Photosynthetic Potential Research Articles

PHOTOSYNTHETIC PERFORMANCE INDICATORS OF VARIEGATED ALFALFA DEPENDING ON THE SOWING METHOD IN THE FOREST STEPPE OF THE MIDDLE VOLGA REGION

Undercrop cultivation of alfalfa is economically justified, since in the year of sowing, cover crops give a full harvest, and also one mowing of alfalfa for hay is carried out, moreover the special preparation of the soil for grasses is not re-quired. In the conditions of the Middle Volga region, the experiment was laid on leached chernozem in 2017 - 2019, where they studied the sowing of variegated alfalfa under the crops of spring wheat, barley, oats, harvested for grain and an-nual grasses - for green fodder, and studied the options for coverless sowing, where the weeds were mowed twice and the herbicide Pivot was applied at the beginning of alfalfa branching. The total biological yield is determined by the leaf area and its photosynthetic activity. Therefore, the purpose of the research is to determine the indicators of alfalfa photosynthetic activity for an objective as-sessment of the influence of cover crops on their forage productivity. It has been established that a more intensive increase in the assimilation surface of alfalfa in the first year of life to 31.6 and 30.6 thousand m2 /ha occurs on coverless sowing with the application of the Pivot herbicide and two-fold mowing of weeds. The dry matter yield was 2.1 and 2.0 t/ha, respectively. A decrease in the illumination of alfalfa plants sown under crops, where the leaf area did not exceed 13.0...15.3 thousand ? m2 / ha, slowed down the photosynthesis processes. Moreover, a more intensive growth of its photosynthetic organs was noted under the crop of barley, the cereal-legume mixture reduced the leaf area by 0.5 thousand m2 /ha, the pho-tosynthetic potential was 898...1051 thousand m2 day/ha.

CHANGE IN INDICATORS OF PHOTOSYNTHETIC ACTIVITY OF ECHINACEA PURPUREA SEEDINGS IN THE SECOND YEAR OF LIFE

The effective implementation of the plants biological potential occurs with a high culture of agriculture, as well as optimal moisture conditions and air temperature. Echinacea Purpurea has long-lasting seed germination and low competition to weeds; therefore, when cultivating it, it is relevant to determine the optimal sowing time and an effective way to combat the weed component. In this case, the study of the photosynthetic apparatus parameters is greatly important. According to the results of studies carried out in 2016 - 2018 on the chernozem-meadow soil of the experimental plot of Federal State Budgetary Educational Institution of Higher Education, Penza State Agricultural Academy, it was found that, regardless of weather conditions, the largest area of the assimilation surface is formed by sub winter crops with pre-emergent application of herbicide Lazurit and subsequent treatment with Miura in the phase of 2-4 weed leaves, and also with manual removal of segetal vegetation. On average, over three years, it reached its maximum in the flowering period and made up 50.3 and 49.9 thousand m2/ha. The photosynthetic potential on sub winter sowing in the shooting stage exceeded this indicator on early spring crops with double chemical weeding by 1.4 times, and during budding and flowering - by 1.2 times, with manual removal of weeds by 1.2, 1.1 and 1.2 times, respectively. The highest average daily net photosynthesis productivity of 2.73 g/m2 ? day was observed on early spring crops in the flowering phase, especially after a single chemical weeding with Miura’s herbicide.

Фотосинтетическая деятельность смешанных посевов трав, их продуктивность и влияние на плодородие дерново-подзолистой почвы в условиях Верхневолжья

