Conversion Of Somatic Embryos Research Articles

LED lighting affects maturation, conversion and metabolic profile of somatic embryos derived from Kelussia odoratissima Mozaff

LED lighting affects maturation, conversion and metabolic profile of somatic embryos derived from Kelussia odoratissima Mozaff

Osmotic priming-induced cryotolerance uncovers rejuvenation of grapevine cell cultures: morphogenetic changes and gene expression pattern highlighting enhanced embryogenic potential.

Cryopreservation is a reliable technique for the long-term storage and preservation of embryogenic cells, maintaining their viability without loss of their embryogenic capacity. However, the large-scale conservation of grapevine embryogenic lines in cryobanks remains limited. A significant challenge is understanding somatic cell rejuvenation. Here, we investigate the encapsulation/dehydration and encapsulation/vitrification for cryopreserving embryogenic material. Cell rejuvenation and enhanced embryogenic competence were observed after cryopreservation, as evidenced through structural cellular changes observed by histology and electron scanning microscopy. Results showed that cryopreserved samples of 110-Richter, Riesling, and Tempranillo using encapsulation/dehydration had better survival rates, averaging 81%, 62%, and 48%, respectively, while encapsulation/vitrification yielded lower survival rates, averaging 58%, 42%, and 32%, respectively. Cryopreservation also improved post-thaw recovery and regeneration efficiency assessed through regrowth of proembryogenic masses and somatic embryo conversion reaching 54-72% against 11-17% in control samples. Cryopreservation triggered changes in gene expression patterns and exhibited considerable increase at genotype-specific basis of 1.5- to 4.5-fold in SERK1, BBM, and WOX associated to embryogenic competence as well as in ChitIV and LEA involved in stress response. Membrane stability index, hydrogen peroxide, and proline contents were used as indicators of oxidative stress uncovering a key role of an osmotic trans-priming effect leading to cryotolerance. Our finding highlighted that cryopreservation enhances embryogenic capacity in senescent callus and probably acts as a screening process allowing safe maintenance of proembryogenic cells and promoting their recovery. This study provides a high throughput innovation to set up cryolines for cell rejuvenation of grapevine and other important plant species.

Analysis of the potential involvement of lncRNAs in embryogenic competence of Solanum betaceum Cav. (tamarillo) calli

Somatic embryogenesis (SE) is a process by which somatic cells reprogram, acquire totipotency and embark on embryo formation. Although SE is a valuable tool for micropropagation in many crops, it presents specific challenges in woody species due to some bottlenecks, such as loss of embryogenic competence during subcultures and the often-low somatic embryo conversion into plantlets. Hence, great interest exists in exploring the regulatory networks involved on SE. As transcription modulators, long non-coding RNAs (lncRNAs) have been found essential in a wide range of biological processes. This work aimed to identify lncRNAs related to the embryogenic competence in Solanum betaceum Cav. (tamarillo). Nanopore® long-read sequencing was conducted in cell lines with distinct cell fates and, based on their coding potential, 60 transcripts were selected as lncRNA candidates. Similar expression patterns were found among embryogenic cell lines (EC) and cells that lost their embryogenic potential (herein long-term callus, LTC), whereas non-EC (NEC) showed differentially expressed lncRNAs. Whereas lncRNAs upregulated in EC and LTC were predicted to target embryogenesis-related genes, such as AGAMOUS-like 15 and WUSCHEL-related HOMEOBOX 2, lncRNAs upregulated in NEC were predicted to target mainly genes involved in carbohydrate metabolism, cell wall formation, auxin and ethylene signalling pathways. Altogether, these results show the involvement of lncRNA in the process of somatic embryogenesis in S. betaceum, indicating that EC present a pattern of lncRNA expression that suggests its action on genes that directly modulate the morphogenic response in vitro, while in NEC the modulation through this type of RNAs seems to be predominantly reflected in genes more related to cellular physiology.Graphical

Spectral qualities and gas exchange affect the maturation and conversion of embryogenic cultures of Bactris gasipaes Kunth

