Horticulture Environment and Biotechnology最新文献

The genus Dendrobium Sw. has great ornamental and medicinal values. However, species classification of this genus is very difficult because of their similar morphological characteristics. The complete chloroplast genome has been widely used as a useful molecular marker for resolving phylogenetic relationships in complicated or closely related species. Therefore, in this study, the complete chloroplast genome of Dendrobium sulcatum was sequenced, assembled and characterized, and compared with published samples of Dendrobium species to investigate its phylogenetic position. The complete chloroplast genome of D. sulcatum was 159,563 bp in length, with 130 genes, including 84 protein-coding genes, 38 tRNA genes, and 8 rRNA genes. The total GC content of the whole genome was 37.14%. Phylogenetic analyses indicated that D. sulcatum is closely related to D. jenkinsii, D. lindleyi, D. exile, D. spatella, D. parciflorum, and D. hainanense. Furthermore, the D. sulcatum chloroplast genome and the 33 published samples were proven to be highly similar in genome size, gene content, and organization. The complete chloroplast genomes of Dendrobium exhibited typical quadripartite structures with lengths from 149,186 bp to 159,563 bp. This study provides useful genetic data of Orchidaceae and enhances our understanding about their phylogenic relationship and evolution.

CL (continuous light)-sensitive lettuce cultivar were treated under high light (HL, 480 µmol·m^− 2·s^− 1, 20/4 h) and CL (400 µmol·m^− 2·s^− 1, 24/0 h) provided by red-blue LEDs (red-blue ratio 3:1) without or with R/B alternation (HL-A and CL-A, alternating duration ratio 3:1) at the same daily light integral. On the 16th day after light treatment, lettuce was diurnally sampled four times at equal 6 h intervals, thus the effects of HL-A and CL-A on growth, leafy injury, yield, and carbohydrate accumulation, oxidative stress and their circadian rhythms of lettuce were investigated and evaluated. The results showed that the lettuce plants under HL-A and CL-A had greater canopy size, leafy area and shoot fresh biomass than those under HL and CL correspondingly. However, the specific leaf weight, SPAD value of new leaves and leaf injury grade were decreased. The contents of starch and sucrose, and DPPH free radical scavenging rate were significantly increased under HL-A and CL-A compared with HL and CL, while the contents of hydrogen peroxide, superoxide anion and MDA were decreased. Compared with HL and HL-A, the above physiological indices of lettuce under CL and CL-A were higher respectively. HL-A and CL-A did not change the circadian rhythm of lettuce. In conclusion, HL-A and CL-A improved the yield and external quality of CL-sensitive lettuce. Importantly, they alleviated HL- and CL-induced physiological injuries of lettuces by reducing the accumulation of ROS only, rather than decreasing carbohydrate accumulation or circadian rhythm disorder.

Hibiscus syriacus L. (Rose of Sharon), is the national flower of Korea. H. syriacus has both ornamental and medicinal value, and many cultivars have been exploited for its development. Cytogenomic information is crucial for elucidating chromosomal composition, ploidy, and specific sequence distribution. In this study, chromosome constitution, genome size, and ploidy were analyzed in ten Hibiscus sp. cultivars with different breeding histories using triple-color fluorescence in situ hybridization (FISH) and flow cytometry. Prelabeled oligonucleotide probes (PLOPs) of three universal tandem repeats (5S rDNA, 45S rDNA, and telomeric DNA) were used for FISH. The chromosome length ranged from 1.20 to 4.84 μm, and the chromosome number varied from 2n = 84 to 2n = 172 with the basic chromosome number x = 21. Based on chromosome number, FISH signals, and genome size, three cultivars were identified as euploids of tetraploid and hexaploid euploids, and the remaining seven cultivars as aneuploids of tetraploid, hexaploid, and octoploid euploids. The number of 5S rDNA signals was two, three, and four for tetraploid, hexaploid, and octoploid, respectively. Whereas 45S rDNA signals varied from two to five pairs among the cultivars. Genome size (2C) ranged from 4.35 to 4.80 pg in tetraploids, 6.35 to 6.78 pg in hexaploids, and 8.20 to 8.94 pg in octoploids, which corresponded to the ploidy identification using FISH chromosome composition. FISH using PLOPs demonstrated that the nuclear DNA content increased proportionally with the ploidy level, indicating that the chromosome composition and genome size were consistent. The findings will be useful for future genomic research on Hibiscus species breeding and development strategies.

