Organic Dry Weight Research Articles

A study on parameter calibration of a general crop growth model considering non-foliar green organs

Accurate crop yield estimation is essential for ensuring national food security and sustainable development. The crop growth model is one of the primary methods for estimating production and has been effectively applied in simulating crop growth and development, environmental factor effects and yield formation processes. However, many related studies have focused on Gramineae crops, such as wheat, rice and maize, while there has been little research on rape and soybean yield estimation. Non-foliar green organs such as rape siliques and soybean pods make vital contributions to plant photosynthesis and influence crop output. The parameter calibration method based on the leaf area index (LAI) cannot satisfy the existing demand for high-precision yield estimation for crops with active non-foliar green organs. Therefore, a new method for crop growth model calibration was proposed, which considers non-foliar green organs and plant photosynthetic succession processes and combines them with those of leaves to construct a photosynthetic area index (PAI). With wheat, rape and soybean as the research objects, their yields were simulated via the proposed crop growth model calibration method. The results showed that using the proposed calibration method to calibrate World Food Study (WOFOST) model parameters on the basis of the PAI improved the yield estimation accuracy over that of the crop model calibration method based on the LAI. The determination coefficient (R2) of the total dry weight of storage organs (TWSO) simulation value increased from 0.73 (using the LAI) to more than 0.90 (using the PAI). The R2 values of TWSO at the rape calibration and verification points were 0.910 and 0.922, respectively, and the R2 values of TWSO at the soybean calibration and verification points were 0.741 and 0.926, respectively. The above results verified the feasibility and effectiveness of the proposed calibration method. Consequently, the application of the crop model calibration method proposed in this paper is important for accurately estimating the crop yield of plants with active non-foliar green organs, promoting the expansion of general crop models for different types of crops and achieving high-precision crop yield estimations.

Modulation of the capillary leakage by exogenous albumin in a rat model of endothelial glycocalyx damage.

Endothelial glycocalyx (EG) plays a crucial role in maintaining the plasma proteins within the intravascular space. We studied whether exogenous albumin protects the EG in an experimental model of EG enzymatic damage in rats. Rats were divided into three groups of 10 animals that received (1) Evans blue (2) Evans blue + hyaluronidase, or (3) Evans blue + hyaluronidase + 20% human albumin via the tail vein. Spectrophotometric analysis was performed 2 h later to quantify the leakage of Evans blue-labeled albumin into the heart, lungs, brain, kidneys, liver, small intestine, spleen, and skeletal muscle. Administration of hyaluronidase numerically increased the capillary leakage of Evans blue in all examined tissues. Co-administration of albumin decreased the leakage of albumin in all tissues except the heart. In the lungs, the ratio between the absorbance and dry organ weight decreased from 5.3 ± 2.4 to 1.7 ± 0.5 (mean ± SD) (P < 0.002), and in the liver, the absorbance decreased from 2.2 ± 0.7 to 1.5 ± 0.4 (P < 0.011). Exogenous albumin decreased the capillary leakage of albumin which was interpreted as a sign of maintained EG integrity.

Effect of growth promotors on morphogenesis, photosynthetic apparatus, productivity and residual substances content in sweet pepper (Capsicum annuum) fruits

