Bud Samples Research Articles

Development and validation of a rapid loop-mediated isothermal amplification assay for the detection of Chrysomyxa and characterization of Chrysomyxa woroninii overwintering on Picea in China

Chrysomyxa rusts cause significant damage to spruce in both natural forests and plantations. Particularly, Three Chrysomyxa species, Chrysomyxa deformans, Chrysomyxa qilianensis, and Chrysomyxa rhododendri, listed as National Forest Dangerous Pests in China, have severely affected many economically and ecologically important spruce native species in China. Also, Chrysomyxa arctostaphyli, an important plant quarantine fungus, causes a damaging broom rust disease on spruce. Therefore, rapid, and efficient detection tools are urgently needed for proper rust disease detection and management. In this study, a sensitive, genus-specific loop-mediated isothermal amplification (LAMP) assay targeting the ITS-28S rRNA region was developed to detect the presence of Chrysomyxa in spruce needle and bud samples. After optimization and validation, the LAMP assay was found to be sensitive to detect as low as 5.2 fg/µL DNA, making it suitable for rapid on-site testing for rust infection. The assay was also specific to Chrysomyxa species, with no positive signals from other rust genus/species. The application of LAMP in the early detection of rust infections in spruce needles and buds was investigated, and spatial colonization profiles as well as the means of overwintering of Chrysomyxa woroninii in infected buds and branches were verified using the LAMP assay. This LAMP detection method will facilitate further studies on the characteristics of the life cycle and inoculation of other systemic rusts.

A gibberellin-assisted study of the transcriptional and hormonal changes occurring at floral transition in peach buds (Prunus persica L. Batsch)

BackgroundFlower load in peach is an important determinant of final fruit quality and is subjected to cost-effective agronomical practices, such as the thinning, to finely balance the sink-source relationships within the tree and drive the optimal amount of assimilates to the fruits. Floral transition in peach buds occurs as a result of the integration of specific environmental signals, such as light and temperature, into the endogenous pathways that induce the meristem to pass from vegetative to reproductive growth. The cross talk and integration of the different players, such as the genes and the hormones, are still partially unknown. In the present research, transcriptomics and hormone profiling were applied on bud samples at different developmental stages. A gibberellin treatment was used as a tool to identify the different phases of floral transition and characterize the bud sensitivity to gibberellins in terms of inhibition of floral transition.ResultsTreatments with gibberellins showed different efficacies and pointed out a timeframe of maximum inhibition of floral transition in peach buds. Contextually, APETALA1 gene expression was shown to be a reliable marker of gibberellin efficacy in controlling this process. RNA-Seq transcriptomic analyses allowed to identify specific genes dealing with ROS, cell cycle, T6P, floral induction control and other processes, which are correlated with the bud sensitivity to gibberellins and possibly involved in bud development during its transition to the reproductive stage. Transcriptomic data integrated with the quantification of the main bioactive hormones in the bud allowed to identify the main hormonal regulators of floral transition in peach, with a pivotal role played by endogenous gibberellins and cytokinins.ConclusionsThe peach bud undergoes different levels of receptivity to gibberellin inhibition. The stage with maximum responsiveness corresponded to a transcriptional and hormonal crossroad, involving both flowering inhibitors and inductors. Endogenous gibberellin levels increased only at the latest developmental stage, when floral transition was already partially achieved, and the bud was less sensitive to exogenous treatments. A physiological model summarizes the main findings and suggests new research ideas to improve our knowledge about floral transition in peach.

