Showing papers in "Horticulture Environment and Biotechnology in 2016"
TL;DR: In this paper, the effects of silver nanoparticles (AgNPs) and silver ions on potato (Solanum tuberosum L.) in terms of silver accumulation, production of reactive oxygen species (ROS), oxidative stress responses, and antioxidative defense systems were examined under in vitro conditions.
Abstract: Under in vitro conditions, we examined the effects of silver nanoparticles (AgNPs) and silver (Ag) ions on potato (Solanum tuberosum L.) in terms of silver accumulation, production of reactive oxygen species (ROS), oxidative stress responses, and antioxidative defense systems. At all concentrations (except at 2 mg•L-1), the amount of Ag in the shoots and roots of Ag ion-treated plantlets was significantly higher than in plantlets treated with AgNPs. In both treatments, total ROS and superoxide anions were increased at concentrations greater than 2 mg•L-1. Damage caused by oxidative stress, such as ion leakage and cell death, was significantly higher in plantlets treated with AgNPs than those treated with Ag ions. Significant increases in the activities of superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase (GR),were found in both AgNP-treated, and Ag ion-treated plantlets compared to the control. However, in AgNP-treated plantlets, GR activity was significantly decreased at 20 mg•L-1. A significant reduction in glutathione (GSH), ascorbate (ASA), and the ratios of GSH to oxidized glutathione (GSSG) and ASA to oxidized ascorbate (DHA)were observed in plantlets treated with both AgNPs and Ag ions at concentrations higher than 2 mg•L-1. Moreover, a greater decrease in GSH and ASA contents was seen in plantlets treated with AgNPs compared to those treated with Ag ions. The present study indicates that both AgNPs and Ag ion treatments impose oxidative stress on potato plantlets under in vitro conditions. Furthermore, based on plantlets’ responses to oxidative damage, the observed alteration in the activities of radical scavenging enzymes and the depletion of GSH and ASA, AgNPs seem to have higher toxicity than the equivalent mass of Ag ions.
84 citations
TL;DR: It is suggested that supplementing the existing visual light spectrum, such as red and blue light, with far-red LEDs improves lettuce growth and bioactive compound content in a closed-type plant production system.
Abstract: The aim of this study was to analyze the growth and bioactive compounds of lettuce in response to far-red LED light supplemented with a combination of red and blue LED light. Sixteen-day-old red leaf lettuce seedlings were transplanted to a growth chamber equipped with red, blue, and far-red LEDs. After setting the ratio of blue (B) to red (R) LEDs to 2:8, the ratio of R to far-red (FR) LEDs was adjusted to 0.7, 1.2, 4.1, or 8.6 (B+R/FR 0.7, 1.2, 4.1, or 8.6). Additionally, plants were irradiated with combined B and R LEDs (B+R) and fluorescent lamps (control) for 24 days. Growth characteristics including cell division rate, epidermal cell density and thickness, and antioxidant phenolic compounds were measured. Supplementation with FR LED light improved shoot and root growth compared to plants under B+R and control treatment. B+R/FR 1.2 treatment resulted in the highest shoot fresh weight and leaf area on day 24 of treatment. Obvious activation of the G2M phase was not observed in plants under far-red treatment, and most far-red treatments besides B+R/FR 4.1 increased the epidermal cell size. Plants treated with B+R/FR ratios of only 0.7 and 1.2 had significantly higher total phenolic levels, antioxidant activity, chlorogenic acid contents, and caffeic acid contents per plant than the control. These results suggest that supplementing the existing visual light spectrum, such as red and blue light, with far-red LEDs improves lettuce growth and bioactive compound content in a closed-type plant production system.
75 citations
TL;DR: While the addition of green light considerably reduced the leaf photosynthetic rate, it did not reduce plant growth and, in the absence of blue light, the plants showed symptoms of the shade avoidance response, which possibly enhanced their growth by improving their light interception.
Abstract: Current LED-based artificial lights for crop cultivation consist of red and blue lights because these spectra effectively promote leaf photosynthesis. However, the absence of green light could be disadvantageous for crop production, as green light plays an important role in plant development. The objective of this study was to investigate whether adding green light to different proportions of red and blue light would affect the leaf photosynthetic rate, growth, and morphology of lettuce plants. Plants were transplanted and grown hydroponically for 25 days under different combinations of red, blue (0, 10, 20, and 30%), and green (0 and 10%) light at 150 ± 15 μmol•m-2•s-1 of photosynthetic photon flux density (PPFD). The leaf photosynthetic rate was highest under 80% red and 20% blue light and decreased significantly with the addition of green light and the absence of blue light. As the fraction of blue light increased, leaf size and plant growth decreased significantly. However, while the addition of green light considerably reduced the leaf photosynthetic rate, it did not reduce plant growth. In the absence of blue light, the plants showed symptoms of the shade avoidance response, which possibly enhanced their growth by improving their light interception. Therefore, the addition of 10% (15 μmol•m-2•s-1) green light did not have a positive effect on the growth of lettuce. Further study using higher intensities of green light is required to investigate the effects of green light on plant growth.
60 citations
TL;DR: In this paper, the effects of exogenous glycine betaine (GB) applications on antioxidant enzyme activity, dry matter, and the contents of organic acids, amino acids, total antioxidants, and total phenolics in lettuce, Lactuca sativa, under salt stress were investigated.
Abstract: We investigated the effects of exogenous glycine betaine (GB) applications on antioxidant enzyme activity, dry matter, and the contents of organic acids, amino acids, total antioxidants, and total phenolics in lettuce, Lactuca sativa, under salt stress. The treatments included four concentrations of GB (0, 5, 10, and 25 mM) and two levels of salinity (0 and 100 mM of NaCl). The 25 mM GB treatment increased dry matter and the content of total phenolics in lettuce plants compared to the non-GB-treated plants under salt stress. Salinity (100 mM NaCl without GB) significantly reduced dry matter, total phenolic content, and total antioxidant content in the plants. However, the lettuce plants grown under salt stress generally had higher amino acid and organic acid contents than those grown under non-salinity conditions. GB treatments had different effect on amino acid and organic acid contents under salinity conditions. Superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX) activities were elevated under the 100 mM NaCl and 0 mM GB treatments, whereas higher concentrations of GB decreased them under salt stress. The 25 mM GB treatment mitigated the negative effect of salt stress and increased the dry matter by 44% compared to the plants that were treated with 100 mM NaCl and 0 mM GB. The results suggested that exogenous GB treatments could ameliorate the tolerance of lettuce to salt stress by increasing the total antioxidants and total phenolics, and regulating antioxidant enzyme activity, and altering the contents of organic acids and amino acids.
