Bud Stage Research Articles

Оptimization of fertilizer and foliar feeding winter rape (Brassica napus L.) in the Western Polissia

Topicality. Significant changes in market conditions and disruptions in the sown area structure in Ukraine require to search for optimal and cost-effective systems of fertilisation and crop management for modern varieties and hybrids of winter rape. The application of sulphur fertilisers, ammonium nitrate in early spring fertilisation and foliar feeding with growth stimulants and microfertilisers improves winter rape growth and development, yield structure and productivity. Purpose. To develop innovative agrotechnical practices involving the compound fertilizers, microfertilizers, growth stimulants, aimed to realize the high yield potential of winter rape in the Western Polissia. Methods. The research was carried out at the Institute of Agriculture of Western Polissia on a typical low-humus light loamy chernozem. General scientific methods and analyses were used to compare the factors under study: field method was used to determine the fertiliser efficiency; visual, measuring and weighing method; laboratory method; comparative and calculation method; statistical method. The results. It was found that on winter rape crops, the best degree of overwintering was 85.5–88.8 % and 83.0–86.0 % for fertilisation with N35P90K120 + N85S40 + N30 and N35S60K90 + N85, compared to N35P60K90 + N85, where these indicators are within 77.3–77.7 %. The highest survivability of plants during the growing season was 98.4–98.6 %, when N35P90K120 + N85S40 + N30 was applied together with foliar feeding (Huliver Stymul + Avanhard Silicon Bio (1.0 + 1.0 l/ha) and Huliver Stymul + Avanhard P Phosphorus + Potassium (1.0 + 0.6 l/ha) in the rosette phase and the beginning of budding. The largest number of pods per plant is 121.5–124.0 pcs, the number of seeds per pod is 24.1–24.7 pcs, the thousand seed weight – 4.54–4.56 g was observed for fertilisation with N35P90K120 + N85S40 + N30 with two foliar feeding with Huliver Stymul + Avanhard Silicon Bio (1.0 + 1.0 l/ha) and Huliver Stymul + Avanhard P Phosphorus + Potassium (1.0 + 0.6 l/ha). The maximum yield of 4.45 t/ha was obtained with fertiliser of N35P90K120 + N85S40 + N30 and foliar feeding with Huliver Stymul + Avanhard P Phosphorus + Potassium (1.0 + 0.6 l/ha). Conclusions. It was found that early spring application of ammonium sulphate N35S40 and ammonium nitrate N50–85 kg/ha was an effective method to increase the winter rape yield to 4.45 t/ha, the increase in yield due to fertilisation varied within 5.1–15 %. When foliar feeding with a growth stimulator and microfertilisers was applied two times in the spring rosette and flower budding stage, the yield increase ranged from 2.8 to 16.5 %. Key words: winter rape, fertilization system, foliar feeding, productivity

Unravelling physiological and biochemical attributes influencing post harvest quality of gladiolus spikes after packaging and low temperature storage

The perishable nature of flowers urge for their appropriate post harvest management especially storage and packaging that keep the quality and potential vase life for better value. Gladiolus, commonly called as Sword lily, is a commercially important cut flower crop with elegant spikes, bright florets and good keeping quality. In the present study, we investigated the physiological and biochemical attributes affecting post harvest life of gladiolus spikes after packaging and storage. The spikes of four gladiolus cvs. Punjab Glance, Punjab Glad-1, Punjab Glad-2 and Punjab Pink Elegance were harvested at tight bud stage and packed in PP sleeves (25 μm) and stored vertically at 4-5°C for 6, 9 and 12 days. After storage, the post harvest quality of both packed and unpacked spikes declined with more adverse effect on unpacked spikes. Among different storage durations, the spikes stored for 9 days showed good keeping quality parameters viz., vase life, per cent flower opened, floret size, days to opening of basal floret, maximum number of florets open at one time and water absorbed per spike which were at par with spikes stored for 6 days. The spikes stored for 12 days were found to be unacceptable in comparison to freshly harvested spikes and spikes stored for 6 and 9 days. The improved quality of spikes stored in sleeves could be accounted due to higher membrane stability index, relative water content, catalase and peroxidase activity as compared to unpacked spikes. Thus, loss in quality of spikes as compared to fresh during storage up to 9 days in PP sleeves is better than the complete loss of produce during transportation and gluts. Hence, the spikes of gladiolus could be stored dry at 4±0.5°C in PP sleeves for 9 days without much influence on its post harvest quality.

