Higher Dry Mass Research Articles

LEAF FUNCTIONAL TRAITS AND STRATEGIES OF PLANTS IN SUBALPINE CALAMAGROSTIS MEADOWS OF THE NORTH-WESTERN CAUCASUS

The analysis of plant functional traits and strategies is the main direction to study the formation mechanisms of the composition and structure of plant communities. Comparison of the mean species trait values with a random sample of a local fl ora allows us to determine the importance of the trait for the plant community formation. Comparison of mean and weighted mean shows the role of the trait in dominance. The aim of this work was to study the role of leaf functional traits and the contribution of Grime’s CSR strategies in the formation of Calamagrostis subalpine meadows, which are the most widespread in the north-western Caucasus. The aboveground biomass in these communities is 384 ± 21 g/m2 (mean and standard error of the mean), the mass of litter of previous years is 393 ± 40 g/m2. The share of grasses in the community is 57,1 ± 2,9%, forbs - 32,9 ± 2,6%, legumes - 8,9 ± 1,4%, sedges and rushes - 1 ± 0,3%. The three species can be considered as dominants: Calamagrostis arundinacea (26,5% of the total phytomass), Festuca varia (23,3%), Hedysarum caucasicum (8%). The dominants of community have a high leaf dry mass, a lower leaf water content, a smaller specifi c leaf area. The community components are characterized by a lower mass of the water-saturated leaf and dry matter content, and a higher specifi c leaf area. Dominants and components in the community are characterized by a greater contribution of the stress-tolerant strategy

Extremely thin but very robust: Surprising cryptogam trait combinations at the end of the leaf economics spectrum

Leaf economics spectrum (LES) describes the fundamental trade-offs between leaf structural, chemical, and physiological investments. Generally, structurally robust thick leaves with high leaf dry mass per unit area (LMA) exhibit lower photosynthetic capacity per dry mass (Amass). Paradoxically, “soft and thin-leaved” mosses and spikemosses have very low Amass, but due to minute-size foliage elements, their LMA and its components, leaf thickness (LT) and density (LD), have not been systematically estimated. Here, we characterized LES and associated traits in cryptogams in unprecedented details, covering five evolutionarily different lineages. We found that mosses and spikemosses had the lowest LMA and LT values ever measured for terrestrial plants. Across a broad range of species from different lineages, Amass and LD were negatively correlated. In contrast, Amass was only related to LMA when LMA was greater than 14 g cm−2. In fact, low Amass reflected high LD and cell wall thickness in the studied cryptogams. We conclude that evolutionarily old plant lineages attained poorly differentiated, ultrathin mesophyll by increasing LD. Across plant lineages, LD, not LMA, is the trait that represents the trade-off between leaf robustness and physiology in the LES.

Genetic diversity and candidate genes for transient waterlogging tolerance in mungbean at the germination and seedling stages.

Mungbean [Vigna radiata var. radiata (L.) Wilczek] production in Asia is detrimentally affected by transient soil waterlogging caused by unseasonal and increasingly frequent extreme precipitation events. While mungbean exhibits sensitivity to waterlogging, there has been insufficient exploration of germplasm for waterlogging tolerance, as well as limited investigation into the genetic basis for tolerance to identify valuable loci. This research investigated the diversity of transient waterlogging tolerance in a mini-core germplasm collection of mungbean and identified candidate genes for adaptive traits of interest using genome-wide association studies (GWAS) at two critical stages of growth: germination and seedling stage (i.e., once the first trifoliate leaf had fully-expanded). In a temperature-controlled glasshouse, 292 genotypes were screened for tolerance after (i) 4 days of waterlogging followed by 7 days of recovery at the germination stage and (ii) 8 days of waterlogging followed by 7 days of recovery at the seedling stage. Tolerance was measured against drained controls. GWAS was conducted using 3,522 high-quality DArTseq-derived SNPs, revealing five significant associations with five phenotypic traits indicating improved tolerance. Waterlogging tolerance was positively correlated with the formation of adventitious roots and higher dry masses. FGGY carbohydrate kinase domain-containing protein was identified as a candidate gene for adventitious rooting and mRNA-uncharacterized LOC111241851, Caffeoyl-CoA O-methyltransferase At4g26220 and MORC family CW-type zinc finger protein 3 and zinc finger protein 2B genes for shoot, root, and total dry matter production. Moderate to high broad-sense heritability was exhibited for all phenotypic traits, including seed emergence (81%), adventitious rooting (56%), shoot dry mass (81%), root dry mass (79%) and SPAD chlorophyll content (70%). The heritability estimates, marker-trait associations, and identification of sources of waterlogging tolerant germplasm from this study demonstrate high potential for marker-assisted selection of tolerance traits to accelerate breeding of climate-resilient mungbean varieties.