Somatic embryogenesis is the most used morphogenetic route for mass propagation of several species of the Arecaceae family, requiring adaptation to environmental conditions, such as the wavelength of light and gas-permeable membranes, which are essential characteristics for plant growth and development. Thus, the objective was to analyze the effect of spectral qualities and sealing types on the maturation and conversion of somatic embryos of Bactris gasipaes. Embryogenic calli (ECs) inoculated in flasks containing 50 mL of MS + Morel's vitamins + myo-inositol (100 mg L−1) + sucrose (30 g L−1) + casein (1 g L−1) + glutamine (1 g L−1) + asparagine (350 mg L−1) + 2.3 g L−1 Phytagel®, adjusted to pH 5.8, prior to autoclaving. The design was completely randomized, in a 4 × 2 factorial, four spectral qualities (white, blue, red, or red/blue LEDs), and two sealing types (rigid lids without holes or with two holes covered by membranes), ten repetitions, with 245 mg of the fresh mass of ECs per flask, kept in a growth room (27±2 °C, 16 h photoperiod, 50 µmol.m−2.s−1). At 120 days, the following were evaluated: color of ECs, conversion of somatic embryos; percentage of ECs with leaves, green and oxidized ECs (%), fresh and dry ECs (g), fresh weight gain, and water content of ECs (%). By means of the Biplot interpretation it was showed that EC should be subjected to blue and blue/red LEDs associated with flasks with gas-permeable membranes in order to enhance the conversion of somatic embryos to plantlets.

Application of Cold Storage and Short In Vitro Germination for Somatic Embryos of Pinus radiata and P. sylvestris.

Somatic embryogenesis (SE) is an advanced vegetative propagation technology that, when used in combination with breeding and cryopreservation, offers the forest industry a powerful tool for the deployment of elite genotypes. Germination and acclimatization are critical and cost-intensive phases in the production of somatic plants. The efficient conversion of somatic embryos into robust plants is a necessity if a propagation protocol is to be successfully adopted by the industry. In this work, these late phases of the SE protocol of two pine species were investigated. A shortened germination protocol and more controlled acclimatization were investigated for Pinus radiata, testing embryos from 18 embryogenic cell lines. A more simplified protocol, including a cold storage phase, was also compared among 10 of these cell lines. A shortened germination period and more controlled protocols significantly improved the acclimatization of somatic embryos directly from the lab to the glasshouse. When results for all cell lines were pooled, there were significant improvements in all growth characteristics (shoot height, root length, root collar diameter, and root quadrant score). When the more simplified protocol involving cold storage was tested, improvements were seen in the root architecture. For Pinus sylvestris, the late phases of somatic embryogenesis were investigated on seven cell lines in a set of two trials (four to seven cell lines per trial). During the germination phase, a shortened and simplified in vitro period, a cold storage option and basal media were explored. Viable plants were obtained from all treatments. However, there is still the need to improve germination and related protocols together with growing regimes for Pinus sylvestris. The improvements to protocols presented here, particularly for Pinus radiata, result in greater survival and quality of somatic emblings, leading to reduced costs and increased confidence in the technology. Simplified protocols using a cold storage option show great promise and, with some further research, could lead to reductions in the cost of the technology.

Somatic embryogenesis and plant regeneration from transverse thin cell layers of adult peach palm (Bactris gasipaes) lateral offshoots.

In this work, we report a successful protocol to obtain in vitro peach palm (Bactris gasipaes Kunth) “Diamantes 10” plants through somatic embryogenesis from transverse thin cell layer (TCL) explants, dissected from three sections (basal, medial, and apical) of lateral offshoots of adult plants cultured on different concentrations of 4-amino-3,5,6-trichloropicolonic acid (picloram). After swelling and development of primary callus in all treatments, without any strong effect of explant origin or picloram concentration, it was possible to observe the formation of embryogenic structures and the exact point from where they developed. Browning was also observed and correlated to the induction treatments, although it was not an impairment for the production of embryogenic structures. Subsequent maturation and conversion of somatic embryos into plantlets allowed their acclimatization 17 months after culture initiation (ACI), which was quicker than previous reports with juvenile tissues (from embryos or seed-germinated plantlets). To the best of our knowledge, this is the first report on peach palm regeneration through somatic embryogenesis from TCL explants from adult plants and could constitute, after fine-tuning the acclimatization stage, a tool for mass clonal propagation of elite genotypes of this open-pollinated crop, as well as for the establishment of conservation strategies of in situ gene bank plant accessions endangered due to aging and other threats.