Spring buds of European woody plants have old 14C age

Trees and shrubs maintain carbon reserves to support their functions during periods when metabolic demand exceeds carbon supply, such as during the dormant season. To gain a better understanding of carbon storage and utilisation dynamics of eight woody plant species in temperate Central Europe, bud scale and leaf samples were collected to determine the radiocarbon age of fresh sprouts in trees and shrubs, at three background sites avoiding local emissions that may influence affect the observed 14C/12C ratio. The accelerator mass spectrometry-based bomb-radiocarbon approach, to determine the age of the mobilized carbon in the plant bud samples from storage, was complemented by stable carbon isotope measurements. The bomb-radiocarbon dating technique was used to determine the age of the samples, while a northern hemispheric atmosphere 14CO2 dataset was used to calibrate the radiocarbon ages of the plant samples. The youngest observed calibrated radiocarbon age of the buds was over 4 years, and the oldest was even 9 years old. There was no significant difference between the ages of bud scales and embryonal leaf laminas. Our results show that there is a considerable amount of stored older carbon in the woody stems that can be used to produce buds in spring, which is a complex mixture of stored carbon of different ages, but there is no relationship between the radiocarbon age and the stable carbon isotope composition. The observed results show that not only the tree species, but shrubs also can store and use significantly older carbon pools, the carbon storage intensity is similar for trees with trunks and short-stemmed shrubs branching directly above the ground, i.e. carbon storage starts in young twigs and continues in ageing branches.

Transcriptome analysis of apical meristem enriched bud samples for size dependent flowering commitment in Crocus sativus reveal role of sugar and auxin signalling.

Cultivation of Crocus sativus (saffron) faces challenges due to inconsistent flowering patterns and variations in yield. Flowering takes place in a graded way with smaller corms unable to produce flowers. Enhancing the productivity requires a comprehensive understanding of the underlying genetic mechanisms that govern this size-based flowering initiation and commitment. Therefore, samples enriched with non-flowering and flowering apical buds from small (< 6g) and large (> 14g) corms were sequenced. Apical bud enriched samples from small and large corms were collected immediately after dormancy break in July. RNA sequencing was performed using Illumina Novaseq 6000 to access the gene expression profiles associated with size dependent flowering. De novo transcriptome assembly and analysis using flowering committed buds from large corms at post-dormancy and their comparison with vegetative shoot primordia from small corms pointed out the major role of starch and sucrose metabolism, Auxin and ABA hormonal regulation. Many genes with known dual responses in flowering development and circadian rhythm like Flowering locus T and Cryptochrome 1 along with a transcript showing homology with small auxin upregulated RNA (SAUR) exhibited induced expression in flowering buds. Thorough prediction of Crocus sativus non-coding RNA repertoire has been carried out for the first time. Enolase was found to be acting as a major hub with protein-protein interaction analysis using Arabidopsis counterparts. Transcripts belong to key pathways including phenylpropanoid biosynthesis, hormone signaling and carbon metabolism were found significantly modulated. KEGG assessment and protein-protein interaction analysis confirm the expression data. Findings unravel the genetic determinants driving the size dependent flowering in Crocus sativus.

Identification of Key Genes Associated with 1,2,6-Tri-O-galloyl-β-D-glucopyranose Accumulation in Camellia sinensis Based on Transcriptome Sequencing

Hydrolyzed tannin 1,2,6-tri-O-galloyl-β-D-glucopyranose (1,2,6-TGGP) possesses significant medicinal properties. However, little is known about its underlying molecular mechanisms. In this study, the levels of 1,2,6-TGGP in tea materials from different cultivars and leaf positions were compared. Additionally, one leaf and one bud sample from six tea cultivars with significant variations in 1,2,6-TGGP levels were analyzed using transcriptome high-throughput sequencing to identify the genes that are responsible for 1,2,6-TGGP accumulation. The sequencing results were mapped to the reference tea genome, revealing a total of 2735 differentially expressed genes (DEGs). This set included four UDP glycosyltransferase (UGTs) and six serine carboxypeptidases-like (SCPLs) genes. Among them, the upregulated SCPLs (CSS0032817) may directly participate in the acylation reaction of 1,2,6-TGGP. In addition, several classes of DEGs, including cytochrome P450, were significantly associated with the 1,2,6-TGGP content, which is potentially involved in their regulation. Overall, these results provide new insights into the molecular mechanism of 1,2,6-TGGP accumulation.

Comparative transcriptome analysis and genetic dissection of vegetative branching traits in foxtail millet (Setaria italica).