The use of plant growth promoting substances in order to optimize crop performance is one of the leading tasks of modern plant physiology. The effect of 0.005% 1-naphthaleneacetic acid (1-NAA), 0.005% gibberellic acid (GA3), 0.005% 6-benzylaminopurine (6-BAP) foliar treatment on morphogenesis, leaf parameters, photosynthetic pigments content, photosynthetic apparatus activity indices, and residual amounts of the used substances in the sweet pepper Capsicum annuum L. variety Antey fruits was investigated. The field experiment was laid on plots of 32 m2. The treatment of plants was carried out at the budding stage. Morphometric indices were determined at the flowering and fruit formation stages. The mesostructure of the middle tier leaves was studied at the fruit formation stage. The content of the chlorophylls was determined in the fresh leaf tissue by the spectrophotometric method. Indices of photosystem II (PSII) activity were determined by registration of chlorophyll fluorescence induction, using a portable single-beam fluorimeter. The assay of the residual content growth of promotors in the fruits was carried out on a Shimadzu GC gas chromatograph with a mass spectrometric detector – GCMS-QP2020 EI. It was revealed that treatment with GA3 increased plant height. All substances increased the number of leaves on the plant, their fresh and dry weight, the leaf area, and the canopy leaf area index. All growth promoting substances thickened leaf laminas due to the growth of chlorenchyma. GA3 and 6-BAP increased the volume of columnar parenchyma cells, and 1-NAA and GA3 increased the size of leaf spongy parenchyma cells. 6-BAP increased the total chlorophyll (a + b) content in the leaves, and under the GA3 treatment this index tended to decrease. 6-BAP increased the chlorophyll index of plants at the fruit formation stage, and GA3 decreased it at the flowering stage. The net photosynthetic rate increased under the influence of 1-NAA and 6-BAP, and decreased under GA3 treatment. GA3 reduced photorespiration and transpiration in leaves, 6-BAP increased transpiration, and 1-NAA decreased it. All substances increased dark respiration. Treatment with GA3 and 6-BAP reliably increased the maximum quantum efficiency of PSII photochemical reactions. 1-NAA and 6-BAP increased the actual quantum efficiency of PSII photochemistry. The coefficient of chlorophyll fluorescence photochemical quenching significantly increased at flowering under the application of 1-NAA, and tended to increase at the stage of fruit formation under the treatment of 1-NAA and 6-BAP. When GA3 was applied, the rate of chlorophyll fluorescence photochemical quenching was significantly reduced. The index of PSII reaction centers fraction that do not reduce the QB acceptor did not change with the use of 1-NAA and GA3 and tended to decrease after the use of 6-BAP. All growth promotors increased the whole plant dry weight. They reduced the net photosynthetic efficiency at the flowering stage, and at the stage of fruit formation it significantly increased under the treatment with 6-BAP. The 6-BAP caused the redistribution of plastic substances into the fruits due to the decrease in the dry weight of vegetative organs. Treatment with 1-NAA increased the proportion of root dry weight. 1-NAA, GA3 and 6-BAP increased the yield of fruits from one plant by 17%, 22% and 20% respectively due to the increase in the number of fruits per plant. The residual amounts of 1-NAA and 6-BAP in ripe sweet pepper fruits did not exceed the maximum permissible sanitary standards.

Yield and Photosynthesis Related to Growth Forms of Two Strawberry Cultivars in a Plant Factory with Artificial Lighting

Appropriate growth forms for strawberry production in a plant factory with artificial lighting (PFAL), which is a recently developed production system, remain undetermined. Improving strawberry productivity in a PFAL requires insights into the interplay between production characteristics (growth and photosynthesis) and growth forms, such as plant height and leaf area (LA), which are major determinants of crop yield. Growth status, yield, and photosynthetic characteristics of the two cultivars of strawberries (Fragaria ×ananassa Duch. Tochiotome and Koiminori) with different growth forms were examined. ‘Koiminori’ exhibited a 1.9-fold higher yield and a 2.0-fold greater total dry weight of respective organs compared with ‘Tochiotome’. The single-plant photosynthetic rate (AP), serving as an index for both cultivars, was 2.2-times higher for Koiminori than for Tochiotome. The photosynthetic rates of a single leaf (AL) and LA were also analyzed as important factors that influence the AP. The AL for ‘Koiminori’ surpassed that of ‘Tochiotome’ by 1.4 times. This was attributed to the elevated photosynthetic photon flux density received by the upper leaves of Koiminori, which is a consequence of its higher plant height in proximity to the light source. Evaluation of four photosynthetic capacities, maximum rate of carboxylation, maximum rate of electron transport, photosynthetic rate under saturating light, and light utilization efficiency, which are potential factors that affect AL, revealed no differences in these capacities between cultivars. ‘Koiminori’ exhibited a significantly larger LA (2.3- to 3.1-times) than ‘Tochiotome’, indicating that the former’s higher AP resulted mainly from its higher AL and larger LA. Thus, strawberry production in a PFAL can be improved by growing cultivars with growth forms such as higher plant height and larger LA.