Parâmetros genéticos e dissimilaridade genética de Gower em aveia preta

ABSTRACT: This research evaluated the agronomic performance through mixed models, and determined the genetic divergence between black oat genotypes. The experiment was carried out at Federal University of Santa Maria, Frederico Westphalen/RS. Fourteen black oat genotypes were evaluated, being 11 lines developed by Breeding Program of University, and three commercial cultivars (IAPAR 61, UPFA 21 - Moreninha and, IPR Cabocla). We evaluated quantitative traits associated to plant height, cycle, dry mass yield and seeds yield; and 19 qualitative traits, being these morphological descriptors. The results showed that lines UFSMFW 2-05 and UFSMFW 2-07 stand out with characteristics such as early cycle, higher dry mass and grain yield. Divergence analysis revealed the formation of three distinct groups, indicating the presence of variability. These results suggested the potential for the development of new cultivars of black oat, presenting early cycle and good grain yield.

Effect of Plant Thickness and Cotton Row Spacing on Dry Mass Accumulation

In thi article, the medium-fiber cotton variety “Ravnaq-1” was processed at different 60 cm (control), 70 cm, and 76 cm row spacings in a cultivator adopted (in Uzbekistan) and a milling cultivator with a 76 cm row spacing, along with the theoretical seedling thickness. The analysis results of the scientific research on dry mass accumulation of cotton leaving 90-100 thousand bushels/ha and 120-130 thousand bushels/ha are presented. In the conducted research, the dry mass of one cotton bush in 2020 was 118.1-97.6 grams, in 2021 it was 131. It was 2-107.5 grams. That is, when the number of saplings is large, the dry mass of one plant decreases, when analyzed per hectare, it was found that higher dry mass was accumulated in all variants when the theoretical thickness of seedlings was 90-100 thousand bush/ha, when it was 120-130 thousand bush/ha. The highest rate of dry mass accumulation per bush in different row spacings was observed in both years of the study in the case of milling cultivator with a row spacing of 76 cm and theoretical seedling thickness of 90-100 thousand bush/ha, proportionally 138.9-151 It was .5 grams. It was found that this indicator accumulated more dry mass by 20.8-41.3 grams in the first year of the study than the control variants, and by 20.3-44 grams in the second year.

Planting season alters the interference of weeds in the common bean

The common bean has social, economic, culinary, and environmental relevance. Considering its low competitive capacity and the intensive use of herbicides, methods such as planting time can help in weed management. To determine the effect of the planting season on controlling weeds affecting common beans, an experiment was conducted during the summer planting and another in winter planting . For that seven incrementing periods were implemented: 0-10, 0-20, 0-30, 0-40, 0-50, 0-60 and 0-80 days after bean emergence with coexistence of weeds and the same periods with control of weeds, which established 14 treatments in four repetitions, under a random block design. Weeds were analyzed using a phytosociological method and their dry mass with yield examined by regression. The non-linear regression analysis determined the pre-interference period (PIP), the critical period for interference prevention (CPIP) and the total interference prevention period (TIP). The relevant species were Nicandra physaloides, Digitaria nuda and Raphanus raphanistrum. The TIP was similar in both planting seasons. The CPIP was 38 and 33 days in summer planting and winter planting, respectively. The PIP had six more days in winter planting compared to summer planting. The higher dry mass in weeds reduced yield by 14.7 % in winter planting, in relation to the summer planting, but the reduction was faster in this season. Winter planting conferred a certain competitive advantage to the crop over some weed species, thus it could be suggested planting common bean in that season

