Leaves Research Articles

Mapping of quantitative trait loci (QTL) in Brassica napus L. for tolerance to water stress.

Brassica napus L. plants are sensitive to water stress conditions throughout their life cycle from seed germination to seed setting. This study aims at identifying quantitative trait loci (QTL) linked to B. napus tolerance to water stress mimicked by applications of 10% polyethylene glycol-6000 (PEG-6000). Two doubled haploid populations, each consisting of 150 genotypes, were used for this research. Plants at the two true leaf stage of development were grown in the absence (control) or presence (stress) of PEG-6000 under controlled environmental conditions for 48h, and the drought stress index was calculated for each genotype. All genotypes, along with their parents, were genotyped using the Brassica Infinium 90K SNP BeadChip Array. Inclusive composite interval mapping was used to identify QTL. Six QTL and 12 putative QTL associated with water stress tolerance were identified across six chromosomes (A2, A3, A4, A9, C3, and C7). Collectively, 2154 candidate genes for water stress tolerance were identified for all the identified QTL. Among them, 213 genes were identified as being directly associated with water stress (imposed by PEG-6000) tolerance based on nine functional annotations. These results can be incorporated into future breeding initiatives to select plant material with the ability to cope effectively with water stress.

Enhancing image recognition robustness in early weed detection through optimal training data curation

Abstract Using convolutional neural networks (CNNs) for image recognition is effective for early weed detection. However, the impact of training data curation, specifically concerning morphological changes during the early growth phases of weeds, on recognition robustness remains unclear. We focused on four weed species (giant ragweed [Ambrosia trifida L.], red morningglory [Ipomoea coccinea L.], pitted morningglory [Ipomoea lacunosa L.], and burcucumber [Sicyos angulatus L.]) with varying cotyledon and true leaf shapes. Creating 16 models in total, we employed four dataset patterns with different growth stage combinations, two image recognition algorithms (object detection: You Look Only Once [YOLO] v5 and image classification: Visual Geometry Group [VGG] 19), and two conditions regarding the number of species treated (four and two species). We evaluated the effects of growth stage training on weed recognition success using two datasets. One evaluation revealed superior results with a single class/species training dataset, achieving >90% average precision for detection and classification accuracy under most conditions. The other dataset revealed that merging different growth stages with different shapes as a class effectively prevented misrecognition among different species when using YOLOv5. Both results suggest that integrating different shapes in a plant species as a single class is effective for maintaining robust recognition success amid temporal morphological changes during the early growth stage. This finding not only enhances early detection of weed seedlings but also bolsters the robustness of general plant species identification.

Functional characterisation of BnaA02.TOP1α and BnaC02.TOP1α involved in true leaf biomass accumulation in Brassica napus L.

Leaves, as primary photosynthetic organs essential for high crop yield and quality, have attracted significant attention. The functions of DNA topoisomerase 1α (TOP1α) in various biological processes, including leaf development, in Brassica napus remain unknown. Here, four paralogs of BnaTOP1α, namely BnaA01.TOP1α, BnaA02.TOP1α, BnaC01.TOP1α and BnaC02.TOP1α, were identified and cloned in the B. napus inbred line 'K407'. Expression pattern analysis revealed that BnaA02.TOP1α and BnaC02.TOP1α, but not BnaA01.TOP1α and BnaC01.TOP1α, were persistently and highly expressed in B. napus true leaves. Preliminary analysis in Arabidopsis thaliana revealed that BnaA02.TOP1α and BnaC02.TOP1α paralogs, but not BnaA01.TOP1α and BnaC01.TOP1α, performed biological functions. Targeted mutations of four BnaTOP1α paralogs in B. napus using the CRISPR-Cas9 system revealed that BnaA02.TOP1α and BnaC02.TOP1α served as functional paralogs and redundantly promoted true leaf number and size, thereby promoting true leaf biomass accumulation. Moreover, BnaA02.TOP1α modulated the levels of endogenous gibberellins, cytokinins and auxins by indirectly regulating several genes related to their metabolism processes. BnaA02.TOP1α directly activated BnaA03.CCS52A2 and BnaC09.AN3 by facilitating the recruitment of RNA polymerase II and modulating H3K27me3, H3K36me2 and H3K36me3 levels at these loci and indirectly activated the BnaA08.PARL1 expression, thereby positively controlling the true leaf size in B. napus. Additionally, BnaA02.TOP1α indirectly activated the BnaA07.PIN1 expression to positively regulate the true leaf number. These results reveal the important functions of BnaTOP1α and provide insights into the regulatory network controlling true leaf biomass accumulation in B. napus.

