Showing papers in "Plant Cell Tissue and Organ Culture in 1997"
TL;DR: Methods for the measurement and control of in vitro environments and the beneficial effects of environmental control on photosynthetic growth, development, and morphogenesis in large-scale production of micropropagated plantlets are presented.
Abstract: Leafy or chlorophyllous explants of a number of plant species currently micropropagated have been found to have high photosynthetic ability. Their growth and development have been promoted on sugar-free medium rather than on sugar-containing medium, provided that the environmental factors, such as CO2 concentration, light intensity and relative humidity, are controlled for promoting photosynthesis and transpiration of explants/shoots/plantlets in vitro. Thus, environmental control is essential for promoting photosynthetic growth and development of in vitro plantlets.
170 citations
TL;DR: IAA is the preferable auxin for in vitro rooting of apple ‘Jork 9’ shoots exposed for three weeks to each of the three auxins commonly used for ex vitro rooting.
Abstract: We have examined in vitro rooting of apple ‘Jork 9‘ shoots exposed for three weeks to each of the three auxins commonly used for ex vitro rooting: indole-3-acetic acid (IAA), indole-3-butyric acid (IBA) and α-naphthaleneacetic acid (NAA). During the initial five days of the rooting treatment, the cultures were incubated in darkness. In this period, the root initials are formed. Then, the cultures were moved to the light. NAA resulted in a low (ca. 8 roots), and IAA or IBA in a high (ca. 15 roots) maximal root number. The maximal root number was reached at a wide range of IAA concentrations (10-100 μM) but at only one concentration of IBA (10 μM) or NAA (3 μM). With NAA and IBA, growth of roots and shoots was much more inhibited than with IAA. For these reasons, IAA is the preferable auxin for in vitro rooting of apple ‘Jork 9’ shoots.
147 citations
Journal Article•
97 citations
TL;DR: Variability among regenerated plants was also found after field testing and colchicine treatment was not effective for the production of tetraploid plants.
Abstract: Somaclonal and in vitro mutagen-induced variability was studied in grapevine. Plants of Vitis vinifera cv. Podarok Magaracha were regenerated from leaf explants through somatic embryogenesis. Chromosome counts of root tips was used for screening of regenerated plants. Among 242 studied plants, six (2.5%) tetraploids (2n=4x=76) were identified; all others were diploid (2n=2x=38). Neither chimeral, nor aneuploid plants were observed. Gamma-irradiation (5-100 Gy) increased tetraploid plant formation frequency of primary (7%) and embryogenic calluses (7.6%) and some aneuploid plants were also found. Colchicine treatment was not effective for the production of tetraploid plants. Variability among regenerated plants was also found after field testing.
89 citations
TL;DR: The addition of different concentrations of AgNO3 to the medium induced shoot regeneration in distal cotyledon except Suyo Long cultivar and effectively increased shoot regeneration response as well as the number of shoots per explant in proximal cotYledon and hypocotyl of all cucumber cultivars.
Abstract: The effect of addition of silver nitrate (AgNO3) on organogenesis of proximal and distal cotyledon and hypocotyl explants of five cucumber (Cucumis sativus L.) cultivars was investigated. Distal cotyledon and hypocotyl were unresponsive while only poor shoot regeneration was observed in proximal cotyledon and hypocotyl explants of all cucumber cultivars. The addition of different concentrations of AgNO3 (10, 30 and 50 µM) to the medium, however, induced shoot regeneration in distal cotyledon except Suyo Long cultivar and effectively increased shoot regeneration response as well as the number of shoots per explant in proximal cotyledon and hypocotyl of all cucumber cultivars.
89 citations
TL;DR: Plant regeneration by somatic embryogenesis was attempted with diploid and triploid bananas and showed that the embryogenic process involves a sequence of similar events for both species.
Abstract: Plant regeneration by somatic embryogenesis was attempted with diploid (Musa acuminata ssp. malaccensis) and triploid ('Grand Nain') bananas. Explants inoculated in vitro were, respectively, immature zygotic embryos and male flower bud primordia. An histological study showed that the embryogenic process involves a sequence of similar events for both species. A yellow-green compact callus was initiated, which consisted of an actively dividing meristematic zone surrounded by several layers of starchy cells. A white and friable callus, characterized by the presence of proembryonic cells, bicellular proembryos and proembryonal masses in its periphery gradually appeared, which finally gave rise to somatic embryos from which plants were recovered. Induction media contained 2,4-D (and also NAA and IAA for the triploid); zeatin and kinetin were necessary for embryo maturation and 6-BA and IAA were used for germination.
