 2019-2022. in UNPK-Agrotechnopark FSBEIHE Izhevsk SAA on soddy medium podzolic medium loamy soil. According to the content of humus, soils of medium degree of cultivation with slightly acidic acidity. The content of mobile phosphorus and mobile potassium is very high. Growing seasons 2019-2020, 2022 were characterized by moderately humid warm weather with a hydrothermal coefficient (HTC) of 0.9-1.5, in 2021 the HTC was < 1, there was a lack of moisture for plants. Studies have found that on average for 2020-2022. The highest yield of green mass of perennial ryegrass of the 2nd life of 15.5-15.6 t/ha was formed during pre-sowing treatment with complex fertilizer Agree's Forsage. On average, according to the experiment, the highest productivity of 14.8 t/ha was obtained when sowing 6 million. Correlation analysis of the yield of green mass with photosynthetic potential and with net productivity of photosynthesis made it possible to establish a direct average relationship (r = 0.45 and r = 0.56, respectively). The highest index of leafiness of perennial ryegrass plants (65.6%) was noted in the variant with Agree's Forsage seed treatment and sowing at a rate of 6 million tons. Keywords: PASTURE RYEGRASS, PRE-SOWING SEED TREATMENT, SEEDING RATE, FOLIAGE, PHOTOSYNTHETIC POTENTIAL, NET PHOTOSYNTHETIC PRODUCTIVITY

Photosynthetic characteristics of subtending leaves and their relationships with soybean pod development under heat, drought and combined stresses

AbstractSoybean is usually grown under rain‐fed conditions, and long‐term drought stress often occurs with short‐term heat stress. This study aimed to investigate changes in the photosynthetic characteristics of subtending leaves and their relationships with pod development under short‐term heat, long‐term drought and their combined stresses. Short‐term heat stress lasted for 5 days began at R5 stage, and long‐term drought stress lasted from R5 stage until maturity, respectively. No significant effect was observed on pod development under short‐term heat stress alone due to unaffected net photosynthetic rate after treatment and PSII recovery after the heat stress release. Except that the reduction of sucrose content had been brought forward from 12 to 5 days after treatment under combined stresses, application of combined stresses caused similar responses to long‐term drought stress alone on the photosynthetic characteristics of subtending leaves and pod development, but more pronounced under combined stresses. Reduced pod weight and seed weight per pod under long‐term drought stress alone or combined stress due to a decrease in the net photosynthetic rate and production of sucrose and starch, especially after 19 days of treatment. Findings from this study demonstrate that under combined stress, long‐term drought stress had a dominant effect on the photosynthetic performance of subtending leaves and pod development over short‐term heat stress; moreover, even short‐term heat stress also exacerbates the negative effects of long‐term drought stress.

Kinetics of net photosynthetic oxygen production of a microalgae suspension at small doses of sulfide

Kinetics of net photosynthetic oxygen production of a microalgae suspension at small doses of sulfide

Photophysiological investigations of the temperature stress responses of Zygnema spp (Zygnematophyceae) from subpolar and polar habitats (Iceland, Svalbard)

ABSTRACT Zygnematophyceae are main primary producers in polar hydro-terrestrial habitats, characterized by extreme abiotic conditions. They are expected to be strongly impacted by climate change, leading to threats to subpolar and polar ecosystems. Two isolates of Zygnema from a subpolar (Iceland, Zygnema sp. I) and a polar Island (Svalbard, Zygnema sp. B) were compared by their photophysiological performance and phenolic content. A phylogenetic analysis was performed in a newly isolated Zygnema I where also morphology and ultrastructure were characterized. The rbcL sequence of the Icelandic Zygnema I was identical to that of Zygnema V, previously isolated from Svalbard, and phylogenetic analysis placed this strain into Zygnema clade 2. Average width of vegetative filaments (28 ± 0.7 µm) and ultrastructure was similar to closely related Zygnema strains. Zygnema I and Zygnema B were exposed to three different treatment temperatures (15, 20 and 25°C) for two weeks, then photophysiological parameters and cellular phenol contents were acquired. The maximum electron transport rate increased significantly with elevated temperatures, but non-photochemical quenching did not change. Net photosynthetic oxygen production was higher in Zygnema B, but decreased in both strains from 10 to 15°C measuring temperature. Zygnema I showed a significant decrease between 15/25°C-treated cultures above 20°C measuring temperature. The phenolic content did not change significantly with experimental treatments, the spectral absorption at 350 nm was significantly lower in Zygnema B when compared with Zygnema I. Taken together our results indicate that Zygnema B and Zygnema I cannot adapt to elevated temperatures.

Plant leaves structural and functional parameters in different breeding periods buckwheat varieties

Crops high productivity is largely determined by plants photosynthetic activity structural and functional indicators genotypic specificity. In this connection, we have conducted field studies on the photosynthetic potential, net productivity, photosynthetic capacity and leaf stomatal conductivity in 11 buckwheat varieties of different selection periods, which were conventionally divided into 3 groups: local populations (Orel region), old varieties - breeding of 1930-1960, and modern varieties - breeding of 1990-2010. It was shown that modern varieties, compared with predecessors, form more powerful photosynthetic potential due to the formation, mainly, large leaf plates, rather than increasing their functioning duration. At the same time, net photosynthetic productivity does not change significantly as a result of breeding. Its value depends to a greater extent on plant vegetation weather conditions than on their hereditary characteristics. At the same time, the leaves photosynthesis, transpiration and stomatal conductivity have undergone significant changes as a breeding result. These indicators values in the formation period and modern cultivars seeds ripening exceeded local populations and older varieties on average by 20.3 … 16.6 and 17.2%, respectively. It is noted that these indicators relationship with the variety final seed productivity is positive, and in some years has a significant value. In this regard, it is proposed in buckwheat crops to carry out directed selection for leaves increasing photosynthetic activity. Work in this direction may well be successful, as indicated by photosynthetic indicators of high heritable conditionality and broad polymorphism. Particular attention should be paid to genotypes with small and dense leaf plates characterized by high photosynthetic activity and low transpiration activity, which will ensure the sun and evaporated water converted energy-efficient use by plants for yield formation.