ECONOMIC AND BIOLOGICAL EVALUATION OF RADISH HYBRIDS FOR GROWING IN OPEN SOIL IN THE CONDITIONS OF THE CENTRAL PART OF THE RIGHT BANK FOREST-STEPPE

Radish is an early vegetable crop with a very short growing season, widely cultivated worldwide. At the same time, the extensive varietal resources of radishes and the changing environmental conditions compel agroproducers to perform more careful selection of varieties/hybrids to achieve high yields of marketable products. For this purpose, an agro-biological evaluation of eight radish hybrids of different maturity periods was conducted in open-field cultivation. Differences were found in both the duration of phenophases and the growing period of radish plants. The hybrids Stellar and Rockstar were characterized by faster entry into phenological phases, root formation, and maturation, reaching the technical maturity phase on the 25th day. In terms of biometric indicators at the technical maturity phase (BBCH 49), the hybrid Adele stood out, with plants having the highest height (18 cm), leaf rosette width (18 cm), number of leaves per plant (8 pcs), and area (17.6 thousand m2/ha). Over the years of research from 2017 to 2019, which were marked by contrasting weather conditions, the highest yield was obtained from the Adele hybrid, at 26.1–27.3 t/ha, with a 15% advantage over the control and a yield increase of 3.5 t/ha. The hybrids were ranked by yield as follows: Adele > Eliza > Stellar > Rockstar > Rosetta > Roxanne > Donar > Rolex. The highest quality indicators were found in the root crops of the Adele, Stellar, and Rockstar hybrids. Based on the visual assessment of radish root crops, analysis of their linear dimensions, and quality indicators, the hybrids were ranked as follows: Adele > Stellar > Rockstar > Eliza > Rosetta > Roxanne > Donar > Rolex. A strong direct correlation was found between yield and root weight (r=1), as well as between the developmental phases of the plants (seedling emergence, appearance of the first true leaf, growth and development of leaves and roots) and the technical maturity of the root crops (r=0.90–1.00). The number of leaves per plant correlated with plant height (0.97) and the developmental phases of the plants (0.91–0.97). The sugar content in the root crop correlated with the dry matter content and the root diameter (0.92). Based on the agro-biological evaluation of radish hybrids of different maturity groups, it was determined that the most productive hybrids with quality root crops for open-field cultivation are the early-maturing Stellar, the mid-maturing Eliza, and the late-maturing Adele, which are recommended for cultivation in farms of various ownership forms in the central part of the Right-Bank Forest-Steppe.

Temporal dynamics of chloroplast biogenesis revealed initiation of photosynthesis-related gene expression and protein complexes during alfalfa seed germination

The chloroplast biogenesis occurs in cotyledon during alfalfa seed germination before true leaf formation, and is extremely important for the followed plant development and growth. In this study, we conducted a simulation of alfalfa seed germination in the soil by using tin foil and focused on 10 pivotal time points of chloroplast biogenesis in cotyledons before and after light exposure, which showed significant differences in multispectral images, and covered the whole process of chloroplast biogenesis from proplastid, etioplast to mature chloroplast. We revealed three phases that referred to the programmed involvements of photosynthesis promotion, ultrastructure maturity, transcriptomic expression, and protein complex construction, and observed distinct transcriptional expressions of genes from nuclear and chloroplast genomes. In phase I at dark germination before light exposure, chloroplast-encoded genes showed up-regulated expressions together with the importation of chloroplast proteins. In phase II for the first day after light exposure, nuclear-encoded genes’ expressions were initiated at 2 h after light exposure (E2h), followed by swift assembly of chloroplast thylakoid membrane protein complexes, and roaring Fv/Fm and contents of chlorophyll a, chlorophyll b and carotenoid. The initiation at E2h was pronounced by the observation of gradual accumulation of single lamella, and facilitated the formation of granum stacks (thylakoid) at E8h in phase II. In phase III from the second day after light exposure, chloroplast became gradually complete with the fully established photosynthetic capacity. Altogether, our results layed a theoretical foundation for enhancing potential photosynthetic efficiency in alfalfa and related species.

