Blade Area Research Articles

The influence of powdery mildew (Sawadaea bicornis (Wallr.) Miyabe) on chlorophyll fluorescence in Norway maple (Acer platanoides L.) seedlings

The article presents the results of research on impact of Sawadaea bicornis (Wallr.) Miyabe on the state of photosynthetic apparatus in Acer platanoides L. seedlings using a technique of chlorophyll fluorescence induction (ChlF) measurement, which at the present time can be implemented through the use of biosensors. The research was conducted in September 2022 in the territory of the Botanical Garden of Oles Honchar Dnipro National University. To diagnose a violation of the native chlorophyll photosynthesis in fresh leaves of A. platanoides, a portable fluorometer “Floratest” was used (selected spectral range for fluorescence intensity measurement was 670–800 nm). The research was carried out on fresh leaves of Norway maple seedlings both not unaffected and affected with powdery mildew. Analysis of the data obtained indicates a high sensitivity of the parameters of chlorophyll fluorescence induction to damage by the disease regardless of environmental conditions of local growth of A. platanoides seedlings. The high informativeness of induction changes in chlorophyll fluorescence in the structural organization of chloroplasts in Norway maple leaves determined by the parameters Fo, Fm, Fv, Fv/Fо, Fv/Fm, (Fm–Fst)/Fst, (Fp–Fо)/Fv was revealed. This study demonstrated the effectiveness of using the studied chlorophyll fluorescence parameters to detect severe stress in Norway maple seedlings caused by powdery mildew exposure when the fungus affects more than 50% of the leaf blade area. It is further necessary to conduct dynamic studies throughout the growing season to determine the effectiveness of using these parameters to detect mild stress in the early stages of infection. Therefore, our research showed that the method of induction of chlorophyll fluorescence using the “Floratest” device allows you to quickly determine the general condition of the plant by evaluating photosynthesis, which is the main life process. Analysis of chlorophyll fluorescence parameters is a powerful and effective tool for determining the effect of a parasitic fungus on a plant.

The effect of blade depth ratio on the performance of in-stream water wheels

The power characteristics of an in-stream water wheel were measured experimentally to explore the influence of the blade depth ratio. The blade depth ratio has a significant effect on the performance of in-stream water wheels, but its influence has been overlooked throughout the literature. It was determined that the blade depth ratio has a greater impact on the power production than the number of blades at all tip-speed ratios. However, the variation between the maximum and minimum available power is greater at high blade depth ratios, so it is important to understand the relationship between the blade depth ratio and tip-speed ratio. Analysis of velocity triangles determined that at the inlet and outlet, the turbine blade contributes negatively to net torque. This effect is increased at higher blade depth ratios. It was also determined that the peak dry coefficient of power is linearly proportional to the blade submergence ratio, which is a measure of the total submerged blade area. This investigation progresses research in this area by highlighting an overlooked parameter and experimentally determining its influence on power characteristics.

Torsional Effects on Wind Turbine Blades and Impact on Field Damages

The purpose of this paper is to present the importance of torsional loads when understanding the significant increase in structural damages on large wind turbine blades. By comparing the stress state of two blades of different length, it is shown that torsional loads grow with an exponent of four (4). Thereby, a function of the length of the blades leading to a new range of challenges that are not met by the current process for design, testing and certification.The paper presents the study of these new challenges in detail, based upon:- An experimental perspective, with results from large-scale cyclic loading tests on two blade cut-outs conducted under controlled laboratory conditions in. Both blades were tested to failure.- A numerical perspective, non-linear geometrical 3D FEM simulations has been performed to study the impact of torsional loads on relevant current structural failure modes on large wind turbine blades.The conclusion is that the larger torsional loads may explain shear-web disbond, as well as sandwich skin debonding in both the transition zone and in the max chord area of wind turbine blades. In view of the findings, the paper includes proposals for remedies that are expected to mitigate some of the significant failures currently seen in the field.