Establishment of a Monitoring Model for the Cotton Leaf Area Index Based on the Canopy Reflectance Spectrum

Cotton is the main economic crop in China and is important owing to its use as an industrial raw material and a cash crop. This experiment was conducted in the main cotton-producing area of Xinjiang, China. A hyperspectrometer was used to monitor the canopy spectral reflectance of cotton at different stages of growth. The results showed that the leaf area index (LAI) increased with the increase in the amount of nitrogen fertilizer added during the early full boll stage and decreased with the increase in nitrogen fertilization in the full and late boll stages. Insufficient or excessive fertilization led to a decrease in the LAI. The visible light band indicated that the canopy spectral reflectance decreased, and the amount of fertilizer increased in all the growth stages. The near-infrared band revealed that the canopy spectral reflectance increased with the amount of nitrogen applied during the bud stage, early boll stage, and the most vigorous period of boll growth. During the flowering period, the spectral reflectance followed the order N3 > N4 > N2 > N1 > N0. During the entire growth period of cotton, the values of the cotton LAI predicted using the ratio vegetation index (RVI) model were found to best fit the measured values. The LAI monitoring models of cotton in each growth stage were different. The TVI model is the best in the bud and early boll stages. The NDVI model is the best in the flowering stage, and the DVI model is the best in the full boll stage. This study provides a basis to accurately monitor the LAI in each growth period of cotton.

Photosynthetic parameters of winter pea sowings under the effect of nitrogen fertilization and seed inoculation in the Right Bank Forest-Steppe of Ukraine

Purpose. To evaluate the photosynthetic parameters of winter pea sowings under the effect of seed inoculation and nitrogen fertilization in the Right Bank Forest-Steppe of Ukraine. Methods. The research was carried out in the years 2019–2021 in the fields of the Agronomic Research Station (a division of NULES of Ukraine, Kyiv region). Winter pea ‘NS Moroz’ was sown in the second half of September at the rate of 1.2 million seeds/ha. The width of the rows was 15 cm, and the seed sowing depth was 4–4.5 cm. The design of the experiment provided for the combined use of such technological factors as seed inoculation (without inoculation; Optimize Pulse, 3.3 l/t) and nitrogen fertilizer [main application + early spring top dressing (N0; N15 + N15; N15 + N30; N15 + N45; N30 + N0; N30 + N15; N30 + N30; N45 + N0; N45 + N15; N60 + N0)]. P45K45 was also applied in the primary fertilization as a background. Results. Seed inoculation and nitrogen fertilizers positively affect the photosynthetic activity of winter pea; however, the efficiency of their action largely depends on the application doses and timing, as well as the stage of crop development. It was established that in the autumn period of winter pea vegetation (complete sprouting–stalking), the influence of the studied agrotechnical measures on the leaf area index (LAI), photosynthetic potential (PP), and net photosynthetic productivity (NPP) was mostly insignificant. In the period of spring-summer vegetation, the effect of the factor of seed inoculation, as well as early spring fertilization with nitrogen, increased significantly, while the main fertilization decreased. The highest LAI (on average according to the experiment 31.4 thousand m2/ha) was formed in the flowering stage, PP during the stages of bean formation – ripening of seeds (0.75 million m²/ha per day). The use of seed inoculation compared to options without it contributed to the increase of these indicators by 5.33 and 0.17 million m2/ha per day, respectively. In the experiment, the maximum values of both LAI (35.77–36.45 thousand m²/ha) and PP (0.91–0.93 million m2/ha per day) were obtained when applying N15 + N30–45 and N30 + N30 on the background of seed inoculation, while the minimal in control treatments (N0). The regularities of the formation of the NPP were radically different. Its highest indicators during the period of the beginning of vegetation – budding (as well as in the following interphase stages) were observed primarily with the minimal application of fertilizers (N30 + N0, N15 + N15) or in the control treatments (N0), 8.1–9.2 g/m2 per day. Seed inoculation had no significant effect on the formation of NPP. The maximum content of chlorophyll a in plants (5.90 mg/g) was formed in the budding stage, gradually decreasing to 5.74 and 5.05 mg/g in the flowering and bean formation stages, respectively. Instead, the content of chlorophyll b was the lowest in the budding stage (12.37 mg/g), reaching its maximum in the flowering stage (19.71 mg/g) and slightly decreasing in the stage of bean formation – 16.37 mg/g of raw mass. Seed inoculation helped to increase the content of chlorophyll a by an average of 0.9–1.0 mg/g over growth stages and chlorophyll b by 1.4–2.2 mg/g. The best fertilization treatment was N15 + N30–45. Conclusions. Seed inoculation and nitrogen fertilization are significant and effective factors to intensify the photosynthetic activity of winter pea sowings. The patterns of the parameters of leaf s area, photosynthetic potential, net productivity of photosynthesis, and the content of photosynthetic pigments revealed in the study may be used to improve the cultivation technology to fully realize the crop potential productivity under the conditions of the Right Bank Forest‑Steppe of Ukraine.