84 citations
TL;DR: Cultured peduncle segments of B. juncea, B. nigra and B. carinata produced shoot buds on Murashige and Skoog medium supplemented with benzyladenine and 1-naphthalene acetic acid that could be rooted and transferred to soil where 75% survived and set seed.
Abstract: Cultured peduncle segments of B. juncea, B. campestris, B. napus, B. nigra and B. carinata produced shoot buds on Murashige and Skoog medium supplemented with benzyladenine and 1-naphthalene acetic acid. Supplementation of the media with 30 µm silver nitrate or silver thiosulfate enhanced the frequency of shoot regeneration. The regenerated shoots could be rooted at a frequency of 95% and transferred to soil where 75% survived and set seed.
81 citations
TL;DR: The process of callus induction, organogenesis and plantlets regeneration of Camptotheca acuminata Decne is reported, and the presence of 10-hydroxycamptothecin in shoots and callus is reported for the first time.
Abstract: The process of callus induction, organogenesis and plantlets regeneration of Camptotheca acuminata Decne is reported. The highest growth rate of callus was observed on MS medium with 1 mg l−1 NAA, 1 mg l−1 kinetin and 60 g l−1 sucrose. All tissues and organs developed in vitro contain camptothecin and 10-hydroxycamptothecin. The presence of 10-hydroxycamptothecin in shoots and callus of Camptotheca acuminata Decne is reported for the first time. The alkaloids were detected and identified using HPLC methods.
79 citations
TL;DR: The increased levels of the two furanones in the treated strawberry cultures is the result of Methylobacterium extorquens oxidative activity on 1,2-propanediol and the bioconversion by the plant cells of this oxidation product, lactaldehyde to DMHF and mesifuran.
Abstract: Two important character-impact compounds of strawberry flavour, the furanones 2,5-dimethyl-4-hydroxy-2H-furan-3-one (DMHF) and 2,5-dimethyl-4-methoxy-2H-furan-3-one (mesifuran) were synthesized by strawberry tissue cultures derived from a cultivated species (Fragaria × ananassa, cv. Elsanta) after these were treated with Methylobacterium extorquens. These flavour compounds were analysed by HPLC-UV and their levels were compared in the treated and control tissues. In Methylobacterium extorquens treated callus cultures DMHF and mesifuran levels were 5.9 and 11.4 µg/g of fresh weight of callus respectively, compared to zero in the untreated ones. When Methylobacterium extorquens was fed with 1,2-propanediol, 2-hydroxy-propanal (lactaldehyde) was formed. This bacterial oxidation of 1,2-propanediol to lactaldehyde linked with the presence of 1,2-propanediol in strawberry suggests that the increased levels of the two furanones in the treated strawberry cultures is the result of Methylobacterium extorquens oxidative activity on 1,2-propanediol and the bioconversion by the plant cells of this oxidation product, lactaldehyde to DMHF and mesifuran.
69 citations
TL;DR: Most cotyledonary somatic embryos studied had no caulinary meristem or starch and protein reserves, thus explaining the low germination rates obtained, and three different culture conditions were compared to determine a means of overcoming poor somatic embryo development.
Abstract: Liquid medium improves and facilitates somatic embryo development from Citrus deliciosa Ten. suspension cultures. Three different culture conditions were compared to determine a means of overcoming poor somatic embryo development. Somatic embryos derived from suspension cultures were plated on solid medium, maintained in suspension culture or temporarily immersed. About 60% of somatic embryos plated on solid medium developed to the cotyledonary stage, but were hyperhydric. Continuous growth in suspension culture at 100 rpm hindered cotyledon and protoderm formation, and somatic embryos were unable to develop beyond the globular stage. Temporary immersion promoted somatic embryo development, i.e. 66% of the somatic embryos produced were cotyledonary, and were morphologically similar to nucellar embryos. This latter culture system also improved regeneration synchronization by hampering secondary embryogenesis at the onset of germination. Irrespective of the culture system used, most cotyledonary somatic embryos studied had no caulinary meristem or starch and protein reserves, thus explaining the low germination rates obtained.
