In Vitro Cellular & Developmental Biology - Plant最新文献

Axonopus compressus (Swartz) Beauv., a perennial herb in the Poaceae that has been introduced to a number of tropical and subtropical countries and regions, can serve as a lawn ground cover while its leaves can be developed as a bioenergy resource. It also displays some resistance to heavy metals, allowing it to be planted in areas and urban green spaces polluted by heavy metals. A. compressus is also used as a traditional Chinese medicine. This study is the first report on tissue culture of A. compressus. Stem explants induced shoot clusters on 6-benzyladenine (BA)-containing Murashige and Skoog (MS) medium, with 2.0 mg L^–1 BA inducing a shoot proliferation coefficient (SPC) of 10.89 within 30 d, while MS medium containing 2.0 mg L^–1 BA and 0.1 mg L^–1 α-naphthaleneacetic acid (NAA) amplified SPC to 12.88 within 30 d. SPC on MS medium supplemented with kinetin (KIN) or thidiazuron (TDZ) was not as high as on medium with BA and never exceeded 3.57 within 30 d. A. compressus formed adventitious roots easily, within 15 d, most efficiently on ½MS medium supplemented with 0.1 to 0.5 mg L^–1 IAA, NAA, or IBA, or even on auxin-free medium. Resulting plantlets displayed a high survival rate (> 98%) when transplanted to a substrate containing humus, or humus mixed with vermiculite or sand. Callus was also successfully induced from leaf sheaths on MS medium containing 1.0 mg L^–1 2,4-dichlorophenoxyacetic acid, even more so when 1.15 g L^–1 l-proline was added. Induced callus was able to differentiate into adventitious shoots on MS medium with 0.1 to 0.5 mg L^–1 KIN or BA. An efficient system of shoot proliferation, callus induction, and regeneration in A. compressus has been established.

This study describes a plantlet regeneration protocol of somatic embryos in Rosa ‘John F. Kennedy’ (hybrid tea rose). Different somatic embryo sizes exhibited significant differences in the single bud (SB type) regeneration rate and multiple bud (MB type) regeneration rate. The highest single bud (SB type) regeneration rate (27.10%) was obtained from the large size (4 mm × 5 mm). The multiple bud regeneration rate was highest at 39.60% for the medium size (3 mm × 4 mm). Changes in the endogenous hormone content and ratios of various types of embryogenic cultures were clearly diverse: higher contents of abscisic acid (ABA) and indole-3-acetic acid (IAA) occurred in the SPC explant (single-piece cotyledonary somatic embryo) with a regenerated single bud (SB type). In a MW-type somatic embryo (milky-white single-piece-cotyledon explant), the gibberellic acid (GA₃)/ABA ratio was the highest (1.807), and the IAA/GA₃ ratio was the lowest (0.902). However, the highest ratios of IAA/GA₃ (6.159) and the lowest ratios of GA₃/ABA (0.383) appeared in SB-type cultures. Additionally, the highest IAA/ABA ratios (6.535) and higher ratios of GA₃/ABA (1.729) were found in MB-type cultures. This indicated that ways to regulate plant cell totipotency in Rosa ‘John F. Kennedy’ somatic embryos differed between single bud (SB type) regeneration and multiple bud (MB type) regeneration. Finally, this study classified and summarized common intermediate materials in in vitro culture based on morphological characteristics and plantlet regeneration pathways.

Cryopreservation is a promising technique for the ex situ long-term conservation of plant biodiversity particularly of species that are not amenable to seed bank conservation. Garcinia indica (Thouars) Choisy is a species endemic to the biodiversity hotspot of the Western Ghats of India. Conservation of this species is difficult as it produces recalcitrant seeds, and therefore, it can only be conserved in the field genebanks or in their natural habitats. This high-value fruit tree species is listed as vulnerable due to the rapid loss of the natural population, and therefore, the conservation of its genetic diversity is imperative. This study described the first successful cryopreservation protocol for G. indica through a modified droplet vitrification technique using in vitro–derived shoots conserved in the In Vitro Gene Bank of the Indian Council of Agricultural Research - National Bureau of Plant Genetic Resources (ICAR-NBPGR), New Delhi. Among vitrification (V) and droplet vitrification (DV) techniques, only the DV technique yielded explant regeneration after cryopreservation. Apical shoots (2 mm long) collected from 24-wk-old explants (IC638183), without any pre-culture, showed maximum regeneration (51.76%) on Murashige and Skoog (MS) medium supplemented with 2.22 μM 6-benzylaminopurine (BAP). The regenerated shoots were hardened in a mist chamber successfully (85% survival), which is essential for the future restoration of the species in the field. With genotypic-dependent variation, this protocol was applicable to the other three accessions (IC638184, IC638185, and IC638186) with an average of 43.7% regeneration after cryopreservation, which can be implemented for the effective conservation of G. indica germplasm.