Formation of biometric parameters of switchgrass on acid soils

Purpose. To establish the peculiarities of the biometric parameters of switchgrass cultivated on acid soils attributed to the category of marginal land. Methods. Field experiment was carried out at the Uladivka-Liulyntsi Experimental Breeding Station of the Institute of Bioenergy Crops and Sugar Beet of the National Academy of Agrarian Sciences in the years 2019–2021. Switchgrass variety ‘Morozko’ was grown in the a three-factor field experiment, with the application of lime (25% of the need), MaxiMarin granulated adsorbent (30 kg/ha), potassium humate (Humifield) (50 g/ha) and Antistress AminoStar (1.0 l/ha) to the soil. The adsorbent was applied two weeks before sowing the crop locally in the rows, foliar application of fertilizers was carried out in the budding stage and the second time after two weeks. Results. In the second year of cultivation, the plant density in the tillering stage was from 12 to 21, in the third year from 16 to 23. Since the plants already formed an optically dense crop in the first half of the vegetation season, there was no further increase in the plant density, and in all treatments of the experiment, the number of plants determined in the tillering stage was preserved at the time of harvesting. Application of lime to the soil did not have a significant impact on the formation of this indicator, and the main differences were only compared to the treatments with applying the adsorbent. The height of the plants in the tillering stage in the experiment was approximately at the same level: in 2020, 24–30 cm and 2021, 12–16 cm. A tendency of the increase was noted only in the treatments with adsorbent. Starting from the stage of leaf-tube formation, the influence of the factor of foliar application of fertilizers increased significantly, the effectiveness of which increased against the background of the adsorbent application. In particular, in the treatment with potassium humate, the plants were 5–15 cm taller in both years of the experiment compared to the corresponding controls, and in the case of the combined application of potassium humate with AminoStar Antistress plant height exceeded by 5–25 cm. Soil deoxidation also had a positive effect on plant growth: on average of the treatments without liming, in the leaf-tube formation, the plants were 48–88 cm tall, while with the application of lime 54–115 cm. In 2020, similar patterns of this indicator formation were noted in the following stages of development. On the other hand, in 2021, at the later stages of the crop vegetation, the difference between these experimental treatments decreased, and in the harvesting stage, the plants in the treatments where lime was not applied were even taller by 6 cm. A similar situation was observed in the treatments with the combined application of the adsorbent and foliar application of humates: in the stage of leaf-tube formation, the plant height was significantly higher, but already in the flowering stage it was practically equal to the control treatments, and at the time of harvesting it was somewhat lower. Conclusions. The maximum values of the biometric parameters of switchgrass were obtained mostly in the treatments with the combination of all three investigated agrotechnical measures. At the same time, their formation was more significantly affected by the use of adsorbent and foliar feeding of plants than by liming the soil, the effect of which was mostly tendentious. At the same time, the effectiveness of these technological factors was largely determined by the weather conditions of the growing season, which in turn affected the growth processes of plants and caused certain variations in their biometric parameters over the years of research.

