Photosynthetic Potential Research Articles

Growth and productivity of winter pea under different weed control practices in the Right Bank Forest Steppe of Ukraine

Purpose. To analyze the features of growth and formation of the winter pea productivity under various weed control options in the Right Bank Forest Steppe of Ukraine. Methods. The research was conducted at the Salyvonky State Enterprise of the Institute of Bioenergy Crops and Sugar Beet of the National Academy of Agrarian Sciences of Ukraine (Bila Tserkva district, Kyiv region) in 2020–2023. The agronomic practices used in the experiment were conventional for the zone of insufficient moisture of the Right Bank Forest Steppe of Ukraine, with the exception of the studied elements. Results. The best conditions for the growth and development of pea plants and leaf area formation were noted for the autumn application of the herbicide Corum in the BBCH 12 stage. This contributed to the fact that during the flowering period, the leaf area of the crop plants was more than 36 thousand m2/ha, and in the spring, it was more than 35 thousand m2/ha. The use of the same herbicide in the BBCH 14 ensured the formation of a leaf area of more than 35 thousand m2/ha, which corresponded to the indicators of the treatment with herbicide Pulsar 40 in the BBCH 12. That is, winter pea crops, during flowering, are able to effectively limit the sprouting of new weed plants and the growth and development of their existing plants, which was facilitated by the timely application of the herbicide. The application of the herbicide Corum turned out to be the best option from the point of view of the formation of a high level of photosynthetic potential (PP) of pea crops. For the application in the herbicide in autumn in the BBCH 12 stage at an application rate of 1.50 l/ha, the FP was 1.57 thousand m2/ha × day. At the same time, application rate of 1.25 l/ha slightly differed from the best in the experiment. The spring application of the herbicide Corum in the BBCH 12 at application rates of 1.25 and 1.50 l/ha contributed to obtaining PP of 1.51–1.52 thousand m2/ha × days, which also provided the highest indicators in the spring block of the experiment. Since, thanks to the application of Corum herbicide, winter pea plants formed a large leaf area, the indicators of net photosynthesis productivity of crops in the best treatments were at the level of 2.89 g/m2 per day for autumn application and 2.64 g/m2 per day for spring application. The highest PP of pea in the experiment was provided by the use of herbicide Pulsar Flex, which was probably achieved due to the slightly smaller leaf area formed by the crops and the mild effect of the herbicide on the plants, which reduced the risk of stress in crops and contributed to active plant growth and development. Conclusions. Autumn application of Corum herbicide to protect crops was the most efficient for increasing pea yield. In all years of research, as well as on average in the experiment, the application of 1.50 l/ha of this herbicide in the BBCH 12 provided the highest yield: 3.08, 1.98, and 3.68 t/ha in 2021, 2022, and 2023, respectively, and 2.91 t/ha on average over three years. In the second place in terms of yield formation efficiency was the application of the same rate of herbicide in the BBCH 14, while later application dates did not contribute to a high level of realization of the crop biological potential. Spring application of Corum was also effective at both application rates in the BBCH 12 stage of weed development: the yield of pea seeds was 2.52 and 2.62 t/ha, respectively.

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.

Effect of growth regulator and microfertilizer on potato yield in Yakutia

The results of studying the effect of growth regulator Novosil and microfertilizer Mag-Bor on growth parameters, photosynthetic activity of plants and yield of potato variety Yakutyanka in conditions of Central Yakutia are presented. The soil of the experimental plot is permafrost floodplain loamy with insufficient content of humus (1.8–2.2%), mobile compounds of magnesium (1.25 mg/100 g), molybdenum microelements (0.03 mg/kg), manganese (29.0 mg/kg), and boron (0.30 mg/kg) in the arable layer. It was found that treatment of potato plantings with Novosil increased plant mass by 19–24%, leaf area and photosynthetic potential by 5–7%, with magnesium-boron fertilizer (at a dose of 5 g/l) by 9 and 2%, respectively. Significant direct relationship of plant weight with its height and number in a bush (r = 0.71. 0.81), leaf area and photosynthetic potential values – with height, number and weight of plants (r = 0.56. 0.82) was revealed. The contribution of the preparations to the variability of indicators was 37–68%, weather conditions and factor interactions – 3–33%. It was demonstrated that treatment of plants with Novosil and together with Mag-Bor 5 g/l increases tuber yield in comparison with the control by 6.4–6.6 t/ha (34–35%), and with magnesium-boron fertilizer at a dose of 5 g/l – by 2.5 t/ha (14%). In the variants Mag-Bor 10 g/l and Novosil + Mag-Bor 10 g/l the yield was at the level of control or increased by 1.6 t/ha (8.5%), and under drought conditions it decreased by 0.5–0.9 t/ha. The share of the preparations' influence on the yield variability amounted to 68%, weather conditions – 26%, and factor interactions – 4%. Regression equations were calculated, allowing to forecast leaf area and tuber yield by plant weight in the flowering phase promptly and with high accuracy. The difference between the actual and the calculated values was 4.4–5.4%.