52 citations
TL;DR: The results indicated that the decrease in photosynthesis was not attributable mainly to damage to PSII, but rather to chilling-induced photoinhibition of PSI, which should be helpful for future selection of plants with low chilling sensitivity.
Abstract: The objective of this study was to examine several cultivars of Ocimum basilicum L. (green, red, cinnamon, lettuce leaf, lemon, and Thai basils) for photosynthetic performance, chlorophyll a fluorescence, and chlorophyll content under chilling stress conditions of 6°C in comparison to non-stressed controls (18°C). The basil plants were grown in a peat substrate for 8 weeks and then exposed to chilling for 8 or 16 days, under a 300 μmol•m-2•s-1 photosynthetic photon flux. After chilling, significant reductions in both the transpiration (E) and net photosynthetic (P
N) rates were observed in basil plants, while the intercellular CO2 concentration (C
i) was higher in the plants treated with 6°C in comparison to the controls. The decrease in P
N and E was associated with decreased water use efficiency (WUE) and stomatal conductance (g
s). The greatest impairment of photosynthesis for Thai basil leaves was observed after 8 days of chilling, and for green basil after the 16-day low temperature treatment. The photosystem II (PSII) activity (Fv/Fm) and variable-to-initial chlorophyll fluorescence (Fv/F0) were decreased after chilling. PSII activity was most affected in lettuce leaf basil after 8 days, and in Thai and red basil plants after the prolonged temperature treatment. Low temperatures did not significantly alter the chlorophyll concentration but did increase the Chl a/b ratio in leaves of basil. The results indicated that the decrease in photosynthesis was not attributable mainly to damage to PSII, but rather to chilling-induced photoinhibition of PSI. The knowledge gained in this study on the genotypic variation in basil response should be helpful for future selection of plants with low chilling sensitivity.
42 citations
TL;DR: In this article, the effects of supplementary white LEDs and pulsed LEDs on red leaf lettuce (Lactuca sativa L. ‘Sunmang’) were investigated and the results indicated that the fraction of red, blue, and green wavelengths of LEDs is an important factor for plant growth and the biosynthesis of bioactive compounds in lettuce.
Abstract: Light-emitting diodes (LEDs) are currently undergoing rapid development as plant growth light sources in a plant factory with artificial lighting (PFAL). However, little is known about the effects of supplementary light and pulsed LEDs on plant growth, bioactive compound productions, and energy efficiency in lettuce. In this study, we aimed to determine the effects of supplementary white LEDs (study I) and pulsed LEDs (study II) on red leaf lettuce (Lactuca sativa L. ‘Sunmang’). In study I, six LED sources were used to determine the effects of supplementary white LEDs (RGB 7:1:1, 7:1:2, RWB 7:1:2, 7:2:1, 8:1:1, 8:2:0 [based on chip number] on lettuce). Fluorescent lamps were used as the control. In study II, pulsed RWB 7:2:1 LED treatments (30, 10, 1 kHz with a 50 or 75% duty ratio) were applied to lettuce. In study I, the application of red and blue fractions improved plant growth characteristics and the accumulation of antioxidant phenolic compounds, respectively. In addition, the application of green light increased plant growth, including the fresh and dry weights of shoots and roots, as well as leaf area. However, the substitution of green LEDs with white LEDs induced approximately 3.4-times higher light and energy use efficiency. In study II, the growth characteristics and photosynthesis of lettuce were affected by various combinations of duty ratio and frequency. In particular, biomass under a 1 kHz 75% duty ratio of pulsed LEDs was not significantly different from that of the control (continuous LEDs). Moreover, no significant difference in leaf photosynthetic rate was observed between any pulsed LED treatment utilizing a 75% duty ratio versus continuous LEDs. However, some pulsed LED treatments may potentially improve light and energy use efficiency compared to continuous LEDs. These results suggest that the fraction of red, blue, and green wavelengths of LEDs is an important factor for plant growth and the biosynthesis of bioactive compounds in lettuce and that supplementary white LEDs (based on a combination of red and blue LEDs) might be more suitable as a commercial lighting source than green LEDs. In addition, the use of suitable pulses of LEDs might save energy while inducing plant growth similar to that under continuous LEDs. Our findings provide important basic information for designing optimal light sources for use in a PFAL.
31 citations
TL;DR: In this article, the effects of an ethylene absorbent and the ethylene inhibitor 1-methylcyclopropene (1-MCP) on tomato (Solanum lycopersicum mill. cv. Dotaerang) during storage were compared.
Abstract: We compared the effects of an ethylene absorbent and the ethylene inhibitor 1-methylcyclopropene (1-MCP) on tomato (Solanum lycopersicum Mill. cv. Dotaerang) during storage. Tomato fruits at the ‘breaker’ stage were harvested and treated with an ethylene absorbent, 1 μL·L-1 1-MCP or 2 μL·L-1 1-MCP and stored at 20°C for 15 days. We then measured weight loss, peel color, firmness, soluble solids content (SSC), titratable acidity, pH, ethylene production and total phenolic and flavonoid contents in the fruits. Color development occurred more rapidly in the control than in fruits treated with the ethylene absorbent or 1-MCP (1 μL·L-1 and 2 μL·L-1 ) on day 6 and 9. The Hunter a value (redness) of 1-MCP (2 μL·L-1 )-treated fruit on day 6 was 2.24 ± 3.8, while that of the control was 13.39 ± 2.23, indicating that color development was delayed by 1-MCP treatment (2 μL·L-1 was more effective than 1 μL·L-1 ). Ethylene absorbent treatment was not more effective at maintaining fruit firmness than 1-MCP (2 μL·L-1 ) treatment. There was no statistically significant difference in fruit firmness between the ethylene absorbent treatment group and the control. Total phenolic and total flavonoid contents increased in all treatment groups during storage. These contents did not significantly differ among groups on day 15. These results suggest that 1-MCP treatment is highly effective in delaying tomato ripening during storage and that 2 μL·L-1 1-MCP treatment is more effective than 1 μL·L-1 treatment. However, the ethylene inhibitor did not influence the levels of antioxidant compounds compared with the control.