Influence of organic-mineral and biological fertilizers on the yield of winter garlic (Allium sativum) under the conditions of their application by drip irrigation

The article presents the results of three-year studies of the impact of the biological preparation Organic-Balance and organo-mineral fertilizer Helprost with Liposam adhesive on the sowing area of garlic of the winter variety Prometheus. It was established that under the conditions of drip irrigation and fertilization with the biological preparation Organic-Balance, organo-mineral fertilizer Helprost and adhesive Liposam with the rate of 2/2/1 l/ha in the phase of intensive growth and development of winter garlic plants were higher than the control variant by 39.4% and 37.3%, the area of the leaf blade is 280.5 cm2 and 252.7 cm2. In the first version, where the plants were watered only with water, the height was 57.4 cm, the area of the assimilation surface was 183.5 cm2. After fertilizing with organo-mineral fertilizer Helprost and adhesive Liposam at the rate of 2/1 and 1/1 l/ha, garlic plants were higher than the control variant by 37.9% and 36.4%, the leaf surface area was 224.0 cm2 and 199.6 cm2 respectively. When fed with the biological preparation Organic-balance and Liposam adhesive with a rate of 2/1 l/ha, the increase in plant height compared to the control was higher by 38.2%, the area of the leaves was 236.5 cm2. The conducted studies show a significant effect of feeding with biopreparations and organic-mineral fertilizers on crop formation. Thus, the best indicator was noted in the case of simultaneous treatment of single-toothed crops with the biological preparation Organic-Balance and organo-mineral fertilizer Helprost with the adhesive Liposam with the rate of 2/2/1 l/ha and with the rate of 2/1/1 l/ha, the yield was the highest 18, 7 and 18.3 t/ha, the yield premium was 6.5 and 6.1 t/ha, respectively. Somewhat lower indicators were obtained for feeding with the biological preparation Organic-balance, but it exceeded the control variant by 5.2 t/ha. When fertilizing with organo-mineral fertilizer Helprost with Lyposam adhesive, higher productivity indicators were obtained in the version with the rate of its application of 2/1 l/ha and prevailed over the control by 2.6%, while when fertilizing with the rate of 1/1 l/ha l/ha supplement to the harvest was 1.9%.

A Numerical study on the effect of solidity on the performance of Transverse Axis Crossflow Tidal Turbines

This paper presents a three-dimensional numerical study employing an actuator line model to investigate the effect of turbine solidity on the performance of a Transverse Axis Crossflow Turbine (TACTs). Transverse Axis Crossflow Turbines have a low rectangular form and are ideally suited to relatively shallow tidal and riverine sites due to their ability to handle bi-directional flow intake. Lift based TACTs are not well understood due to their complex hydrodynamics when the downstream sweep passes through the wake produced by the turbine shaft and the upstream sweep. The blade loading, hydrodynamics and ultimately power produced during the downstream sweep depends on the number of blades and turbine solidity. This numerical study is carried out using OpenFOAM and replicates planned fieldwork where the power and in-service blade loading will be monitored as a function of turbine solidity. Turbine solidity is a dimensionless parameter that measures the proportion of blade area to the projected turbine frontal area. Turbines achieve peak performance at an optimum solidity and tip speed ratio. Solidity can be varied by changing the number of blades or changing the turbine radius. An increase in solidity causes the peak performance to reduce and shift to a lower tip speed ratio albeit with a greater torque.
 This paper also explores the effect that maintaining turbine solidity has on turbine performance over a range of typical inflow velocities. Turbine solidity is held constant by varying both the number of blades and turbine diameter. Iso-solidity has been investigated for horizontal axis wind turbines but little is known about the effect of maintaining turbine solidity on TACT performance.