Integrated Lipidomic and Transcriptomic Analysis Reveals Phospholipid Changes in Somatic Embryos of Picea asperata in Response to Partial Desiccation.

Partial desiccation treatment (PDT) is an effective technology for promoting the germination and conversion of conifer somatic embryos (SEs). PDT, as a drought stress, induces intensive physiological responses in phospholipid metabolism, which are not well understood in the conifer SEs. Here, we integrated lipidomics, transcriptomics and proteomics analyses to reveal the molecular basis of lipid remodeling under PDT in Picea asperata SEs. Among the 82 lipid molecular species determined by mass spectrometry, phosphatidic acid (PA) had a significant effect after PDT and was the most critical lipid in the response to PDT. The transcriptomics results showed that multiple transcripts in the glycerolipid and glycerophospholipid metabolism pathways were differentially expressed, and these included five PLDα1 transcripts that catalyze the conversion of phosphatidylcholine (PC) to PA. Furthermore, the enzyme activity of this phospholipase D (PLD) was significantly enhanced in response to PDT, and PDT also significantly increased the protein level of PLDα1 (MA_10436582g0020). In addition, PA is a key factor in gibberellin, abscisic acid and ethylene signal transduction. One GDI1, one DELLA, three ABI1s, two SnRK2s, one CTR and 12 ERFs showed significantly differential expression between SEs before and after PDT in this study. Our data suggest that the observed increases in the PA contents might result from the activation of PLDα by PDT. PA not only affects the physical and chemical properties of the cell membrane but also participates in plant hormone signal transduction. Our work provides novel insight into the molecular mechanism through which PDT promotes the germination of SEs of coniferous tree species and fills the gap in the understanding of the mechanism of somatic embryo lipid remodeling in response to PDT.

Somatic embryogenesis from flower tepals of Hippeastrum aiming regeneration of virus-free plants

Hippeastrum hybridum is an important bulbous flower plant in world floriculture, which are propagated conventionally by the technique known as double or twin scales to obtain plants with clonal origin. However, this technique promotes the propagation of systemic diseases, particularly mosaic-inducing viruses. The aim of this paper was to evaluate the somatic embryogenesis (SE) from tepals as an alternative to provide a technique for SE induction and to obtaining virus-free plantlets of Hippeastrum from infected plants. The concentrations of 2,4-Dichlorofenoxiacetic Acid (2,4-D) and thidiazuron (TDZ) was evaluated in SE induction pathway. The monitoring of viruses during the assays with tepals was performed by Reverse Transcription-Polymerase Chain Reaction. SE induction was obtained, for the first time, in tepal segments from flower buds of Hippeastrum. The 2,4-D was the main factor for embryogenic callus induction, and TDZ increased the SE induction rate. However, conversion of somatic embryos into plantlets were only developed in free-2,4-D media, replaced by 1.0 mg L−1 6-Benziladenine. Out of five virus species monitored during the experiment, Cucumber mosaic virus was detected in tepals and Hippeastrum mosaic virus in leaves of donor plants. The SE-derived plantlets that germinated in vitro were acclimatized and tested negative for all viruses assayed.

The Chemical Environment at Maturation Stage in Pinus spp. Somatic Embryogenesis: Implications in the Polyamine Profile of Somatic Embryos and Morphological Characteristics of the Developed Plantlets.