29 citations
TL;DR: In this article, the authors investigated whether grafting can influence and reduce arsenic translocation in the root and/or aerial organs, and how tomato plants irrigated with arsenic-enriched nutrient solution (100 μg·L-1) accumulate this metalloid, and if arsenic poses a potential risk to fruit quality.
Abstract: Arsenic is a toxic and cancerogenic metalloid that poses a threat to food crop consumption. Previous studies have shown that grafting vegetables onto certain rootstocks may restrict the uptake of some toxic metals, such as cadmium, lead, and so on, but these studies did not investigate the uptake of arsenic. The aim of this work was to determine the following: i) if grafting can influence and reduce arsenic translocation in the root and/or aerial organs; ii) how tomato plants irrigated with arsenic-enriched nutrient solution (100 μg·L-1) accumulate this metalloid; and iii) if arsenic poses a potential risk to fruit quality. We found that differences in plant growth and the qualitative traits of fruits were mainly related to the adopted rootstock rather than to the addition of arsenic. Grafting influenced metalloid accumulation in roots and its translocation from roots to shoots and fruits. Tomato plants accumulated arsenic in their roots, and only a small portion was translocated to shoots and fruits, making the risk for human consumption negligible. Therefore, the uptake of this toxic element and its translocation are influenced by the rootstock utilized.
28 citations
TL;DR: In this article, the authors monitored accumulation in terms of different types of anthocyanidin, in association with fruit skin coloration, in ‘Bluecrop’ high-bush blueberry (Vaccinium corymbosum L.) at three stages of ripening: pale green, ca. 30 days after full bloom (DAFB); reddish purple, ca 40 DAFB; and dark purple, c. 50 DOFB.
Abstract: We monitored accumulation in terms of different types of anthocyanidin, in association with fruit skin coloration, in ‘Bluecrop’ highbush blueberry (Vaccinium corymbosum L.) at three stages of ripening: pale green, ca. 30 days after full bloom (DAFB); reddish purple, ca. 40 DAFB; and dark purple, ca. 50 DAFB. Total anthocyanin contents increased during ripening, while fruit skin color steadily became darker and bluer, as reflected in decreasing L* (a color space coordinate describing lightness) and b* (describing blue-yellow coloration). Of the six anthocyanidins commonly found in fruits, pelargonidin was absent throughout the ripening process. Cyanidin was first detected at the pale green stage. Peonidin, delphinidin, petunidin, and malvidin were first detected after fruits had passed through the reddish purple stage. The contents of delphinidin and malvidin increased more rapidly than those of other anthocyanidins, and were closely correlated with changes in fruit skin color, demonstrating that the types and quantities of anthocyanidins, which in turn form anthocyanins, were major determinants of fruit skin coloration. Four anthocyanins were detected at the reddish purple stage, and 22 were identified at the dark purple stage. All anthocyanins detected were glycosylated with glucose, galactose, or arabinose.
28 citations
TL;DR: The quantitative trait loci (QTL) for resistance to CMVP1 using a single-seed-descent F3 segregating population derived from a cross between a resistant line, ‘A1’, and a susceptible line,’ and a SNP map consisting of 906 SNP markers was constructed showed 12 linkage groups with a total linkage distance of 1,272.9 cM.
Abstract: Cucumber mosaic virus (CMV), a member of the Cucumovirus genus in the family Bromoviridae, is a frequently occurring virus in pepper worldwide. A broad host range, which includes many weed species and a large number of insects, means it is difficult to control CMV in the field. CMV resistance has been reported in Capsicum spp. In Korea, the C. annuum ‘Bukang’ cultivar is resistant to the CMVFNY and CMVKorean strains; however, a new strain (CMVP1) is able to infect the resistant cultivars. Therefore, it is necessary to pursue CMVP1 resistance in pepper breeding. In this study, we surveyed the quantitative trait loci (QTL) for resistance to CMVP1 using a single-seed-descent (SSD) F3 segregating population derived from a cross between a resistant line, ‘A1’, and a susceptible line, ‘2602.’ A total of 174 plants were evaluated for resistance to CMVP1 at 30 days after mechanical inoculation, with phenotypes confirmed by reverse transcription PCR. The number of resistant and susceptible plants was 88 and 86, respectively. Of these, 96 individuals including 48 resistant lines and 48 susceptible lines were used for a genotyping-by-sequencing (GBS) analysis. Approximately 19,000 single-nucleotide polymorphism (SNP) genotypes were obtained. Using the SNP data, a pepper genetic linkage map consisting of 906 SNP markers was constructed. The map showed 12 linkage groups with a total linkage distance of 1,272.9 cM. QTL analysis using a composite interval mapping (CIM) method revealed that two QTLs, cmvP1-5.1 and cmvP1-10.1, located on chromosomes 5 and 10, respectively, had R
2 (coefficient of determination) values of 17.81% and 22.78%. This information will be helpful for developing SNP markers linked to CMVP1-resistant QTLs and for developing new CMVP1-resistant pepper cultivars.
28 citations
TL;DR: The chloroplast genome sequence was obtained by next-generation sequencing technology and compared with those of four other Solanaceae species to develop specific markers for S. nigrum, which can be used to select somatic fusion products and accelerate breeding using S.nigrum.