Assessment of the Drought-Tolerance Criteria for Screening Peach Cultivars

The article presents an analysis of the artificial dehydration effect of peach leaf tissues, simulating natural drought, on various physiological, morphological, and anatomical parameters described in the literature, associated with the trait of drought resistance. An investigation aimed to identify the most informative criteria for peach drought resistance which correlate with water loss during dehydration. The results present an assessment of the amount of water loss in 60 peach cultivars selected from different geographical areas and having different genetic origins. Four contrasting genotypes were identified, based on the results of the cluster analysis performed on the cultivar’s water regime. The influence of water regime parameters (leaf water content, water saturation deficit, dynamic of water loss), the morphological and anatomical structure of the leaf, the content of photosynthetic pigments, and the activity of the photosynthetic apparatus on drought resistance were investigated for selected peach cultivars. It was revealed that the most informative criteria for assessing drought resistance were dry and fresh leaf weight, leaf blade length, leaf width, and area (among morphometric parameters); stomatal pore length, stomata density, adaxial and abaxial epidermis thickness, and adaxial cuticle thickness (among anatomical parameters); and Fv/Fm—maximum photochemical quantum yield of PSII, Y(NO)—quantum yield of unregulated non-photochemical light energy dissipation in PS II and Y(NPQ)—controlled quantum losses (among indicators of photosynthetic activity).

Crescimento e produção da couve-flor com águas salobras em condições hidropônicas

ABSTRACT Historically, and in the aggravating climate change scenario, droughts are increasingly severe in arid and semi-arid regions, limiting the use of irrigation. As an alternative for these regions, brackish waters have been used, despite the severe risks of soil salinization, as well as losses in crop production and quality. Thus, the adoption of adequate technologies should mitigate or control the impacts caused by salt stress. Therefore, in the present study two experiments were conducted to evaluate the cultivation of cauliflower with brackish waters using a nutrient film technique (NFT) hydroponic system from July to October 2019 (winter-spring) and from October 2019 to January 2020 (spring-summer). Cauliflower plants were subjected to six values of ECw: 0.3 - control (without NaCl), 1.5, 2.5, 3.5, 4.5, and 5.5 dS m-1 (with NaCl), in a randomized block design with six replicates. For the leaf blade area at inflorescence harvest, reductions per dS m-1 increment in ECw of 7.22 and 6.41% were found in the winter-spring and spring-summer experiments, respectively. The quality losses of cauliflower inflorescences were more pronounced in the spring-summer experiment, varying according to the ECw used. Therefore, it is possible to grow cauliflower hydroponically under ECw of up to 5.5 dS m-1; however, in the hottest seasons these waters should be reserved and used only for the preparation of nutrient solutions or replacement of water consumed by plants.

On the development of a generalized atmospheric boundary layer velocity profile for offshore engineering applications considering wind–wave interaction

Within industrial standards, effects due to wind–wave interaction on the marine atmospheric boundary layer (ABL) may be included via the Charnock sea-surface roughness parameter for open-sea and near-coastal waters. This roughness parameter does not accommodate the wide variety of wave states possible, nor does it modify the ABL to include speed-up effects resulting from an undulating wave profile. In an attempt to provide an updated definition of the general ABL profile for offshore wind engineering applications, an experimental and numerical study is performed to assess the interaction of the ABL on a fixed wave geometry. By extracting the mean velocity field during the wind–wave interaction, bespoke values of the velocity profile power exponent and wind risk factor can be obtained. A range of wave heights and wave lengths are considered from which a Kriging surrogate model is trained to supply the relevant wind profile parameters depending on the wave state. These newly garnered parameters enable the practitioner to define a reference wind velocity, and then adjust the velocity profile characteristics to contain the influence of the wave. This approach provides a new inlet velocity condition that can be used within computational wind engineering investigations without the need to explicitly model the wave surface, as well as flexibility in specifying the underlying wave conditions. Application of the re-calibrated velocity profile shows that wind forces are significantly greater throughout an offshore wind turbine (OWT) swept blade area when large (H= 15 m) and small (H= 1.5 m) wave heights are compared.