Salinity stress is one of the abiotic stressors that threatening medicinal plant yield with adverse effects on the biochemical and morphological parameters. One strategy to manage salt stress is to use plant nutritional modifiers to lessen its harmful effects. In this study, the positive role of coated Fe-nanoparticles with chitosan (coated Fe-NPs) has been investigated in modulating the negative effects of salinity stress on the growth and the biochemical responses of Ajowan (Trachyspermum ammi L.) plants. In the treated plants with coated Fe-NPs (5, 10, and 15 μM L⁻¹) significantly improved nutritional conditions (absorption of N, P, K, Fe, and Cu), growth parameters (e.g. shoot height, root length, shoot fresh weight, root fresh weight, and leaf number), and biochemical under control, low, moderate, and intense (0, 25, 50, and 75 mM NaCl, respectively) salinity stress conditions. Increased Fe in treated plants with coated Fe-NPs (especially 15 μM L⁻¹) decreased Na, increased N, P, K, Fe, and Cu, preserved their more photosynthetic pigments, and relative water content compared to other treated plants, and presented higher levels of key osmolytes, such as soluble sugars in the shoots and lower levels of soluble sugars in root and proline in root and shoot. Coated Fe-NPs may alleviate the adverse effects of salt stress on Ajowan growth by affecting plant biochemical properties, which is of economic and health significance.

The ethylene inhibitor 1-methylcyclopropene (1-MCP) is widely used in the apple industry as a post-harvest fumigation application to slow down the ripening process and maintain fruit quality during storage. With the development of a sprayable formulation (Harvista™, Agrofresh Inc, USA), it is becoming increasingly common in the apple industry to apply 1-MCP as a pre-harvest spray. This study investigated the impact of pre-harvest 1-MCP applied 1 week prior to harvest as a foliar application at 11.4 L ha⁻¹ in 1000 L water, on the quality and respiration rate of ‘Scilate’ apples grown in the Huon Valley, Southern Tasmania, Australia. Two trials were undertaken, trial 1 examined fruit quality, flesh browning (FB) and fruit softening in 1-MCP treated and untreated fruit while trial 2 compared the respiration rate of 1-MCP treated and untreated fruit. Despite no effect on fresh fruit quality attributes, pre-harvest spray application of 1-MCP influenced post-harvest fruit quality, storability, and respiration rate of apples. Fruit treated with 1-MCP showed higher malic acid concentration (1.2 g L⁻¹ vs 0.9 g L⁻¹) and lower juice pH (4.6 vs 4.9) even after 7.5 months of regular air cold-storage along with a six-fold reduction in fruit softening in comparison to untreated fruit (2% vs 13%). Pre-harvest treatment of 1-MCP reduced respiration rate by 32%, and incidence of CO₂ injury by over 40%. The incidence of radial type (senescent related) FB was reduced by 100%. A significant proportion of treated apples still suffered from severe CO₂ injury. This study has demonstrated that pre-harvest application of 1-MCP to ‘Scilate’ fruit can be useful in maintaining long-term fruit quality during storage, reducing respiration rate, and lowering the incidence of FB in general. However, the risk of severe CO₂ injury remains, especially with larger fruit harvested from trees with lighter crop loads.