69 citations
TL;DR: Embryogenic tissues obtained from stamen filament cultures of horse chestnut were cultured on maturation media supplemented with different combinations of abscisic acid, polyethylene glycol 4000, mannitol or activated charcoal to increase viability, shoot elongation and conversion.
Abstract: Embryogenic tissues obtained from stamen filament cultures of horse chestnut (Aesculum hippocastanum L.) were cultured on maturation media supplemented with different combinations of abscisic acid, polyethylene glycol 4000, mannitol or activated charcoal. Somatic embryos were subjected to different desiccation procedures after a culture period on maturation media. After a slow desiccation, obtained by placing the somatic embryos in empty and non-sealed Petri dishes under the laminar air flow for 48 h, an increase in viability, shoot elongation and conversion was observed for the embryos previously cultured on medium enriched with ABA (80 μM) alone or plus PEG (50 g l−1).
TL;DR: The approach for screening and testing bacterial isolates for antagonistic effects on the growth of Cryphonectria parasitica in vitro is described.
Abstract: Chestnut blight (Cryphonectria parasitica) is a severe disease of European (Castanea sativa) and American chestnut (Castanea sativa). Antagonistic bacteria have been shown to have a potential use in the control of plant diseases [1]. This report describes our approach for screening and testing bacterial isolates for antagonistic effects on the growth of Cryphonectria parasitica in vitro.
TL;DR: In the present study, the possibility to improve the multiplication rate and quality of in vitro cultured plants of Azorina vidalii (Wats.) Feer was investigated and the influence of high and low ratios of blue/red light and red/far red light on the development of shoot cultures was evaluated.
Abstract: In the present study, the possibility to improve the multiplication rate and quality of in vitro cultured plants of Azorina vidalii (Wats.) Feer was investigated. For these purposes the influence of high and low ratios of blue/red light (2.3 and 0.9, respectively) and red/far red light (1.1 and 0.6, respectively) on the development of shoot cultures of Azorina vidalii (Wats.) Feer was evaluated. Maximum plant length (87.9 ± 5.3 mm) (p ≤ 0.05) and internode length (6.6 ± 0.5 mm) (p ≤ 0.05) were obtained for the plants cultured under the low ratio of red/far red light. In contrast, when blue light was supplemented, plant height was reduced, due to shorter internodes. Highest number of axillary shoots per plant (2.4 ± 0.5) was obtained in the plants growing under a high level of red/far red light, while the lowest number (0.7 ± 0.2) was obtained in the plants cultured under the low level of red/far red light. Leaf area was increased in plants cultured under a low level of red/far red (1,522.5 ± 129.5 mm2) while blue/red light treatments inhibited leaf expansion. For chlorophyll a and total carotenoid contents, statistical differences (p ≤ 0.05) were observed between the plants exposed to the red/far red light treatments and the plants from the control.
TL;DR: A stimulating effect of proline on plant regeneration was observed in short-term cultures of callus as well as in long- term cultures of suspension aggregates, and an optimum proline concentration for plant regenerate was found at 12.5 mM.
Abstract: The effects of proline additions to culture systems of Miscanthus x ogiformis Honda Giganteus' were investigated Proline was added in concentrations of 0, 125, 25, 50, 100 or 300 mM to the callus induction and suspension culture media containing either Murashige and Skoog or N6 basal salts and 226 µM 2,4-dichlorophenoxyacetic acid Shoot apices and leaves from in vitro-propagated shoots, and immature inflorescences from greenhouse-grown plants were used as explants for callus induction and formation Suspension cultures initiated from embryogenic callus of immature inflorescences were used to test the effect of proline in suspension cultures The proline additions affected the formation of embryogenic callus and the growth of suspension cultures Improvements depended on the proline concentration and the basal salts of the medium Addition of 125 to 50 mM proline to callus induction medium with Murashige and Skoog salts increased embryogenic callus formation on shoot apices and leaf explants while proline had no effect on embryogenic callus formation in medium with N6 salts Increased growth with increasing proline concentration was obtained in suspension aggregates grown in medium with N6 salts, whereas proline only increased growth of suspension aggregates grown in medium with Murashige and Skoog salts at concentrations of 125 or 25 mM A stimulating effect of proline on plant regeneration was observed in short-term cultures of callus as well as in long-term cultures of suspension aggregates An optimum proline concentration for plant regeneration was found at 125 mM
TL;DR: Shoot tips from accessions of wild cherry selected from British woodland, and also the P. avium rootstock cvs.