Light Use Efficiency of broccoli (Brassica oleracea var. italica Plenck) and rocket (Eruca sativa L.) during the initial plant growth stages

The solar radiation (SR) is one of the key factors for plant adaptation, and of its growth and development, and for several horticultural crops is important for reaching good yield and produce quality. The SR vary in Europe from 2189 to 517 kwh m−2 from Sicily to North cape. Sprouts, microgreens, and baby-leaves, recognized as novel foods due to their high nutraceutical value, have attracted significant attention in the market. The novel foods production could be affected by solar radiation especially when it is carried out in greenhouse in several countries and along their latitudes. Our study aimed to investigate how solar radiation affects the growth of these plants by conducting a thorough analysis of their morphometric characteristics and biochemical profiles. Two different genotypes of commercial rocket, namely Eruca sativa L. var. darkita and var. lobata, along with the Sicilian Black sprouting broccoli (Brassica oleracea var. italica Plenck, Broccolo nero), were examined at different initial plant growth stages, sprouts, microgreens, and baby-leaves. The experimental trial was carried out in Sicily (Italy) utilizing black shade nets with varying levels of solar radiation (SR100, SR60, SR40). The harvested plantlets were analysed for their main morphometric traits, as sprout weight, hypocotyl length, cotyledon dimensions, in addition to the dimensions of the first true leaf for microgreens, and stem length for baby-leaves. Several biochemical parameters, such as total phenolic content (TPC), total flavonoid content (TFC), and several antioxidant assays including DPPH (2,2-diphenyl-1-picrylhydrazyl), ORAC (oxygen radical absorbance capacity), and FRAP (ferric reducing antioxidant power) were determined. The total glucosinolate content, the sucrose, fructose, fructooligosaccharides (FOS), and total sugars amount were detected. We observed significant variations in the sugar content, particularly under reduced solar radiation and during the baby-leaves stage, characterized by decreased FOS levels and simultaneous increases in sucrose, glucose, and fructose. Moreover, antioxidant capacity showed a progressive enhancement from sprouts to baby-leaves. FRAP and DPPH capacity were significantly affected by the genotype. Interestingly, TFC was the most influenced by SR100, particularly in microgreens. This expanded knowledge base not only advances scientific understanding of these novel foods but also provides substantial adaptation to the different solar radiation conditions in different latitude of the world, permitting to individuate the genotypes more efficient in relation to the solar radiation available.

Taxonomic Implication of Conducting Elements in the Acrocarpous Mosses

Present study deals with the structure and development of conducting elements in the nine orders of acrocarpous mosses. The significance of conducting tissues in mosses in relation to their habitat conditions, growth forms and leaf cell patterns has been discussed. Features of cells in different portions of the stem and the laminal cell patterns and costa are taken into consideration. Although water-conducting cells are unspecialized in mosses, yet the study shows that they seem to play a vital role in the conduction and provide additional criteria for the distinction of taxa. Four categories have been determined as (i) Acrocarpous mosses with a distinct thick-walled conducting strand (6-7 layered) as hydrome which is surrounded by patches of leptoids. Cortex consists of thick walled cells (6-10 layered). Costa has stereidal cells and well developed conducting elements in leaf, example Polytrichum (ii) Acrocarps with thick-walled, narrow, elongated conducting strand (4-5 layered), cells angular in the cortex (6-8 layered). Leaf cells are rectangular, irregular and porous with incrassate walls, example Dicranum (iii) Acrocarps with conducting tissue (2-5 layered) stereidal, thick walled or thin walled varying in the course of development. Leaf cells are mutipapillate, rounded-quadrate, costa is present, examples Hyophila, Philonotis and (iv) Epiphytic pleurocarps with conducting cells rudimentary, thickened, scattered (2-4 layers) and parenchymatous, cortical cells (2-3 layered) thick walled. Leaf cells are small, rounded or linear and papillate, costa may be present or absent, example Leucodon . The study would constitute a formidable task, especially if intraspecific structural variability is considered. It serves a model system in the eco-physiological aspects.