Two major genetic loci, qTN5.1 and qAB9.1, were identified and finely mapped to the 255Kb region with one potential candidate gene for tiller number and the 521Kb region with eight candidate genes for axillary branch number, respectively. Vegetative branching including tillering and axillary branching are vital traits affecting both the plant architecture and the biomass in cereal crops. However, the mechanism underlying the formation of vegetative branching in foxtail millet is largely unknown. Here, a foxtail millet cultivar and its bushy wild relative Setaria viridis accession were used to construct segregating populations to identify candidate genes regulating tiller number and axillary branch number. Transcriptome analysis using vegetative branching bud samples of parental accessions was performed, and key differentially expressed genes and pathways regulating vegetative branching were pointed out. Bulk segregant analysis on their F2:3 segregating population was carried out, and a major QTL for tiller number (qTN5.1) and two major QTLs for axillary branch number (qAB2.1 and qAB9.1) were detected. Fine-mapping strategy was further performed on F2:4 segregate population, and Seita.5G356600 encoding β-glucosidase 11 was identified as the promising candidate gene for qTN5.1, and eight genes, especially Seita.9G125300 and Seita.9G125400 annotated as B-S glucosidase 44, were finally identified as candidate genes for regulating axillary branching. Findings in this study will help to elucidate the genetic basis of the vegetative branching formation of foxtail millet and lay a foundation for breeding foxtail millet varieties with ideal vegetative branching numbers.

Phytochemical Profiles and Antimicrobial Activity of Selected Populus spp. Bud Extracts.

Buds of poplar trees (Populus species) are often covered with sticky, usually polyphenol-rich, exudates. Moreover, accessible data showed that some Populus bud extracts may be excellent antibacterial agents, especially against Gram-positive bacteria. Due to the fragmentary nature of the data found, we conducted a systematic screening study. The antimicrobial activity of two extract types (semi-polar-ethanolic and polar-ethanolic-water (50/50; V/V)) from 27 bud samples of different poplar taxons were compared. Antimicrobial assays were performed against Gram-positive (five strains) and Gram-negative (six strains) bacteria as well as fungi (three strains) and covered the determination of minimal inhibitory, bactericidal, and fungicidal concentrations. The composition of extracts was later investigated by ultra-high-performance liquid chromatography coupled with ultraviolet detection (UHPLC-DAD) and with electrospray-quadrupole-time-of-flight tandem mass spectrometry (UHPLC-ESI-qTOF-MS). As a result, most of the extracts exhibited good (MIC ≤ 62.5 µg/mL) or moderate (62.5 < MIC ≤ 500 µg/mL) activity against Gram-positives and Helicobacter pylori, as well as fungi. The most active were ethanolic extracts from P. trichocarpa, P. trichocarpa clone 'Robusta', and P. tacamahaca × P. trichocarpa. The strongest activity was observed for P. tacamahaca × P. trichocarpa. Antibacterial activity was supposedly connected with the abundant presence of flavonoids (pinobanksin, pinobanksin 3-acetate, chrysin, pinocembrin, galangin, isosakuranetin dihydrochalcone, pinocembrin dihydrochalcone, and 2',6'-dihydroxy-4'-methoxydihydrochalcone), hydroxycinnamic acids monoesters (p-methoxycinnamic acid cinnamyl ester, caffeic acid phenethylate and different isomers of prenyl esters), and some minor components (balsacones).

Quick and Concise Nonaqueous Capillary Electrophoresis Approach for Simultaneous Separation and Determining Five Phytohormones

A new, quick and concise nonaqueous capillary electrophoresis approach has been matured to separate phytohormones involving indobutyric acid, indoleacetic acid, abscisic acid, 1-naphthaleneacetic acid and gibberellin. Using a running buffer composed of 85% methyl cyanide, 0.8% 1.0 M caustic soda and 20.0 mM methanol ammonium acetate, satisfactory separation of five phytohormone standards was achieved within 4 mins. The lowest detection limit was obtained for 1-naphthaleneacetic-acid (0.06 and#181;g/ml) and the highest for gibberellin (1.71 and#181;g/ml). The approach has been utilized for wheat bud samples with spiked 5 phytohormones using a solid phase extraction procedure, acquiring recovery percentage ranging from 95 to 102%.