Comparative Analysis of Grapevine Epiphytic Microbiomes among Different Varieties, Tissues, and Developmental Stages in the Same Terroir

There is limited knowledge about the relationships of epiphytic microbiomes associated with the phyllosphere of different Vitis vinifera cultivars in the same vineyard and terroir. To address this research gap, we investigated the microbiome compositionof 36 grapevine genotypes grown in the same vineyard in different plant sections during the growing season. Using high-throughput NGS-based metagenomic analysis targeting the ITS2 and the V4 regions of the 16S ribosomal gene of fungal and bacterial communities, respectively, weassessed the impact of grapevine genotypes on microbial assemblages in various parts of the phyllosphere. The results indicated that different phyllosphere tissues display high microbial diversity regardless of the cultivars’ identity and use. The selected three phyllosphere parts representing three distinct phenological stages, namely bark and bud, berry set, and fruit harvest, had almost a similar number of fungal OTUs, while a difference was recorded for the bacterial species. The fruit harvest stage hosted the highest number of bacterial OTUs, whereas the bark and bud stage contained the lower. Bacterial dominant phyla were Proteobacteria, Bacteroidetes, Actinobacteria, and Firmicutes, and the genera were Gluconacetobacter, Erwinia, Gluconobacter, Zymobacter, Buchnera, Pseudomonas, Pantoea, Hymenobacter, Pedobacter, Frigoribacterium, Sphingomonas, and Massilia. For fungi, the dominant phyla were Ascomycota and Basidiomycota, and the genera were Aureobasidium, Cladosporium, Alternaria, Aspergillus, Davidiella, Phoma, Epicoccum, Rhodosporidium, Glomerella, Botryosphaeria, Metschnikowia, Issatchenkia, and Lewia. Both the genotype of the cultivar and the phenological stage appeared to considerably impact the shape of microbial diversity and structure within the same terroir. Taken together, these results indicate that microbiome analysis could be proved to be an important molecular fingerprint of cultivars and provide an efficient management tool for the traceability of wine and grape end products. Moreover, the unique identity of cultivars’ microbial signatures highlights the need for further development of precision management to support viticulture sustainability in the face of climate change.

Physiological changes and gene responses during Ganoderma lucidum growth with selenium supplementation.

Ganoderma lucidum basidiomycota is highly appreciated for its health and nutrition value. In the present study, Ganoderma lucidum was cultivated as selenium transformation carrier, and the physiological changes and gene responses by selenium supplementation were revealed through high-throughput RNA-Seq technology. As a result, selenium supplementation increased the stipe length and the cap size, but decreased the cap thickness of G. lucidum. Mineral salt supplementation could greatly promote the formation of triterpene acids and selenium in G. lucidum. The highest yield was gained in the treatment with selenium content of 200 µg/g. Subsequently, the tissues of G. lucidum at budding and mature stages in this treatment group were sampled for transcriptome analysis and compared to those of a control group without selenium supplementation. A total of 16,113 expressed genes were obtained from the transcriptome of G. lucidum, and GO-annotated unigenes were mainly involved in molecular functions and KEGG-annotated ones were highly expressed in ribosomal pathway. Furthermore, genes involved in carbon metabolism pathway were most promoted by selenium at budding stage of G. lucidum, while gene expression was the highest in the pathway of amino acid biosynthesis at mature stage of G. lucidum. Specially, selenium-related genes in G. lucidum, such as GL23172-G, GL29881-G and GL28298-G, played a regulatory role in oxidoreductase, antioxidant activity and tryptophan synthesis. The results provide a theoretical basis for further study of selenium-enriched mushrooms and aid to development of Se-enriched foodstuff and health products made from fungi.

Shikimate Kinase Plays Important Roles in Anthocyanin Synthesis in Petunia.

In plants, the shikimate pathway is responsible for the production of aromatic amino acids L-tryptophan, L-phenylalanine, and L-tyrosine. L-Phenylalanine is the upstream substrate of flavonoid and anthocyanin synthesis. Shikimate kinase (SK) catalyzes the phosphorylation of the C3 hydroxyl group of shikimate to produce 3-phosphate shikimate (S3P), the fifth step of the shikimate pathway. However, whether SK participates in flavonoid and anthocyanin synthesis is unknown. This study characterized the single-copy PhSK gene in the petunia (Petunia hybrida) genome. PhSK was localized in chloroplasts. PhSK showed a high transcription level in corollas, especially in the coloring stage of flower buds. Suppression of PhSK changed flower color and shape, reduced the content of anthocyanins, and changed the flavonoid metabolome profile in petunia. Surprisingly, PhSK silencing caused a reduction in the shikimate, a substrate of PhSK. Further qPCR analysis showed that PhSK silencing resulted in a reduction in the mRNA level of PhDHQ/SDH, which encodes the protein catalyzing the third and fourth steps of the shikimate pathway, showing a feedback regulation mechanism of gene expression in the shikimate pathway.