FORMATION OF THE PHOTOSYNTHETIC PRODUCTIVITY OF SOYBEAN CROPS UNDER A BIOLOGIZED FOOD SYSTEM

The process of photosynthesis and the intensity of its work are the basis of the formation of productivity and the level of productivity of agrophytocenoses of agricultural crops, including soybeans. One of the main tasks of modern intensive cultivation technologies is the creation of optimal conditions for the development of the assimilation surface, its long-term operation and the maximum accumulation of organic matter by plants. This scientific article presents the results of field research on the impact of biological preparations of different mechanisms of action created on the basis of phosphorus and potassium mobilizing and mycorrhizal forming bacteria on the photosynthetic productivity of soybean crops at different levels of mineral fertilization, namely on the dynamics of the leaf surface area, the formation of the photosynthetic potential of crops and net productivity of photosynthesis. Field research was conducted on gray forest medium-loamy soils at the experimental field of the Agronomic Research Field of VNAU during 2017-2021. According to the results of the research and the processing of the obtained data, it was established that the use of Groundfix soil biofertilizer at the rate of 5 l/ha during the pre-sowing cultivation period and the pre-sowing treatment of seeds with the biological preparation Micofrend at the rate of 1,5 l/t against the background of complete mineral fertilization ensured the formation of the maximum in the experiment the area of the assimilation surface was 40,4 thousand m2/ha, which exceeded the control by 11,6 thousand m2/ha. In addition, based on the calculations, it was found that this version of fertilizer provided the formation of the highest photosynthetic potential in the experiment at the level of 3,153 million m2 days/ha, and the net productivity of photosynthesis, which, depending on the interphase period, was 5,44, 2,16, 1,76, 2,53 and 1,34 g/m2 per day. The article also provides the results of correlation calculations of the closeness of the connection between the area of the leaf surface, the amount of accumulated dry matter and the level of productivity.

Sap flow and leaf gas exchange response to a drought and heatwave in urban green spaces in a Nordic city

Abstract. Urban vegetation plays a role in offsetting urban CO2 emissions, mitigating heat through tree transpiration and shading, and acting as deposition surfaces for pollutants. The frequent occurrence of heatwaves and of concurrent drought conditions significantly disrupts the processes of urban trees, particularly their photosynthesis and transpiration rates. Despite the pivotal role of urban tree functioning in delivering essential ecosystem services, the precise nature of their response remains uncertain. We conducted sap flux density (Js) and leaf gas exchange measurements of four tree species (Tilia cordata, Tilia × europaea, Betula pendula, and Malus spp.) located in different urban green areas (Park, Street, Forest, and Orchard) in Helsinki, Finland. Measurements were made over two contrasting summers 2020 and 2021. Summer 2021 experienced a local heatwave and drought, whereas summer 2020 was more typical of Helsinki. In this study, we aimed to understand the responses of urban tree transpiration (measured with sap flux density) and leaf gas exchange to heatwave and drought conditions, and we examined the main environmental drivers controlling the tree transpiration rate during these periods. We observed varying responses of Js during the heatwave period at the four urban sites. When comparing the heatwave and no heatwave periods, a 35 %–67 % increase in Js was observed at the Park, Forest, and Orchard locations, whereas no significant change was seen at the Street site. Our results also showed that Js was higher (31 %–63 %) at all sites under drought conditions compared with non-dry periods. The higher Js values during the heatwave and dry periods were mainly driven by the high atmospheric demand for evapotranspiration, represented by the high vapor pressure deficit (VPD), suggesting that the trees were not experiencing severe enough heat or drought stress that stomatal control would have decreased transpiration. Accordingly, photosynthetic potential (Amax), stomatal conductance (gs), and transpiration (E) at the leaf level did not change during heatwave and drought periods, excluding the Park site where a significant reduction in gs was seen. VPD explained 55 %–69 % of the variation in the daily mean Js during heatwave and drought periods at all sites. At the Forest site, the increase in Js saturated after a certain VPD level, likely due to low soil water availability during these hot and dry periods. Overall, the heat and drought conditions were untypical of the region but not excessive enough to restrict stomatal control and transpiration, indicating that ecosystem services such as cooling were not at risk.