Changes in the chemical environment at the maturation stage in Pinus spp. somatic embryogenesis will be a determinant factor in the conversion of somatic embryos to plantlets. Furthermore, the study of biochemical and morphological aspects of the somatic embryos could enable the improvement of somatic embryogenesis in Pinus spp. In the present work, the influence of different amino acid combinations, carbohydrate sources, and concentrations at the maturation stage of Pinus radiata D. Don and Pinus halepensis Mill. was analyzed. In P. radiata, the maturation medium supplemented with 175 mM of sucrose and an increase in the amino acid mixture (1,100 mgL–1 of L-glutamine, 1,050 mgL–1 of L-asparagine, 350 mgL–1 of L-arginine, and 35 mgL–1 of L-proline) promoted bigger embryos, with a larger stem diameter and an increase in the number of roots in the germinated somatic embryos, improving the acclimatization success of this species. In P. halepensis, the maturation medium supplemented with 175 mM of maltose improved the germination of somatic embryos. The increase in the amount of amino acids in the maturation medium increased the levels of putrescine in the germinated somatic embryos of P. halepensis. We detected significant differences in the amounts of polyamines between somatic plantlets of P. radiata and P. halepensis; putrescine was less abundant in both species. For the first time, in P. radiata and P. halepensis somatic embryogenesis, we detected the presence of cadaverine, and its concentration changed according to the species.

Plant Regeneration and In Vitro Growth Performance of Male-Sterile Somatic Plantlets of Sugi (Japanese Cedar, Cryptomeria japonica) Derived from Different Embryogenic Cell Lines

With the spread of pollinosis caused by sugi (Japanese cedar, Cryptomeria japonica) pollen, the use of pollen-free somatic seedlings of sugi is expected in Japan. However, there is a lack of knowledge on the relationship between the abilities during somatic embryogenesis, initial in vitro growth traits, and subsequent growth of somatic seedlings. In the present study, we provide the first basic information on somatic embryo maturation efficiency, somatic embryo germination, and plantlet conversion frequencies, as well as on in vitro growth performance of pollen-free somatic plantlets derived from different embryogenic cell lines (ECLs). Somatic embryo maturation efficiency varied from 34 to 514 cotyledonary embryos per plate and the average for the 19 ECLs tested was 244 embryos per plate. Subsequently, the overall average rates of somatic embryo germination and conversion among ECLs were 87.8% and 85.3%, respectively. The results of in vitro growth performance of pollen-free somatic plantlets showed significant differences in growth rate among ECLs.

Effect of Plant Growth Regulators on Somatic Embryogenesis and Plantlet Development of Turkey Berry (Solanum torvum SW)

In the present study it was reported on direct somatic embryogenesis and plant regeneration from cotyledon and leaf explants of Turkey berry/pea egg plant (Solanum torvum SW), a medicinally important plant. Somatic embryogenesis has several advantages over other routes of in vitro plant regeneration. Somatic embryogenesis was induced directly from cotyledon and leaf explants on MS medium fortified with BAP (0.5 mg/L)+NAA (0.5-6.0 mg/L). High percentage of somatic embryogenesis (90%), maximum number of somatic embryos formation (62±0.18) along with high percentage (76%) conversion of somatic embryos into bipolar embryos was observed on cotyledon explants in 0.5 mg/L BAP+2.5 mg/L NAA. At the same concentration of BAP (0.5 mg/L)+NAA (2.5 mg/L) also resulted on the maximum percentage of somatic embryogenesis (92%), the highest number of somatic embryos formation (88±0.15) and the highest percentage (76%) of somatic embryos conversion into bipolar embryos in leaf explants. A mixture of globular, heart and torpedo-shaped embryos were germinated on MS medium supplemented with 0.5 mg/L IAA+1.0-4.0 mg/L BAP. Maximum germination frequency (75±0.14) of somatic embryos and plantlet formation was found in 0.5 mg/L IAA+2.0 mg/L BAP, but they didn’t germinate on ½ MSO and MSO media. The survival rate of regenerated plants after field transfer was recorded to be 75%. These regenerated plants were found morphologically similar to donor plants. The present protocol can be used for conservation of the species and also for genetic transformation experiments in S. torvum.