Sexually Dimorphic Gene Expression in X and Y Sperms Instructs Sexual Dimorphism of Embryonic Genome Activation in Yellow Catfish (Pelteobagrus fulvidraco).

Paternal factors play an important role in embryonic morphogenesis and contribute to sexual dimorphism in development. To assess the effect of paternal DNA on sexual dimorphism of embryonic genome activation, we compared X and Y sperm and different sexes of embryos before sex determination. Through transcriptome sequencing (RNA-seq) and whole-genome bisulfite sequencing (WGBS) of X and Y sperm, we found a big proportion of upregulated genes in Y sperm, supported by the observation that genome-wide DNA methylation level is slightly lower than in X sperm. Cytokine-cytokine receptor interaction, TGF-beta, and toll-like receptor pathways play important roles in spermatogenesis. Through whole-genome re-sequencing (WGRS) of parental fish and RNA-seq of five early embryonic stages, we found the low-blastocyst time point is a key to maternal transcriptome degradation and zygotic genome activation. Generally, sexual differences emerged from the bud stage. Moreover, through integrated analysis of paternal SNPs and gene expression, we evaluated the influence of paternal inheritance on sexual dimorphism of genome activation. Besides, we screened out gata6 and ddx5 as potential instructors for early sex determination and gonad development in yellow catfish. This work is meaningful for revealing the molecular mechanisms of sex determination and sexual dimorphism of fish species.

Quorum sensing signals: Aquaculture risk factor

AbstractBacteria produce several virulence factors and cause massive mortality in fish and crustaceans. Abundant quorum sensing (QS) signals and high cell density are essentially required for the production of such virulence factors. Although several strategies have been developed to control aquatic pathogens through antibiotics and QS inhibition, the impact of pre‐existing QS signals in the aquatic environment has been overlooked. QS signals cause detrimental effects on mammalian cells and induce cell death by interfering with multiple cellular pathways. Moreover, QS signals not only function as a messenger, but also annihilate the functions of the host immune system which implies that QS signals should be designated as a major virulence factor. Despite QS signals' role has been well documented in mammalian cells, their impact on aquatic organisms is still at the budding stage. However, many aquatic organisms produce enzymes that degrade and detoxify such QS signals. In addition, physical and chemical factors also determine the stability of the QS signals in the aqueous environment. The balance between QS signals and existing QS signals degrading factors essentially determines the disease progression in aquatic organisms. In this review, we highlight the impact of QS signals on aquatic organisms and further discussed potential alternative strategies to control disease progression.

Anatomical study on the developmental process of the swollen internodes of Phryma (Phrymaceae, eudicots).

We discovered that the internodal swellings of Phryma (eudicots) stems were same as the internodal pulvini of Poaceae (monocots) from the viewpoints of internal structures and functions. The stems of eudicots are usually rod-shaped and are composed of nodes, attached by leaves, and internodes. The internodes of some species, belonging to the clade 'asterids' and its sister clade 'Caryophyllales' of eudicots, have swellings, which have negative tropism, at the basal or apical part of each internode. To know the internal features of the swollen internodes, we performed outer morphological and anatomical studies on the swollen internodes of Phryma, eudicots, one of the genera having swollen internodes, from the winter bud stage to the flowering stage. The results revealed the following: (i) the swollen regions of the internodes were composed of less lignified tissues (e.g., endodermis without Casparian strips, and xylem having less lignified xylem fibers); (ii) the internodal less lignified parts were supported by collenchyma; (iii) the endodermis includes amyloplasts, having accumulated starch granules, which would function as statoliths for negative gravitropism. Consequently, we determined that the swollen parts of the Phryma internodes are same as the internodal pulvini of Poaceae of monocots from the viewpoints of internal structures and functions.