Effect of Predominant Mycoflora (A. alternata and M. phaseolina) on Seed Quality Parameters of Sesamum

Sesamum is an important oilseed crop affected by toxigenic fungal pathogens viz., Alternaria, Macrophomina, Fusarium and Aspergillus spp. Among these, A. alternata and M. phaseolina are seed borne pathogens causing yield loss to an extent of 20 to 40 per cent. The effect of A. alternata and M. phaseolina on seed quality parameters of susceptible cv. Swetha was investigated during 2022-2023. The A. alternata and M. phaseolina inoculated and uninoculated seeds of both test pathogens were tested for germination and seedling growth by rolled paper method and pot culture studies. Significant differences in seed germination, seedling length, seedling dry mass, seedling vigour index (SVI) - I and II and seed moisture content were observed in susceptible cv. Swetha. The results indicated that A. alternata recorded lower seed germination percentage (60.50%), seedling length (6.56 cm), dry mass (9.12 mg) and SVI-I and II (656 and 552 respectively) over untreated seeds recording high germination (82.25%), seedling length (14.84 cm), dry mass (13.17 mg) and SVI-I and II (1221 and 1116 respectively). Similar results were observed in M. phaseolina treated seeds where the pathogen treated seeds recorded lower seed germination percentage (70.75%), seedling length (9.42 cm), dry mass (8.71 mg) and SVI-I and II (667 and 599 respectively) than pathogen untreated seeds recording high seed germination (82.50%), seedling length (14.25 cm), dry mass (13.30 mg) and SVI-I and II (1175 and 1097 respectively).

A simulated drier climate reduces growth and alters functional traits of Eucalyptus trees: A three-year experiment in South China

Global climate change is triggering more occurrences of drought events, which is continuously enlarging a worldwide area of arid and semi-arid regions. South China is a typical area that suffers seasonal drought events, which reduce plantation productivity and increase tree mortality. Eucalyptus is widely cultivated in South China due to its fast growing speed and high dry mass yield, but its response to severe drought stress is still not assessed. In this study, we analyzed how a 50 % throughfall reduction (TR) and season affected stand growth, foliar gas exchange parameters, leaf stomatal morphological traits, and hydraulic conductance. Three-year observations showed that TR intensified drought stress in the dry season by decreasing soil relative water content, resulting in the diameter at breast height growth, tree height growth, and stand volume growth of TR were 12.6 %, 19.0 %, and 23.7 % lower than those of the control treatment (CK), respectively. With the continuous drought, TR decreased the net photosynthetic rate, while having little effect on the transpiration rate and water use efficiency. Photosynthetic pigment analysis revealed a significant interaction between throughfall reduction and season, TR markedly decreased photosynthetic pigments during the wet season. Hydraulic conductivity declined by TR, which primarily existed during the dry season. To limit water loss, Eucalyptus adapted to drought stress by altering these functional traits, which were not entirely consistent with the drought resistance mechanisms of other tree species. Overall, our study indicated that the simulated drier climate included growth decline and variation in functional traits of Eucalyptus trees in South China. This study is important for understanding the drought resistance mechanisms of Eucalyptus, as well as predicting the risk of declining Eucalyptus timber production owing to global climate change.

Growth and development of Paspalum virgatum L.

The objective of the work was to evaluate the growth and development of the razor-blade grass (Paspalum virgatum L.). The experimental design was a randomized complete block design with 17 treatments, and the growth evaluations were performed at 20, 27, 34, 41, 48, 55, 62, 69, 76, 83, 90, 97, 104, 111, 118, 125, 132 days after sowing (DAS) and five replications, considering as sowing date the day the seeds were placed in the plastic boxes. The evaluated characteristics were: total dry mass (Mt), shoot dry mass (Ma) and dry mass of roots (Mr), number of leaves and number of tillers per plant. The quantitative variables related to plant growth were analyzed by applying the F test on the analysis of variance followed by non-linear log-logistic regressions, with the objective of modeling the data in the form of equations. The razor-blade grass (Paspalum virgatum L.) is a weed with slow initial development and growth, but with high dry mass production at the end of the cycle.