Hydrangeas with large inflorescences are widely used as cut flowers and in floral arrangements. However, the genetic diversity of commercially grown hydrangeas has been limited owing to the breeding focus on popular species. Therefore, this study was conducted to suggest interspecific breeding strategies for expanding the genetic diversity in Hydrangea L. by evaluating genetic diversity in the seven main species collected in Korea and analyzing cross compatibility via intra- and interspecific hybridization. Interspecific diversity evaluation using simple sequence repeat markers resulted in the segregation of 35 varieties accounting for seven species into five groups as follows: (1) Hydrangea paniculate group, (2) Hydrangea arborescnes group, (3) Hydrangea anomala and Hydrangea aspera group, (4) Hydrangea quercifolia group, and (5) Hydrangea macrophylla and Hydrangea serrata group. Cross compatibility was confirmed via intra- and interspecific crossing, and hybrids were obtained in 18 crossing combinations. Intraspecific hybrids tend to be easy to obtain, but interspecific hybrids are difficult to obtain due to a variety of factors. While most of the interspecific hybrids were obtained using ovule culture, the crossing between H. macrophylla and H. serrata created hybrids from seed sowing, indicating that H. serrata is a subspecies of H. macrophylla. Bilateral and unilateral incompatibilities were observed across the obtained hybrids. Particularly, weak bilateral compatibility was observed between H. serrata and H.paniculata. Accordingly, it was proposed that hybrids between H. macrophylla and H. serrata can be successfully used as parental materials in crossing with H. paniculata to improve cold tolerance. In addition, cross compatibility was improved in interspecific crossing using H. macrophylla and H. arborescens as maternal plants. It is anticipated that these finding will help improve the genetic diversity in commercial hydrangeas.

Ozone (O₃) absorption through leaf stomata disrupts plant physiological processes, prompting various defense mechanisms to mitigate O₃-induced harm. This study measured parameters including cell structure, gas exchange, carbon assimilation, lipid peroxidation, and biogenic volatile organic compounds (BVOCs) emissions to evaluate the physiological impact of Prunus × yedoensis under elevated ozone (E-O₃) exposure. The seedlings exhibited a slight stimulatory effect during the early phases of E–O₃ exposure; however, E–O₃ beyond a specific threshold significantly and negatively affected photosynthetic parameters, pigment content, and potential antioxidant capacity, and E–O₃ was significantly correlated with the BVOCs emission rate. After three weeks of E–O₃ exposure, no significant differences were observed in leaf stomatal appearance in the field emission scanning electron microscopy results, but according to the results of leaf mesophyll cell ultrastructure, grana degradation, membrane decomposition, cell wall thickening, wart–like protrusion formation, and increased plastoglobulus density within the chloroplasts were observed. Chlorophyll content significantly decreased by 38.71%, and solute leakage increased by 20.57% in the E–O₃ group. The net photosynthetic rate was almost two times lower with E–O₃. In contrast, there were no significant differences in stomatal conductance. In conclusion, E–O₃ can induce a hormetic stimulatory effect during the early exposure phase. However, when the critical threshold is exceeded, O₃ adversely affects the physiology of P. × yedoensis seedlings. Therefore, E–O₃ is a harmful air pollutant that hinders the growth of woody plants, and urban trees require the continuous management of O₃ phytotoxicity.

Reynoutria sachalinensis is an herbaceous plant that has gained attention as a promising functional ingredient in bio-health. However, information on the propagation of this plant remains limited, and information on the germination and dormancy characteristics of R. sachalinensis seeds native to Korea is yet to be established. This study aimed to determine the optimal method for breaking dormancy by classifying the dormancy types in R. sachalinensis seeds collected from Ulleungdo. Initial observations revealed that R. sachalinensis seeds exhibited water permeability and fully developed embryos. However, further investigation into seed dormancy was warranted due to the low germination percentage of less than 20%. To address this dormancy, a cold stratification treatment lasting four weeks was employed, which confirmed the presence of physiological dormancy (PD) in R. sachalinensis seeds. Additionally, prolonged after-ripening, without any special treatment, led to the loss of dormancy. Both treatments demonstrated that the dormancy of R. sachalinensis seeds could be overcome by alternative methods for non-germinated seeds. Accordingly, scarification was used to treat seeds whose dormancy was broken by after-ripening, and all viable seeds germinated. Therefore, it is assumed that R. sachalinensis seeds have two types of PD—non-deep and intermediate, exhibiting polymorphism as an adaptive strategy to thrive in challenging environments. Through this study, the scope of industrial use can be expanded based on stable and uniform seedling production by establishing conditions that efficiently break dormancy in R. sachalinensisseeds that exhibit polymorphism.