Potential of Ecoenzymes and N2 Nanobubbles on the Growth of Phalaenopsis sp. Orchid at the Acclimatization Stage

Growth is a quantitative change during one plant’s life cycle and is irreversible.withaddition An in crease the volume or dry weight of plants or other organs is due to the adding, of new structural elements. Phalaenopsis (moth orchid) is a genus of orchids appeal. The diversity of colors, shapes, and textures, as well as its aroma, make Phalaenopsis orchids one of the charming flowers of Indonesia. Ecoenzyme is a solution of complex organic substances produced from the fermentation of organic residues, sugar, and water. Nanobubbles (NBs) are an example of nanotechnology. NBs have a diameter of 1-100 nm and are nanoscopic gas bubbles in a solution or water that can change the characteristics of water and are stable. This study aims to determine the potential of giving Ecoenzyme and NBs N2 on the growth of Phalaenopsis orchids during the acclimatization stage. This research was conducted from October to December 2022 at the Orchidology and Nursery Laboratory, Islamic University of Malang. This study used an experimental method with a completely randomized design (CRD) with 10 treatments, namely 0 mL/L (control), 1 mL/L Ecoenzyme, 2 mL/L Ecoenzyme, 3 mL/L Ecoenzyme, 4 mL/L Ecoenzyme, 4 combination NBs N2 and Ecoenzymes, and 5 mL NBs N2 with 3 replications, making a total of 30 treatment units. The research parameters included the number of leaves, leaf length, number of roots, root length, plant height, fresh weight, and plant dry weight. The results of this study showed that the treatment of 3 mL/L Ecoenzyme showed potential in increasing the number of leaves by 4 pieces: at the same time the optimal concentration of the combination of Ecoenzyme and NBs was 2 mL/L plus 5 mL NBs N2 in increasing the number of roots by 10 pieces, and the optimal concentration of NBs was 5 mL in increasing the root length by 7.07 cm, plant height by 17.10 cm leaf. length, plant weight by 4.16 g and dry weight by 0.85 g in Phalaenopsis orchids.

Effect of Chicken Manure Fermentation Extract as an Alternative to Chemical Fertilizer on Cucumber Growth and Soil Microbiome Environment

ABSTRACT In recent years, the destruction of the soil environment caused by excessive application of chemical fertilizers has attracted attention to using organic fertilizers to replace chemical fertilizers. Previous studies have shown that chicken manure fermentation extract (CMFE) as an organic fertilizer may also directly influence soil nutrient availability from the soil native pool and fertilizer application. However, it is unclear whether application CMFE can partially replacing chemical fertilizer to reduce the amount of chemical fertilizer without reducing cucumber yield. Therefore, an experiment was conducted in Yantai Agricultural Science Academy of Shandong Province in 2018 and 2019. In 2018, five fertilization combinations were set up, namely CK (900 kg·ha−1 chemical fertilizer), T1 (750 kg·ha−1 chemical fertilizer +150 L·ha−1 CMFE), T2 (675 kg·ha−1 chemical fertilizer +225 L·ha−1 CMFE), T3 (600 kg·ha−1 chemical fertilizer +300 L·ha−1 CMFE) and T4 (525 kg·ha−1 chemical fertilizer +375 L·ha−1 CMFE). Selected the optimal combination T3 for testing in 2019. The yield, quality, photosynthesis and growth indicators of cucumber, as well as soil nutrients and microbial content were determined. The results showed that the fertilization combination of 600 kg·ha−1 chemical fertilizer +300 L·ha−1 CMFE (T3) can minimize the amount of chemical fertilizer used without reducing yield. Compared with conventional fertilizer application, CMFE partially replacing chemical fertilizer did not reduce cucumber yield, but significantly increased cucumber vitamin C and protein content. CMFE partially replacing chemical fertilizer increased the root to shoot ratio as well as the fresh and dry weight of vegetative organs in cucumber, optimizing the growth and development of cucumber. Compared with conventional fertilizer application, CMFE partially replacing chemical fertilizer increased the content of soil organic matter, improved the composition structure of soil microbial community, increased the relative abundance of Actinomycete and Acinetobacter, and reduced the relative abundance of Bacteroides, Ascomycota, and Basidiomycetes. Overall, CMFE partially replacing chemical fertilizer optimized the growth and development of cucumbers, increased the root to shoot ratio, increased soil organic matter content, increased microbial abundance and diversity, and improved the composition structure of soil microbial communities. Therefore, in order to reduce the use of fertilizers, it is recommended to partially replacing chemical fertilizers with CMFE, with the optimal combination of 600 kg·ha−1 chemical fertilizer +300 L·ha−1 CMFE (T3).