Arbuscular Mycorrhizal Fungi Improve the Growth, Water Status, and Nutrient Uptake of Cinnamomum migao and the Soil Nutrient Stoichiometry under Drought Stress and Recovery.

Drought greatly influences the growth and ecological stoichiometry of plants in arid and semi-arid regions such as karst areas, where Cinnamomum migao (C. migao) is an endemic tree species that is used as a bioenergy resource. Arbuscular mycorrhizal fungi (AMF) play a key role in nutrient uptake in the soil-plant continuum, increasing plant tolerance to drought. However, few studies have examined the contribution of AMF in improving the growth of C. migao seedlings and the soil nutrient stoichiometry under drought-stress conditions. A pot experiment was conducted under natural light in a plastic greenhouse to investigate the effects of individual inoculation and Co-inoculation of AMF [Funneliformis mosseae (F. mosseae) and Claroideoglomus etunicatum (C. etunicatum)] on the growth, water status, and nutrient uptake of C. migao as well as the soil nutrient stoichiometry under well-watered (WW) and drought-stress (DS) conditions. The results showed that compared with non-AMF control (CK), AM symbiosis significantly stimulated plant growth and had higher dry mass. Mycorrhizal plants had better water status than corresponding CK plants. AMF colonization notably increased the total nitrogen and phosphorus content of C. migao seedlings compared with CK. Mycorrhizal plants had higher leaf and stem total carbon concentrations than CK. The results indicated that AM symbiosis protects C. migao seedlings against drought stress by improving growth, water status, and nutrient uptake. In general, the C. migao seedlings that formed with C. etunicatum showed the most beneficial effect on plant growth, water status, and nutrient uptake among all treatments. In the future, we should study more about the biological characteristics of each AMF in the field study to understand more ecological responses of AMF under drought stress, which can better provide meaningful guidance for afforestation projects in karst regions.

Multiple stressors, allostasis and metabolic scaling in developing zebrafish.

Deoxygenation and warming affect adult fish physiology in all aquatic ecosystems, but how these stressors impact the energetics of sensitive developing stages is largely unknown. Addressing this knowledge gap, we investigated chronic and acute effects of two stressors (high temperature and hypoxia) in yolk-sac larval (48-168 hpf) zebrafish (Danio rerio) energy budgets measuring, oxygen consumption rate, growth rate (absolute and specific), % net conversion efficiency, net cost of growth and scaling relationships. Embryos and larvae were raised under four chronic treatments: (1) control (28°C and PO221 kPa, T28O21), (2) high temperature (31°C and PO221 kPa, T31O21), (3) hypoxia (28°C and PO211 kPa, T28TO11) and (4) high temperature and hypoxia (31°C and PO211 kPa, T31O11). From each chronic treatment, larvae were acutely exposed to the same combinations of stressors for 1 h in a respirometer. At hatching, larvae from chronic high temperature (T31O21 and T31O11) treatments were larger (higher dry mass and standard length) than controls (T28O21 and T28O11), but by the end of the yolk-sac stage, increased metabolic demands diverted energy away from growth, increasing net cost of growth and lowering % net conversion efficiency. Control metabolic scaling relationships were significant and differed from 0.75, but metabolic levels were lower in acute hypoxia and high temperature/hypoxia. Thus, high temperature dominated larval energetics, acting synergistically with hypoxia to increase cumulative energetic costs and making allostasis difficult compared with older stages.

Nitrogen metabolism of two tropical forage grass species: nitrogen availability × cultivars

The understanding about N metabolism in roots and/or shoots of forage grasses should help determine how some cultivars use N more efficiently. This study was designed to determine whether two Brachiaria brizantha cultivars and two Panicum maximum cultivars differ in their N metabolism. Two cultivars of Panicum maximum and two cultivars of Brachiaria brizantha were investigated under the supply of low and high nitrogen rates in a greenhouse experiment. Some characteristics such as dry mass production, total nitrogen, nitrate and ammonium concentrations and contents; nitrate reductase (NR) and glutamine synthetase (GS) activities; and total free amino acid concentrations in shoots and roots were measured. The results showed that Panicum cultivars showed higher NR activity and GS activity in diagnostic leaves (DL) than Brachiaria cultivars. Brachiaria cultivars showed the highest ammonium concentrations in roots at low N supply and Panicum cultivars at high N supply. The total amino acid concentrations in DL were highest in Panicum and root total amino acid concentrations were highest in Brachiaria. Panicum and Brachiaria cultivars differed in their nitrogen metabolism with varying N supply. The results indicate that at low nitrogen supply to the pasture, Brachiaria brizantha cultivar Piatã may be an option to use in less intensive production environments, instead of high dry mass production. For those pastures with high nitrogen availability, the cultivars Mombaça and Aruana of Panicum maximum were clearly superior to Piatã, which suggests priority in the selection of these cultivars to be used in more intensive production systems that apply more nitrogen