Contribution of ovule anatomy to the taxonomic context of Parodia Spegazzini (Cactaceae)

Abstract The taxonomic history of Parodia Speg. is marked by many incongruences regarding its circumscription. The main question remains regarding the union of five genera into Notocactus s.l. and, later, the union of Notocactus s.l. with Parodia s.s., leading to Parodia s.l. Given that the ovules are conserved structures and that their anatomical structure remains unexplored within the genus, we sought to identify whether the anatomical traits of these structures show potential taxonomic applicability and whether they provide information that allows the genus to be circumscribed. Samples of flower buds of 15 species and two taxa in synonymy were processed and stained using plant anatomy methods for light microscopy. The ovules of Parodia are campylotropous, bitegmic, and crassinucellate, with the micropyle delimited by the inner integument; in Parodia s.s. we observed the nucellus and embryo sac projection and changes to the micropyle type, characteristics that reflect the circumscriptions that distinguish this genus from others in the synonymy of Parodia s.l. The results may also be useful with regard to infrageneric issues, allowing the distinction of some morphologically similar taxa, adding to the discussion of their infrageneric positions. Thus, we highlight the importance of ovule anatomical traits within the taxonomic context of Parodia.

Solvent-Free Determination of Selected Polycyclic Aromatic Hydrocarbons in Plant Material Used for Food Supplements Preparation: Optimization of a Solid Phase Microextraction Method.

The exploitation of waste and by-products in various applications is becoming a cornerstone of the circular economy. A range of biomasses can be employed to produce food supplements. An example is a particular extract obtained from plant buds (rich in bioactive molecules), which can be easily retrieved from cities' pruning. In order to safely use this material, its possible contamination by organic pollutants needs to be estimated. A green and simple method to detect priority polycyclic aromatic hydrocarbons (PAHs) in bud samples by head space solid phase microextraction coupled to GC-MS was developed. This strategy, optimized through experimental design and response surface methodology, requires a minimal sample pre-treatment and negligible solvent consumption. The final method was found to be accurate and sensitive for PAHs with mass up to 228 Da. For these analytes, satisfactory figures of merit were achieved, with detection limits in the range 1-4 ng g-1, good inter-day precision (relative standard deviation in the range 4-11%), and satisfactory accuracy (88-105%), along with specificity guaranteed by the selected ion monitoring detection. The method was applied to bud samples coming from differently polluted areas, thus helping in estimating the safety of their use for the production of food supplements.

Morphological diversity of pollen grains within the flowering stages of Tecoma stans (L.) Juss. ex Kunth

The study of the morphology of pollen grains is essential to understand plant evolution, adaptation, diversity and discrimination of taxa. This study aims to determine the importance of choosing the perfect stage of flower development in the study of pollen morphological characters as a taxonomical tool. In this work a woody, perennial street tree Tecoma stans was chosen as a model species belonging to family Bignoniaceae. Tecoma stans has many polymorphic forms native to North America and flourished in hot climates. This tree is commonly planted in both Cairo and Alexandria streets. Samples of flower buds in nine different stages were gathered from five to six different trees from March to June 2023. Non-acetolysed pollen grains were investigated using both light and Scanning electron microscopes. The results showed that pollen density, size, shape beside colpi length as well as their state varied between the different developmental flowering stages and cannot be relied on taxonomical decisions, while exine ornamentation slightly differed between the pollen grains from stage two to nine, but it was faint in immature flower bud (stage one). This study confirms that we must be precise in choosing the correct flower stage in pollen morphological studies to obtain significant morphological description. The results obtained revealed that the aperture type is more stable than pollen shape and size.

From endodormancy to ecodormancy: the transcriptional landscape of apple floral buds.