Investigation of physiological energetic response of the thick shell mussel, Mytilus coruscus, to microplastics and low salinity: Potential countermeasures to multi-environmental changes

Microplastics (MPs) contamination and salinity fluctuation are two common phenomena on the East China Sea coast. The purpose of this experiment was to evaluate the combined effects of MPs and salinity on the energy budget of the thick shell mussel Mytilus coruscus. Juvenile mussels were exposed to six combined treatments with three MPs levels (0, 10 and 1000 items L−1) and two salinity levels (15, 25) for 28 d. The clearance rate, food absorption efficiency, respiration rate, ammonium excretion rate, and O:N ratio were significantly reduced, and the fecal organic dry weight ratio was significantly increased at salinity 15, inducing a reduction in the scope for growth. Under salinity 15, 1000 items L−1 MPs had significant negative effects on growth at Day 28. However, under salinity 25, the results were opposite in that the level of 1000 items L−1 MPs brought an obvious increment in scope for growth at Day 28. This meant that there were interactions between salinity and MPs in scope for growth at Day 28. These results suggest that the physiological energetics of juvenile M. coruscus can acclimate to MPs contamination with little physiological effect under normal salinity. This experiment has revealed that although marine MPs contamination is of concern, marine organisms likely have a significant capacity to adapt to it.

Allometric Relationships between Dry Matter Weights of Maize Organs and Their Responses to Drought

To understand the drought response mechanisms of dry matter partitioning of maize, pot experiments under drought conditions were conducted during the vegetative and reproductive growth periods of maize. The aim was to calculate allometric relationships between the dry matter weight of different organs and their responses to drought. Results showed that allometric relationships between the roots, above-ground plant, and total biomass gradually increased with maize growth approaching maturity under a normal water supply. Drought during the vegetative period reinforced allometric relationships during the growth process and after rewatering and increased the size-dependence of the root shoot ratio. However, drought during the reproductive period weakened them. The ear–shoot allometric relationship was more significant during growth than at later growth under normal conditions but strengthened during later growth in those plants suffering droughts during the vegetative and reproductive stages. The ear–shoot allometric relationship and the size-dependence of harvest index at later growth were significantly enhanced by drought during the reproductive period compared to the vegetative period.

Cytokinins and auxins in organs of aquatic carnivorous plants: what do they reflect?

Aquatic carnivorous plants have typical rootless linear shoots bearing traps and exhibit steep physiological polarity with rapid apical growth. The aim was to analyse auxin and cytokinin metabolites in traps, leaves/shoots and shoot apices in several species of genera Aldrovanda and Utricularia to elucidate how the hormonal profiles reflect the specific organ functions and polarity. The main auxin and cytokinin metabolites were analysed in miniature samples (>2 mg dry weight) of different organs of Aldrovanda vesiculosa and six Utricularia species using ultraperformance liquid chromatography coupled with triple quadrupole mass spectrometry. Total contents of biologically active forms (free bases, ribosides) of all four main endogenously occurring cytokinin types were consistently higher in traps than in leaves in four Utricularia species with monomorphic shoots and/or higher than in shoots in two Utricularia species with dimorphic shoots. In Aldrovanda traps, the total content of different cytokinin forms was similar to or lower than that in shoots. In U. australis leaves, feeding on prey increased all cytokinin forms, while no consistent differences occurred in Aldrovanda. In four aquatic Utricularia species with monomorphic shoots, the content of four auxin forms was usually higher in traps than in leaves. Zero IAA content was determined in U. australis leaves from a meso-eutrophic site or when prey-fed. Different cytokinin and auxin profiles estimated in traps and leaves/shoots of aquatic carnivorous plants indicate an association with different dominant functions of these organs: nutrient uptake by traps versus photosynthetic function of traps. Interplay of cytokinins and auxins regulates apical dominance in these plants possessing strong polarity.