Abstract: Solanum nigrum is a wild non-tuber-bearing species that serves as an excellent resource in potato breeding due to its resistance potential against biotic and abiotic stresses. However, sexual hybrids between S. nigrum and S. tuberosum are difficult to produce because these species are highly incompatible. Therefore, somatic hybridization is used to introduce various traits from this wild species into potato. After somatic hybridization, it is essential to select fusion products often the aid of molecular markers. In this study, we obtained the chloroplast genome sequence of S. nigrum by next-generation sequencing technology and compared it with those of four other Solanaceae species to develop specific markers for S. nigrum. The chloroplast genome has a total sequence length of 155,432 bp. Its size, gene content, order and orientation are similar to those of the four other Solanaceae species, but there are some structural variations at repeat and junction areas. Phylogenic analysis revealed that S. nigrum is located in the same clade as Nicotiana tabacum and S. tuberosum is the least closely related species. After detailed comparisons of the chloroplast genome sequences of the five Solanaceae species, we identified 76 InDels (Insertion/Deletions), including 47 insertions and 29 deletions in the intergenic and intragenic regions. Based on these InDels, we developed seven markers for discriminating S. nigrum from other Solanum species. The results obtained in this study can be used to select somatic fusion products and accelerate breeding using S. nigrum.
TL;DR: In this article, the authors investigated the impact of hot salicylic acid treatment on the browning and nutritional quality of fresh-cut pomegranate arils during 12 days of storage at 4°C.
Abstract: In this study, we investigated the impact of hot salicylic acid treatment on the browning and nutritional quality of fresh-cut pomegranate arils during 12 days of storage at 4°C. Aril browning was concurrent with malondialdehyde (MDA) and H2O2 accumulation. Due to reduced polyphenol oxidase (PPO) activity in conjunction with higher phenylalanine ammonia-lyase (PAL) activity, pomegranate arils treated with hot salicylic acid exhibited higher total phenolic and anthocyanin contents during storage at 4°C for 12 days, leading to arils with higher DPPH radical scavenging capacity. Pomegranate arils treated with hot salicylic acid also exhibited lower H2O2 accumulation, which was caused by higher activity of the antioxidant enzymes catalase (CAT), ascorbate peroxidase (APX), superoxide dismutase (SOD), and glutathione reductase (GR) during the storage period. The higher ascorbic acid content in pomegranate arils treated with hot salicylic acid can be attributed to higher APX/GR system activity. Thus, hot salicylic acid treatment not only enhances the health-promoting attributes of arils due to increased antioxidant molecule accumulation, but it also delays aril browning by increasing ROS scavenging enzyme activity, which helps maintain membrane integrity, as revealed by reduced MDA accumulation.
TL;DR: In this article, the effects of foliar spraying with boron and calcium on the qualities of light red maturity-stage ‘Unicorn’ cherry tomato were investigated and the results indicated that B + Ca treatment increases cell-wall compactness, reduces the respiration rate, reduces fresh weight loss, increases shelf life, maintains flesh firmness, and increases vitamin C content in cherry tomato.
Abstract: This study was conducted to investigate the effects of foliar spraying with boron and calcium on the qualities of light red maturity-stage ‘Unicorn’ cherry tomato. Increased cell -wall compactness was observed after boron (B) + calcium (Ca) treatment. The respiration rate was lowest in B + Ca-treated tomato fruits at harvest time and after storage. Firmness increased and was retained during the storage period in B + Ca treated tomato fruits. The least fresh weight loss and best shelf life were observed in B + Ca-treated tomato fruits. The vitamin C content was higher in B + Ca-treated tomato fruits than in the control. These results indicate that B + Ca treatment increases cell -wall compactness, reduces the respiration rate, reduces fresh weight loss, increases shelf life, maintains flesh firmness, and increases vitamin C content in cherry tomato.
TL;DR: The findings show that the KASP assay is suitable for high-throughput screening of large populations in tomato breeding, and convenient markers for the Mi-1 gene locus using Kompetitive Allele-Specific PCR (KASP) genotyping chemistry are described.
Abstract: Tomato (Solanum lycopersicum) is an economically important vegetable worldwide. Root-knot nematodes have a wide host range and cause serious problems in areas where tomatoes are grown. Developing tomato varieties that are resistant to root-knot nematodes is an effective crop management strategy. The Mi-1 gene in tomato confers effective resistance against three common root-knot nematodes, i.e., Meloidogyne incognita, M. javanica, and M. arenaria. Nematode screening assays are commonly used in resistance breeding programs; however, they are time-consuming, laborious, and expensive. Molecular markers within, or linked to, the Mi-1 gene have enabled rapid screening of resistance alleles, without requiring nematode inoculation. Here we describe convenient markers for the Mi-1 gene locus using Kompetitive Allele-Specific PCR (KASP) genotyping chemistry. Sequences of SNP markers for resistance to root-knot nematodes on chromosome 6 were converted for usage in a KASP genotyping assay and tested. Our findings show that the KASP assay is suitable for high-throughput screening of large populations in tomato breeding.
TL;DR: A rapid and practical marker development strategy that can be used not only for rind traits but also for other agriculturally important traits in watermelon and applied for conventional breeding is suggested.
Abstract: A three-locus model for rind phenotypes in watermelon (Citrullus lanatus) was previously proposed based on genetic analysis. These three loci, S (foreground stripe pattern), D (depth of rind color), and Dgo (background rind color), segregate in a Mendelian manner. Whole genome sequencing of watermelon offers a new strategy for marker development in these rind phenotype-related loci. A genotype analysis using subsets of 188, 273, 287 and 113 probes was performed for the ‘0901’, ‘10909’, ‘109905’ and ‘90509’ rind trait-segregating F2 populations, respectively. A total of 26, 34, 30 and 15 linkage groups with 175, 254, 269 and 79 probes were constructed for the ‘0901’, ‘10909’, ‘109905’ and ‘90509’ populations, respectively. The genetic order of the probes was mostly collinear with the physical order on the reference genome, except for some probes on chromosomes 1, 3 and 11. The three rind-related loci, S, D, and Dgo were anchored near chr6_25767 on chromosome 6, chr8_26061 on chromosome 8 and chr4_150/chr4_249 on chromosome 4, respectively. The three loci are located on different chromosomes, and the three-locus model was therefore verified through molecular genetic analysis. We suggest a rapid and practical marker development strategy that can be used not only for rind traits but also for other agriculturally important traits in watermelon and applied for conventional breeding.