This study endeavors to explore the transcriptomic profiles of two apple cultivars, namely, 'Honeycrisp' and 'Cripps Pink,' which represent late and early-blooming cultivars, respectively. Using RNA-sequencing technology, we analyzed floral bud samples collected at five distinct time intervals during both endodormancy and ecodormancy. To evaluate the transcriptomic profiles of the 30 sequenced samples, we conducted principal component analysis (PCA). PC1 explained 43% of the variance, separating endodormancy and ecodormancy periods, while PC2 explained 16% of the variance, separating the two cultivars. The number of differentially expressed genes (DEGs) increased with endodormancy progression and remained elevated during ecodormancy. The majority of DEGs were unique to a particular time point, with only a few overlapping among or between the time points. This highlights the temporal specificity of gene expression during the dormancy transition and emphasizes the importance of sampling at multiple time points to capture the complete transcriptomic dynamics of this intricate process. We identified a total of 4204 upregulated and 7817 downregulated DEGs in the comparison of endodormancy and ecodormancy, regardless of cultivar, and 2135 upregulated and 2413 downregulated DEGs in the comparison of 'Honeycrisp' versus 'Cripps Pink,' regardless of dormancy stage. Furthermore, we conducted a co-expression network analysis to gain insight into the coordinated gene expression profiles across different time points, dormancy stages, and cultivars. This analysis revealed the most significant module (ME 14), correlated with 1000 GDH and consisting of 1162 genes. The expression of the genes within this module was lower in 'Honeycrisp' than in 'Cripps Pink.' The top 20 DEGs identified in ME 14 were primarily related to jasmonic acid biosynthesis and signaling, lipid metabolism, oxidation-reduction, and transmembrane transport activity. This suggests a plausible role for these pathways in governing bud dormancy and flowering time in apple.

Rare earth elements in tea garden soils and their bioavailability to tea buds in Taiwan

Tea (Camellia sinensis) is a widespread beverage plant that prefers aluminum-enriched acidic soils. However, rare earth elements (REEs) might be highly phyto-available in these soils. With the increasing demands for REEs in high-technology industries, understanding the dynamics of REEs in the environment is essential. Thus, this study identified the total concentration of REEs in the root-zone soils and corresponding tea buds (n = 35) collected from tea gardens in Taiwan. Additionally, the labile REEs in the soils were extracted with 1 M KCl, 0.1 M HCl, and 0.05 M ethylenediaminetetraacetic acid (EDTA) to elucidate the fractionation tendency of REEs in the soil-plant system and the relationships between REEs and Al in the tea buds. The concentration of light REEs (LREEs) was higher than those of medium REEs (MREEs) and heavy REEs (HREEs) in all soil and tea bud samples. According to the upper continental crust (UCC) normalization, MREEs and HREEs were more abundant than LREEs in the tea buds. Furthermore, REEs remarkably increased with increasing Al in the tea buds, whereas the linear correlations between Al and MREEs and HREEs were stronger than between LREEs. Compared with LREEs, the extractabilities of MREEs and HREEs by all single extractants in the soils were higher, coinciding with their higher UCC-normalization-based enrichments in the tea buds. Moreover, the 0.1 M HCl- and 0.05 M EDTA-extractable REEs were affected by soil properties and significantly correlated with the total REEs in the tea buds. The concentration of REEs in the tea buds was successfully predicted by empirical equations of extractable REEs with 0.1 M HCl and 0.05 M EDTA, as well as general soil properties including pH, organic carbon, dithionite-citrate-bicarbonate-extractable iron, aluminum, and phosphorus. However, this prediction should be further verified using many soil and tea types in the future.

Dynamics of GFLV, GFkV, GLRaV-1, and GLRaV -3 grapevine viruses transport toward developing tissues

AbstractViral diseases in grapevine cause large economic losses due to decreased irregular yield and unbalanced ripening, and can even lead to plant mortality. There is a large number of grapevine viral agents, and a few of them have a prominent impact due to their worldwide distribution, virulence, and incidence. Although previous research has evaluated variations in viral load between organs and time since infection, there is still a lack of knowledge on how the viruses are transported toward developing tissues. In this work, we present the results of two experiments that contribute to understanding the spread dynamics of four major grapevine viruses (GFLV, GFkV, GLRaV-1, and GLRaV -3). Bud and leaf tissues were sampled from shoots obtained from cv. ‘Garnacha’ cuttings known to be infected with one of these viruses. Bud samples taken at early development stages were used to understand short-distance transport, while leaves taken from young shoots represented long-distance transport, driven mainly through the phloem. Our results show that all viruses were able to invade tissues from the beginning of development. The dissemination ability of GFLV was considerable, as the viral load detected in young organs was as high as in the dormant shoot. Furthermore, for GFLV and GFkV, it was shown that the viral load in young shoots does not follow the general assumption of older tissues accumulating a higher viral load but, conversely, a higher viral load closer to the shoot tip might be driven by the sink strength.