Pear Tree Growth Simulation and Soil Moisture Assessment Considering Pruning

Few studies deal with the application of crop growth models to fruit trees. This research focuses on simulating the growth process, yield and soil moisture assessment of pear trees, considering pruning with a modified WOrld FOod Studies (WOFOST) model. Field trials (eight pruning treatments) were conducted in pear orchards in Alaer and Awat in Xinjiang, China and data were measured to calibrate and evaluate the modified model. In two pear orchards, the simulated total dry weight of storage organs (TWSO) and leaf area index (LAI) were in good agreement with the field measurements of each pruning intensity treatment, indicating that the R2 values of TWSO ranged from 0.899 to 0.976, and the R2 values of LAI ranged from 0.849 to 0.924. The modified model also showed high accuracy, with a normalized root mean square error (NRMSE) ranging from 12.19% to 26.11% for TWSO, and the NRMSE values for LAI were less than 10%. The modified model also had a good simulation performance for the soil moisture (SM) under all eight pruning intensity treatments, showing good agreement (0.703 ≤ R2 ≤ 0.878) and low error (NRMSE ≤ 7.47%). The measured and simulated results of different pruning intensities showed that the highest yield of pear trees was achieved when the pruning intensity was about 20%, and the yield increased and then decreased with the increase in pruning intensity. In conclusion, the modified WOFOST model can better describe the effects of summer pruning on pear tree growth, yield and soil moisture than the unmodified model, providing a promising quantitative analysis method for the numerical simulation and soil moisture assessment of fruit tree growth.

Morphology and Nitrogen Uptake and Distribution of Wheat Plants as Influenced by Applying Remedial Urea Prior to or Post Low-Temperature Stress at Seedling Stage

Wheat production is dramatically influenced by temperature. Low-temperature stress that frequently occurs seriously hampers the growth and development of wheat seedlings. In order to alleviate the damage of low temperature to wheat plant growth, remedial nitrogen was applied prior to or post low-temperature stress at seedling stage using controlled-temperature incubators to explore the difference in wheat morphology and nitrogen absorption and utilization efficiency. Nitrogen amendment significantly increased the leaf area, seedling height, tiller number and dry matter weight of wheat plants as compared with the treatment without nitrogen amendment under temperature stress. Remedial nitrogen applied prior to low-temperature stress (N-LT) was more conducive to increase the above parameters than that applied post low-temperature stress (LT-N). In addition, N-LT enhanced the ability of roots to absorb remedial 15N urea, promoted the growth and development of wheat plants under low-temperature stress, resulting in higher leaf SPAD readings, more new tillers, as well as increased dry weight of roots and above-ground organs. This study suggested that remedial nitrogen should be applied prior to low-temperature stress because it is more effective in restoring the growth of wheat plants under low-temperature stress.

Synthesized effects of medium-term exposure to seawater acidification and microplastics on the physiology and energy budget of the thick shell mussel Mytilus coruscus

Ocean acidification (OA) and microplastics (MPs) contamination are two results of human excises. In regions like estuarine areas, OA and MPs exposure are happening at the same time. The current research investigated the synthesized effects of OA and MPs exposure for a medium-term duration on the physiology and energy budget of the thick shell mussel Mytilus coruscus. Mussels were treated by six combinations of three MPs levels (0, 10 and 1000 items L−1) × two pH levels (7.3, 8.1) for 21 d. As a result, under pH 7.3, clearance rate (CR), food absorption efficiency (AE), respiration rate (RR), and scope for growth (SFG) significantly decreased, while the fecal organic dry weight ratio (E) significantly increased. 1000 items L−1 MPs led to decrease of CR, E, SFG and increase of AE under pH 8.1. Interactive effects from combination of pH and MPs were found in terms of CR, AE, E and RR, but not for SFG of M. coruscus.

Effects of the Light Irradiance on the Growth and Lipid Content of Amphidinium carterae (Dinophyceae) for Biofuel Production

The irradiance level used in the microalgae cultures can modify the growth and proximate composition; however, this response is specie specific. The dinoflagellate group has the potential to be used as a source of biofuel production. This study evaluated the effect of five irradiance levels (50, 100, 150, 200, and 250 µmol photon m−2 s−1) on the growth rate, proximal composition, pigment content, and photosynthesis of Amphidinium carterae. The highest cell concentration was for the cultures at 150 µmol photon m−2 s−1 (130 × 103 cells mL−1) and the lowest value for 50 µmol photon m−2 s−1 (49 × 103 cells mL−1). The cultures maintained under the lowest irradiance had the highest values of organic dry weight (ODW) and inorganic dry weight (IDW). The protein and carbohydrate content changes significantly concerning the irradiance level, with the higher values (1599.46 pg cell−1 and 557.24 pg cell−1, respectively) at an irradiance of 200 µmol photon m−2 s−1. Lipid content was modified by the effect of irradiance, with the highest values (6920.89 pg cell−1) at the lowest irradiance used. As a general trend, the high irradiances increased the photosynthesis rates. These findings demonstrate that the strain of A. carterae used in this work can grow in high irradiances (100 to 250 µmol photon m−2 s−1) and significantly increase the lipid content at low irradiance used.