Pre-planting treatment of potato tubers with biopreparations in conditions of Central Yakutia

The results of the study of the influence of pre-planting treatment of tubers with biopreparations based on Bacillus subtilis bacterial strains on the growth, photosynthetic activity of plants, disease damage and yield of the Yakutyanka potato variety under the conditions of Central Yakutia are presented. The experiment scheme included control (tubers without treatment), treatment of the tubers before planting with the biofungicide Phytosporin-M and the suspension of an equal ratio of B. subtilis TNP-3 and B. subtilis TNP-5 bacterial strains isolated from permafrost soils of Yakutia. It was found that treatment of tubers before planting with biopreparations accelerated sprouting by 2-4 days, increased biomass and photosynthetic activity of the plants (by 6-19%), the number (11) and weight (48–57%) of tubers, reduced the damage of the plants by a complex of diseases by 1.8–2.9 times and increased the yield by 7.4–8.8 t/ha (54–64%). The share of biopreparation influence in the variability of economically valuable indicators and yield was shown to be 45–96%, weather conditions 1–38%, factor interaction 1–11%. Significant positive correlation of the yield, number and weight of the tubers with the height, number and weight of the plants, leaf area, photosynthetic potential (r = 0.81...0.98), and negative correlation with rhizoctonia disease, potato scab, and common mosaic (r = –0.80...–0.96) were revealed. There was an inverse relationship between disease prevalence and indices of plant growth and photosynthetic activity (r = –0.33...–0.96). Damage by potato scab and rhizoctonia disease increases 1.4–1.8 times in arid conditions, while blackleg, rugose and common mosaic damage decreases 1.6–2.5 times. Regression equations were calculated, which allow to predict leaf area, photosynthetic potential and yield by plant mass promptly and with high accuracy (R2 = 0.85...0.95). When the bush weight in the flowering phase increased by 100 g, the leaf area of the plants increased by 2.3 thousand m2/ha, photosynthetic potential during the growing season by 120 thousand m2 · day/ha, and the yield by 9.7 t/ha. The difference between actual and calculated values amounted to 2.7–4.7%.

Late nitrogen fertilization increases biomass of cotton bolls by reinforcing source[sbnd]sink performance

The decrease in reproductive organ biomass is a principal constraint for cotton yield under conditions of limited nitrogen (N). We aimed to alleviate this challenge by reasoning N applications in order to exploit the photosynthetic potential and improve the distribution of photosynthates. Cotton crops were grown in a two-year field experiment (2019–2020) under N-reduced cultivation (23.9 ×104 plants ha−1, 76 cm row spacing, and applied 240 kg N ha−1), N fertigated with five ratios at squaring (SQ): flowering to peak boll (FPB): late peak boll (LPB), i.e., 4:6:0 (N460), 3:6:1 (N361), 2:6:2 (N262, Control), 1:6:3 (N163) and 0:6:4 (N064). Impacts of N treatment (ratio) were investigated for leaf area, chlorophyll content, photosynthetic characteristics, photosynthetic N use efficiency (PNUE), sink capacity characteristics, and biomass accumulation. Correlations between traits were also analyzed. Compared with conventional N262, N064 increased reproduction organs biomass by 10.1–10.3%. Furthermore, during the LPB to boll opening stage, N064 increased fruit branch leaf area by 1.4–26.8%, chlorophyll content by 6.4–27.6%, net photosynthetic rate by 15.1–35.9%, actual photosynthetic efficiency by 14.4–41.6%, photochemical quenching by 18.0–57.7%, PNUE by 15.7–41.0%, and sink capacity by 6.7–10.5%; while it decreased foliage branch leaf area by 13.1–22.4% and chlorophyll a/b by 6.1–10.2%. Overall, late N fertilization was an effective strategy to (1) retain post-flowering photosynthetic capacity by developing more fruit branch leaf area with higher chlorophyll content and lower chlorophyll a/b, (2) optimize sourcesink relationship by increasing boll capacity, and (3) increase biomass in reproductive organs, thus enhancing sustainable and efficient production of cotton under N-reduced cultivation in arid regions.