Biosystematic Studies, Distribution and Conservation Status of Guaiacum officinale L. in Karnataka State

Guaiacum L. is an evergreen tree indigenous to South America, West Indies and USA. It was introduced during British period. The stem is hard, abundant resin wood, ash- grey-green bark and paripinnate leaves. The flowers are blue-purple in colour and occur in axillary clusters. The fruit is a capsule. Anomocytic, Paracytic and tertacytic types of stomata present only on abaxial surface of the leaf, trichomes absent on both surface. Pollen monad, radialy sysmmetric, tricolporate. The secondary veins are joined to form a loop at the margin. Phenolic test, alkaloid test etc. gave positive results. This plant is having commercial as well as medicinal value. In Karnataka state this plant found only in two places, one in Lalbagh, Bangalore and another in Karnataka College, Dharwad. Silviculture experiments were conducted but not succeeded. In both the places flowers are many, but fruit setting is negligible. It inhibits the spreading of the species in Karnataka.

Medicinal and Aromatic Weed Diversity in Botanic Garden and their Sustainable Utilisation for Conservation

Total 81 weeds belonging to 59 genera and 31 families growing in the University botanic garden at Sagar were found medicinally important. Various parts of all the weeds have been analyzed for their medicinal utility. Out of 81 weeds, leaves of 64 plants are found useful for various disorders. This is followed by root of 25 plants which are medicinally important. Disease wise analysis has also been carried out. Analysis reveals that for cut, wounds, boils and burns about 29 weed plants are used, whereas 21 weed species each are used for asthma and skin diseases.

Crucial role of SWL1 in chloroplast biogenesis and development in Arabidopsis thaliana.

The disruption of the SWL1 gene leads to a significant down regulation of chloroplast and secondary metabolites gene expression in Arabidopsis thaliana. And finally results in a dysfunction of chloroplast and plant growth. Although the development of the chloroplast has been a consistent focus of research, the corresponding regulatory mechanisms remain unidentified. In this study, the CRISPR/Cas9 system was used to mutate the SWL1 gene, resulting in albino cotyledons and variegated true leaf phenotype. Confocal microscopy and western blot of chloroplast protein fractions revealed that SWL1 localized in the chloroplast stroma. Electron microscopy indicated chloroplasts in the cotyledons of swl1 lack well-defined grana and internal membrane structures, and similar structures have been detected in the albino region of variegated true leaves. Transcriptome analysis revealed that down regulation of chloroplast and nuclear gene expression related to chloroplast, including light harvesting complexes, porphyrin, chlorophyll metabolism and carbon metabolism in the swl1 compared to wild-type plant. In addition, proteomic analysis combined with western blot analysis, showed that a significant decrease in chloroplast proteins of swl1. Furthermore, the expression of genes associated with secondary metabolites and growth hormones was also reduced, which may be attributed to SWL1 associated with absorption and fixation of inorganic carbon during chloroplast development. Together, the above findings provide valuable information to elucidate the exact function of SWL1 in chloroplast biogenesis and development.

INDIGENOUS CUCURBITS AND GRAFTING TECHNIQUES AFFECT CUCUMBER PRODUCTIVITY BY MODULATING MORPHO-PHYSIO-BIOCHEMICAL INDICES