Pengaruh Pemberian GA3 terhadap Perkecambahan Embrio Somatik Kakao

<p><em>Germination process of somatic embryos is one of critical steps in somatic embryogenesis. The conversion of somatic embryos into plantlets is still low and adding kinetin, ABA, NAA, and GA<sub>3</sub> to the germination medium of cacao somatic embryos may increase it. The study aimed to investigate the effect of GA<sub>3</sub> on somatic embryo germination at the cotyledonary phase. The study was conducted in the Indonesian Industrial and Beverage Crops Research Institute (IIBCRI) Tissue Culture Laboratory from May to November 2017. The study used a factorial completely randomized design (CRD) with seven replications. The first factor was the cacao genotypes, namely SCA 6 and MCC 02, and the second factor was four concentrations of GA<sub>3</sub>, namely 0.0; 1.0; 3.0; and 5.0 mg/l. Characters observed were the percentage of shooting cotyledonary embryos, the percentage of rooting cotyledonary embryos, the percentage of shooting and rooting cotyledonary embryos, percentage of browning cotyledonary embryos, root length, shoot length, and hypocotyl length at one and two months old. The results showed no interaction between genotypes and GA<sub>3</sub> concentrations on all observed characters. Adding GA<sub>3</sub> at 1,0 mg/l concentration tends to increase the percentage of shooting cotyledonary embryos of SCA 6 and rooting cotyledonary embryos of MCC 02. SCA 6 clone has a higher percentage of shooting cotyledone, shooting and rooting cotyledone, and browning cotyledone compared to those of MCC 02.</em></p>

Slow-growth conservation- cryopreservation and Analysis of genetic stability of in vitro regenerated Coelogyne Nervosa A.Rich A endemic orchid

Coelogyne Nervosa A. Rich., an endangered medicinal epiphyte (lithophyte) is a strict endemic of the Western Ghats distributed across Karnataka, Kerala and Tamil Nadu. KC medium supplemented with 2,4-D is best suited for direct embryo induction from 80 days old protocorms. Hormone-free KC basal medium supported the conversion of somatic embryos into complete plantlets. For the medium-term storage experiment, somatic embryos were placed on storage media containing various growth inhibitors (such as different levels of chlormequat, maleic hydrazide and paclobutrazol). They were stored for ten months to assess the percentage of survival. The surviving shoots were transferred to the recovery medium for eight weeks. At 8°C, the highest survival rate was observed with ABA at 0.2 mg L−1. For cryopreservation: droplet-vitrification best results were obtained when the somatic embryos, after 20 days of subculture were immersed in an osmoprotectant solution. Osmo-protected samples were immersed in PVS2 (15% ethylene glycol and 15% DMSO) at 0°C for 30 min. Pre-prepared Somatic embryos were plunged into cryovials for one day. Regrowth levels were as high as 70%. DNA samples extracted from leaves of the mother plant, somatic embryos without storage, regenerates of slow growth preservation and cryopreservation. The samples were analysed by DNA based molecular marker – inter simple sequence repeats (ISSR) and found no genetic changes during the cryopreservation process.

English

A critical factor in the in vitro propagation protocol via somatic embryogenesis of coffee is the survival and growth of plants under ex vitro conditions. The objective of this work was to determine the effect of VIUSID Agro™ during the conversion of somatic embryos of coffee cv. Red Caturra rojo-884 in semi-controlled culture conditions. Two solutions (0.5 and 0.8 mL L-1) of the biostimulant were evaluated on in vitro plant. Applications were done twice daily for the first three days and thereafter once a day from day 7 to 90 days after transplanting. Survival rate at 15 days and morpho-physiological characteristics at 30, 60 and 90 days after transplanting were evaluated. All treatments with VIUSID-Agro™ and the control resulted in 100% survival. The concentration of 0.5 mL L-1 of VIUSID-Agro™ registered the better results in morpho-physiological variables. These results constitute the first report of the use of VIUSID Agro™ on in vitro plant of coffee during acclimatization phase.   Key words: Ex vitro acclimatization, coffee, conversion, somatic embryos, VIUSID Agro™.