Biometric parameters and yield of maize hybrids in dependence on agricultural technology elements

Modern innovative corn hybrids of the intensive type have a significant individual response of morphometric and photosynthetic indicators to the density of the coenosis. Establishing correlations of these indicators with the level of grain yield of different genotypes of corn hybrids and determining the optimal parameters for the manifestation of these characteristics allows technological measures to ensure the realization of productive potential. The purpose of the research was to establish the peculiarities of the formation of biometric and photosynthetic indicators of innovative corn hybrids depending on the genotype, and the density of the coenosis, and to determine the correlationregression dependence of these characteristics. Field experiments were conducted during 2019-2021 in the agroecological zone of the Central Forest Steppe. The soil of the experimental site is typical chernozem, the precursor is soybean. With the help of field, morphometric, laboratory, and statistical (dispersion and correlation analysis) it was established that the height of the plant, the height of attachment of the upper (productive) cob, the area of the assimilation surface of one plant, and the photosynthetic potential depended on the studied factors – the genotype of the hybrid and the density of the coenosis. A medium and strong positive correlation was established between productivity and these characteristics, which indicates the need to technologically ensure optimal plant growth and development at various stages of the development of corn plants of all hybrids. The mid-ripe hybrid Zedan 32 (FAO 320) showed maximum productivity at a density of 80,000 plants/ha and sharply reduced productivity at a density of up to 100,000 plants/ha. Mid-early hybrids showed maximum yield at a density of 90,000 plants/ha, while an increase or decrease in plant density from the optimum led to a decrease in grain yield. Therefore, each hybrid has its optimal coenosis density for obtaining the maximum grain yield, and increasing the photosynthetic potential of crops by agrotechnical measures does not always guarantee a parallel increase in the grain yield of corn hybrids

Photosynthetic activity of winter barley crops (Hordeum vulgare L.) depending on mineral nutrition and biostimulators

Barley in Ukraine has always been and is the leading fodder crop, the grain of which is the most balanced in terms of amino acid composition. The use of mineral fertilizers remains the most influential and necessary factor in increasing plant productivity and an effective means of preserving soil fertility. The goal is to determine the indicators of the leaf surface area of barley plants and the photosynthetic activity of winter barley varieties depending on the complex application of doses of mineral fertilizers and biological preparations in the conditions of Right-Bank Forest Steppe. The highest indicators of the leaf surface area of winter barley plants were recorded in the areas where mineral fertilizers were applied; foliar top dressing with nitrogen fertilizers was carried out, and the biological preparation Agrinos B was applied. With the introduction of mineral fertilizers and biological preparation N10P26K26 + N46 + N8 + Agrinos B, 1.0 l/ha in the phase of the beginning of emergence into the tube, the leaf surface area of plants in the earing phase was the highest, in Atlant Myronivskyi variety — 58.30 thousand m2/ha, which is by 25.68 thousand m2/ha more than the control plots, PASO barley variety — 61.13 thousand m2/ha, which is more than the control plots by 27.71 thousand m2/ha. On average, during the three years of research, when applying a dose of N10P26K26 + N34 fertilizers in top dressing in the phase of the beginning of tillering, the photosynthetic potential of the Atlant Myronivsky winter barley variety was 1.76 million g/m2 per day, the PASO variety, respectively, 1.90 million g/m2 per day, which is more than the control areas by 0.58– 0.69 million g/m2 per day. The highest indicators of net productivity were noted on the plots where mineral fertilizers and biopreparation N10P26K26 + N46 + N8 + Agrinos B were applied, 1.0 l/ha in the phase of the beginning of emergence into the tube, variety Atlant Myronivskyi — 3.04 g/m2 per day, variety PASO 3.12 g/m2 per day.