Two polyamines -responsive WRKY transcription factors from Anoectochilus roxburghii play opposite functions on flower development

Anoectochilus roxburghii is a rare and precious plant with medicinal and healthcare functions. Embryo abortion caused the lack of resources. Polyamine promoted its flowering and stress resistance in our previous study. But the mechanism remains unclear. The WRKY transcription factor family has been linked to a variety of biological processes in plants. In this study, two WRKY TFs (ArWRKY5 and ArWRKY20) of A. roxburghii, which showed significant response to Spd treatment, were identified and functionally analyzed. Tissue specific expression analyzation showed both of them mostly present in the flower. And ArWRKY5 expressed highest in the flower bud stage (−1 Flowering), while ArWRKY20 showed the highest expression in earlier flower bud stage (−2 Flowering) and the expression gradually decreased with flowering. The transcriptional activation activity assay and subcellular localization revealed that ArWRKY5 and ArWRKY20 were located in the nucleus and ArWRKY20 showed transcriptional activity. The heterologous expression of ArWRKY5 in Arabidopsis thaliana showed earlier flowering, while overexpression of ArWRKY20 delayed flowering. But the OE-ArWRKY20 lines had a robust body shape and a very significant increase in the number of rosette leaves. Furthermore, stamens and seed development were positively regulated by these two ArWRKYs. These results indicated that ArWRKY5 and ArWRKY20 not only play opposite roles in the floral development, but also regulate the plant growth and seed development in A. thaliana. But their specific biological functions and mechanism in A. roxburghii need to be investigated further.

The Influence of the Bud Stage at Harvest and Cold Storage on the Vase Life of Narcissus poeticus (L.) Flowers

The Narcissus poeticus (L.) species stands out from other narcissus due to its unique ornamental and sensory values. In our experiment, the flowers of N. poeticus were harvested at five different stages. After cutting, the plants were placed directly at room temperature or at 4 °C for 1 week. The opening status of the flowers was recorded every 12 h, and based on this, the ornamental value of the flowers was calculated. Additionally, the flower diameter, the scape and flower weight, the dry matter content, the water soluble K, Ca, and Mg content of the plant parts, and the chlorophyll content of the scapes were measured. The complete senescence of the stored flowers was noted to be earlier (after 6.6–7.5 days) than that of the fresh flowers (7.5–8.5 days) and depended on the bud stage at harvest. Flowers opened from all the buds, but the flower size was smaller in the early developmental harvest stage (a 10 mm reduction in diameter and a 0.38 g reduction in fresh weight between the green bud and the large white bud harvest stages). Cold storage delayed further bud development and reduced the flower size in several cases, but it increased the maximum decorative value of the flowers for those flowers that had been harvested as big white buds.

Transcriptome Analysis and Screening of Genes Associated with Flower Size in Tomato (Solanum lycopersicum)

Flower development is not only an important way for tomato reproduction but also an important guarantee for tomato fruit production. Although more and more attention has been paid to the study of flower development, there are few studies on the molecular mechanism and gene expression level of tomato flower development. In this study, RNA-seq analysis was performed on two stages of tomato flower development using the Illumina sequencing platform. A total of 8536 DEGs were obtained by sequencing, including 3873 upregulated DEGs and 4663 down-regulated DEGs. These differentially expressed genes are related to plant hormone signaling, starch and sucrose metabolism. The pathways such as pentose, glucuronate interconversion, and Phenylpropanoid biosynthesis are closely related and mainly involved in plant cellular and metabolic processes. According to the enrichment analysis results of DEGs, active energy metabolism can be inferred during flower development, indicating that flower development requires a large amount of energy and material supply. In addition, some plant hormones, such as GA, may also have effects on flower development. Combined with previous studies, the expression levels of Solyc02g087860 and three of bZIPs were significantly increased in the full flowering stage compared with the flower bud stage, indicating that these genes may be closely related to flower development. These genes were previously reported in Arabidopsis but not in tomatoes. Our next work will conduct a detailed functional analysis of the identified bZIP family genes to characterize their association with tomato flower size. This study will provide new genetic resources for flower formation and provide a basis for tomato yield breeding.

Foliar feeding of boron influencing biochemical attributes and enzyme activity in dragon fruit (Selenicereus monacanthus)