CLINICAL VARIANT OF OSSIFYING MYOSITIS IN PEDIATRIC PRACTICE

Introduction. Ossifying myositis is a pathological process in muscles characterized by the formation of ossification in soft tissues. At present, the etiological factors of the disease remain not fully elucidated. The triggering factors of the disease are considered to be traumatic injuries, invasive medical manipulations against the background of genetic predisposition.Aim. Invite attention of general practitioners and pediatricians to a rare disease, namely progressive ossifying fibrodysplasia in children and the peculiarities of its diagnosis.Results. The article presents a clinical case of progressive ossifying fibrodysplasia (Munchmeyer's disease) in a 4-year-old girl. At birth, the child was diagnosed with a foot deformity characteristic of this pathology (shortening of the first metatarsal finger, flexion-rotation contracture of both feet). The clinic of the disease manifested itself at the age of 3 years, when, after falling on the back, a dense formation was noticed in the area of the left shoulder blade. Half a year after the fall, swelling and pain appeared in the sacro-coccygeal region of the spine. The girl was consulted by an orthopedist, dermatologist, and oncologist. During the examination of the child, characteristic clinical features of progressive ossifying fibrodysplasia were revealed, namely, deformation and fixed position of the chest, tense neck muscles, sharp limitation of movements in all parts of the spine, limitation of bending in the left elbow joint, clinodactyly, valgus deformity of the big toes. During the ultrasound examination, the following changes were diagnosed: swelling of muscle tissue in the neck area, subscapular area on the left and sacrococcygeal joint; multiple hypoechoic formations of irregular shape, heterogeneous echo structure with hyperechoic inclusions with an acoustic shadow; a focal change in the muscle structure in the form of a loss of the characteristic pinnate structure of the perimysium. The diagnosis was confirmed histologically. No characteristic changes were found in clinical and biochemical studies. The girl is under supervision. No worsening of the child's condition has been recorded over the past four years.

Changes in the morphometric and anatomical parameters of shoots and leaves of Acer platanoides L. after rejuvenation pruning

The influence of rejuvenation pruning on changes in anatomical and morphometric characteristics of annual shoots and leaves of Acer platanoides L. in the conditions of Dnipro (Ukraine) has been investigated. In the first two years after pruning, a significant intensification of growth processes is observed. The length and diameter of annual shoots, the number of internodes and leaves, and the area of the leaf blade increased. Pruning has a particularly noticeable effect on the increase in the length of annual shoots and the area of the assimilation surface of the shoot – in the first year after pruning, they increased by 4.6 and 3.2 times, respectively. In rejuvenated plants, a thickening of the leaf blade occurs, mainly due to the development of a spongy parenchyma. In the fourth year after pruning, the intensity of growth processes decreases and differs little from the control (unpruned) plants. The leaves of crowned plants are damaged more significantly than those of unpruned ones. In four years, the rejuvenated plants restore their crowns well.

Structural and functional changes in the leaves of black currant seedlings using nanoparticle solutions

When propagating black currant by lignified cuttings in order to obtain high-quality planting material in one growing season in the conditions of the forest-steppe zone of the Krasnoyarsk Territory, solutions of biogenic ferrihydrite nanoparticles were used in three modifications with the addition of traditional growth hormone (indolyl-3-acetic acid): control (soaking cuttings in water); treatment of cuttings with indolyl-3-acetic acid (IAA); IAA+ferrihydrite (IAA+Feh); IAA+Co-doped ferrihydrite (IAA+Feh_Co); IAA+ferrihydrite doped with Mn (IAA+Feh_Mn). The object of the study is blackcurrant plants of the Selechenskaya variety. The area of the assimilation surface and the pigment composition of the leaves were assessed in dynamics. Before planting, black currant cuttings were soaked in nanoparticle solutions (exposure 12 h), then, during the growing season, four times (with an interval of 14 days) exogenous treatment of the leaf surface of rooted cuttings with the same solutions of nanoparticles, but without the addition of IAA, was carried out. The results of studying the concentration of pigments in leaves and biometric observations in the dynamics of the growing seasons of 2021 and 2022 are presented. It has been established that the maximum concentration of chlorophyll a and b, carotenoids in black currant leaves by the end of the growing season was affected by the use of solutions of ferrihydrite nanoparticles doped with cobalt and manganese with the addition of IAA. Thus, the concentration of chlorophyll a, b increased by 1.3 and 1.6 times, respectively, in the variant with cobalt-doped ferrihydrite nanoparticles compared to the control. In our studies, the values of the assimilation surface of leaves depended on the climatic parameters of the year of study and on the content of photosynthetic pigments in blackcurrant leaves. Between the area of the leaf blade and the concentration of chlorophyll a, a direct relationship was noted (r=0,87), a close relationship: in 2021 between the area of the leaf blade of black currant and the amount of precipitation (r=0,83-0.94), in 2022 between the area of blackcurrant leaf blade and air temperature (r=0,85-0,93). It has been established that the best conditions for the formation of the assimilation surface of blackcurrant leaves of the Selechenskaya variety are created by soaking cuttings and foliar treatment of vegetative plants with ferrihydrite nanoparticles doped with cobalt and manganese.