SnRNA-seq and mRNA hybridization indicate key bud events and LcFT1 and LcTFL1-2 mRNA transportability during floral transition in litchi.

In flowering plants, floral induction signals intersect at the shoot apex to modulate meristem determinacy and growth form. Herein, we reported a snRNA-seq analysis of litchi apical buds at different developmental stages. A total of 41,641 nuclei expressing 21,402 genes were analyzed, revealing 35 cell clusters corresponding to 12 broad populations. We signature genes associated with floral transition and propose a model that profile the key events associated with litchi floral meristem identity by analyzing 567 identified floral meristem cells at single cell resolution. Interestingly, snRNA-seq data indicated that all putative FT and TFL1 genes were not expressed in bud nuclei, but significant expressions of them were detected in bud samples using RT-PCR. Based on the expression patterns and gene silencing results, we highlight the critical role of LcTFL1-2 in inhibiting flowering and propose that LcFT1/LcTFL1-2 expression ratio may determine the success flower transition. And the transport of LcFT1 and LcTFL1-2 mRNA from the leaf to the shoot apical meristem was proposed based on in-situ and dot blot hybridization results. These findings allowed for a more comprehensive understanding of the molecular events that occur during the litchi floral transition, as well as the identification of new regulators.

Small RNA and Degradome Sequencing in Floral Bud Reveal Roles of miRNAs in Dormancy Release of Chimonanthus praecox.

Chimonanthus praecox (wintersweet) is highly valued ornamentally and economically. Floral bud dormancy is an important biological characteristic in the life cycle of wintersweet, and a certain period of chilling accumulation is necessary for breaking floral bud dormancy. Understanding the mechanism of floral bud dormancy release is essential for developing measures against the effects of global warming. miRNAs play important roles in low-temperature regulation of flower bud dormancy through mechanisms that are unclear. In this study, small RNA and degradome sequencing were performed for wintersweet floral buds in dormancy and break stages for the first time. Small RNA sequencing identified 862 known and 402 novel miRNAs; 23 differentially expressed miRNAs (10 known and 13 novel) were screened via comparative analysis of breaking and other dormant floral bud samples. Degradome sequencing identified 1707 target genes of 21 differentially expressed miRNAs. The annotations of the predicted target genes showed that these miRNAs were mainly involved in the regulation of phytohormone metabolism and signal transduction, epigenetic modification, transcription factors, amino acid metabolism, and stress response, etc., during the dormancy release of wintersweet floral buds. These data provide an important foundation for further research on the mechanism of floral bud dormancy in wintersweet.

Variability in P2X receptor composition in human taste nerves: implications for treatment of chronic cough.

Antagonists to the P2X purinergic receptors on airway sensory nerves relieve refractory or unexplained chronic cough (RCC/UCC) but can evoke unwanted dysgeusias because the gustatory nerves innervating taste buds express this same family of receptors. However, the subunit composition of the P2X receptors in these systems may differ, with implications for pharmacological intervention of RCC/UCC. In most species, the extrapulmonary airway nerves involved in cough predominantly express P2X3 subunits that form homotrimeric P2X3 receptors. In contrast, most sensory nerves innervating taste buds in mice express both P2X2 and P2X3 subunits, so the majority of receptors in that system are likely P2X2/P2X3 heteromers. Since neural P2X subunit composition can differ across species, we used immunohistochemistry to test whether taste nerves in humans and rhesus macaque monkeys express both P2X2 and P2X3 as in mice. In taste bud samples of fungiform papillae and larynx from humans and monkeys, all taste bud samples exhibited P2X3+ nerve fibres, but the majority lacked substantial P2X2+. Of the 35 human subjects, only four (one laryngeal and three fungiform) showed strong P2X2 immunoreactivity in taste nerves; none of the rhesus monkey samples showed immunoreactivity for P2X2. These findings suggest that for most humans, unlike mice, taste buds are innervated by nerve fibres predominantly expressing only P2X3 homomeric receptors and not P2X2/P2X3 heteromers. Thus, antagonists specific for P2X3 homomeric receptors might not be spared from affecting taste function in RCC/UCC patients.