Boron plays crucial role in metabolic processes during fruit ripening and in turn ensures better fruit quality. However limited studies have been conducted to assess the influence of boron on fruit quality of dragon fruit. In the present study, the efficacy of boron was investigated on red-fleshed dragon fruit (Selenicereus monacanthus). Four levels of boron (100 mgL-1, 200 mgL-1, 300 mgL-1 and 400 mgL-1) were applied on 7- and 14-day-old flower buds. The highest pollen germinability, seed weight, fruit weight (274.32 ± 36.72g), pulp content (70.80 ± 1.79%) and pulp firmness (2.74 ± 0.18 N) were recorded when B was applied@300 mg L-1 on 7-day old flower bud. The same treatment also manifested higher soluble solid contents (17.42 ± 0.62 °Brix), sugar content, total carbohydrate (15.92 ± 1.12%), protein (1.33±0.11%), ascorbic acid (112.66 ± 4.98 µg/g), betacyanin (32.86±2.52 µg/g), total phenol (95.26 ± 3.72 µg GAE/ 100g), total flavonoid (37.65 ±2.14 mg QE/100g) and anti-oxidative activity (27.71±2.14 mM Fe II/100g). Correlation studies elucidated significant positive influence of pollen germinability on fruit weight, pulp content and pulp firmness. The activities of α-amylase, invertase and sucrose synthase enzymes were significantly upregulated with the application of B 300 mg L-1 on 7-day old flower bud. On the other hand, the activities of cell wall degrading enzymes such as cellulase, polygalacturonase and pectin methyl esterase were reduced with increasing levels of boron. The principal component analysis (PCA) illustrated the maximal proximity of most of the quality attributes with B 300 mgL-1, applied at 7-day old flower bud stage, thus exemplifying it as the best treatment.

Identification of Phenological Growth Stages of Four Morus Species Based on the Extended BBCH-Scale and Its Application in Fruit Development with Morphological Profiles and Color Characteristics

Mulberry (Morus L.; Moraceae; Rosales) is an economically important tree with a long history in China and valued for its rich nutrient, flavor content, medicinal value and useful ecological functions. Morus species are widely distributed in Asia, Europe, North and South America and Africa and exhibit obvious differences in morphological characteristics and phenological stages due to being distributed in diverse climate zones. The morphological description of the phenological stages of black mulberry (Morus nigra L.) has been established in Mediterranean climates and this study extended the BBCH scale for application in different Morus species, especially for mulberry trees grown in subtropical monsoon climates. In this study, we used the BBCH (Biologische Bundesanstalt, Bundessortenamt and CHemische Industrie) scale to describe in detail the phenological growth stages for Morus species in Wuhan, China (a subtropical monsoon climate). Based on this general scale, eight principal stages, i.e., bud, leaf and shoot development stage, inflorescence emergence stage, flowering stage, fruit development stage, fruit maturation stage, senescence and beginning of dormancy stage, were described. We provide photographic images of some primary and secondary developmental stages to better define and standardize morphological characteristics and phenological descriptions of these mulberries (Morus spp.). In addition, because the color of mulberry fruit varies from white, purple, black, or pink to red at maturity, with mostly monosexual flowers, we have also presented detailed descriptions of morphological traits of flower sexuality and fruit color among these four species. In addition, two late phenological germplasms (late bud sprouting associated with late blooming and late fruit ripening) were screened out according to the BBCH scale. Overall, this study will contribute to advance the field of mulberry breeding and implementation of agronomic practices and facilitate convenient communication between mulberry cultivators and researchers in different areas.

Dental niche cells directly contribute to tooth reconstitution and morphogenesis.

Mammalian teeth develop from the inductive epithelial-mesenchymal interaction, an important mechanism shared by many organs. The cellular basis for such interaction remains elusive. Here, we generate a dual-fluorescence model to track and analyze dental cells from embryonic to postnatal stages, in which Pitx2+ epithelium and Msx1+ mesenchyme are sufficient for tooth reconstitution. Single-cell RNA sequencing and spatial mapping further revealed critical cellular dynamics during molar development, where tooth germs are organized by Msx1+Sdc1+ dental papilla and surrounding dental niche. Surprisingly, niche cells are more efficient in tooth reconstitution and can directly regenerate papilla cells through interaction with dental epithelium. Finally, from the dental niche, we identify a group of previously unappreciated migratory Msx1+ Sox9+ cells as the potential cell origin for dental papilla. Our results indicate that the dental niche cells directly contribute to tooth organogenesis and provide critical insights into the essential cell composition for tooth engineering.