Multi-objective optimization design of shaftless rim-driven thruster

This paper proposes a multi-objective optimization design method for shaftless rim-driven thruster (RDT) based on the ISIGHT platform. The pitch ratio, the blade area ratio and the advance coefficient of RDT were considered as the design optimization variables, the thrust and efficiency of the RDT were the optimization objectives. The multi-objective optimization design method was based on the surrogate module and the optimization module in the ISIGHT platform. Two analytical methods (response surface methodology (RSM) and radial basis function Model (RBF)) were used to build the surrogate model. The Muti-Island GA optimization algorithm was adopted in the optimization module. The paper indicates that both RSM model and RBF model are feasible to build the surrogate model, the RBF model has better accuracy and reliability than RSM model. The blade obtained by RBF method has larger thrust and smaller torque than that of the blade obtained by RSM method. For the large advance coefficient ( J > 0.6), the efficiency of the blade obtained by RBF method is slightly higher than that of the blade obtained by RSM method.

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Trichomes are extensions of the epidermis, frequently used as diagnostic traits for determining plant species. Solanum L., 1753 is a widespread and taxonomically complex genus. Although the genus Solanum has been the subject of numerous types of research, little attention has been given to the trichomes of the wild species found in Egypt. Therefore, the objective of the current study was to examine trichome types in ten wild Solanum species and assess their taxonomic importance. Using light, scanning electron microscopy and line drawings, indumentum characteristics on the abaxial leaf surface are investigated. The results showed a wide range of variation in trichome density on a 1 mm2 area of leaf blade (sparse, moderate, and dense), nature (glandular or non-glandular, simple or stellate), and structure (number of composing cells in simple non-glandular and glandular stalk and head; the number of radiating rays in stellate hairs). SEM revealed the existence of unique wax structures, including warty granules in addition to flakes. Our observations are consistent with the general characteristics of the subgenus Leptostemonum and the subgenus Solanum. This work provides strong evidence for the separation and interspecific delimitation of the investigated Solanum species using trichome morphology as a significant taxonomic trait.

THE INFLUENCE OF THE AREA OF THE LEAF LABEL ON THE ROOTING OF THE GREEN VIRLAND TREES

According to the research results, it was found that rooting and further development of rooted green viburnum cuttings of the usual variety depends on the area of the leaf blade. Analyzing the influence of the size of the leaf surface on the rooting of cuttings of the Velikoplidna variety in the studied period of cuttings, it should be noted the high rooting of cuttings in the variant without shortening of the leaf surface. A gradual decrease in the area of the leaf plate led to a significant decrease in the rooting of green cuttings. Green cuttings of the Velikoplidna variety harvested during the period of mass flowering from the basal part of the shoot with whole leaf plates were characterized by significantly higher rooting, number and length of the root system compared to cuttings harvested from the medial and apical parts.Green cuttings of the Velikoplidna variety harvested during the period of intensive growth of shoots from the medial part of the shoot with whole leaf plates were characterized by significantly higher rooting, number and length of the root system compared to cuttings harvested from the basal and apical parts. Green cuttings of the Velikoplidna variety harvested during the period of slow growth of shoots from the apical part of the shoot with whole leaf plates were characterized by significantly higher rooting, number and length of the root system compared to cuttings harvested from the basal and medial parts. Rooting and subsequent growth and development of rooted viburnum cuttings of the ordinary Velikoplidna variety depends on the area of the leaf surface. A decrease in the area of the leaf plate leads to a significant decrease in rooting and negatively affects the development of the adventitious root system. The best indicators are characterized by green cuttings from the basal part, harvested during the period of mass flowering, during the period of intensive growth of shoots, cuttings harvested from the medial part of the shoot, during the period of slow growth of shoots - from the apical part of the shoot.