TL;DR: The results of this study suggest that multiple shoots of rugosa roses can be used in commercial-scale bioreactors to produce useful bioactive compounds for the pharmaceutical and cosmetic industries.
Abstract: Rosa rugosa Thunb. is a popular ornamental and medicinal plant native to eastern Asia. In this study, a successful bioreactor culture system was established for the production of secondary metabolites of rugosa roses. We tested different concentrations and combinations of plant hormones in growth media for maximum shoot proliferation and production of bioactive compounds, different bioreactor systems for maximum biomass production and production of bioactive compounds, and different ratios of nitrogen sources for maximum shoot growth and accumulation of bioactive compounds. For multiple shoot proliferation, Murashige and Skoog (MS) medium was used, supplemented with different concentrations and combinations of plant hormones: 6-benzylaminopurine (BA; 0-13.2 µM), thidiazuron (TDZ; 0-13.5 µM), and indole butyric acid (IBA) at 2.5 µM, used alone or in a combination of IBA with BA or TDZ. Rapid micropropagation of multiple shoots of rugosa roses was successfully achieved using shoot tips explanted in semisolid MS medium supplemented with 4.4 µM BA. The average number of shoots grown was 15.6 per explant and the maximum shoot length was 2.7 cm at 8 weeks of culture. To investigate the effect of nitrogen sources on shoot growth and bioactive compound accumulation, shoots were treated with different ratios of nitrogen sources (NH4
+:NO3
-) for 1 week after 7 weeks of shoot culture. Next, to scale up biomass production for the generation of useful phytochemicals, multiple-shoot cultures were developed in large-scale bioreactors. Four bioreactor systems were used: continuous immersion bioreactor (CIB), continuous immersion bioreactor with net (CIB-N), temporary immersion bioreactor (TIB), and temporary immersion bioreactor with net (TIB-N). Solid and liquid media were used as controls. Of the different bioreactor types, the CIB system produced the highest biomass, followed by the TIB system. Multiple shoots grown in the CIB system resulted in the accumulation of 39.21 mg·g-1 dry weight (DW) of total phenolics and 13.28 mg·g-1 DW of total flavonoids. The productivity of total phenolics and flavonoids was highest in the shoots harvested from the CIB system. The results of this study suggest that multiple shoots of rugosa roses can be used in commercial-scale bioreactors to produce useful bioactive compounds for the pharmaceutical and cosmetic industries.
TL;DR: The factors constraining rooting are addressed, alternative methods to promote in vitro rooting are described, and a summary of in vitro Rooting studies performed across a large number of leguminous species are provided.
Abstract: Leguminous plants include many of the most important food crops and are also cultivated for forage, used as a rich fiber source, and are important in the manufacture of pharmaceutical compounds. Their ability to biologically fix atmospheric nitrogen enhances soil fertility. Beyond conventional propagation methods, modern in vitro technology offers new means for propagating these plants. Significant progress has been achieved in somatic embryogenesis and embryo rescue, despite legumes’ notorious recalcitrance to transformation and regeneration of legumes. The establishment of stable and reproducible regeneration protocols has resulted in commercially successful propagation of some legume species. Still, regeneration protocols for many other legumes have not been successful, primarily due to poor in vitro rooting during regeneration. This review addresses the factors constraining rooting, describes alternative methods to promote in vitro rooting, and provides a summary of in vitro rooting studies performed across a large number of leguminous species.
TL;DR: This study investigated and compared the biological effectiveness and mutagenesis efficiency of gamma-rays and a carbon beam (a heavy ion beam) in a chili pepper landrace of Korea and identified individuals in each population with various developmental mutations through phenotypic analysis.
Abstract: Mutagenesis using ionizing radiation has been widely used for the development of genetic and breeding resources with novel characteristics. Although mutation breeding using X- and gamma-rays has been attempted in peppers, information on the effectiveness of other ionizing radiation and a comparative analysis of mutagenic effects of different forms of radiation is limited. Therefore, we investigated and compared the biological effectiveness and mutagenesis efficiency of gamma-rays and a carbon beam (a heavy ion beam) in a chili pepper landrace of Korea, ‘Yuwol-cho’. The survival and shoot growth rate obtained by irradiation at serial doses showed that the LD50 was about 140 and 35 Gy, and the RD50 was about 80 and 32 Gy for gamma rays and carbon beams, respectively. The optimal doses for mutation breeding for these forms of radiation were estimated to be 80-100 and 15-20 Gy for gamma rays and carbon beams, respectively. We also developed M2 populations consisting of 1,836 lines by gamma-ray irradiation (100 Gy) and 154 lines by carbon beam irradiation (20 Gy). The frequency of dwarf or male sterile individuals showed that the mutagenic effect of the carbon beam was higher than that of gamma-rays. We identified individuals in each population with various developmental mutations through phenotypic analysis and categorized the mutations into four groups (mutations in plant architecture and development, leaf, flower, or fruits). This study provides basic information for mutation breeding using ionizing radiation and useful materials for the identification of genes related to the diverse characteristics in chili pepper.
TL;DR: In this paper, the authors used 50 μg·mL-1 nisin combination with 1% (w/v) citric acid (N+C) to wash fresh-cut onions and the phenolic compounds, antioxidant capacity, microbial load, slice color were evaluated during the storage period.
Abstract: Nisin and citric acid are generally recognized as safe (GRAS) for using as a food ingredient and often used to control the microbial contamination of fresh-cut fruits and vegetables. However, their effects on phenolics and antioxidants remain unclear. Here we used 50 μg·mL-1 nisin combination with 1% (w/v) citric acid (N+C) to wash fresh-cut onions and the phenolic compounds, antioxidant capacity, microbial load, slice color were evaluated during the storage period. N+C treatment decreased the total polyphenols (TP) and quercetin contents (p < 0.05), as compared to the control at day 0, but did not affect phenolic acids and antioxidant capacity (ABTS, DPPH, and FRAP assays). During storage, antioxidant capacity, TP, and flavonoid contents increased. Storage had mixed effects on the phenolic acids (caffeic acid, vanillic acid, and ferulic acid increased, chlorogenic acid remained fairly stable). N+C treatment reduced the microbial counts and total viable counts (TVC) of fresh-cut onions below the detection limit until 5 days of storage. After 15 days storage, TVC of N+C treated samples remained significantly (p < 0.05) lower than controls. In addition, N+C treatment led to better color retention during storage. Therefore, N+C might be used as a safe preservative for fresh-cut onions.