Abstract: Shoot tips from accessions of wild cherry (Prunus avium L.) selected from British woodland, and also theP. avium rootstock cvs. F12/1 and Charger, were successfully establishedin vitro, and most were easily micropropagated on Murashige and Skoog (MS)-based media. In one accession, adventitious shoots occasionally developed from the extrafloral nectaries positioned at the base of leaf petioles of the initial explants. Micropropagation of cv. Charger was improved by culture on a Quoirin and Lepoivre and Woody Plant-based medium, and by supplementing the medium with 1-phenyl-3-(1, 2, 3-thiadiazol-5yl)urea (thidiazuron). Poor shoot production by F12/1 on 1, 3, 5-trihydroxybenzene (phloroglucinol)-free media was not improved by up to 18 months of regular subculture. Study of cv. F12/1 showed that shoots produced on a MS-based medium with 1 mM phloroglucinol, 0.49 μM indolebutyric acid, 4.4 μM benzyladenine (BA) and 0.29 μM gibberellic acid (GA3), were easier to root over several subcultures than shoots produced on a similar medium with no GA3 and only 2.2 μM BA, but only in a rooting medium supplemented with 1 mM phloroglucinol.
TL;DR: Several types of explants, growth regulators, sugars and gelling agents were tested to induce somatic embryogenesis in Anthurium scherzerianum Schott and converted to entire plants on a medium with 0.46 μM kinetin.
Abstract: Several types of explants, growth regulators, sugars and gelling agents were tested to induce somatic embryogenesis in Anthurium scherzerianum Schott For induction, leaf pieces from micropropagated plants were found to be the best explant on a medium with 18 μM 2,4-dichlorophenoxyacetic acid and a high sucrose concentration (6), solidified with Gelrite Somatic embryos converted to entire plants on a medium with 046 μM kinetin Plantlets were transferred to greenhouse conditions for evaluation of plant uniformity
TL;DR: The ability to regenerate buds was correlated with the presence of oil glands at a stage in germination when oil secretion was not yet occurring, indicating the absence of polyploidisation during cell differentiation and under in vitro conditions.
Abstract: Up to 70% regenerating hypocotyls provided with 5 to 20 buds were obtained on MS medium containing 0.01 or 1 mg l-1 NAA and 0.2 mg l-1 BA or 0.2 mg l-1 BA and 0.2 mg l-1 TDZ. The ability to regenerate buds was correlated with the presence of oil glands at a stage in germination when oil secretion was not yet occurring. The regeneration of shoot meristems took place from the cells involved in the differentiation of these glands. Such glands could also appear during callus redifferentiation, giving rise to indirect regeneration. Rooting of the regenerants was efficient using a two-step procedure of induction under darkness in the presence of 3 mg l-1 IBA, followed by root development on medium devoid of growth regulators under a 16-h photoperiod, the medium being solidified with Gelrite. Regenerated plants showed no phenotypic alterations. Nuclear DNA contents in mother-plant material and regenerants were analysed using flow cytometry. There was no evidence of polyploidy in any of the samples, indicating the absence of polyploidisation during cell differentiation and under in vitro conditions. No regeneration was obtained from leaf or stem explants from micropropagated plantlets.
TL;DR: The morphological changes of treated plantlets, including substantial deposition of epicuticular wax and modified leaf surface anatomy were associated with increased ex vitro survival after four weeks in the greenhouse.
Abstract: Polyethylene glycol was added to the rooting medium ofmicropropagated grape shoots to induce water stress. At the end of the rooting stage, plantlets treated with 2% polyethylene glycol were compared with untreated control plantlets and greenhouse-grown plants. Leaves of treated plantlets had the highest deposition of epicuticular wax, followed by those of the greenhouse and control. Stomatal index did not vary among treatments. However, differences in leaf epidermal cell configuration were observed among treatments. The morphological changes of treated plantlets, including substantial deposition of epicuticular wax and modified leaf surface anatomy were associated with increasedex vitro survival after four weeks in the greenhouse.