Vegetable grafting is a unique surgical horticultural technology for inducing soilborne biotic and abiotic stress tolerance in cucumbers. Indigenous cucurbit germplasm as rootstocks may show more tolerance potential compared to exotic ones. However, it needs evaluation for compatibility testing through various grafting techniques. Therefore, this study was planned to test available cucurbits as rootstocks for graft success vis-à-vis cucumber growth and productivity. It was carried out in the Plant Propagation and Physiology lab at MNS University of Agriculture, Multan, Pakistan. The seeds of the indigenous open-pollinated cucurbits were sown in 64-celled plug trays with peat moss as growing media, followed by shifting to 50-celled plug trays at the first true leaf emergence stage. The seeds of selected scion (cucumber) were sown after the emergence of rootstock seeds. Different grafting techniques were performed at the first true leaf stage of the scion, followed by healing and acclimatization. In this experiment, hybrid cucumber (cv Yalla F1) was grafted on three indigenous cucurbits, namely ridge gourd (Luffa acutangular), bottle gourd (Lagenaria sicearia) and pumpkin (Cucurbit pepo. L) for graft compatibility success by using three grafting techniques: cleft grafting, one cotyledon grafting and hole insertion. Non-grafted cucumber was grown to compare with grafted plants for growth and productivity. Overall, significant (p ≤ 0.5%) results were obtained regarding a 90% survival rate in cucumber plants grafted onto the bottle gourd through cleft grafting compared to the other grafting techniques. Additionally, the cucumber plants grafted on bottle gourd showed the highest morphological (root length, shoot length, root fresh weight, shoot fresh weight and rootstocks, and scion gir th), physiological (photosynthetic rate, transpiration rate, stomatal conductance, and sub-stomatal conductance), biochemical (antioxidants activities, SOD, CAT, and POX) and yield indices (average fruit length, weight, numbers, and yield) as compared to the non-grafted plants. Conclusively, cucumber grafting onto indigenous bottle gourd with cleft grafting technique exhibited maximum compatibility confirmed through physio-chemical attributes and improved plant biomass and yield, thereby suggested for cucumber grafting.

Physiological Responses and Tolerance of Three Acacia Species to Cadmium Stress During Germination and Early Seedling Growth

Soil contamination with cadmium (Cd) is a serious threat to ecosystems. Phytoremediation is a cost-effective green technology that can be used to clean up Cd pollution, and Acacia species are potential phytoremediation agents due to their fast growth, significant biomass, and tolerance to environmental stresses. Most studies of Cd stress on Acacia focused on later vegetative stages and the tolerances during germination and early seedling are elusive. This study aimed to assess the tolerance of Acacia mangium, Acacia crassicarpa, and Acacia auriculiformis to Cd stress during germination and early seedling growth. In response to 250 μM Cd treatment, A. auriculiformis germination was slightly increased compared to the control. Leaf organ formation remained largely unaffected by Cd stress, except for the true leaf number in A. mangium, which was significantly higher in response to 125 µM Cd than those to 250 µM Cd treatment and control at 8 and 10 weeks after treatment. The onset of phyllode development transition from true leaf was significantly delayed in A. mangium compared with the other two Acacia, irrespective of the presence of Cd. There were no significant differences in leaf gas exchange parameters (photosynthesis, stomatal conductance, and transpiration), leaf-level water use efficiency, or leaf chlorophyll content between Cd-treated and control plants, suggesting that the three Acacia species are tolerant to Cd at both germination and early seedling phases. Cd accumulation during the experiment was very low in A. mangium seedlings (2.8 mg kg-1 upon 250 µM Cd) and insignificant in A. crassicarpa and A. auriculiformis, indicating non-hyperaccumulation or Cd exclusion at the seedling stage.

Effects of Dark Treatment on Lignin and Cellulose Synthesis in Celery

To clarify the impact of continuous dark stress on lignin and cellulose synthesis in celery, shade-tolerant celery varieties were screened. Yellow celery variety ‘Qianhuang No.1’ and green celery variety ‘Qianlv No.1’ were separately grown in vegetable greenhouses. Dark treatments were applied using PVC shading sleeves for 4, 8, 12, and 16 d after celery had grown 10–13 true leaf blades. This study aimed to investigate the impact of varying periods of dark treatment on the morphological characteristics, lignin accumulation, and cellulose accumulation in celery. The results showed that dark treatment led to celery yellowing, a reduced stem thickness, and an increased plant height. Analysis of lignin and cellulose contents, as well as the expression of related genes, showed that dark treatment caused down-regulation of AgLAC, AgC3′H, AgCCR, AgPOD and AgCAD genes, leading to changes in lignin accumulation. Dark treatment inhibited the expression of the AgCesA6 gene, thus affecting cellulose synthesis. Under dark conditions, the expression of AgF5H and AgHCT genes had little effect on lignin content in celery, and the expression of the AgCslD3 gene had little effect on cellulose content. Analysis of morphological characteristics, lignin accumulation and cellulose accumulation after different lengths of dark treatment demonstrated that ‘Qianlv No.1’ is a shade-tolerant variety in contrast to ‘Qianhuang No.1’.