The Effects of Photobioreactor Type on Biomass and Lipid Production of the Green Microalga Monoraphidium pusillum in Laboratory Scale

Mass production of microorganisms, algae among them, for new bioactive compounds and renewable innovative products is a current issue in biotechnology. The greatest challenge of basic research on this topic is to find the best solution for both physiology and scalability. In this study, the main goal was to highlight the contradictions of physiological and technological optimization in the same, relatively small, laboratory scale. The green alga Monoraphidium pusillum (Printz) Komárková-Legnorová was cultured in a conventional Erlenmeyer flask (as air bubbled in a tank-type photobioreactor) and in a hybrid (fermenter type + helical tubular type) photobioreactor of the same volume (2.8 L). Higher cell numbers from 1.7–2.3-fold, 2–2.8-fold higher dry masses, and 1.9–2.6-fold higher total lipid contents (mg·L−1) were measured in the tank reactor than in the hybrid reactor. Cultures in the conventional tank reactor were characterized with better nutrient utilization (42.8–77.7% higher phosphate uptake) and more diverse lipid composition than in the hybrid reactor. The study highlights that well-scalable arrangements and settings could be not optimal (or unsuitable in some cases) from a physiological point of view. The results suggest certain developmental directions for complex, well-scalable devices and highlight the importance of testing the gained physiological optima on these systems.

Resposta agronômica de melancia em semeadura direta e transplantio de mudas

ABSTRACT Watermelon is traditionally grown under direct sowing system. However, due to high costs of good quality seeds of improved cultivars, seedling transplanting is a promising alternative for watermelon production. This study aimed at evaluating, during two production cycles, the performance of watermelon under direct sowing cultivation system and seedling transplanting. The field trials were carried out from May to September, 2015 and 2016, at Setor de Horticultura da Escola de Agronomia of Universidade Federal de Goiás. In 2015, the experimental design was randomized blocks (DBC) with four replicates in a 2x4 factorial scheme (two hybrids: Manchester and Talisman, and two planting methods: direct sowing and transplanting 15-, 20- and 25-day old seedlings). In 2016, the experimental design was DBC with six replicates. The treatments consisted of three direct sowing dates (0, 5 and 10 days) and three different seedling ages (15, 20 and 25 days). Number of leaves, plant height and dry mass of seedlings of different ages, vine length and virus incidence along the crop cycle were evaluated. Upon significant F-test (5%) for seedling age, regression analysis was performed, and when cultivar effect was significant, Tukey test (5%) was used. Planting methods (direct sowing X seedlings) were compared by orthogonal contrasts. In 2016, the beginning of flowering was evaluated, and in both trials, the average crop cycle for each treatment was determined. Fruit length and width, fruit mass, thickness of the white part of the rind, and soluble solids content were evaluated at harvesting. The 25-day old seedlings had higher number of leaves, as well as, higher dry mass, comparing with seedlings on the transplanting day. Yield and fruit quality were not influenced by treatments. No significant differences for virus disease incidence were detected, in both production cycles. Direct sowing reduced the crop cycle in both field trials, with no differences in production and quality of fruits. Considering the costs of establishing watermelon fields as relevant, the results suggest the importance of direct sowing as the most viable method for watermelon cultivation, due to the ease of the process, as well as, reduction in costs related to seedling production and transplanting operations.