TL;DR: Polymerase chain reaction and Southern blot analysis revealed stable integration of transferred DNA in Agrobacterium rhizogenes A4 induced hairy roots on stem sections of gentian plants.
Abstract: Agrobacterium rhizogenes A4 harboring the agropine type root-inducing plasmid (pRiA4) induced hairy roots on stem sections of gentian plants. Transgenic gential plants were regenerated from the hairy roots at a frequency of 19% adventitious shoot regeneration on Murashige and Skoog medium containing 30 g l-1 sucrose, 10 mg l-1 N-phenyl-N′-1,2,3-thiadiazol-5-yl urea, 1 mg l-1 1-naphthaleneacetic acid and 2 g l-1 gellan gum. The shoots were grown to maturity in a growth chamber after acclimatization. The mature transformed plants showed distinct variations in their phenotypes, such as dwarfness. Polymerase chain reaction and Southern blot analysis revealed stable integration of transferred DNA.
TL;DR: It was conduded that the four Gentiana species were amenable to propagation in vitro, except in G. lutea, in which adventitious roots were induced by applying naphthaleneacetic acid.
Abstract: The growth of axillary shoots was initiated on nodal stem segments, excised from aseptically grown seedlings of Gentiana acaulis L., G. cruciata L., G. lutea L. and G. purpurea L. In later subcultures, a basal callus tissue developed on the shoots, giving rise to de novo formed buds. Optimum benzyladenine and indoleacetic acid combinations for shoot development were established. They were slightly different in the four species. From 35-70% of shoots rooted spontaneously, except in G. lutea, in which adventitious roots were induced by applying naphthaleneacetic acid. It was conduded that the four Gentiana species were amenable to propagation in vitro.
TL;DR: The results showed that lawsone accumulation in vivo is restricted to the aerial part of the plant, and the possibility of inducing lawsone biosynthesis in root cultures was studied.
Abstract: The improvement of axillary shoot formation of Lawsonia inermis L. cultured in vitro depended on the iron concentration in the culture medium. Regenerated shoots were rooted on a hormone-free half-strength Murashige and Skoog medium (1/2 MS) before transfer to greenhouse conditions. Determination of lawsone in the plant material was investigated using a new HPLC method. The results showed that lawsone accumulation in vivo is restricted to the aerial part of the plant. In addition, the possibility of inducing lawsone biosynthesis in root cultures was studied. Hairy root cultures were established by a co-culture method using leaf segments of L. inermis and Agrobacterium rhizogenes NCIB 8196. Of several basal media tested, the production of lawsone (0.13% dry weight) was only observed in hairy roots tissues incubated in the dark and cultured in 1/2 MS or MS media.
TL;DR: An efficient and novel method of direct shoot regeneration from root tips in garlic was developed and has potential applicability for rapid propagation of garlic.
Abstract: An efficient and novel method of direct shoot regeneration from root tips in garlic was developed. The influence of growth regulators, basal media and age of root explant on shoot initiation and proliferation was examined. The best growth regulator combination was 1-naphthaleneacetic acid and 6-benzyladenine at 1 and 10 µM, respectively, inducing shoot initiation from 75% of the explants. The frequency of shoot initiation on different basal media was similar. Explant root tips from plantlets taken 15 to 18 days after sprouting showed the highest shoot initiation (95%). In contrast to Murashige and Skoog medium, which produced more than 10 shoots per explant, B5 medium produced smaller shoots, although the number was higher. Rooting of individual shoots was induced after transfer to medium without growth regulators. Plantlets, after acclimatization in a growth cabinet, were successfully transplanted to the field, and no phenotypic variation was observed among them. The technique has potential applicability for rapid propagation of garlic.
TL;DR: In all cases, shoot cultures of N. confusus were capable of galanthamine biosynthesis, with the best results at 9% sucrose concentration, and the growth of the regenerated plants treated with 9% fructose was significantly greater.