Effects of Neonicotinoid Seed Treatments on Cotton Seedling Physiology, Nutrition, and Growth

Plant growth and physiology can be affected by environmental and chemical factors that have the potential to influence yields. Among the factors that influence plant growth, neonicotinoid seed treatments have shown significant effects on plant growth, particularly in cotton. The dual benefits seen from neonicotinoids on plant growth and insect control show promise in improving cotton yields but little is known about how different seed treatments affect seedling physiology. A greenhouse experiment was undertaken to investigate how three neonicotinoid seed treatments (clothianidin, thiamethoxam, and imidacloprid) affect the physiology and growth of cotton seedlings in controlled environmental conditions. A randomized complete block design was used to examine seed treatments and an untreated control. Cotton seeds were treated, grown, and evaluated for physiological changes until the fifth true leaf-stage and measurements were taken at each of these stages. Data were collected on plant height, shoot fresh weight, leaf area, root length, and root biomass. In addition, chlorophyll pigments and nutrient analysis were performed on cotton seedlings. The seedlings of imidacloprid treated seeds had greater height, shoot fresh mass, leaf area, and relative growth rate by the fifth true leaf stage compared to other treated plants; however, clothianidin showed comparative performance at earlier stages in plant development that equilibrated over time. While all neonicotinoid seed treatments showed positive effects, imidacloprid showed the most potential as a bioactivator on plant growth.

First report of Ralstonia pseudosolanacearum causing bacterial wilt on Rosa sp. in Greece.

In March 2021, a sample of nine-month-old, non-grafted, diseased rose (Rosa sp.) plants was sent by a grower to the Benaki Phytopathological Institute for examination. The plants exhibited symptoms of dieback with black necrosis of pruned shoots, brown discoloration of shoot and root vascular tissues, and whitish slime exudation on cutting wounds of the shoots. The symptoms resembled those caused by Ralstonia pseudosolanacearum (Tjou-Tam-Sin et al. 2016). According to the sample's information sheet, the sample had been collected in a commercial greenhouse rose crop for cut flowers with a 10% disease incidence in the area of Troizinia-Methana (Regional Unit of Islands, Greece). Microscopic examination of symptomatic shoot and root vascular tissues revealed masses of bacterial cells streaming out of them. Sections of symptomatic tissues were suspended in water and in the resulting suspension, bacteria of the R. solanacearum species complex (RSSC) were detected by an indirect immunofluorescence (IF) assay using polyclonal antibodies (Plant Research International, the Netherlands) and a qPCR assay (RS-I-F/RS-II-R primers, RSP-55T probe) (Vreeburg et al. 2016). Furthermore, colonies with typical characteristics of RSSC were isolated from vascular tissues of shoots and roots on non-selective (NA) and semi-selective (mSMSA) media (EPPO 2022), and their identification as RSSC was confirmed by the above-mentioned IF and qPCR assays. Also, the isolates were assigned to: i) biovar 3, based on their ability to metabolize three disaccharides (maltose, lactose, D(+) cellobiose) and three hexose alcohols (mannitol, sorbitol, dulcitol) producing acid (EU 2006) and ii) phylotype I, by multiplex conventional PCR (Opina et al. 1997; Fegan and Prior 2005). A representative isolate was selected for sequencing part of the genes: 16S rDNA (1464bp), mutS (729bp) and egl (795bp) with GenBank Accession Nos. OR102443, OR683617 and OR702781, respectively. Blast analysis of these sequences showed 100% identity with those of various RSSC strains (e.g. GenBank Ac. Nos. CP025741.1, CP021762.1, MF141029.1, respectively). The obtained egl sequence conforms with the characteristics of phylotype I based on the DNA barcoding tool (EPPO 2021) and is 100% identical to that of the Dutch strain PD7216 (MF141029.1) reported to be sequevar I-33 (Bergsma-Vlami et al. 2018). The pathogenicity of two isolates was tested by inoculating: i) tomato seedlings (cv. 'Belladona') at their stem between the cotyledons and the first true leaf (EU 2006) and b) rose plants (cv. 'Aqua' and 'Papa Meilland') at their shoot base (Tjou-Tam-Sin et al. 2016), with bacterial suspensions in water (108 cfu/ml). The inoculated plants were maintained at a day/night temperature about 28/20°C with tomato plants exhibiting leaf wilting (7-17 dpi) and rose plants exhibiting chlorosis and necrosis of leaves (17 dpi). The pathogen was re-isolated on mSMSA from both artificially infected plant species and identified by the IF assay described above, thus fulfilling Koch's postulates. This is the first diagnosis in Greece of: i) rose plants infected by a Ralstonia species and ii) a crop infected by R. solanacearum phylotype I that corresponds to the R. pseudosolanacearum species (EPPO 2022). Official phytosanitary measures imposed in the affected area include an annual survey of rose crops for the presence of this pathogen, aiming at an early detection and prevention of its spread in such a highly valued ornamental crop.