TL;DR: In this paper, the effect of two potassium levels (4.5 and 9.0 mM) on salt tolerance was quantified using a solution culture experiment using salt-tolerant (Nagina) and salt-sensitive (Peto-86) Solanum lycopersicum (tomato) cultivars grown under NaCl stress.
Abstract: To quantify the effect of two potassium levels (4.5 and 9.0 mM) on salt tolerance, we conducted a solution culture experiment using salt-tolerant (Nagina) and salt-sensitive (Peto-86) Solanum lycopersicum (tomato) cultivars grown under NaCl stress (0, 75, and 150 mM). Potassium is known to minimize oxidative stress and enhance photosynthesis in salt-stressed plants. A 30-day treatment with potassium, differentially increased stomatal conductance and transpiration, decreased oxidative stress, lowered the activities of antioxidant enzymes (i.e., superoxide dismutase, catalase, and glutathione reductase), increased leaf K+ levels and the K+/Na+ ratio, and improved the membrane stability index in the salt-tolerant and salt-sensitive tomato cultivars exposed to salt stress. The salt-sensitive cultivar had significantly higher malondialdehyde (MDA) concentrations and lower antioxidant enzyme activity than the salt-tolerant cultivar. These results indicate that potassium can be used to alleviate salt-induced oxidative stress and photosynthetic limitations in tomato plants and ultimately improve survival under salt stress.
TL;DR: The genotypes selected on the basis of their phytochemical content could be used to develop new tomato cultivars with high antioxidant contents and activities.
Abstract: Genotypic diversity of antioxidants is important for the development of tomato cultivars with high antioxidant contents. The contents and antioxidant activities of major antioxidant phytochemicals (carotenoids, ascorbic acid, total phenolics, and flavonoids) of 119 cherry and non-cherry tomato genotypes (16 commercial cultivars and 103 germplasm lines) were analyzed. Antioxidant activity was evaluated using FRAP, ABTS, and DPPH assays. Significant genotypic differences were observed in the content and antioxidant activity of all of the studied antioxidant phytochemicals. Relatively higher genotypic variation was found in carotenoid, ascorbic acid, and flavonoid content than in total phenolic content and antioxidant activities. Most variation in total carotenoid content of tomato fruits was caused by lycopene, followed by s-carotene and lutein. One cherry tomato line, TG-110, and 3 non-cherry tomato germplasm lines, IT237605, IT237703, and IT237706, had much higher lycopene contents (> 1930 mg·kg -1), and thus higher total carotenoid contents, than did the other lines. The highest ascorbic acid and total flavonoid contents were found in TG-106 (388 mg·kg -1) and TC-053 (2353.0 mg·kg -1), respectively. Two cherry tomato lines, TC-019 and TC-053, and 3 non-cherry tomato lines, TG-107, TG-112, and TG-113, had significantly higher total phenolic contents and antioxidant activities than did the commercial cultivars. The genotypes selected on the basis of their phytochemical content could be used to develop new tomato cultivars with high antioxidant contents and activities.
TL;DR: The results suggest that the content of phytochemicals, and their associated health benefits, may be affected by red pepper harvest time throughout the harvest season.
Abstract: Red pepper (Capsicum annuum L.), an important horticultural crop, is typically harvested several times within one season. The goal of this study was to elucidate the harvest time-dependent variation and accumulation patterns of phytochemicals and any associated antioxidant activity in red pepper. Fully matured red pepper fruits, grown in an open field, were harvested six times during the season. They were evaluated for their proximate nutrient contents, as well as their minerals, vitamins, capsaicinoids, total flavonoid, total phenols, squalene, phytosterols, and fatty acids, and for antioxidant activity. The content of most phytochemicals varied significantly at different times of harvest. Phytochemicals such as capsaicinoids, vitamin C, total phenols, total flavonoid, s-carotene, and calcium, as well as antioxidant activity, had higher values in the initial and final harvests, while P, K, and Na decreased continuously with the progression of the harvest season. Squalene content increased continuously, while vitamin E and phytosterol contents were relatively stable throughout the harvest season. Different phytonutrients exhibited different levels of harvesting time-dependent variation; capsaicinoid had the highest coefficient of variation (CV, 55.44%), followed by squalene (40.51%), total flavonoids (15.97%), and vitamin C (10.57%). Total vitamin E, phytosterols, fatty acids, and the proximate nutrients were relatively constant, with low CVs (<10.0%). Among the phytonutrients, total flavonoids (r = 0.841), vitamin C (r = 0.801), s-carotene (r = 0.738), and total phenol (r = 0.705) were highly positively correlated with antioxidant activity throughout the harvesting season. These results suggest that the content of phytochemicals, and their associated health benefits, may be affected by red pepper harvest time throughout the harvest season.
TL;DR: It is suggested that the chemical composition of the fertilizer and concentration of chitosan used affect the degree to which Begonia × hiemalis growth is stimulated and pathogen resistance is improved.
Abstract: Chitosan has been proposed to elicit defense responses in plants. In this study, we evaluated the potential roles of chitosan as a fertilizer supplement to stimulate Begonia × hiemalis Fotsch ‘Schwabenland Red’ growth and resistance to gray mold caused by the fungus Botrytis cinerea. We evaluated the effect of treatment with fertilizer containing various ratios of N, P, and K in combination with different concentrations of chitosan on plant growth and disease resistance. Of the sixteen treatments examined, the treatment consisting of an N:P:K ratio of 2.8:1.0:1.4 and chitosan concentration of 0.10 g·L-1 had the most positive effect on plant height, crown development, and other horticultural traits (i.e., flowering time, flower diameter, and flower quantity) at 20, 40, and 60 days after treatment, and significantly reduced the severity and incidence of gray mold compared to the controls and other treatments at 60 days after treatment. Furthermore, this treatment markedly increased superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and phenylalanine ammonia-lyase (PAL) activities. Based on these findings, we suggest that the chemical composition of the fertilizer and concentration of chitosan used affect the degree to which Begonia × hiemalis growth is stimulated and pathogen resistance is improved.