Osmotic stress-induced somatic embryo maturation of coffee Coffea arabica L., shoot and root apical meristems development and robustness

Somatic embryogenesis (SE) is the most important plant biotechnology process for plant regeneration, propagation, genetic transformation and genome editing of coffee, Coffea arabica L. Somatic embryo (SEs) conversion to plantlets is the principal bottleneck for basic and applied use of this process. In this study we focus on the maturation of SEs of C. arabica var. Typica. SEs conversion to plantlet up to 95.9% was achieved under osmotic stress, using 9 g/L gelrite, as compared with only 39.34% in non-osmotic stress. Mature SEs induced in osmotic stress developed shoot and root apical meristems, while untreated SEs were unable to do it. C. arabica regenerated plants from osmotic stress were robust, with higher leaf and root area and internode length. To understand a possible regulatory mechanism, gene expression of key genes of C. arabica, homologous to sequences in the Arabidopsis thaliana genome, were analyzed. A set of two component system and cytokinin signaling-related coding genes (AHK1, AHK3, AHP4 and ARR1) which interact with WUSCHEL and WOX5 homedomains and morphogenic genes, BABY-BOOM, LEC1, FUS3 and AGL15, underwent significant changes during maturation of SEs of C. arabica var. Typica. This protocol is currently being applied in genetic transformation with high rate of success.

Slow-growth conservation- cryopreservation and Analysis of genetic stability of in vitro regenerated Coelogyne Nervosa A.Rich A endemic orchid

Coelogyne Nervosa A. Rich., an endangered medicinal epiphyte (lithophyte) is a strict endemic of the Western Ghats distributed across Karnataka, Kerala and Tamil Nadu. KC medium supplemented with 2,4-D is best suited for direct embryo induction from 80 days old protocorms. Hormone-free KC basal medium supported the conversion of somatic embryos into complete plantlets. For the medium-term storage experiment, somatic embryos were placed on storage media containing various growth inhibitors (such as different levels of chlormequat, maleic hydrazide and paclobutrazol). They were stored for ten months to assess the percentage of survival. The surviving shoots were transferred to the recovery medium for eight weeks. At 8°C, the highest survival rate was observed with ABA at 0.2 mg L−1. For cryopreservation: droplet-vitrification best results were obtained when the somatic embryos, after 20 days of subculture were immersed in an osmoprotectant solution. Osmo-protected samples were immersed in PVS2 (15% ethylene glycol and 15% DMSO) at 0°C for 30 min. Pre-prepared Somatic embryos were plunged into cryovials for one day. Regrowth levels were as high as 70%. DNA samples extracted from leaves of the mother plant, somatic embryos without storage, regenerates of slow growth preservation and cryopreservation. The samples were analysed by DNA based molecular marker – inter simple sequence repeats (ISSR) and found no genetic changes during the cryopreservation process.

Pinus spp. Somatic Embryo Conversion under High Temperature: Effect on the Morphological and Physiological Characteristics of Plantlets

Climatic variations in the current environmental scenario require plants with tolerance to sudden changes in temperature and a decrease in water availability. Accordingly, this tolerance will enable successful plantations and the maintenance of natural and planted forests. Consequently, in the last two decades, drought tolerance and high temperatures in conifers have been an important target for morphological, physiological, and epigenetic studies. Based on this, our research team has optimized different stages of somatic embryogenesis (SE) in Pinus spp. improving the success of the process. Through this method, we can obtain a large amount of clonal material and then analyze the somatic plants under different conditions ex vitro. The analysis of the morphological and physiological parameters in somatic embryos (ses) and plants with different tolerances to abiotic stress can provide us with valuable information about the mechanisms used by plants to survive under adverse environmental conditions. Thus, the objective of this work was to evaluate the influence of high temperatures (23, 40, 50, and 60 °C, after 12 weeks, 90, 30, 5 min, respectively) on the morphology of somatic embryos obtained from Pinus radiata D.Don (Radiata pine) and Pinus halepensis Mill. (Aleppo pine). In addition, we carried out a physiological evaluation of the somatic plants of P. radiata submitted to heat and water stress in a greenhouse. We observed that the number of somatic embryos was not affected by maturation temperatures in both species. Likewise, P. radiata plants obtained from these somatic embryos survived drought and heat stress in the greenhouse. In addition, plants originating from embryonal masses (EMs) subjected to high maturation temperature (40 and 60 °C) had a significant increase in gs and E. Therefore, it is possible to modulate the characteristics of somatic plants produced by the manipulation of environmental conditions during the process of SE.