Effect of Potash Fertilizers on Changes in Some Physiological Parameters of Beetroot (Beta vulgaris var. esculenta Salisb.) under Absheron Conditions

During the years of research, depending on the norms of fertilizers, the leaf surface area, the content of chlorophyll in the leaves, the photosynthetic potential of the sowing field, the coefficient of economic efficiency of photosynthesis, the specific surface density of the leaves, the total wet and dry biomass were studied plants, and the results were subjected to statistical processing and their level of reliability was assessed. The introduction of organic and mineral fertilizers for beetroot plants has a positive effect on the leaf surface area, the value of photosynthetic potential, the indicators of coefficient of economic efficiency of photosynthesis and specific surface density of the leaves, as well as on the amount of total dry and wet biomass.

ОЦЕНКА ПОКАЗАТЕЛЕЙ ФОТОСИНТЕТИЧЕСКОЙ ДЕЯТЕЛЬНОСТИ ПОСЕВОВ TRITITRIGIA CZICZINII TZVEL. В УСЛОВИЯХ МОСКОВСКОЙ ОБЛАСТИ

The study of the photosynthetic activity of crops allows us to more fully characterize the agricultural crop and identify signs that can later be used in the breeding of this crop and obtaining highly productive varieties. The research was conducted in the conditions of the Moscow region in 2021-2022. The objects of research were the variety of a new synthetic culture of trititrigia - Pamyati Lyubimovoy, the line of trititrigia M12 and the variety of winter wheat Rubezhnaya. In 2021, the line № 3202 had the maximum leaf area (23.2±4.4 thousand m2/ha), and the Pamyati Lyubimovoy had the maximum value of photosynthetic potential (366.5±19.5 (thousand m2 x day)/ha). The highest biological yield capacity of trititrigia was 506.4±52.7 g/m2 (M12), while the biological yield capacity of Rubezhnaya was 722.9±106.8 g/m2. In 2022, the largest leaf area and photosynthetic potential were noted on trititrigia of Pamyati Lyubimovoy variety (48.81±6.1 thousand m2/ha, 754.5±133.4 (thousand m2 x day)/ha, respectively). The greatest biological yield capacity of trititrigia was observed in the Pamyati Lyubimovoy variety (693.1 ± 29.7 g/m2). Biological yield capacity of winter wheat Rubezhnaya reached 1056.9 ±69.5 g/m2. Thus, the morphological and biological features of trititrigia are largely reflected in photosynthetic indicators and differ from photosynthetic processes occurring in winter wheat crops.

Growth and yield of soybean plants under water deficit and application of foliar fertilizer

The objective of this work was to assess the effects of a commercial foliar fertilizer (H2 Protector; H2 Agrosciences, Orizona, Brazil) on growth and yield of soybean plants grown under water deficit. The experiment was conducted for 105 days from November 2021 to February 2022 in a greenhouse at the State University of Goiás, in Ipameri, GO, Brazil. A completely randomized design was used, with a 2×5 factorial arrangement and three replications. The first factor consisted of foliar fertilizer rates (0 and 300 mL ha-1), and the second factor consisted of water depths applied to the plants (25%, 50%, 75%, 100%, and 125% of the daily evapotranspiration). Morphological variables and agronomic components of the crop were analyzed at 60 and 90 days after emergence. Water deficit at the R5 reproduction stage limits the growth and yield of soybean plants. The important results found for vegetative and reproductive growth of plants treated with the foliar fertilizer were due to the greater number of leaves and transpiration of these plants, even under water deficit, denoting a higher photosynthetic potential. The foliar fertilizer did not mitigate water deficit effects on soybean plants grown in pots, but denoted potential for mitigation of damages in the field

Improving the yield and nitrogen use efficiency of hybrid rice through rational use of controlled-release nitrogen fertilizer and urea topdressing.