Exogenous DCPTA Treatment Increases Mung Bean Yield by Improving Carbon Metabolism Pathway and Up-Regulating Photosynthetic Capacity and Antioxidants.

Mung bean is characterized by having a good edible and medicinal value, while its flowers and pods have low production. Being a tertiary amine, DCPTA [2-(3,4-dichlorophenoxy) triethylamine] substantially regulates the growth and development of crops, maintaining production. Yet it is still limited in terms of the regulation of DCPTA on growth and development, including the yield and sugar metabolism of mung bean. In this study, DCPTA was sprayed at the beginning of mung flowering through a two-season cultivation, to assess its effects on the yield, leaf area per plant, plant height, seed setting rate, photosynthesis, chlorophyll content, and endogenous protective enzymes. Experimental results illustrated that relative to the control (CK), the DCPTA application significantly (p < 0.05) improved the yield of Bailv 11 mung bean, which rose to 6.9% in 2020 and 7.8% in 2021, respectively. This effect positively corresponded to a significant (p<0.05) increase in the number of pods and grains per plant and pod setting rate, but a non-significant difference in 1,000-grain weight. DCPA application also increased the area and fresh weight of leaf, mung height, and its organ dry weight (i.e., leaf, branch, and stem). During plant growth over DCPTA application, the increased activities of SOD, POD, and CAT improved the net photosynthetic rate, stomatal conductance, and transpiration. In addition, transcriptome sequencing further demonstrated that DCPTA treatment significantly (p < 0.05) up-regulated the sucrose synthase, invertase, and fructose kinase in all organs (i.e., leaves, pod skins, and grains) of the plant. In particular, this effect was much greater in the sucrose synthesis (i.e., sucrose content) in leaves. Our study, therefore, concludes that DCPTA application promotes the yield of mung bean via likely enhancing its photosynthetic capacity and sucrose synthase, fructokinase, and beta-fructofuranosidase expression regulation.

The usage of fulvic acid and zeolite on the absorption of cadmium in Spinacia oleracea var. inermis.

Purpose: One of the problems in today's world is the pollution of the environment with heavy metals, which extraction of metals from mines, industrial and agricultural activities have caused significant pollution of soils and waters to metals. Research method: Fulvic acid at 15, 30, and 60 L ha-1 and zeolites at 1000, 2000, and 4000 kg ha-1 have formed the treatments, and the cadmium content was added to the region. The absorbance of cadmium, zinc, and nitrogen elements, as well as the dry weight of aerial organs and root of Spinacia oleracea var. inermis, was investigated. Findings: The application of fulvic acid and zeolite resulted in higher absorption of the elements and higher biomass weight compared to the control. In this case, fulvic acid at 30 L ha-1 and zeolite at 4000 kg ha-1had the best results own, and the accumulated amounts of cadmium and zinc in the root of the Spinach were higher than that of the aerial organs. Due to its acidic nature, fulvic acid caused higher mobility of elements than zeolite. Also, the application of the treatments caused better vegetative growth of the plant and moderation of the effects of stress. Limitations: There was no restriction on conducting this research. Originality/Value: Based on the results, the use of fulvic acid and zeolite can significantly increase the absorption of cadmium toxic metal from the organs of the Spinach plant and help the further release of this element from the soil.