Pre-dehydration treatments and quality of processed potatoes during storage

ABSTRACT The aim of this work was to study pre-dehydration treatments to maintain consumption quality of processed potatoes (Solanum tuberosum) over a long storage period. Tubers of the cultivars Asterix, Macaca and Agata were cut into cubes and submitted to the following pre-dehydration treatments: water (control), blanching, and blanching with different doses of sodium metabisulfite. Sulphur dioxide residue and microorganism detection were determined right after the dehydration process was completed. Water activity, color, rehydration ratio, cooking time and rehydration ratio after cooking were determined at the beginning and after one and two years of storage. Blanching, cultivar and storage affected rehydration ratio, an important parameter used to measure the quality of dehydrated products. Tubers with higher dry mass content resulted in lower water activity and rehydration ratio, longer cooking time and higher rehydration ratio after cooking than those with lower dry mass. The combination of blanching with sodium metabisulfite improves product quality, reduces microbial load, enhances dehydration rate and prevents oxidation and browning reactions during processing and storage. The effects of the structural damages of pre-dehydration and dehydration treatments on the rehydration ratio and the rehydration ratio after cooking increase with storage of processed potatoes.

Correction to: Nano-Silicon Complexes Enhance Growth, Yield, Water Relations and Mineral Composition in Tanacetum parthenium under Water Deficit Stress

Developing methods and approaches for preserving water relations, plant growth and productivity are essential under water deficit conditions. New nano-silicon complexes were synthesized (glycine nano-silicon, glutamine nano-silicon and histidine nano-silicon) to evaluate their foliar application in different concentrations (0, 1.5 and 3.0 mM) on growth, essential oil yield, water relations, and mineral composition of field grown feverfew (Tanacetum parthenium L.) under drought. Drought stress was imposed by different irrigation intervals (4, 8 and 12 days). By increasing irrigation interval, leaf relative water content and leaf water potential were declined which decreased biomass, leaf area, flower formation, essential oil production and health of the plant. Potassium and organic osmolytes accumulation under moderate drought stress alleviated the adverse effects water deficit condition. This was mainly due to proline and potassium accumulation in the plants’ leaves. Although accumulation of soluble carbohydrates also was observed in the drought stressed plants, it was found to be a passive response to plant growth inhibition under drought. Moreover, drought stress decreased plant phosphorous content, but had no significant effect on plant nitrogen content. Foliar application of nano-silicon by improving the plant’s water content and phosphorus absorption, recovered the plants’ health and growth under moderate and severe drought conditions. In this regard, no significant differences were observed between 1.5 and 3.0 mM nano-silicon treatments. However, glycine nano-silicon treated plants represented higher drought tolerance (higher dry mass, leaf area, number and greenness) than the other complexes. Accordingly, foliar application of 1.5 mM glycine nano silicon for mitigating adverse effects of drought stress on feverfew was recommended.

Soilless Cultivation System, Electrical Conductivity of Nutrient Solution, and Growing Season on Yield and Quality of Baby-Leaf Oak-Leaf Lettuce

The floating system (FL) is a common soilless method for baby-leaf production, whereas the ebb and flow system (EF) has been proposed as an alternative. Both of them allow managing plant saline stress while preventing reduction in plant growth and yield and increasing product quality. The oak-leaf lettuce response to the growing conditions (hydroponics, salinity) in interaction with climate and genotype has been little studied. Two experiments were carried out with two oak-leaf cultivars (green- and red-colored type) grown in FL and EF systems at two levels of nutrient solution (NS) electrical conductivity (EC) (EC = 2.5 and 3.5 dS m−1; EC2.5, EC3.5, respectively) under autumn and late-spring conditions. The EF system caused an increase in salinity in the substrate where roots mainly develop, so it overcomes the effect of the EC3.5 treatment. In the autumn cycle, irrespective of the EC, EF-grown plants had improved leaf thickness (specific leaf area), color, and antioxidative (total phenol and carotenoid contents) properties; however, a reduction in yield was observed in the most productive cultivar (green type). In late spring, higher yield and product quality (processability, nitrate content) were obtained at the expense of color, with the FL showing the best productivity in the green type cultivar. The red type cultivar had higher dry mass, phenol, and carotenoid concentrations.