The conservation of threatened exceptional plants, which cannot be conserved by seed banking, requires in vitro technologies for many of the approaches needed for their long-term ex situ conservation. This study evaluated the current in vitro plant literature, as represented in Web of Science, to determine its taxonomic overlap with the families and genera of the 775 species currently listed as exceptional. Web of Science was searched using the terms micropropagation, somatic embryogenesis, zygotic embryo, and cryopreservation, and the target genera and families were identified in the more than 19,000 articles evaluated. There were five families with significant overlap between the in vitro literature and exceptional species: Fabaceae, Asteraceae, Orchidaceae, Arecaceae, and Rutaceae. However, there was less overlap at the level of genus, with Citrus, Coffea, and Quercus having the most articles. Significant gaps were also found, with 14 exceptional families and half of the exceptional genera having no representation in the Web of Science search results. The 20 exceptional species with the most articles were all economically important species, and these had 343 threatened congeners that could be prioritized for research. A highly important group of exceptional plants that was significantly under-represented in the literature was tropical woody species, which form the backbone of the diversity of the world’s threatened rainforests. Overall, there are areas of strength upon which to build future work, but significant gaps where research should be prioritized for effectively conserving exceptional plants.

Mitogen-activated protein kinase (MAPK) cascade is a widely distributed signaling pathway, which is involved in growth, development, and stress responses in plants. Nardostachys jatamansi (Caprifoliaceae) is a perennial, high-altitude Himalayan medicinal plant, which experiences varying environmental fluctuations throughout its life span. However, how the fluctuating environment is regulated via MAPKs in high-altitude medicinal plants, such as Nardostachys jatamansi as well as in other members of the Caprifoliaceae family, is poorly understood. In the present study, Lonicera japonica Thunb. (Caprifoliacae) was used as a model for genome-wide understanding of MAPKs in the Caprifoliaceae family; further, Nardostachys jatamansi was used for expression profiling of MAPKs under various growth stages and abiotic stress conditions. Twenty LjMAPKs and 20 NjMAPKs were identified from the Lonicera japonica genome and Nardostachys jatamansi transcriptome database. The identification, characterization, subcellular localization, phylogenetic analysis, chromosomal localization, gene structure, synteny, and cis-acting elements of the LjMAPKs and NjMAPKs gene family were evaluated using in silico approaches. Phylogenetic and other in silico investigations showed maximum similarity between LjMAPKs and NjMAPKs protein sequences. Cis-regulatory elements identified in the promoter region of LjMAPKs included development, light, phytohormone, and stress-responsive elements. Tissue-specific expression profiling showed ubiquitous expression of MAPKs in both L. japonica and N. jatamansi. However, differential transcript abundance was observed in leaf and root tissues of NjMAPKs under varying abiotic stress conditions. The present study’s findings provided a fundamental understanding of MAPKs in L. japonica and N. jatamansi and may contribute towards a better understanding of the molecular mechanisms regulating plant development and abiotic stress response.

Somatic embryogenesis is a developmental pathway where somatic cells of plants generate embryogenic cells that subsequently mature into somatic embryos under favorable conditions. This process is one of the most important in vitro techniques for plant propagation, with diverse practical implications. In this study, ectopic proliferation and somatic embryos from Tecoma stans (L.) Juss. ex Kunth cell cultures were induced by employing primary conditioning Murashige and Skoog medium supplemented with 1.0 mg L⁻¹ 2,4-dichlorophenoxyacetic acid. Subsequently, a secondary induction medium supplemented with a combination of 1.0 mg L⁻¹ 2,4-dichlorophenoxyacetic acid with various concentrations of 6-benzyladenine cytokinin (1 to 5 mg L⁻¹) was used to promote embryogenesis. The results revealed the successful formation of pre-embryonic and embryonic stages, including globular, heart, torpedo, and cotyledon stages within a 2-wk incubation period under the specified hormonal conditions, leading to subsequent development into the mature vegetative phase after an additional 4 wk. Significant embryo production (16 ± 2.0 torpedo stage embryos per 50 mL culture media) was observed in Murashige and Skoog medium enriched with 1.0 mg L⁻¹ 2,4-dichlorophenoxyacetic acid and 2.0 mg L⁻¹ 6-benzyladenine, surpassing the results observed with other concentrations (p-value < 0.0001). The generated somatic embryos can serve as a potential in vitro tool for the propagation, generation, and organogenesis of T. stans, contributing to its role as both an ornamental and medicinal plant. Moreover, the induction of somatic embryogenesis opens avenues for the potential production of T. stans bioactive secondary metabolites and diverse applications in biotechnology, biotransformation, and biocatalysis, particularly in the conversion of both exogenous and endogenous substrates, such as tecomine—the principal antidiabetic alkaloid in the leaf extract.