USING COLORED SHADE NETS AND ORGANIC MULCH TO IMPROVE MICROCLIMATE, GROWTH, AND YIELD OF YELLOW SWEET PEPPER

The study was carried out to investigate the effect of using color shade nets and organic mulch on improvement microclimate, growth, yield, and its components and fruit quality of yellow sweet pepper cv. Yellow Star F1 under high temperature. The study was conducted at El- Arish Agriculture Research Station, Agric. Res. Center, North Sinai Governorate, Egypt, during the summer seasons of 2018 and 2019. The results indicated that application of color shade nets modified microclimate around pepper plants where decreased average monthly of air temperature and light intensity; however, increased air relative humidity compared with unshaded. On the other hand, using black, green, and white shade nets combined with dry vegetable residues mulch followed by barley straw mulch reflected the lowest soil temperature at depths 10 and 20 cm in both growing seasons. Also, the results showed that using green shade nets followed by black shade nets combined with dry vegetable residues or barley straw mulches recorded the highest values for a fresh and dry weight of pepper plant organs. Besides, the highest contents of Chlorophyll b in leaves and vitamin C in fruit juice were obtained when covered by green nets combined with dry vegetable residues mulch in both seasons. Also, results revealed that the interaction between shading of yellow fruit pepper plants by black and green color nets with dry vegetable residues mulch significantly increase average fruit weight and total fruit yield for marketable yield compared to the open field without mulching in the first and second season. For that, it is recommended using of shade color nets (Black and green) with organic mulch (dry vegetable residues mulch and/or barley straw mulch) under high-temperature regions for modifying microclimate conditions of pepper plants and soil to improve growth, productivity, and fruit quality traits.

Effect of Tebuconazole on Growth Processes, Content and Redistribution of Carbohydrates in Horse Bean Seedlings under Scotomorphogenesis

The article presents a study of changes in the functioning of the source-sink system in the heterotrophic phase of development of horse beans (Vicia faba L.) under the conditions of the artificial combination of external (darkness) factor and internal factor (antigiberelline retardant) during germination. It was found that the action of the drug significantly reduced the length of the epicotyl, root and total seedling. Similarly, the dry matter mass of the seedling organs decreased. The level of using seed spare substances under the influence of retardant decreased, as evidenced by the maximum dry matter of cotyledons in plants of this variant and a decrease in the utilization of reserve substances for root and epicotyl formation during germination. Tebuconazole inhibited the breakdown of starch in the dark. The higher content of sugars in the seeds of scotomorphic plants in comparison with the control is associated with a less intensive outflow for the needs of organogenesis – the formation of root and epicotyl structures. Quantitative changes in nitrogen content in scotomorphic seeds were much smaller than changes in starch content. This indicates that the retardant in the dark inhibits the hydrolysis of the reserve protein of the seed, but the process is started after the hydrolysis of starch. The purpose of the study was to establish the effect of tebuconazole on the processes of germination and redistribution of carbohydrates in seedlings of Vicia faba L. Material and methods. The work was carried out on seedlings of horse beans (Vicia faba L.) of Vivat variety, which is a medium-ripe high-yielding variety with a vegetation period of 100-105 days. The variety is technological, resistant to major diseases, has high resistance to lodging, shedding of beans and their cracking. Results and discussion. The combined effect of darkness and the drug of anti-gibberellin action of tebuconazole were used to regulate the intensity of source-sink relations during the germination of horse bean seeds. The seeds of the experimental variant were soaked for a day in 0.5% solution of the triazole-derived drug tebuconazole. Tebuconazole is a transparent crystalline substance of hazard class 3. The seeds of the control variant were soaked for 24 hours in distilled water and sown in cuvettes with wet sand. The biological replication of the experiments is fivefold. The experiment was performed under the action of light and in dark in order to study the implementation of programs of skoto-and photomorphogenesis. Morpho-biometric parameters (root length, seedling length, dry matter weight of individual organs and the whole plant) were determined on the day of 18 of germination. Determination of nitrogen content was carried out according to Keldal method, starch in the organs of seedlings was performed by iodometric method, to determine the content of total sugar and reducing sugar we used Bertrand method in modification by V. Kosolapov. Conclusion. The combination of exogenous and endogenous factors during seed germination significantly changed the intensity of donor-acceptor relations in horse bean seedlings. Under the action of the drug significantly slowed the growth of seedlings in the dark. There was the decrease in the dry matter of the organs of the seedling in dark and noted lower rates of use of reserve substances for organogenesis during germination

RESPONSE OF PEAR SEEDLINGS TO SOME NON-AND MAGNETIZED SALINE IRRIGATION WATER AND HUMIC ACID AND THEIR EFFECT ON GROWTH, LEAF PHYSIOLOGICAL PROPERTIES, LEAF PIGMENTS AND ELEMENTS CONTENTS