The Effect of Different Harvest Times on Phenolic Content and Antioxidant Activity in Some Microgreens

Microgreens, which have only become popular during the last decades, are rich in phytochemicals, including phenolic compounds, which act as antioxidants. The study aimed to examine the effects of two different harvest times (cotyledon [embryonic leaves] and 1.5-true leaf stage) of five microgreens on the bioactive compounds in terms of antioxidant capacity and total phenolics. The total phenolic components ranged from 60.9 to 2153.2 mg GAE g-1 in cotyledon leaves, whereas the value varied from 96.2 to 2113.9 mg GAE g-1 in the true leaves of microgreens. Increases in the phenolic content of the first true leaves in dill and chia were detected as 57.8% and 29.6% compared to the cotyledon leaf. Among the cotyledon microgreens, the maximum phenolic content was detected in the garden cress. The antioxidant capacity of the cotyledon and true leaf stages ranged between 485.4±2.3-1985.67±24.9 µg g-1 and 508.87±5.3-2393.56±12.6 µg g-1, respectively. The maximum antioxidant capacity was detected in radish, followed by garden cress. The biggest variation between the cotyledon and first true leaves in the study was observed for red beetroot. This study revealed the alteration in the phenolic content and antioxidant activity of five cultivars based on growth stages of cotyledonary and true leaves in microgreen form.

Unveiling the mechanism of source-sink rebalancing in cucumber-pumpkin heterografts: the buffering roles of rootstock cotyledon.

Grafting onto pumpkin rootstock is widely applied in cucumber production to improve growth and yield, as well as to overcome soil-borne diseases and enhance resistance to abiotic stresses. In this study, we constructed the cucumber-pumpkin heterografts with the one-cotyledon grafting method, and examined the effects of heterografting on biomass allocation and sugar partitioning, with cucumber and pumpkin self-grafts used as control. Compared with cucumber self-grafts, heterografting onto pumpkin rootstock promoted photosynthesis in cucumber scion, and led to higher sucrose contents in the 1st true leaf (source) and newly emerged leaf (sink). Thereby, the scion part of heterografts accumulated more biomass than cucumber self-grafts. In contrast, when compared to pumpkin self-grafts, grafting with cucumber scion reduced root vigor and biomass but promoted cotyledon growth in pumpkin rootstock. The roots (sink) of heterografts contained less sucrose and hexoses, and showed reduced sucrose synthase (SuSy) and hexokinase (HXK) activities. However, the rootstock cotyledon (source) contained more sucrose and starch, and showed higher activities of HXK, cell-wall invertase (CWIN), and enzymes for starch synthesis and degradation. Furthermore, removal or shade of rootstock cotyledon led to reduced growth of root and scion. Silencing of CmoMEX1a gene in rootstock cotyledon inhibited maltose export and reduced root growth of heterografts. These results indicated that rootstock cotyledon, especially its starch content, played a buffering role in the growth regulation of cucumber-pumpkin heterografts. Taken together, our results provided a major contribution to our understanding of source-sink sugar partitioning and scion-rootstock growth balancing in cucumber-pumpkin heterografts.

Organic fertilizer type and dose affect growth, morphological and physiological parameters, and mineral nutrition of watermelon seedlings.