The results of long-term research on the photosynthetic activity of mixed crops of perennial grasses are presented, their productivity and the effect on the fertility of potentially poor soddy-podzolic soils are studied. It was found that in herbage based on clover, the maximum area (68.8 thousand m2/ha) and the photosynthetic potential of leaves (718 thousand m2/ha × day) on the control were formed by mixed crops of clover and festulolium, and against the background of mineral nutrition – mixtures clover with timothy (68.4 thousand m2/ha and 718) and festulolium (66.6 thousand m2/ha and 704 thousand m2/ha × day). In mixed crops with alfalfa mixtures with timothy and ryegrass, they had the highest leaf area – 57.9 and 57.5 thousand m2/ha and FP of 620 and 611 thousand m2/ha × day, respectively. A high leaf surface index was found in clover herbage with festulolium in control (6.88), timothy (6.84) and festulolium (6.66) against the background of mineral nutrition. Grass mixtures of alfalfa in productivity exceeded clover ones, the most productive on both backgrounds in terms of the yield of fodder units and protein collection turned out to be a grass mixture of alfalfa with festulolium – 7.19 in the control and 8.53 thousand / ha of fodder units when applying mineral fertilizers, 1069 and 1194 kg/ha of protein, respectively, sugar – festulolium on the control and festulolium and ryegrass on the background of mineral nutrition. The smallest amount of stubble-root residues (SRR) – 7.99, 8.32 in the control and 11.9, 14.5 t/ha against the background of mineral nutrition, respectively, accumulated grass stands of meadow clover with ryegrass and fescue due to a weak root system. The application of mineral fertilizers increased the amount of SRR in clover mixtures more strongly (by 55% on average) than in alfalfa (only by 26%), although in terms of the total amount of accumulated bio-residues, mixed crops of alfalfa exceeded clover crops – their maximum amount is 13.7 and 12.6 t/hectares on the control and 17.2, and 15.8 t/ha against the background of mineral nutrition accumulated mixtures of alfalfa with timothy and festulolium. Herbal mixtures with alfalfa accumulated more symbiotic nitrogen – from 54 to 58 kg/ha on the control and 56–74 kg/ha on the background of mineral nutrition. Mineral fertilizers significantly affected the symbiotic activity of only clover grass stands, increasing the amount of nitrogen fixed by them by 56%, and their effect on alfalfa mixtures was insignificant.

Photosynthetic Activity of Cup Plant Depending on the Method of Seeding

Biological farming throughout the world is becoming a necessity for the production of safe products, and the preservation of fertility and biodiversity. In this direction, there is a significant interest of the scientific community in the perennial culture – cup plant. The cup plant has a wide range of uses in economic activities and due to its high resistance to diseases and pests, the long-term use of its plantations without replanting, and the accumulation of a significant mass of organic matter in the soil, it can be used to expand the species diversity of perennial grasses in the biological farming system. The aim of the study was to examine the influence of the seeding method and seeding rate on photosynthetic activity and dry matter productivity of the cup plant in the forest-steppe conditions of Western Siberia. It was found that with an ordinary method of sowing at a seeding rate of 4 million pcs/ha, the grass stand in the first cut had the highest rates of photosynthetic activity on average over the years of research: the leaf area was 14.8 m2 /m2 , the photosynthetic potential was 4.0 million m2 day/ha and the net productivity of photosynthesis was 2.0 g/m2 ⋅ day. In the second cut, the figures were 8.4 m2 /m2 , 1.9 million m2 day/ha and 2.8 g/m2 ⋅ day, respectively. The optimal density of herbage and active photosynthetic activity in the cup plant using this method of sowing contributed to a significant yield of dry matter of 12.6 t/ha with a high level of PAR absorption of 2.9%.
 Keywords: cup plant, yield, photosynthesis, sowing method

Increase of Onion Productivity by Regulation of Growing Technology Elements

This article describes the impact of growth regulators used as foliar dressing on the high-quality commercial production of Mars and Candy F1 hybrid onion bulbs grown in the Rostov Region. The highest yield of finished product per 1 thousand m2 of leaf area and 1 thousand units of photosynthetic potential (PSP) was observed when the Candy and Mars hybrids were treated with Novosil (3.9-4.1 t and 45.0-47.0 kg, respectively), which also produced the highest rates of net photosynthesis productivity: 8.5-8.7 g / m2 per day. The effect of the agent on growth processes was slightly more effective in the Candy hybrid. It was established that the use of Novosil and Immunocytophytes foliar dressing in growing technology makes it possible to obtain the Mars and Candy hybrids at the level of 49.0-50.1 t / ha, reduce the consumption of additional irrigation water per unit of production and improve the quality of commercial onion bulbs and their storage for a long winter period. The increase in storage resulting from the use of Novosil occurred due to the decrease in the natural loss and mass of the sprouted bulbs.
 Keywords: onion, hybrid, yield, stimulant fertilizer, storage, quality

Effects of row spacing and sowing rate on vertical distribution of photosynthetically active radiation, biomass, and grain yield in winter wheat canopy.