Abstract: In order to produce galanthamine, an alkaloid currently being tested in Alzheimer's disease therapy, we have used in vitro organ cultures of Narcissus confusus (Amaryllidaceae) plants starting from two different explants: double scale segments with basal plate from bulbs (organogenic cultures), and mature seeds (callogenic-organogenic cultures). Shoot-clumps were induced from buds obtained from twin-scales and from organogenic calluses on a MS medium supplemented with 1 mg l−1 2,4-D and 5 mg l−1 BA. Shoot-clumps were then developed partially submerged in a liquid medium. After one month of precondition, the shoot-clumps were cultured in liquid media with different concentrations of sucrose, from 3% to 18% (w/v) for 14 days. The growth of the regenerated plants treated with 9% sucrose was significantly greater. Under a photoperiod 16 h light/8 h dark, the shoot-clump cultures subjected to the two highest sucrose concentrations gave rise to higher dry weight/fresh weight ratios. Different doses of sucrose affected not only the alkaloid profile in the shoot-clump tissues but also that excreted to the medium. In all cases, shoot cultures of N. confusus were capable of galanthamine biosynthesis, with the best results at 9% sucrose concentration.
TL;DR: A method has been developed for rapid propagation in vitro of Vitis vinifera cv from axillary-bud microcuttings harvested from plantlets initially cultured in vitro, and IBA at 2.5 µM was found to induce a good rooting- system in 100% of the shoots.
Abstract: A method has been developed for rapid propagation in vitro of Vitis vinifera cv. 'Pinot noir' from axillary-bud microcuttings harvested from plantlets initially cultured in vitro. The requirement of plant growth regulators for the different stages of the micropropagation was examined. BA at 8.9 µM added to MS basal medium was found to be optimal for culture establishment, while for subcultures, the concentration of BA was reduced to 4.4 µM to prevent hyperhydricity. Among the two auxins (NAA and IBA) tested for rooting, IBA at 2.5 µM was found to induce a good rooting- system in 100% of the shoots. The advantages of this method, using microcuttings from established plants in vitro, is discussed.
TL;DR: The investigation revealed that the majority of somatic embryos showed normal root formation and consisted of highly vacuolated cells in the poorly structured shoot apex, and the implications for genetic improvement of banana and plantain by in vitro mutation breeding and gene technology are discussed.
Abstract: The origin of somatic embryos derived from rhizome explants of triploid Musa cv. Grand Nain was the subject of histological studies during different phases of ontogenetic development. The investigation revealed that the majority of somatic embryos showed normal root formation and consisted of highly vacuolated cells in the poorly structured shoot apex. The embryogenic mass and somatic embryos were mostly derived from several morphologically competent cells. Single cell origin depended on the presence of organogenetically functional vascular cells of rhizome explants and occurred infrequently. The implications of these findings for genetic improvement of banana and plantain by in vitro mutation breeding and gene technology are discussed.
TL;DR: There is a great possibility that reintroduction of certain micro-organisms or their combinations to tissue culture propagules, bacteria and vesicular-arbuscular mycorrhiza in particular, can be utilized in agricultural and horticultural practices for the purpose of transplants protection against diseases, improvement of establishment and overall performance.
Abstract: In natural habitats, free-living micro-organisms play an important role in plant growth, development and adaptation to extreme environments [1–4]. They form close associations with plant roots and colonize internal and external tissues [2–5]. Production of axenic plantlets under tissue culture conditions devoids plants of these natural allies. Combination of the culture conditions, high humidity and high sugar in particular, and lack of microbial elicitors triggering or enhancing certain metabolic pathways, make tissue culture transplants vulnerable to pathogens and other environmental stresses [6]. It is well documented that plantlets have reduced photosynthetic capacity [7], lower wax deposits [8], poorly functioning stomata [9,10], underdeveloped root system, and very few leaf and root hairs [6,10]. There is a great possibility that reintroduction of certain micro-organisms or their combinations to tissue culture propagules, bacteria and vesicular-arbuscular mycorrhiza in particular, can be utilized in agricultural and horticultural practices for the purpose of transplants protection against diseases, improvement of establishment and overall performance ([3,4,6,7] and papers by A.C. Cassells and E. Wilhelm in this Proceedings).
TL;DR: Though smaller in size, in vitroFlorets were morphologically comparable to the in vivo florets, and studies by scanning electron microscopy showed some discrepancies in the pollen wall development in vitro.