Organic agriculture has grown rapidly in recent years due to its environmental friendliness, sustainability, and improved farm profitability. Transplants are commonly used for fruits and vegetables to achieve consistent quality, uniformity, and easy field spacing control. The efficacy and optimal amounts of fertilizers for organic transplant production need to be investigated. The effects of three organic fertilizers (Sustane 4-6-4, Nature Safe 7-7-7, and Dramatic 2-4-1) and one conventional fertilizer Peters Professional 20-20-20 (Conventional) with four doses (nitrogen (N) content was matched among fertilizers in each level, as 0.14 g/L, 0.28 g/L, 0.56 g/L, and 0.84 g/L N, respectively) on watermelon seedlings were compared in this study. The results showed that all organic fertilizer treatments were not significantly different from the Conventional group in terms of watermelon germination. The only exception was the highest dose of Sustane 4-6-4 (0.84 g/L N) which decreased the germination rate and relative emergence index. Generally, growth index, shoot fresh and dry weights, true leaf number, and stem diameter increased as the amount of N increased within each fertilizer type. The best shoot growth was observed in the highest doses of Conventional and Dramatic 2-4-1 treatments (0.84 g/L N). However, Dramatic 2-4-1 treatments resulted in the lowest root growth when compared to other fertilizers at the same N dose. The second highest fertilization dose (0.56 g/L N) of Sustane 4-6-4 had the best root growth according to root fresh weight, root volume, root area, total root length, as well as the numbers of root tip and crossing when compared to other treatments. For seedlings, a well-developed root system can ensure a good seedling establishment and high survival rate under stressful field conditions after transplanting. Thus, Sustane 4-6-4 at 14 g/L (0.56 g/L N) is recommended to produce high-quality organic watermelon seedlings among the treatments applied in this study.

Response of conventional sunflower cultivars to drift rates of synthetic auxin herbicides.

The agrochemical industry has launched several new synthetic auxin herbicides in rice to combat increasing numbers of herbicide resistant weeds to other modes of action. Excessive or inappropriate use of these herbicides has resulted in unintended consequences near the sites of application, such as herbicide drift. This study was conducted to determine the impact of drift of quinclorac and florpyrauxifen-benzyl+penoxsulam (FBP) on the yield and yield components of two sunflower cultivars. In a growth chamber experiment, quinclorac and FBP were applied to 2-4 true leaf stages at rates ranging from 2.93 to 93.75 and from 0.51 to 16.25 g ai ha-1, respectively. Nonlinear regression analyses indicated that the cultivar Bosfora was more sensitive to quinclorac and FBP than the cultivar Tunca. In field experiments, these sunflower cultivars were treated with drift rates of quinclorac (<375 g ai ha-1) and FBP (<65 g ai ha-1) when they were at the 8-10 true leaf stage. Quinclorac and FBP drift rates resulted in up to 52-61% and 85-100% injury and 82-88% and 100% yield loss, respectively. Crop injury and yield data clearly showed that cultivar Bosfora was more sensitive to FBP and quinclorac rates than cultivar Tunca, and both cultivars were more sensitive to FBP than quinclorac. In our work, we also found that plant height reduction caused by quinclorac at early growth stages may be a valuable indicator to evaluate crop injury and yield loss.

The importance of stimulators in cultivating a non-traditional plant-indigofera Tinctoria L

The article depicts the duration and norms of the use of various stimulants in the cultivation of the non-traditional leguminous plant Indigofera (Indigofera tinctoria L.) and its effect on seed yield, root and stem residues, and the amount of total proteins grown in the conditions of the meadow alluvial soils of the Khorezm, the northern region of the Republic of Uzbekistan. To get a high and quality seed yield from Indigofera, it should be sown at 3 kg per hectare in the third ten days of April, and a geohumat stimulator is applied at a rate of 1.0 l/ha along with sowing, 1.6 l/ha during the period of 3–4 true leaf appearances, and 1.6 l/ha in the flowering season of the vegetation. When applied at the rate of, a higher seed yield of 18.3 t/ha was obtained compared to the control option without stimulant use, 6.8 t/ha, and 2.9 t/ha compared to the option where Uzgumi as a chosen option was used only with planting, and it is based on the fact that 1.6 t/ha of additional seed yield can be obtained compared to the option where Geohumat stimulator was used only with planting. Also, it has been scientifically justified that the amount of total proteins increased up to 12.960% in the plant leaf, 30.980% in the seed, and 6.945% in the root when the geohumat stimulator was used at acceptable rates along with planting, during the 3–4 true leaves of the growing season, and during the flowering period. It indicates that the result is 1.249, 1.47, and 1.307% more proportionally than options grown without the stimulator.