To clarify the effects of row spacing and sowing rate on the vertical distribution of canopy PAR, biomass, and grain yield in winter wheat, a field experiment was conducted without increa-sing water and fertilizer input. There were two row spacing modes, R1 (equal spacing, 20 cm+20 cm) and R2(wide and narrow row spacing, 12 cm+12 cm+12 cm+24 cm), and three sowing rates, D1 (low, 120 kg·hm-2), D2 (medium, 157.5 kg·hm-2), D3 (high, 195 kg·hm-2). The canopy photosynthetically active radiation (PAR) interception and utilization rate in different heights, population photosynthetic capacity, biomass, and grain yield were measured during the main growth stages of winter wheat. The results showed that both total PAR interception and upper layer PAR interception of winter wheat canopy under R1 treatment were significantly higher than those in R2 treatment, but those of the middle layer and lower layer were higher in R2 than in R1, and with significant difference in the middle layer. From flowering to maturity, the photosynthetic potential (LAD), population photosynthetic rate (CAP), PAR conversion rate, and utilization rate in R2 were all significantly higher than those in R1 under the same sowing rate, with the highest value under R2D2 treatment. With the increasing sowing rate, the population biomass (BA) and leaf biomass (BL) at different layers increased, but the individual biomass (BP) showed an opposite trend. Under the same sowing rate, BA, BL and BP in R2 were higher than that in R1 after the flowering stage. Among them, BA and BP had significant difference in row spacing treatments at the maturity stage, with significant difference between the two row spacing treatments being observed in BL of the middle and lower layers under D2 and D3 sowing rates. The spike number, grain number per spike, 1000-kernel weight, and grain yield of winter wheat among different treatments were the highest in R2D3, R2D1, R2D1, and R2D2, respectively. The 1000-kernel weight, grain number per spike and grain yield in R2 treatment were significantly higher than R1. In summary, the PAR interception in the middle and lower layers of winter wheat canopy was improved by changing row spacing, with positive consequence on the photosynthetic capacity of individual plant and population, PAR utilization and transformation efficiency, which finally increased biomass and grain yield. Therefore, optimizing the field structure and shaping the ideal population photosynthetic structure should pay more attention during the high-yield cultivation of winter wheat. Making full use of light resources per unit land area and excavating the photosynthetic production potential of crops were also critical to achieve high yield and efficiency. In this experiment, the population photosynthetic capacity, photosynthetic effective radiation utilization rate, and yield were the highest under the treatment of R2D2.

Construction of dominant rice population under dry cultivation by seeding rate and nitrogen rate interaction

This study used the rice cultivar Suijing 18 to investigate the effects of morphological characteristics, photosynthetic changes, yield, as well as nitrogen absorption and utilization. The interaction between seeding rate and nitrogen rate was also assessed to identify the most suitable values of the dominant population for both factors under dry cultivation. Furthermore, the photosynthetic physiological characteristics of the upper three leaves in the dominant population were also explored. The results showed that a combination of 195 kg/ha seeding rate and 140 kg/ha nitrogen rate achieved high yield, high nitrogen utilization, and moderate morphological characteristics. This was achieved by a coordination of the combined advantages of population panicle number and spikelets per panicle. The photosynthetic potential of the population was improved by coordinating the reasonable distribution of light energy in the upper three leaves, which led to the emergence of a dominant rice population under dry cultivation.

Photosynthetic productivity of winter wheat cultivated using No-till technology

The article presents studies of photosynthetic productivity of winter wheat plants cultivated using No-till technology and traditional technology, conducted in 2016-2019 at the North Caucasus Federal research agricultural center. As a result of research, it was found that the cultivation of winter wheat using No-till technology contributes to the formation of a more developed photosynthetic apparatus with a high content of photosynthetic pigments ( on average, 36.9% higher than in plants grown using traditional technology), while a higher concentration of chlorophyll is preserved at later stages of plant development, which indicates a longer operation of the photosynthetic apparatus, this is confirmed by the value of the chlorophyll photosynthetic potential (CFS is 9.2% higher, than crops according to the traditional technology). A high level of mineral nutrition with the use of No-till technology reduces the load on the photosynthetic apparatus, and the net productivity of photosynthesis is 7.8 % lower than with traditional technology. An increase in the photosynthetic productivity of winter wheat plants cultivated using No-till technology ultimately leads to an increase in yield, on average over three years by 14.4% compared to traditional technology applications.