Interspecific hybridization in the genus Rosa (Rosaceae) is a common natural phenomenon. Hybrids often exhibit heterosis and new combinations of traits, which can provide raw materials for horticultural breeding. DNA barcodes and microsatellites have been proposed to facilitate species discrimination and hybrid detection. However, most SSR markers developed for roses have been found unapplicable to Rosa sect. Synstylae because of null alleles or failed amplification. In this study, we designed 15 pairs of microsatellite primers, along with four previously developed primers specifically for Rosa sect. Synstylae; we then analyzed 174 individuals of three closely related and sympatrically distributed Rosa species as a test case to evaluate the consistency between morphological and genetic hybrid identifications and to compare the discrimination efficiency of the DNA barcodes versus SSRs in detecting admixture. Principle coordinate analysis identified several individuals with intermediate phenotypes among the three rose species. Hybridization, intraspecific morphological polymorphism, and sample collection at different growth stages or phenological phases may have hindered species identification based on morphology and distorted the morphological clustering results. The molecular analyses showed that 12 (6.8%), 13 (7.4%), and 15 (8.6%) individuals were identified as admixed by STRUCTURE, NewHybrids, and nrITS sequences, respectively, of which only seven hybrids showed signs of admixture across all three methods. About 81% of the morphologically identifiable hybrids exhibited admixture based on SSRs. Meanwhile, approximately 69% of morphologically identifiable hybrids were detected, but four morphologically pure species individuals were identified as genetically admixed based on nrITS sequences. Some morphologically pure species individuals were genetically identified as hybrids while some morphological hybrids were identified as pure individuals based on certain molecular markers. Overall, EST-SSRs discriminated morphological hybrids more accurately than nrITS. We inferred that there is ongoing interspecific gene exchange among the three wild Rosa species that obscures morphospecies boundaries. Combining multiple data types and analytical approaches offers powerful utility for hybrid detection, regardless of the level of hybridization.

Kimchi cabbage, a staple in South Korean cuisine, exhibits taste variations depending on the season of cultivation, with significant implications for kimchi production quality. In this study, we conducted comprehensive metabolomic analyses of kimchi cabbage grown in diverse environments throughout the year. We identified 15 primary metabolites, 10 glucosinolates, and 12 hydrolysates, providing valuable insights into the metabolic composition of kimchi cabbage. Using this data, we developed predictive models for taste and quality differentiation in kimchi cabbage based on the season of cultivation. Three regression models, including Orthogonal Partial Least Squares regression (OPLS), Partial Least Squares (PLS) regression, and Random Forest regression, were employed to predict seasonal variation. The models exhibited high accuracy, with R² values ranging from 0.77 to 0.95, indicating their potential for distinguishing seasonal differences. Notably, hydroxyglucobrassicin, 5-oxoproline, and inositol consistently emerged as significant metabolites across all models. Additionally, we developed regression models for predicting sweetness and bitterness in kimchi cabbage. Metabolites such as malic acid, fructose, and glucose were positively correlated with sweetness, while neoglucobrassicin and glucobrassicin were negatively correlated. Conversely, metabolites like glucoerucin and glucobrassicin were positively correlated with bitterness, while malic acid and sucrose were negatively correlated. These findings provide a valuable foundation for understanding the metabolic basis of taste variation in kimchi cabbage and offer practical applications for improving kimchi production quality. By incorporating more varieties and multi-year data, future research aims to develop even more accurate predictive models for kimchi cabbage taste and quality, ultimately contributing to the consistency of kimchi production.

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