Abstract: Seedling explants of Bambusa arundinacea were cultured in a Murashige & Skoog (MS) based liquid medium, supplemented with sucrose (2), coconut water (5) and 6-benzylaminopurine (22 μM) In 3–6 months about 70 of the cultures flowered A comparison was made between in vitro and in vivo flowering Though smaller in size, in vitro florets were morphologically comparable to the in vivo florets Anthesis in in vivo flowering took place in the morning hours It was more or less synchronized and was dependent on the atmospheric temperature and humidity The lemma and palea opened to expose both androecium and gynoecium to the pollinating agent (wind) In in vitro flowering, some florets opened as in their in vivo counterparts, some did not open but the anthers protruded from the tip of the partially opened lemma and palea Anthesis was not synchronized under in vitro conditions Pollen fertility in in vivo and in vitro flowerings were approximately 93 and 31 respectively Studies by scanning electron microscopy showed some discrepancies in the pollen wall development in vitro The trifid stigmas of in vivo florets were highly feathery with many papillae and withered soon after pollination or within few hours The stigmas of in vitro developed florets were smaller with fewer and stouter papillae They remained turgid for relatively longer periods Seed production in in vivo flowering was profuse whereas in in vitro flowering seeds were produced only when many florets opened at the same time, in the same culture vessel
TL;DR: Adding growth regulators to the artificial endosperm and culture of the single nodes for root primordia initiation for 3, 6 or 9 days in darkness before encapsulation allowed production of 58%, 60% and 66% of plantlets, respectively.
Abstract: In order to be considered usable as synthetic seeds, encapsulated explants sown underin vitro orex vitro conditions must be able to produce whole plantlets. Ninety percent of non-encapsulated M.26 apple rootstock single nodes produced a plantlet (i.e., a well-formed shoot with a root system) after 30 days of culturein vitro if the explants were previously given a 24-hour treatment with 24.6 µM IBA and 15 g 1−1 sucrose in darkness. In contrast, when the single nodes were encapsulated in a calcium-sodium alginate bead immediately after the same treatment only 10% of the encapsulated explants formed a plantlet. Addition of growth regulators to the artificial endosperm and culture of the single nodes for root primordia initiation for 3, 6 or 9 days in darkness before encapsulation allowed production of 58%, 60% and 66% of plantlets, respectively.
TL;DR: Young inflorescences of two Brazilian soybean cultivars were subjected to 4 °C pretreatment for 0, 5, and 10 days and Histological analysis of such embryos showed that they were similar to zygotic embryos.
Abstract: Young inflorescences of two Brazilian soybean cultivars (IAS 5 and RS 7) were subjected to 4 °C pretreatment for 0, 5, and 10 days Cytological examinations of the t in vitro anthers were done during the first four weeks of culture The cold pretreatment had no clear effect on the frequencies of symmetrical-binucleate microspores or multinucleate grains The multinucleate grains might originate either by symmetrical or assymmetrical division The best medium for callus and embryo induction was B5 long containing 20 mg l−1 2,4-dichlorophenoxy acetic acid and 05 mg l−1 benzyladenine The frequency of anthers/calli with embryos was about 2% in all cultivars Histological analysis of such embryos showed that they were similar to zygotic embryos
TL;DR: Encapsulation of somatic embryos did not negatively affect the maintenance of their embryogenic competence, the mean number of secondary embryos being significantly increased when the alginate beads included the growth regulators of the secondary embryogenesis medium.
Abstract: Somatic embryos of Camellia japonica were hydrogel encapsulated using 3% sodium alginate and 01 M calcium chloride to produce synthetic seeds Both germinability and repetitive embryogenesis capacity of the encapsulated embryos were investigated The frequency of in vitro germination into plants of artificial seeds was affected by various nutrient additives included in the encapsulating matrix The addition of Ca-free Murashige and Skoog basal medium plus 3% sucrose plus 144 µM gibberellic acid and 285 µM indole-3-acetic acid to the alginate capsule resulted in 63% plant recovery rate, which was similar to that of non-encapsulated embryos Encapsulation of somatic embryos did not negatively affect the maintenance of their embryogenic competence, the mean number of secondary embryos being significantly increased when the alginate beads included the growth regulators of the secondary embryogenesis medium (444 µM 6-benzyladenine and 041 µM indole-3-butyric acid) Storage at 4°C significantly reduced the survival and germination into plants frequencies of both encapsulated and non-encapsulated embryos, but the reduction was much greater for non-encapsulated embryos Plant recovery of encapsulated embryos was 40% and 30% following storage for 30 and 60 days, respectively