Automated Quantification of Wind Turbine Blade Leading Edge Erosion from Field Images

Wind turbine blade leading edge erosion is a major source of power production loss and early detection benefits optimization of repair strategies. Two machine learning (ML) models are developed and evaluated for automated quantification of the areal extent, morphology and nature (deep, shallow) of damage from field images. The supervised ML model employs convolutional neural networks (CNN) and learns features (specific types of damage) present in an annotated set of training images. The unsupervised approach aggregates pixel intensity thresholding with calculation of pixel-by-pixel shadow ratio (PTS) to independently identify features within images. The models are developed and tested using a dataset of 140 field images. The images sample across a range of blade orientation, aspect ratio, lighting and resolution. Each model (CNN v PTS) is applied to quantify the percent area of the visible blade that is damaged and classifies the damage into deep or shallow using only the images as input. Both models successfully identify approximately 65% of total damage area in the independent images, and both perform better at quantifying deep damage. The CNN is more successful at identifying shallow damage and exhibits better performance when applied to the images after they are preprocessed to a common blade orientation.

Improving rowing performance by adjusting oar blade size and angle.

The principal aim of the work presented here is to investigate and demonstrate that a forward tilted rowing blade would result in a more efficient and effective motion of the blade through the water that would result in a higher boat speed when an equal input power is provided. A 1:5 scaled rowing boat is used to determine the performance of rowing blades with different sizes and blade angles. This is used to validate the results of a previous study where the optimal blade angle of 15 with respect to the oar shaft was determined ( 1). The input power and speed of the rowing boat can be compared between original and modified oar blades. Measurements in a towing tank demonstrate that a modified rowing blade result in faster rowing by 0.4% at the same input power. Maintaining the same stroke rate, the improvement of the blade efficiency is compensated by using a 4-6% increased blade area to yield the same input power.

Static numerical simulation of radial deformation of ultra-thin dicing blade

Grinding with dicing blade is an important method to cut or slot electronic and optical devices. The deformation of grinding tools will definitely affect the processing of workpiece. However, this effect has been disregarded during processing. In order to improve the machining accuracy in the precision grinding method, this deformation is worth considering. In this research, the grinding state of the ultra-thin dicing blade was simplified as a static problem. The force model of the ultra-thin dicing blade during grinding was established, which centrifugal force was adopted in the whole blade and triangular distribution grinding forces were adopted in the grinding area. The radial deformation of the ultra-thin dicing blade was determined by finite element simulation, and the influence of grinding parameters on its radial deformation was analyzed. The simulation results showed that the grinding area of the ultra-thin dicing blade occurred radial expansion deformation at high rotational speed (more than 8000 rpm), and the value could reach 1.75 μm (rotational speed at 23,000 rpm, feed speed at 600 mm/min, and grinding depth at 0.12 mm). The deformation increased in a form of power function with the increase of rotational speed, and decreased linearly with the increase of feed speed and grinding depth. This work can provide reference data for deformation compensation, which is helpful to improve the dimensional accuracy of grinding groove.

Numerical analysis of the effect of the blade number on the hydrodynamic performance of shaftless rim-driven thruster

In this work, numerical investigations were performed to the study the effect of blade number on the hydrodynamic performance of shaftless Rim-driven Thruster (RDT) with certain blade area ratio and pitch ratio. The work investigated and compared the thrust coefficient, torque coefficient and efficiency of the RDTs with different blade numbers. Additionally, this work detected and analyzed the pressure distribution on the blade surface and velocity distribution around the blade and in the wake. The results demonstrate that for a certain advance coefficient, the thrust coefficient and torque coefficient of the RDT increase with the blade number, however the efficiency of the RDT decreases with the increase of blade number. For the same cross-section and advance coefficient, the 7-blade RDT has higher thrust and torque than the 3-blade RDT due to the large friction and pressure difference between the suction and pressure surfaces. The high velocity of both RDTs appears at the junction between each blade and the duct, and the 7-blade RDT has higher velocity in the wake and in the cross-section than the 3-blade RDT. The 3-blade RDT has the high pressure at the leading edge on the suction surface of each blade. However, the 7-blade RDT has not only the high pressure at the leading edge, but also the high negative pressure at the blade root on the suction surface of each blade, so 7-blade RDT has higher torque that 3-blade RDT.