ВПЛИВ РЕГУЛЯТОРІВ РОСТУ РОСЛИН НА ОНТОГЕНЕЗ СОРТІВ ЯЧМЕНЮ ЯРОГО

Мета статті – визначити вплив регуляторів росту рослин на продуктивність ячменю ярого у виробничих умовах Полтавської області. Оцінювання ефективності використання регуляторів рос-ту рослин та природного мінералу бішофіт виконано на базі експериментальних даних. Експериме-нтальну роботу проведено у виробничих умовах на базі ФГ «Горобець С. Г.» Полтавської області. Для обробки посівів використовували регулятори росту Циркон та Епін-екстра, а також, 1 % роз-чин природного мінералу бішофіт. Показники фотосинтетичного потенціалу та чистої продуктив-ності фотосинтезу визначено розрахунковим методом за загальноприйнятими методиками. За да-ними п’ятирічних досліджень визначено динаміку впливу регуляторів росту рослин та природного мінералу бішофіт на чисту продуктивність фотосинтезу, фотосинтетичний потенціал та площу листкової поверхні. Установлено, що за 3 роки проведення експериментальних спостережень при обробці нашими регуляторами росту вихід у трубку стався на 1–3 дні раніше, ніж у контрольному варіанті (без використання регуляторів). На дослідній ділянці 2017–2019 рр. найскоріше сходи спос-терігались у сорту Геліос при обробці стимулятором Циркон, тоді як у контролі сходи зафіксовані на 3 дні пізніше. Кущіння ячменю ярого сорту Геліос та вихід у трубку відбувалось найшвидше при дії 1 % розчину бішофіту, а при дії інших стимуляторів (Епін-екстра, Циркон) сходи та повна стиг-лість фіксувалися на 3 дні пізніше. Застосування стимуляторів Циркон і 1 % розчин бішофіту (для сортів Геліос та Парнас) прискорило настання фази колосіння на 2–4 дні, Епін-екстра – тільки на 1–2 дні. У середньому за час проведення досліджень тривалість фаз розвитку рослин ячменю ярого, оброблених стимуляторами, зменшилася на 1–4 дні порівняно з контрольним варіантом. При вико-ристанні регуляторів росту збільшилася площа листкової поверхні у посівів ячменю ярого порівняно з контролем, що дає змогу найбільш повно використовувати ґрунтово-кліматичні ресурси регіону й отримати максимальний ефект від прийомів агротехнічного впливу. Запропоновані моделі техноло-гій дають змогу без застосування десикації зменшити тривалість вегетаційного періоду в посівах ячменю ярого. При обробці посівів у фазі кущіння стимуляторами росту Епін-Екстра, Циркон і 1% розчином бішофіту скорочується період вегетації на 2–4 дні при вирощуванні ячменю ярого на дер-ново-підзолистих ґрунтах; стимулятор Епін-Екстра і 1 % розчин бішофіту збільшують асиміляцій-ну поверхню листя в рослин ячменю ярого на 8,5 і 11,1 % відповідно, потенціал фотосинтетичного процесу – на 5,7 % і чисту продуктивність фотосинтезу на 3 і 10 %.