Controlled-release fertilizers effectively improve crop yield and nitrogen use efficiency (NUE). However, their use increases the cost of crop production. Optimal management modes involving urea replacement with controlled-release N fertilizers to increase rice yield through enhanced NUE are not widely explored. Field experiments were conducted from 2017 to 2018 to determine the effects of different controlled-release N fertilizers combined with urea [urea-N (180kg ha-1, N1)]. We used controlled-release N (150kg ha-1, N2) as the base, and four controlled-release N and urea-N ratio treatments [(80%:0% (N3), 60%:20% (N4), 40%:40% (N5), or 20%:60% (N6) as the base with 20% urea-N as topdressing at the panicle initiation stage under 150kg ha-1] to study their impact on the grain yield and NUE of machine-transplanted rice. Grain yield and NUE were positively correlated with increases in photosynthetic production, flag leaf net photosynthetic rate (Pn), root activity, N transport, and grain-filling characteristics. The photosynthetic potential and population growth rate from the jointing to the full-heading stage, highly effective leaf area index (LAI) rate and Pn at the full-heading stage, root activity at 15d after the full-heading stage, and N transport in the leaves from the full-heading to mature stage were significantly increased by the N4 treatment, thereby increasing both grain yield and NUE. Furthermore, compared with the other N treatments, the N4 treatment promoted the mean filling rate of inferior grains, which is closely related to increased filled grains per spikelet and filled grains rate. These effects ultimately improved the grain yield (5.03-25.75%), N agronomic efficiency (NAE, 3.96-17.58%), and N partial factor productivity (NPP, 3.98-27.13%) under the N4 treatment. Thus, the N4 treatment with controlled-release N (60%) and urea-N (20%) as a base and urea-N (20%) as topdressing at the panicle-initiation stage proved effective in improving the grain yield and NUE of machine-transplanted hybrid indica rice. These findings offer a theoretical and practical basis for enhancing rice grain yield, NUE, and saving the cost of fertilizer.

Role of microalgae as a sustainable alternative of biopolymers and its application in industries

The escalating accumulation of petroleum-based polymers has depleted resources and raised environmental concerns due to their non-recyclable and non-biodegradable nature. Consequently, there has been a growing interest in bio-based plastics, particularly algal-based biopolymers, which offer recyclability and eco-friendliness. Algae-derived polymers have distinct advantages, such as autotrophic growth reducing greenhouse gas emissions, rapid growth rate, low nutritional requirements, and resilience to harsh environments. Additionally, algae exhibit higher photosynthetic potential (10-20%) compared to terrestrial plants (1%-2%). The range of algal-derived polymers includes alginate, laminarin, fucoidan, carrageenan, agar, ulvan, polyhydroxyalkanoates (PHA), and poly-(Hydroxybutyrate) (PHB). However, further efforts are required to implement them on a large scale. This review highlights algae's potential as a raw material for biopolymer production, exploring their characteristics and applications in diverse industries like food and pharmaceuticals.

The Effect of Gamma Irradiation, Salinity and Nano-Fertilizer on the Biological Parameters of Brassica napus L. Cultivated in Iraq

Canola (Brassica napus L) is currently one of the most significant oily seeds. It has a variety of nutrients, and its oil is safe for people to ingest as well as medicinal properties that help to relieve the symptoms of a variety of disorders. Soil salinity is one of the major issues of decreasing canola crop productivity that correlated with declines in the photosynthetic potential, since salt levels that are damaging to crop growth affect large terrestrial regions around the world are seriously impaired by soil salinity this research focused on the capability of canola seeds to grow under saline environment before and after gamma irradiation. Also, the most recent study intended to employ nano-fertilizer in Iraq and characterize its influence on the chemical makeup of canola seeds. Simple technique employed as a tissue culture using ground water with different EC. Seeds treated by two gamma irradiation dose and grown over cotton irrigated with salty water. Field experiment was carried out in Al-zafraniya station in Baghdad, Iraq, to investigate the effect of khazra iron nano chelate fertilizer foliar application on one rapeseed variety for increasing yield and yield components. The native local variety pactol was more reliable than olifera var at germination rate, plant high, number of leave and root. Irradiation negatively affects the biological parameter of Canola seeds with capablity to germinate and developed. Percentage of fatty acids significantly differed between fertilizer treatments. The myristic (C14:0) ranged from 0.1±0.012 to 0.14±0.011, Palmitic (16:0) from 3.6±0.024 to 3.91±0.029, 3.91±0.029 from 1.5±0.11 to 1.7±0.012, Arachidic (20:0) from 0.6±0.038 to 0.84±0.065, Behenic (22:0) range from 0.3±0.0028 to 0.41±0.032, Lignoceric (24:0) from 0.2±0.012 to 0.27±0.018, Palmitoleic (16:1) from 0.2±0.010 to 0.26±0.0021, Oleic (18:1) from 61.6±5.78 to 67.8±5.91, 67.8±5.91 from 1.4±0.13 to 1.64±0.15, Erucic (22:1) from 0.2±0.014 to 0.23±0.019, Linoleic (18:2n-6) from 21.7±3.1 to 23.4±3.7, Alpha Linolenic (18:3n3) from 9.6±0.87 to 10.1±2.8, Total Saturated from 6.3±5.4 to 6.8±4.9, Total MUFA was in the rangier from 62.4±7.1 to 64.5±7.1 and Total PUFA range from 31.3±4.1 to 37.4±5.1 for conventional canola and nano canola oils respectively.