TL;DR: Results indicate that exogenous Spd pre-treatment could enhance salinity tolerance by increasing proline levels and regulating ion and polyamine metabolism.
Abstract: Spermidine (Spd) acts as a plant protectant under salinity stress. The objective of this study was to determine whether exogenous Spd pre-treatment could improve the salinity tolerance of Kentucky bluegrass (Poa pratensis L.). Exogenous Spd was applied before the grass was exposed to 200 mM sodium chloride (NaCl) for 28 d in the growth chamber. Salinity stress decreased chlorophyll (Chl) content, K+/Na+ ratio and K+, Ca2+, and Mg2+ contents, and increased electrolyte leakage (EL), proline, Na+, putrescine (Put), Spd and Spermine (Spm) levels and the activities of arginine decarboxylase (ADC), ornithine decarboxylase (ODC), S-adenosylmethionine decarboxylase (SAMDC) and polyamine oxidase (PAO). Pre-treatment with 1 mM Spd effectively alleviated the decline of Chl content, K+/Na+ ratio and K+, Ca2+, and Mg2+ contents under salinity stress conditions. Spd pre-treatment also reduced EL, Na+ content, Put levels and the activities of ADC and PAO, but increased proline content, endogenous Spd and Spm levels and the activities of ODC and SAMDC upon salinity stress. These results indicate that exogenous Spd pre-treatment could enhance salinity tolerance by increasing proline levels and regulating ion and polyamine metabolism.
TL;DR: The results suggest that climate change scenarios may have a profound impact on the cultivation of Kimchi cabbage and that effective mitigation strategies may be needed to ensure that this economically important crop has the necessary resilience under such climate change.
Abstract: We evaluated the effects of interacting climate change factors on the morphology, growth, physiological responses, and yield of Kimchi cabbage leaves. Kimchi cabbage was cultivated under two climate change scenarios predicted by the Intergovernmental Panel on Climate Change; Representative Concentration Pathway (RCP) 4.5 and RCP 8.5. For the RCP 4.5 and RCP 8.5 treatments, the air temperatures were maintained 3.4 and 6.0°C above the prevailing control air temperatures and the CO2 concentrations were maintained at 540 and 940 µmol·mol -1, respectively, using newly developed extreme weather growth-chambers. Control plants were grown outside during the autumn. The RCP 4.5 and RCP 8.5 treatments led to tipburn disorders and rough leaves. The light compensation and saturation points of control plants were greater than those of the treatment plants. The maximum carboxylation rate, maximum rate of electron transport, and triose phosphate utilization rate of the RCP 8.5 treatment plants were significantly lower than those of the control. The control plants had the greatest yield among the studied plants, with a 65% reduction in yield observed in the RCP 4.5 treatment plants. The RCP scenarios retarded the growth and assimilation rates, and negatively affected leaf morphology, photosynthesis efficiency, and yield. These results suggest that climate change scenarios may have a profound impact on the cultivation of Kimchi cabbage and that effective mitigation strategies may be needed to ensure that this economically important crop has the necessary resilience under such climate change.
TL;DR: In a random amplified polymorphic DNA (RAPD) analysis, a monomorphic banding profile was obtained from the plants derived from synthetic seeds that had been stored at 4°C for 120 days, which confirmed the genetic fidelity of the plantsderived from the stored artificial seeds.
Abstract: We developed a protocol to produce synthetic seeds of mango ginger (Curcuma amada Roxb.) for large-scale propagation, storage, and germplasm exchange. The seeds were produced by encapsulating somatic embryos in a calcium–alginate matrix. Embryogenic callus was induced from leaf sheath explants on 0.8% agar solidified with full-strength Murashige and Skoog (MS) medium supplemented with 3% (w/v) sucrose, 2.0 mg·L-1 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.5 mg·L-1 6-benzyladenine (BA). Somatic embryos were induced by transferring the calli to 1/2 MS liquid medium supplemented with 3% (w/v) sucrose and 0.3 mg·L-1 BA. A synthetic seed coat for the somatic embryos that is uniform in size and shape was produced by incubating the embryos in 3% (w/v) sodium alginate in 1/2 MS liquid medium and exposure to 100 mM calcium chloride (CaCl2.2H2O) for 15 min. The highest germination percentage of synthetic seeds (91.66%) was achieved on 1/2 MS solid medium supplemented with 3% (w/v) sucrose and 0.25 mg·L-1 gibberellic acid (GA3) in darkness (24 h) for 35 days. Sucrose-dehydrated synthetic seeds showed better storability than fresh seeds. Synthetic seeds that were dehydrated in 8.55% (w/v) sucrose solution and stored at 4?C showed germination percentages of 88.10% after 30 days of storage and 54.16% after 120 days of storage. Plantlets were successfully acclimatized to ex vitro conditions (survival rate, 82.66%) and showed normal phenotypes. In a random amplified polymorphic DNA (RAPD) analysis, a monomorphic banding profile was obtained from the plants derived from synthetic seeds that had been stored at 4°C for 120 days. This confirmed the genetic fidelity of the plants derived from the stored artificial seeds.
TL;DR: In this article, three-week-old seedlings were transplanted to a wick culture system supplied with Hoagland solution (EC 1.0, 1.5, 2.0 and 2.5 dS·m -1) as a control or with five different concentrations of NSC.