This study was conducted during two successive seasons of 2018 and 2019 at El Kanater Horticultural Research Station, Qalyoubeia Government Egypt. The aim of this investigation was to study the effect of salinity levels of non-and magnetized irrigation water alone and in combination with humic acid on one-year-old pear seedlings (Pyrus communis) rootstock. Obtained results revealed that, the two higher concentrations of saline water (1500 and 3000 mg/l) resulted in a gradual significant decreased in all vegetative measurements, dry weights of pear seedling organs, both leaf succulence grade, water potential and leaf content of pigments as well as some leaf elements contents of N, P, K, Mg, Fe, Zn and Mn, Whereas an opposite trends were observed with leaf osmotic pressure, proline content and leaf content of Ca, Na and Cl as compared to the control (270 mg/l –fresh water). On the other hand, seedlings treated with either humic acid or magnetized water were exited significantly an increasing values of vegetative parameters, dry weights of different plant organs, leaf pigments and some macro and micro-nutrients beside Na and Cl as well as both leaf succulence grade and water potential as compared to control (non-magnetized water or non-humic acid) in both seasons of study. The obtained data concluded that the use of magnetized water technique with humic acid applications would be efficiently and safe alternative tool to resolve the problem of irrigating with saline water and to enhance pear rootstock seedlings growth grown under similar conditions of this study.

RESPONSE OF PEAR SEEDLINGS TO SOME NON-AND MAGNETIZED SALINE IRRIGATION WATER AND HUMIC ACID AND THEIR EFFECT ON GROWTH, LEAF PHYSIOLOGICAL PROPERTIES, LEAF PIGMENTS AND ELEMENTS CONTENTS

This study was conducted during two successive seasons of 2018 and 2019 at El Kanater Horticultural Research Station, Qalyoubeia Government Egypt. The aim of this investigation was to study the effect of salinity levels of non-and magnetized irrigation water alone and in combination with humic acid on one-year-old pear seedlings (Pyrus communis) rootstock. Obtained results revealed that, the two higher concentrations of saline water (1500 and 3000 mg/l) resulted in a gradual significant decreased in all vegetative measurements, dry weights of pear seedling organs, both leaf succulence grade, water potential and leaf content of pigments as well as some leaf elements contents of N, P, K, Mg, Fe, Zn and Mn, Whereas an opposite trends were observed with leaf osmotic pressure, proline content and leaf content of Ca, Na and Cl as compared to the control (270 mg/l –fresh water). On the other hand, seedlings treated with either humic acid or magnetized water were exited significantly an increasing values of vegetative parameters, dry weights of different plant organs, leaf pigments and some macro and micro-nutrients beside Na and Cl as well as both leaf succulence grade and water potential as compared to control (non-magnetized water or non-humic acid) in both seasons of study. The obtained data concluded that the use of magnetized water technique with humic acid applications would be efficiently and safe alternative tool to resolve the problem of irrigating with saline water and to enhance pear rootstock seedlings growth grown under similar conditions of this study.

Impacts of Smooth Pigweed (Amaranthus hybridus) on Cover Crops in Southern Ontario

Amaranthus hybridus is a noxious weed in Ontario, with demonstrated allelopathic properties that can lead to decreased agricultural production. We tested the germination and growth of five cover crop species exposed to A. hybridus extracts, and to dried or fresh materials in soil. A germination index was calculated, and the dry weight of plant organs were measured to quantify responses to treatments. All species had reduced germination (≤29%) in 100% extract. Trifolium pratense had significant root weight reductions in extract (52%) and dried (72%) treatments, whereas shoot weight only decreased (48%) in dried treatment. Medicago sativa shoot weight decreased (52%) in 20g fresh treatment, while root weight decreased (62%) in dried treatment. Shoot weight of Raphanus sativus increased (32%) at mid-extract concentrations, while root weight increased (33%) only with dried treatment; however, both its shoot and root weight decreased (&gt;40%) in fresh treatment. Only the shoot weight of Lolium multiflorum increased (41% in 75% extract and 55% in dried treatment). Both Cichorium intybus shoot and root weights decreased (~50%) in fresh treatment. Crop responses to A. hybridus are complex, and material and species-dependant. Further testing in the field may provide a more comprehensive understanding of how to improve the management of A. hybridus.