Genome-wide comparison and identification of myosin gene family in Arabidopsis thaliana and Helianthusannuus

Myosins are essential components of organelle trafficking in all the eukaryotic cells. Myosin driven movement plays a vital role in the development of pollen tubes, root hairs and root tips of flowering plants. The present research characterized the myosin genes in Arabidopsis thaliana and Helianthus annuus by using different computational tools. We discovered a total of 50 myosin genes and their splice variants in both pant species. Phylogenetic analysis indicated that myosin genes were divided into four subclasses. Chromosomal location revealed that myosin genes were located on all five chromosomes in A. thaliana, whereas they were present on nine chromosomes in H. annuus. Conserved motifs showed that conserved regions were closely similar within subgroups. Gene structure analysis showed that Atmyosin2.2 and Atmyosin2.3 had the highest number of introns/exons. Gene ontology analysis indicated that myosin genes were involved in vesicle transport along actin filament and cytoskeleton trafficking. Expression analysis showed that expression of myosin genes was higher during the flowering stage as compared to the seedling and budding stages. Tissue specific expression indicated that HanMYOSIN11.2, HanMYOSIN16.2 were highly expressed in stamen, whereas HanMYOSIN 2.2, HanMYOSIN 12.1 and HanMYOSIN 17.1 showed higher expression in nectary. This study enhance our understanding the function of myosins in plant development, and forms the basis for future research about the comparative genomics of plant myosin in other crop plants.

Multi-omics analyses reveal new insights into nutritional quality changes of alfalfa leaves during the flowering period.

High-quality alfalfa is an indispensable resource for animal husbandry and sustainable development. Its nutritional quality changes dramatically during its life cycle and, at present, no molecular mechanisms for nutrient metabolic variation in alfalfa leaves at different growth stages have been clearly reported. We have used correlation and network analyses of the alfalfa leaf metabolome, proteome, and transcriptome to explore chlorophyll, flavonoid, and amino acid content at two development stages: budding stage (BS) and full-bloom stage (FBS). A high correlation between the expression of biosynthetic genes and their metabolites revealed significant reductions in metabolite content as the plant matured from BS to FBS. l-Glutamate, the first molecule of chlorophyll biosynthesis, decreased, and the expression of HemA, which controls the transformation of glutamyl-tRNA to glutamate 1-semialdehyde, was down-regulated, leading to a reduction in leaf chlorophyll content. Flavonoids also decreased, driven at least in part by increased expression of the gene encoding CYP75B1: flavonoid 3'-monooxygenase, which catalyzes the hydroxylation of dihydroflavonols and flavonols, resulting in degradation of flavonoids. Expression of NITRILASE 2 (NIT2) and Methyltransferase B (metB), which regulate amino acid metabolism and influence the expression of genes of the glycolysis-TCA pathway, were down-regulated, causing amino acid content in alfalfa leaves to decrease at FBS. This study provides new insights into the complex regulatory network governing the content and decrease of chlorophyll, amino acids, flavonoids, and other nutrients in alfalfa leaves during maturation. These results further provide a theoretical basis for the generation of alfalfa varieties exhibiting higher nutritional quality, high-yield cultivation, and a timely harvest.

Molecular and metabolic insights into floral scent biosynthesis during flowering in Dendrobium chrysotoxum.

Dendrobium chrysotoxum is considered as an important ornamental dendrobium because of its strong and long-lasting floral scent. Nevertheless, few information is known about the dynamic changes and related formation mechanism of dendrobium floral scent at different flowering stages. In this study, the characteristics and biosynthetic mechanism of floral scent in D. chrysotoxum during flowering was revealed by using widely-targeted volatilomics (WTV) combined with transcriptome analysis. Over 500 kinds of volatile organic compounds (VOCs) were detected in the floral scents of D. chrysotoxum, which improved the knowledge about floral scent components of dendrobium. A total of 153 differential VOCs and 4,487 differentially expressed genes (DEGs) were identified between flowers of different flowering stages, respectively. The results for both volatilomics and transcriptomics data indicated that terpenes and related genes played an important role in the formation of floral characteristics of D. chrysotoxum. But in general, the expression of genes showed an opposite trend to the accumulation of metabolites during flowering, suggesting that the regulation of floral scent biosynthesis might have started at the budding stage in D. chrysotoxum. Additionally, a transcriptional metabolic regulatory network consisting of terpenes, terpene synthases and candidate transcription factors was established. This research is the first systematic and comprehensive exploration of floral characteristics and related mechanisms during flowering in D. chrysotoxum. It provides basis for exploration of mechanisms on the floral scents and the breeding of aromatic dendrobium.