Maturation and Conversion of Somatic Embryos Derived from Seeds of Olive (Olea europaea L.) cv. Dahbia: Occurrence of Secondary Embryogenesis and Adventitious Bud Formation.

Maturation and conversion of somatic embryos are two crucial steps that hamper the development of efficient somatic embryogenesis systems in olive. Herein, a simple and efficient protocol for the maturation and conversion of olive somatic embryos is reported. Globular somatic embryos derived from seeds of cv. Dahbia were cultured on either half-strength olive (OM) or olive cyclic embryogenesis (ECO) media, with and without plant growth regulators (PGRs). The embryos reached the cotyledonary stage in 9 weeks, but those cultured on ECO medium containing 0.1 mg·L−1 6-(dimethylallylamino)purine (2iP), 0.1 mg·L−1 6-benzyladenine (BA) and 0.05 mg·L−1 indole-3-butyric acid (IBA) exhibited the largest sizes, with an average of 4.7 mm. Somatic embryo conversion into plantlets was evaluated using different culture media (half-strength OM or one-third strength Murashige and Skoog (MS)), light conditions (light or dark) and desiccation pretreatments. The highest rate of somatic embryo conversion (45%) was observed under a 16 h photoperiod on half strength OM medium containing 0.1 mg·L−1 gibberellic acid (GA3) and 0.1 mg·L−1 1-naphthalene acetic acid (NAA). The embryos that failed to germinate showed either necrosis, cotyledon greening with no further conversion, adventitious bud formation or secondary embryogenesis. The findings of this study will be beneficial for biotechnological applications in olive.

Enhancing hybrid Liquidambar somatic seedling production using a temporary immersion bioreactor

Temporary immersion bioreactors can improve hybrid sweetgum somatic embryo conversion and somatic seedling growth rates compared to semisolid medium, significantly improving somatic seedling production efficiency for hybrid sweetgum, an emerging woody biomass crop. Fast-growing hybrid southern hardwood trees should make excellent material for woody biomass production in the Southeastern US, if elite clones can be identified and efficiently propagated. We have enhanced the potential of sweetgum (Liquidambar styraciflua) as a biomass species by generating hybrids between the tree and its Chinese relative, Liquidambar formosana, and propagating the most promising clones via somatic embryogenesis. Some of the hybrid clones have already demonstrated superior biomass productivity compared to elite L. styraciflua trees. However, production of somatic seedlings from these clones remains labor-intensive. Bioreactors, specifically temporary immersion designs, such as the RITA®, have been applied to improve the efficiency of in vitro propagation of a number of woody species. We tested RITA® bioreactors for their potential to improve the production efficiency of high-quality hybrid sweetgum somatic seedlings. In one tested genotype, a RITA® with 50 somatic embryos had about 66% higher conversion frequency (p < 0.05) and produced about 40% more “high-quality” somatic seedlings (p < 0.05) than when somatic embryos were germinated on semisolid medium in GA-7 vessels. In all the genotypes we tested, somatic seedlings produced in RITA® bioreactors had higher survival percentages by the end of acclimatization than somatic seedlings produced on semisolid medium in GA-7 vessels.

Somatic embryogenesis of scots pine: current status and perspective of application in forestry

In the review it is come up with information on the possibilities of breeding programs and the creation of seed orhards of Scots pine (Pinus sylvestris L) as one of the key species of forests in Eurasia, which has significant economic value. Somatic embryogenesis is a promising biotechnological method that allows mass propagation of valuable individuals obtained, including during the implementation of breeding programs. Using the example of various species of the Pinus genus, the main stages of somatic embryogenesis are described. The influence of the conditions and period of cultivation on the effectiveness of somatic embryogenesis and the subsequent conversion of somatic embryos into the plants are considered. Particular attention is paid to the growth and physiology of clones in the field.