Effect of sand and crosswind on the performance of solar chimney power plant

AbstractA solar chimney power plant (SCPP) is suitable to be deployed in desert areas, but there are few studies on the impact of desert wind and sand. In this paper, numerical simulations for the Spanish prototype SCPP were conducted to investigate desert environmental parameters, including sand movement, crosswind, and sand deposition, on the output performance of SCPP. The results indicate that the main erosion area of the turbine blade in the SCPP is the leading edge of the blade pressure surface. The erosion area of the suction surface is much less than that of the pressure surface, mainly concentrated on the leading edge. The output power of SCPP is reduced by 73.3% because of the crosswind and it decreases by 16.9% after the windbreak wall is installed. The sand and dust deposition would affect the transmissivity of the solar radiation through the collector cover. In a dusty environment for 1 month, the system output power decreased by 12.9%, and the collector efficiency decreased from 34% to 23% due to the sand deposition. These results show that the sand has a considerable negative effect on the performance of SCPP in ways of sand erosion and deposition. Sand removal is necessary for SCPP.

QUANTITATIVE AND QUALITATIVE INDEXES OF THE FUNCTIONING OF PHOTOSYNTHETIC APPARATUS OF ORNAMENTAL SUNFLOWER PLANTS WITH DIFFERENT SEEDING RATES UNDER CONDITIONS OF THE SOUTHERN STEPPE OF UKRAINE

The research revealed the tendency for an increase in the index of the average area of an individual leaf blade when the seeding rate rose from 50 to 60 thous. pcs./ha, and further there was a reduction in this index when the seeding rate increased to 70 thous. pcs./ha. The average index in the variant of the hybrid Teddy F1 was 72.6 cm<sup<2</sup<, Double Sunking F1 - 70.3 cm<sup<2</sup<, Santa Fe F1 - 70.8 cm<sup<2</sup<, respectively. The dependence of the index of leaf blade thickness of sunflower hybrids on the factors under study was analogous: this index was minimal in the variant of the hybrid Teddy F1 - 0.58 mm, it fell to 0.55 mm in the variant of the hybrid Double Sunking F1, it was minimal in the variant of the hybrid Santa Fe F1 - 0.52 mm on the average by Factor В. According to our data, the dependence of the intensity of green color of a leaf blade of sunflower hybrids was similar: this index was not essentially dependent on Factor А, but an increase in the seeding rate caused a reduction in the intensity of green color of leaves in comparison with the sample. If the intensity of the sample color is considered to be 100%, the color of a leaf blade in the variant of the hybrid Teddy F1 was at the level of 73%, that of the hybrid Double Sunking F1 - 69%, and that of the hybrid Santa Fe F1 - 69% of the sample. The least intensity of green color of sunflower leaves was with the maximum seeding rate and did not exceed 62% on the average by Factor А. On the average by Factor В, the hybrid Teddy F1 was considered to be a leader by the content of green pigment in its leaves - 8.69 mg/g, in the variant of the hybrid Santa Fe F1 it was 7.45 mg/g, Double Sunking F1 - 8.02 mg/g. The maximum area of the crop photosynthetic apparatus was formed in the variant of the hybrid Teddy F1 being 30.7 thous. m2/ha at the stage of flowering, in the variant of the hybrid Double Sunking F1 - 29.5 thous. m<sup<2</sup</ha and in the variant of the hybrid Santa Fe F1 - 26.1 thous. m<sup<2</sup</ha, respectively. In all the variants of the crop hybrids there was a correlation according to which there was an increase in the index of leaf surface area when the seeding rate rose from 50 to 60 thous. pcs./ha, and when there was a further increase in the seeding rate to 70 thous. pcs./ha, vice versa, this index started decreasing considerably. The index of net productivity of photosynthesis reached its maximum values in the variant of the hybrid Teddy F1 being 1.99 g/m<sup<2</sup</day, on the average by Factor В, that of the hybrid Double Sunking F1 - 1.93 g/m<sup<2</sup</day and that of the hybrid Santa Fe F1 - 1.84 g/m<sup<2</sup</day, respectively.