ВПЛИВ ЗМІН КЛІМАТУ НА УРОЖАЙНІСТЬ СОНЯШНИКУ В ПІВНІЧНОМУ СТЕПУ УКРАЇНИ: АНАЛІЗ І ПРОГНОЗ

Глобальні зміни клімату формують нові умови для всіх галузей світової та української економіки, включаючи сільське господарство. З їх впливом пов’язані агрокліматичні умови вирощування сільсь-когосподарських культур, зокрема соняшнику. Необхідність оцінити ці умови є актуальною, тому що вони вкрай важливі при врахуванні потенційної адаптації соняшнику до кліматичних змін і рен-табельності вирощування в окремих природо-кліматичних зонах України. Метою цього дослідження було виявити ступінь впливу кліматичних змін на врожайність культури соняшнику. Для оцінки впливу змін клімату на врожайність соняшнику використовуються сучасні сценарії RCP2.6 і RCP4.5 (помірного та середнього рівня викидів парникових газів). За сценаріями RCP2.6 і RCP4.5 дослідже-ний кліматичний період з 2021 по 2050 рр. Для порівняльного аналізу сценарних метеорологічних зна-чень з минулими даними взятий період з 1980 по 2010 роки. Дослідження формування урожайності соняшнику проводили з використанням математичної моделі оцінки агрокліматичних ресурсів фор-мування продуктивності сільськогосподарських культур, адаптованої для культури соняшнику. Згід-но з розрахунками збільшення ФАР (на 8 і 21 %) за обома сценаріями призведе до збільшення потен-ційного урожаю соняшнику (до 163 ц/га і 183 ц/га проти 151 ц/га). За сценарієм RCP2.6 агроклімати-чні умови (підвищений температурний режим (на 0,7 ºС) і достатня за вегетацію для посухостійко-го соняшнику сума опадів, 223 мм) сприятимуть збільшенню фотосинтетичного потенціалу незнач-ного, але зростання ММУ (83 ц/га проти 81 ц/га). Очікуватиметься деяке збільшення врожаю насін-ня (на 4 %). Агрокліматичні умови за сценарієм RCP4.5 будуть більш посушливими в період цвітіння–достигання. Але на урожайність соняшнику ці умови суттєво не вплинуть. Урожай насіння очіку-ється такий, як при фактичних середніх багаторічних умовах (2,3 т/га). У разі реалізації обох сце-наріїв унаслідок позитивного впливу очікуваних кліматичних умов на всі категорії урожайності со-няшнику найближчі три десятиліття він буде однією з найбільш затребуваних і рентабельних сільськогосподарських культур у Північному Степу України.

OPTIMIZATION OF THE SOWING METHODS FOR CULTIVATION OF FOENICULUM VULGARE (COMMON FENNEL) AS A NICHE CROP

Research findings are given herein concerning Foeniculum Vulgare (common fennel) sowing method optimization with the implementation of the organic cultivation technique in a climate of the Polissia region, having an impact on the targeting of the main crop outputs. Common fennel is grown mainly in the southern and western regions of Ukraine. However, an option to grow fennel in a climate of the Polissia region has become real because of changes in the climatic conditions. The demand for domestically made products involving niche medicinal herbs has grown significantly in these recent times. Common fennel is known to be among the most popular niche medicinal crops. At the same time, a demand arose for increasing crop cultivation areas, as well as geographical spread thereof. It is found that the implementation of a wide-row sowing method (60 cm) has contributed to the increased seed yield of common fennel. Maximum gain in green weight of common fennel has been noted during main vegetative phases of the crop sown with a wide-row technique (60 cm), i.e. 2,471 g/sq.m in blooming period. The photosynthetic activity of fennel plants has been varied with exposure to the factor investigated. Assimilating leaf area of common fennel was ranged from 24.2 to 25.5 thousand sq.m/hectare, photosynthetic potential: from 1.512 to 1.685 million sq.m / hectare * 24h, and net photosynthetic productivity: from 3.39 to 3.65 g/sq.m * 24h. Implementation of the ordinary row sowing method (15 cm) negatively affected both the development of photosynthetic activity and the yielding ability of common fennel seeds. Over the years of research (2017-2019), the highest yield of common fennel seeds, i.e. 0.96 T/hectare (on average) was achieved with the crop sown with rows spaced 60 cm between each other. Due to the said option, the highest possible yield of dry matter (6.10 T/hectare) was achieved, thus providing for the gain of 1.13 tons per hectare.