Histological Studies in Vegetative and Reproductive Mango Buds

The present study was conducted on ten mango cultivars namely Alphonso, Bangalora, Kalepad, Himayuddin, Sendura, Mulgoa, Neelum, Rumani, Banganapalli and Swarnarekha and seasons are main and off-season at Kanyakumari and Tenkasi. The stem along with bud sample was collected during the month of October and November and conducted to examine the relation between internal structure of leafy and reproductive bud. During main season. Among ten mango cultivars, Bangalora and Swarnarekha have well developed at kanyakumar during main season for stage I, whereas Tenkasi, Alphonso and Bangalora well developed buds during the main season in stage I was observed. During off-season observed at kanyakumari Neelum and Alphonso had well developed for vegetative bud in stage I. At Tenkasi cultivars Kalapad and Bangalora had well developed for vegetative bud in stage I. The climatic factors prevailing at Kanyakumari during the main and off seasons for the months of August to September low temperature (190C to 210C) and high humidity (85 to 90%) and main season for the month of October to November, low temperature (210C to 230C) and humidity (80 to 85%). Whereas reproductive stage observed mango cultivars, Alphonso, Bangalora, Kalapad, Neelum and Swarnarekha had well developed reproductive buds in stage II &amp; III during main season at kanyakumari. During off-season, cultivars of Himampasand, Kalapad, Alphoso, Neelum and Swarnarekha had well developed reproductive bud for stag II &amp; III was favoured different stages of bud differentiation in the ten cultivars of mango.

In vitro embryo formation and plantlet regeneration from unpollinated ovaries of Lilium L

AbstractThe in vitro culture of unpollinated ovaries is one of the techniques used to induce gynogenesis. To explore the mechanism of lily gynogenesis and obtain haploids to shorten the breeding cycle, the in vitro effects of flower bud sampling time, exogenous plant growth regulators (PGRs), and different concentrations of picloram on embryo formation in unpollinated ovaries of Lilium L. ‘Sorbonne’ (oriental hybrids) were studied. The results indicated that flower buds ≥8 cm in length were most suitable. The PGRs picloram and 2,4‐dichlorophenoxyacetic acid (2,4‐D) with 6‐benzylaminopurine (6‐BA) or kinetin were useful in inducing ovule expansion in vitro. However, most ovules did not survive on the media containing 2,4‐D, whereas those grown on media containing picloram developed normally. In particular, a lower concentration of picloram (0.5 mg L−1) was found to be beneficial to the development of ovules into embryogenic shoots, whereas higher concentrations were more favorable to the development of shoots from the ovary wall. In total, 87 regenerated plants were obtained from unpollinated ovaries of Sorbonne. The chromosome ploidy of 20 of these was determined by counting root tip chromosomes, and eight of the regenerated plants were found to be haploids.

Application of hydroxylated multi-walled carbon nanotubes as depigmentation agent in the determination of multiple pesticide residues in Lonicerae japonicae flower buds

Lonicerae japonicae flower buds have been used as functional foods for many years, however, the problem of pesticide residues has attracted extensive attention in recent years. In this study, a sorbent package consisting of a combination of hydroxylated multi-walled carbon nanotubes (MWNTs-OH), primary secondary amine, and MgSO4 was developed for modified solid-phase extraction of 57 easily contaminated pesticides residues from Lonicerae japonicae flower bud samples. The pesticides were then detected by gas chromatography coupled to an electron impact ionization triple quadrupole mass spectrometer. Six multi-walled carbon nanotubes were compared for purification efficiency and recovery and found that the best results were achieved with MWNTs-OH (20–50 nm in diameter and 10–30 μm in length). Under optimized conditions, good linearities were obtained in the 1–100 ng·mL−1 range. The average recoveries at three spiked levels were in the 80.4–118.5% range, with relative standard deviations (RSDs) ≤ 20%. The quantification limits were 0.4–5.0 μg·kg−1. Compared with QuEChERS and traditional HLB purification methods, the application of MWNTs-OH could better remove the pigment from a complex sample matrix, as well retain the target analytes as much as possible. Advantages of this newly established method include less analytical time, less solvent consumption and good recovery.