Effects of light environments within Cinnamomum camphora canopy on leaf functional traits and photosynthetic characteristics.

To explore the adaptive mechanism of leaf photosynthetic capacity in different light environments within Cinnamomum camphora canopy and enhance carbon sequestration, we investigated morphological structures, nutritional and physiological traits and photosynthetic characteristics of leaves in different orientations of C. camphora canopy, southern side in the outer layer (100% full light), southern side in the inner layer (34% full light) and northern side (21% full light). We analyzed the main limitation resulting in down-regulation of photosynthetic capacity in low light environments. Results showed that specific leaf weight, the thickness of lower and upper epidermal cuticle, lower epidermis, palisade tissue as well as cell number and width of palisade tissue, the thickness ratio of palisade to spongy tissue, cell structure closely degree significantly decreased with decreasing light intensity within canopy, opposite to the responses of spongy tissue thickness, cell length-width ratio of palisade tissue, and cell structure loose degree. The contents of leaf carbon, soluble protein, soluble sugar and starch were significantly lower in two low light environments compared with full light, whereas nitrogen content was markedly higher in north side. Low light prominently reduced gas exchange parameters, i.e., net photosynthetic rate (Pn), dark respiration rate, stomatal conductance to CO2(gsc), mesophyll conductance to CO2(gm), total conductance to CO2(gtot), intercellular CO2 concentration (Ci), CO2 concentration at the chloroplast (Cc). Pn was positively correlated with gsc, gm, gtot and Cc. There were no differences in maximum quantum photochemical efficiency, actual quantum photochemical efficiency, photochemical quenching coefficient, maximum rate of Rubisco carboxylation (Vc max) and maximum rate of electron transport (Jmax) among light environments. Vc max and Jmax were positively correlated to Pn. Of the shading-induced limitations to photosynthesis, gm limitation was the most important, and gsc limitation was enhanced with further weakened light intensity while biochemical limitation was rather limited. In summary, the results suggested that full light could improve leaf photosynthetic potential in C. camphora canopy leaves, reduce the effects of gm and gsc limitation on photosynthesis, and consequently enhance carbon assimilation capacity.

Impact of technological practices on the photosynthetic productivity of spring barley in Northern Forest-Steppe conditions

Aim. To determine the features of the formation of the photosynthetic apparatus in spring barley plants depending on the influence of individual elements of cultivation technology and to identify the most effective combinations for maximizing the genetic potential of the crop under the conditions of the northern part of the Right-Bank Forest-Steppe of Ukraine. Methods. During the research, a field study method, visual observation, weighing, the «cutting» method, calculations, and statistical analysis were applied. Results. The research conducted during 2018–2020 has shown that the fertilization system, the use of growth stimulants, and the preceding crop significantly influence the photosynthetic activity of spring barley plants at different stages of organogenesis. The leaf surface index values increased and reached their maximum at the VII and IX stages of organogenesis, after which they gradually decreased. The maximum leaf surface area of 5.03 to 5.24 m2/m2 was achieved in crops with the application of N60P80K80+N60(IV) in the presence of the preceding crop’s by-product. The photosynthetic potential of crops during the period from the II to XI stages of organogenesis was at the level of 1.02–2.42 million m2/ha·day when grown after soybeans and 0.92–2.39 million m2/ha·day when grown after corn for grain. The period from the IV to VIІІ stages of plant organogenesis was characterized by the most active accumulation of dry matter and the most significant influence of all studied agronomic practices on the formation of this indicator. Conclusions. Optimal indicators of photosynthetic activity of spring barley crops (leaf area index of 4.65 m²/m² at the VIII stage of organogenesis, net photosynthesis productivity of 6.71 g/m² per day, dry matter accumulation of 9.51 t/ha at the XI stage of organogenesis) are ensured by the cultivation technology that involves the application of mineral fertilizers at a rate of N45P90K90+N45(IV) against the background of the predecessor’s (corn for grain) byproduct and the use of growth stimulants for pre-sowing seed treatment and foliar application at the IV stage of organogenesis. Such parameters of plant photosynthetic apparatus operation contribute to obtaining a barley grain yield at the level of 4.88–5.27 t/ha.