Growth of Alfavaca-Cravo in Response to Different Levels of Shade and Tiririca Density

The species Ocimum gratissimum L. is widely utilized in food, cosmetics, and folk medicine, and is also an important source of essential oils. Understanding its behavior in response to environmental conditions is of paramount importance to improving crop management methods. In this context, the following study aimed to evaluate the effects of shade, and of competition with weeds (Cyperus rotundus L.), on the growth of Ocimum gratissimum L. The experimental design adopted was randomized blocks, in a 5 × 5 factorial scheme, with 5 levels of shading (48%, 75%, 77%, 83% and 90%) and 5 densities of Cyperus rotundus L. (0, 5, 10, 15 and 20 per pot), with 4 repetitions. The variables analyzed were main stem height (MSH), diameter of stem base (DSB), number of leaves on the principal branch (NL), number of ramifications (NR), chlorophyll index of leaves (CIL), foliar area (FA), dry mass of the aerial part of the medicinal species (DMAPm), dry mass of the aerial part of the weed species (DMAPw) and essential oil content (EOC). The results demonstrate that the Ocimum gratissimum L. plants presented compatible tolerance responses to up to 70% shading, and that competition with Cyperus rotundus L. was detrimental in a density above 13 plants per pot in interaction with shading. The highest dry mass production and, consequently, the highest oil yield, were obtained from the 48% shading treatment.

Биологические особенности и условия поверхностного культивирования штаммапродуцента микробиопрепарата Т-1 Trichoderma sp. против возбудителей фузариоза льна масличного

To develop technological regimen for production of microbiopreparations in a preparation form ‘wetting powder’ we studied biological features and conditions of surface cultivating of a strain-producer Т-1 Trichoderma sp. – an antagonist of pathogen Fusarium oxysporum Schlecht. emend. Shyd. et Hans. var. orthoceras (App. еt Wr.) Bilai and Fusarium poae (Peck) Wollenw., Lewis on oil flax. To study cultural and physiological qualities of the strainproducer we used agar and liquid mediums. Surface cultivation of a fungus on agar and liquid Rudakov’s medium at a temperature 25–30 оС was the most favorable for mycelium growth and spore formation. Stationary fungus cultivation on liquid medium with рН from 3 to 6 provided maximal mycelium growth with spore formation and the highest dry mass. Addition of starch into the Chapek’s nutrient medium caused maximal growth of fungus mycelium and increase of its dry mass. The best source of nitrogen for a fungus strain was corn extract. Rudakov’s and No1 mediums are optimal compound liquid nutrient mediums for a surface cultivation of the strain-producer. Optimal period of the surface cultivation of the fungal strain Т-1 Trichoderma sp. on liquid Rudakov’s nutrient medium was 10 days, and a volume of sowing culture to a nutrient medium – 2.0%.

Characterization of winter wheat (Triticum aestivum L.) germplasm for drought tolerance

AbstractClimate change realities such as high-temperature levels are among the causes of drought episodes affecting the productivity and yield stability of crops worldwide. Breeders, therefore, have a daunting challenge to overcome and a large gap to seal in the agricultural sector arising due to drought through the improvement of new tolerant germplasm. It is in this endeavour that the present study, which included nine winter wheat genotypes grown in the greenhouse, was conducted to evaluate their performance under well-watered and drought stress treatments for the traits: heading time, plant height, above-ground biomass, seed number/plant, grain yield/plant, harvest index, root length and root dry mass. A lower grain yield/plant was observed for each studied genotype under drought stress conditions than for those under well-watered conditions. Additionally, grain yield/plant depression varied from 69.64 to 81.73% depending on the genotype. Positive significant correlations between grain yield/plant and heading time, above-ground biomass, and seed number/plant under the drought stress treatment were obtained. Genotypes that recorded high root dry mass had both high above-ground biomass and seed number/plant under drought stress conditions. Positive correlations between grain yield/plant depression and plant height, seed number/plant, and harvest index depressions were also observed. Grain yield for each genotype under drought stress conditions was recorded, and the varieties ‘Plainsman V.’, ‘GK Berény’ and germplasm ‘PC61’, ‘PC110’ showed the best drought tolerance. These genotypes and germplasm will be used in different drought tolerance experiments and breeding programmes.