Abstract: The medicinal plant Crepidiastrum denticulatum, which is found throughout East Asia, contains various health-promoting phytochemicals. The aim of this study was to evaluate the effects of a newly developed nutrient solution (referred to as NSC) on the growth of this plant and to determine the proper EC level of NSC for stable phytochemical production in plant factories. Three-week-old seedlings were transplanted to a wick culture system supplied with Hoagland solution (EC 1.0 dS·m -1) as a control or with five different concentrations of NSC (EC 0.5, 1.0, 1.5, 2.0, and 2.5 dS·m -1). We grew the plants under normal conditions (20°C, 310 ± 10 µmol·m -2·s -1 PPF, CO2 1,000 µmol·mol -1, and a 16 hours photoperiod) for 6 weeks and evaluated their photosynthetic rates and growth characteristics, such as the fresh and dry weights of shoots and roots, leaf area, number of leaves, and S/R ratios, at 6 weeks after transplanting. We also measured the total phenolic content, antioxidant capacity, and chicoric acid content each week for 6 weeks after transplanting. The fresh weights of shoots and roots, leaf area, and number of leaves significantly increased in plants supplied with 2.0 and 2.5 dS·m -1 NSC compared with the control, while the photosynthetic rate did not change under different concentrations of NSC. The total phenolic content and antioxidant capacity per shoot significantly increased with increasing in EC level of NSC; this trend became more pronounced over time. Moreover, the chicoric acid content significantly increased during growth up to 6 weeks after transplanting. These results suggest that NSC increases the biomass of C. denticulatum and that an EC level of 2.0 or 2.5 dS·m -1 is proper for accumulating high levels of phytochemicals, such as chicoric acid, in C. denticulatum grown in plant factories.
TL;DR: The results suggest that these genotype selections had desirable compositions of individual GSLs and higher nutritional value for commercialization as functional vegetables.
Abstract: The aim of this research was to evaluate the profile and concentration of individual glucosinolates (GSL), and the total phenol content (TPC), total flavonoid content (TFC), ascorbic acid content, and antioxidant activity of broccoli florets and flower stalks (10 commercial cultivars, 19 F1 hybrids, and 20 inbred lines). All broccoli heads were harvested at their marketable stage, and their flower stalks and florets were subjected to phytochemical analysis. GSL, TPC, TFC, and ascorbic acid content varied significantly depending on broccoli genotype. Altogether, nine GSLs were identified, four of which (glucoraphanin, progoitrin, glucoerucin, and glucobrassicin) were the most common in both broccoli flower stalks and florets. In florets, glucobrassicin was the most abundant GSL (4.46 μmol·g-1 DW), followed by glucoraphanin (1.93 μmol·g-1 DW), whereas glucoraphanin was the most abundant in flower stalks (1.47 μmol·g-1 DW). The concentrations of total GSLs, TPC, and TFC in florets were relatively higher than those in the flower stalks, whereas the concentration of ascorbic acid was higher in the flower stalks than the florets. Almost all F1 hybrids and inbred lines exhibited higher TPC, TFC, ascorbic acid concentration, and antioxidant activities than those in the commercial cultivars. Three F1 hybrids; 5075, 5078, and 5079, and one inbred line (5308) had the highest glucoraphanin and total GSL content. Three inbred lines, 5307, 5311, and 5409 had the higher concentration of glucobrassicin and total GSLs, superior antioxidant activity with low PRO+EPI content. These results suggest that these genotype selections had desirable compositions of individual GSLs and higher nutritional value for commercialization as functional vegetables.
TL;DR: In this paper, a coupled biochemical model of photosynthesis was adopted to simultaneously predict the photosynthesis, stomatal conductance, transpiration, and temperature of sweet basil leaves, and the photosynthetic parameters, maximum carboxylation rate, potential rate of electron transport, and rate of triose phosphate utilization were determined by regression analysis of the A-Ci curve.
Abstract: For the production of plants in controlled environments such as greenhouses and plant factories, crop modeling and simulations are effective tools for configuring the optimal growth environment. The objective of this study was to develop a coupled photosynthetic model of sweet basil (Ocimum basilicum L.) reflecting plant factory conditions. Light response curves were generated using photosynthetic models such as negative exponential, rectangular hyperbola, and non-rectangular hyperbola functions. The light saturation and compensation points determined by regression analysis of light curves using modified non-rectangular hyperbola function in sweet basil leaves were 545.3 and 26.5 µmol·m-2·s-1, respectively. The non-rectangular hyperbola was the most accurate with complicated parameters, whereas the negative exponential was more accurate than the rectangular hyperbola and could more easily acquire the parameters of the light response curves of sweet basil compared to the non-rectangular hyperbola. The CO2 saturation and compensation points determined by regression analysis of the A-Ci curve were 728.8 and 85.1 µmol·mol-1, respectively. A coupled biochemical model of photosynthesis was adopted to simultaneously predict the photosynthesis, stomatal conductance, transpiration, and temperature of sweet basil leaves. The photosynthetic parameters, maximum carboxylation rate, potential rate of electron transport, and rate of triose phosphate utilization determined by Sharkey’s regression method were 102.6, 117.7, and 7.4 µmol·m-2·s-1, respectively. Although the A-Ci regression curve of the negative exponential had higher accuracy than the biochemical model, the coupled biochemical model enable to physiologically explain the photosynthesis of sweet basil leaves.
TL;DR: TGE has emerged as a novel plant-breeding tool that represents an alternative approach to classical breeding, but with higher mutagenic efficiency, and their potential use to improve the traits of horticultural crops through genome engineering is discussed.
Abstract: Improving crops through plant breeding, an important approach for sustainable agriculture, has been utilized to increase the yield and quality of foods and other biomaterials for human use. Crops, including cereals, vegetables, ornamental flowers, fruits, and trees, have long been cultivated to produce high-quality products for human consumption. Conventional breeding technologies, such as natural cross-hybridization, mutation induction through physical or chemical mutagenesis, and modern transgenic tools are often used to enhance crop production. However, these breeding methods are sometimes laborious and complicated, especially when attempting to improve desired traits without inducing pleiotropic effects. Recently, targeted genome editing (TGE) technology using engineered nucleases, including meganucleases, zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and clustered regularly interspaced short palindromic repeat (CRISPR) nucleases, has been used to improve the traits of economically important plants. TGE has emerged as a novel plant-breeding tool that represents an alternative approach to classical breeding, but with higher mutagenic efficiency. Here, we briefly describe the basic principles of TGE and the types of engineered nucleases utilized, along with their advantages and disadvantages. We also discuss their potential use to improve the traits of horticultural crops through genome engineering.