Effect of Different Ratios of Red and Blue Light on Maximum Stomatal Conductance and Response Rate of Cucumber Seedling Leaves

Light can regulate leaf stomatal development and movement, but the effects of different red-to-blue light mass ratios on leaf stomatal morphology and openness are not fully understood. In this trial, five different red-to-blue light (R:B) ratio treatments were used to study the changes in morphology, photosynthesis, and stomatal-related indexes of cucumber seedlings under fixed light intensity (200 μmol·m−2·s−1). The results showed that the thickness of spongy tissue and stomatal size (SZ) of cucumber seedling leaves decreased, and the photosynthetic potential, stomatal density (SD), maximum stomatal conductance and stomatal responsiveness increased with decreasing R:B content. The experimental results showed that when R:B = is 1:9, cucumber seedlings had the greatest stomatal density and the fastest response rate, and the stomatal opening rate was accelerated with the increase in the proportion of blue light; when R:B = is 3:7, the stomatal conductance was the greatest and the net photosynthetic rate was the highest. This trial provides some implications for changing plant light quality and thus affecting stomatal development and movement.

Salt-Induced Modulation of Ion Transport and PSII Photoprotection Determine the Salinity Tolerance of Amphidiploid Brassicas.

Brassica species show varying levels of resistance to salt stress. To understand the genetics underlying these differential stress tolerance patterns in Brassicas, we exposed two widely cultivated amphidiploid Brassica species having different genomes, Brassica juncea (AABB, n = 18) and Brassica napus (AACC, n = 19), to elevated levels of NaCl concentration (300 mM, half the salinity of seawater). B. juncea produced more biomass, an increased chlorophyll content, and fewer accumulated sodium (Na+) and chloride (Cl-) ions in its photosynthesizing tissues. Chlorophyll fluorescence assays revealed that the reaction centers of PSII of B. juncea were more photoprotected and hence more active than those of B. napus under NaCl stress, which, in turn, resulted in a better PSII quantum efficiency, better utilization of photochemical energy with significantly reduced energy loss, and higher electron transport rates, even under stressful conditions. The expression of key genes responsible for salt tolerance (NHX1 and AVP1, which are nuclear-encoded) and photosynthesis (psbA, psaA, petB, and rbcL, which are chloroplast-encoded) were monitored for their genetic differences underlying stress tolerance. Under NaCl stress, the expression of NHX1, D1, and Rubisco increased several folds in B. juncea plants compared to B. napus, highlighting differences in genetics between these two Brassicas. The higher photosynthetic potential under stress suggests that B. juncea is a promising candidate for genetic modifications and its cultivation on marginal lands.

Influence of mineral components on photosynthetic activity and productivity of cucumber plants “Monsoon F1”

In the conditions of the greenhouse of I.A.Bunin YSU, the influence of water-soluble multicomponent micronutrients - Green Lift, Nutrivant Plus - was studied Melon, Vitanol Micro on the physiological development of cucumber plants “Monsoon F1”. It was established that multicomponent micro fertilizers affect plant growth. The high efficiency of non-root fertilizing on growth processes in variants with the use of Green Lift was revealed. The smallest result was obtained between control and application Vitanol. The highest effect on the photosynthetic potential of plants from the applied fertilizers was obtained in the variant with the use of Vitanol.