ФОРМИРОВАНИЕ АГРОФИТОЦЕНОЗА И ПРОДУКТИВНОСТЬ ЯРОВОЙ ТВЁРДОЙ ПШЕНИЦЫ ПРИ ПРИМЕНЕНИИ МИНЕРАЛЬНЫХ УДОБРЕНИЙ

The article shows the results of the research on the development of methods for increasing spring durum wheat yield (Triticum Durum) in the system of application of liquid mineral fertilizers: Megamix for pre-sowing seed preparation, treatment of crops during the growing season with mineral fertilizers N16P16K16 for pre-sowing soil preparation in the forest-steppe conditions of the Middle Volga region. The research was carried out on the experimental field of Samara State Agrarian University in 2017-2020. In the course of a three-factor field experiment, the main biometric parametres were assessed: sprout density and plant survivability in crops, formation of aboveground mass and accumulation of dry matter, photosynthetic activity with analysis of leaf area, formation of photosynthetic potential and photosynthesis net productivity. It was found that the best parametres are formed on the variants with seed treatment of with Megamix Seeds or Megamix Profi, followed by two-fold treatment during the growing season with Megamix Profi 0.5 l / ha (tillering phase) + Megamis Nitrogen 0.5 l / ha (flag leaf phase ), with application of N16P16K16 fertilizer. It was revealed that, in this case, the sprout density is formed at the level of 78.0 ... 77.7%. The usage of Megamix for seed treatment system + treatment of crops with Megamix stimulants ensures the maximum increase of the aboveground mass in the variant of seed treatment with Megamix Seeds and treatment of crops with Megamix Profi - 1582.0 g / m2; as well as a mixture of Megamix Profi + Megamix Nitrogen - 1614, 0 g / m2 after applying N16P16K16. In these variants, the maximum leaf area and photosynthetic potential of 0.776 ... 0.981 million m2 / ha days are formed and, as a consequence, the maximum yield with the parametres of 2.89 ... 3.03 t / ha. It was found that application of liquid mineral fertilizers in all variants of the experiment significantly increases spring durum wheat yield.

High photosynthetic plasticity may reinforce invasiveness of upside-down zooxanthellate jellyfish in Mediterranean coastal waters.

Ecological profiling of non-native species is essential to predict their dispersal and invasiveness potential across different areas of the world. Cassiopea is a monophyletic taxonomic group of scyphozoan mixotrophic jellyfish including C. andromeda, a recent colonizer of sheltered, shallow-water habitats of the Mediterranean Sea, such as harbors and other light-limited, eutrophic coastal habitats. To assess the ecophysiological plasticity of Cassiopea jellyfish and their potential to spread across the Mare Nostrum by secondary introductions, we investigated rapid photosynthetic responses of jellyfish to irradiance transitions—from reduced to increased irradiance conditions (as paradigm of transition from harbors to coastal, meso/oligotrophic habitats). Laboratory incubation experiments were carried out to compare oxygen fluxes and photobiological variables in Cassiopea sp. immature specimens pre-acclimated to low irradiance (PAR = 200 μmol photons m−2 s−1) and specimens rapidly exposed to higher irradiance levels (PAR = 500 μmol photons m−2 s−1). Comparable photosynthetic potential and high photosynthetic rates were measured at both irradiance values, as also shown by the rapid light curves. No significant differences were observed in terms of symbiont abundance between control and treated specimens. However, jellyfish kept at the low irradiance showed a higher content in chlorophyll a and c (0.76±0.51SD vs 0.46±0.13SD mg g-1 AFDW) and a higher Ci (amount of chlorophyll per cell) compared to jellyfish exposed to higher irradiance levels. The ratio between gross photosynthesis and respiration (P:R) was >1, indicating a significant input from the autotrophic metabolism. Cassiopea sp. specimens showed high photosynthetic performances, at both low and high irradiance, demonstrating high potential to adapt to sudden changes in light exposure. Such photosynthetic plasticity, combined with Cassiopea eurythermal tolerance and mixotrophic behavior, jointly suggest the upside-down jellyfish as a potentially successful invader in the scenario of a warming Mediterranean Sea.

The potential implications of a plasma membrane aquaporin in improving CO2 transport capacity, photosynthetic potential and water use efficiency under contrasting CO2 source in Solanum lycopersicum (tomato)

Mesophyll conductance has been increasingly recognized as a limiting-factor for carbon transport and fixation during photosynthetic process. Despite mesophyll conductance performs a significant role in determining photosynthetic and yield potential, its molecular mechanisms are uncertain and controversy. In the present study, the function of a plasma membrane aquaporin SlPIP1;2 in facilitating CO2 transport across the plasma membrane under contrasting CO2 concentrations was evaluated, according to the photosynthetic performance of transgenic lines of overexpression and knock-out. The relative importance of PIP-channel in determining membrane permeability and mesophyll conductance is largely depend on the ambient and intercellular CO2 concentration. Under the current ambient CO2 concentration, SlPIP1;2 had minor effect on photosynthetic performance. Overexpression of the target gene substantially enhanced CO2 membrane permeability under CO2 enrichment, according to the photosynthetic performance: overexpression SlPIP1;2 significantly improved mesophyll conductance and photosynthesis rate, which translated into improvement in crop productivity and water use efficiency. The present results suggested that SlPIP1;2 is potentially involved in facilitating CO2 transport across the plasma membrane under CO2 enrichment, which subsequently affect crop productivity and water use efficiency.

Effects of Mechanically Transplanting Methods and Planting Densities on Yield and Quality of Nanjing 2728 under Rice-Crayfish Continuous Production System

Rice–crayfish continuous production system offers high economic and ecology benefits, which developed rapidly in China. To investigate the effects of different mechanical transplanting methods and planting densities on rice yield and quality, Nanjing 2728 was used to determine rice growth performance under mechanically transplanted carpet seedling (MTCS) with equal row spacing (30 cm) at five spacings and mechanically transplanted pot seedling (MTPS) with wide and narrow rows (23 + 33 cm) at five spacings. The results showed that MTPS presented significantly higher rice yields than MTCS as more spikelets per panicle. Rice yields of both mechanical transplanting methods first increased and then reduced with decreasing planting density, and its highest value was obtained at 77.9 × 104 seedlings ha−1. Compared with MTCS at the same stage, rice tiller dynamics of MTPS first increased and then decreased. Additionally, its dry matter accumulation per stem at jointing, heading, and maturity stages, leaf area index, photosynthetic potential, crop growth rate, and net assimilation rate were all significantly higher relative to MTCS. For each mechanical transplanting method, dry matter accumulation per panicle, leaf area index, photosynthetic potential, crop growth rate, and net assimilation rate from the sowing to jointing stages declined with decreasing planting density, while dry matter accumulation per stem and net assimilation rate from the heading to maturity stages increased. Compared with MTCS, MTPS significantly improved rice milling and appearance quality, decreasing density was also beneficial to rice milling and appearance quality, while grain content of amylose and protein were not sensitive to both transplanting method and planting density. Consequently, MTPS with 13.8 cm plant spacing is a suitable mechanical transplanting method for Nanjing 2728 to obtain better yield and quality under rice–crayfish continuous production system.

Influence of thin-layer soil analogues on the production process of lettuce plants in intensive artificial-light culture

Relevance.The solution to the problem of providing the population of our country with high - quality plant production all year round is possible when creating high-tech automated phytotechnological complexes based on innovative, resource-saving technologies for growing plants in an artificial climate, including the development of a new generation of root inhabited thin-layer analogues of soils.Materials and methods. The research was carried out under controlled conditions of intensive artificial-light culture, when growing lettuce plants of the Typhoon variety on thin - layer analogs of soil of various composition and a low-volume soil analogue based on high-moor peat with a low degree of decomposition "Agrofit", selected as a reference for comparison, in plant growing light equipment developed at Agrophysical Institute.Results. Evaluation of the influence of thin-film analogues of the soil based on the suspensions Cambrian clay, and /or sapropel in different ratios on the production process of lettuces showed when compared with control (hydrophilic fabric): a positive tendency to increase of height, number of leaves per plant; a significant increase in wet mass by 25-35%, dry mass in 54-80%, percent dry matter in 16-36%; increase of leaf area and photosynthetic capacity at 20-36%, net productivity of photosynthesis by 16-45%; a significant or in a form of tendency to increase in the content of potassium by 14-17%, calcium by 27-35%, zinc by 29-53% and disaccharides by 28-68%. In comparison with the low-volume analogue of the soil based on high-moor peat of a low degree of decomposition "Agrophyte" (standard), it was found an increase in the form of a pronounced positive trend in growth indicators - the height and number of leaves. wet, dry mass of plants, percentage of dry matter; net productivity of photosynthesis, a reliable or in form of trend to increase in leaf area, photosynthetic potential by 20-30%; an increase in the content of mineral elements in lettuce leaves. Possible reasons for the lower productivity of lettuce plants in the control were determined, and it associated with an increase in water intake in leaf tissues against the background of the absence of additional mineral and / or organic nutrition. The content of heavy metals and nitrates did not exceed the maximum permissible concentration (MPC) in all variants. All thin-layer analogs of the soil with the application of suspensions of various compositions can be recommended for growing lettuce in any cultivation facilities in conditions of intensive artificial-light culture.

Photosynthetic production of biodiesel in Synechocystis sp. PCC6803 transformed with insect or plant fatty acid methyltransferase.

Biodiesel contains methyl or ethyl esters of long-chain fatty acids and has recently attracted increasing attention. Microalgae have emerged as a sustainable biodiesel production system owing to their photosynthetic potential. However, the conversion of microalgal biomass to biodiesel requires high energy and is costly. This study aimed to overcome the high cost of the pretreatment process by generating cyanobacteria converting fatty acids to fatty acids methyl ester (FAME) in vivo by introducing the fatty acid methyl ester transferase (FAMT) gene. Two FAMT genes from Drosophila melanogaster and Arabidopsis thaliana were selected and their codons were optimized for insertion in the Synechocystis sp. PCC6803 genome through homologous recombination, respectively. FAMT mRNA and protein expression levels were confirmed through reverse-transcription PCR and western blot analysis, respectively. Furthermore, heterologous expression of the FAMT genes yielded FAME, which was analyzed by gas chromatography. We found that FAMT transformants can be further metabolically optimized and applied for commercial production of biodiesel.

Photosynthetic activity of soybean crops in response to different sowing times under the environmental conditions of the Russian Far East

The aim of this study was to determine the optimal sowing time for photosynthetic activity in the soybean varieties «Batya» and «Khabarovskiy Yubilyar» in the Russian Far East. We studied the influence of several parameters that induce photosynthetic activity on the productive qualities of soybean seeds from these varieties at different sowing dates. Studies have shown that the factor which most significantly determines biological productivity is leaf area. Here, leaf area accounted for 92.3% of the total productivity, with 77.3% depending on the photosynthetic potential of the soybean plants. Optimal conditions for the growth of soybean leaves and the duration of their function were created during the May sowing dates. The leaf area of «Batya» and «Khabarovskiy Yubilyar» varieties decreased by 6–36% and 11–27%, respectively, at later sowing dates. The lowest net photosynthetic productivity in «Batya» was 2.0 g/m2/day during the late sowing period, and the maximum value recorded was 4.2 g/m2/day when sowing was at the end of May. The lowest photosynthetic productivity for the variety «Khabarovskiy Yubilyar» (3.4 g/m2/day) was also recorded in plants from the late sowing period.

Resistance of sunflower (Helianthus annuus L.) to oxyfluorfen when applied during the growing season

The article reflects the results of studies carried out in the period from 2017 to 2019 in the dry steppe zone of the Russian Federation to assess the resistance of sunflower and the effectiveness of weed control when using oxyfluorfen before sowing and during the growing season of the crop in various doses and tank mixtures. The dynamics of weediness of sunflower crops according to the growing season of the crop and the timing of the use of herbicides and their tank mixtures has been established. The data of accounting for the increase in leaf area, as well as determining the photosynthetic potential of crops and the net productivity of photosynthesis when using herbicides before sowing and during the growing season of sunflower in different doses and tank mixtures are presented. Indicators of sunflower productivity and quality of seeds were determined for the studied schemes of herbicide application. The data obtained from the economic and energy assessment of the effectiveness of the use of oxyfluorfen on sunflower in terms of crop vegetation are analyzed.

Влияние экологических условий выращивания на фотосинтетический потенциал декоративных растений

The article presents the results on the influence of environmental conditions of growth on the photosynthetic potential of different flower crops. It is established that the conditions of different ecological zones dramatically affect the growth and development of plants, which is interrelated with their photosynthetic activity. In the absence of sources of contamination, plants are able to accumulate the maximum amount of pigments. Flower crops often used in urban landscaping and landscape architecture, such as Tagetes, Pelargonium, Salvia, and Cineraria, were selected for the study. The study of the content of pigments (chlorophylls a, b and carotenoids) in ornamental and floral plants was determined in extracts using spectrophotometric analysis. The analysis of the study showed that pelargonium has the least sensitivity of all the studied flower material to unfavorable conditions of development. Keywords: DECORATIVE AND FLORAL PLANTS, CHLOROPHYLLS, CAROTENOIDS, PHOTOSYNTHESIS