Herein, an in vitro multiplication protocol for Prunus campanulata was evaluated. The effects of 15.0, 30.0, and 45.0 g L⁻¹ sucrose and three flask sealing methods (PVC film, rigid polypropylene lid, and rigid lid with membrane) were analyzed at the multiplication, rooting, and acclimatization stages. For in vitro multiplication, shoot tips of approximately 1 cm in length containing two pairs of leaves from seedlings germinated in vitro in Woody Plant Medium (WPM) were used. Evaluations considered the multiplication of shoot apexes in three subcultures (at 40, 80, and 120 d) for survival, number of shoots, shoot length, number of leaves, and multiplication rate. In the rooting phase, the rooting percentage, number of roots, and root length were assessed. In the acclimatization phase under shaded and full sun conditions, seedling survival and biometric characteristics were evaluated, including stem diameter, height, and number of leaves. The addition of sucrose to the medium, at a concentration of 45.0 g L⁻¹, associated with sealing using PVC plastic film, showed inadequate results for in vitro multiplication of P. campanulata. The addition of sucrose to the culture medium in concentrations ranging from 15.0 to 30.0 g L⁻¹ favored in vitro rooting. The use of a permeable membrane for sealing enabled the growth of more vigorous shoots in terms of percentage of rooting and root length, and these seedlings stood out in the acclimatization phases with greater rates of survival and improved biometric characteristics.

Abstract

Gerbera represents one of the top five most important traditional cut flowers. A major factor influencing the success of the cut flower industry is vase life which in turn has a significant influence on consumer preference. Therefore, the present study considered the effect of silver nanoparticles (AgNPs) supplied in temporary immersion bioreactors (TIBs) on the growth and subsequent shelf life of gerbera flowers. The results showed an initial lag in the growth of plantlets produced from tissue culture, but this effect was reversed by the end of the study, particularly for plants exposed to AgNPs. Although AgNPs did not shorten the time to flowering (67 d in control plants compared with 73 d in AgNPs-treated plants), flower characteristics were not adversely affected by this delay. A significant finding from this study was the observation of improved vase life of flowers grown from plants treated with AgNPs (9.8 d) relative to control plants (8.2 d). This indicated the potential of AgNPs to sustain the longevity of cut flowers after harvest.

Areca concinna Thwaites (Arecaceae) is an endangered plant species endemic to South-Western Sri Lanka and distributed primarily in Sri Lanka, India, and Southeast Asia. This palm was listed under endangered plants species by IUCN (The International Union for Conservation of Nature) due to habitat loss. Clonal propagation is essential for conservation and maintenance of this endangered species. In an effort to conserve this plant species, a protocol was developed for clonal multiplication of A. concinna Thwaites. Immature inflorescence, immature embryos, and mature embryos were tested for callogenesis and subsequent somatic embryogenesis in M72 basal medium supplemented with the auxins 2,4-D and picloram. Of the three explants, somatic embryos were obtained only from mature embryos. Callus multiplication and somatic embryo formation in M72 basal medium supplemented with 2,4-D were found to be better over picloram media. Serial transfer of explants from higher to lower concentrations was essential for sustaining the multiplication of callus as well as for induction of somatic embryos. Somatic embryos grown in Y3 or 1/2 Y3 basal medium supplemented with 1.0 mg L⁻¹ BAP, 0.5 mg L⁻¹ NAA, and 0.25 mg L⁻¹ IBA exhibited shoot initiation and plantlet development. This protocol has its application in rapid multiplication of A. concinna Thwaites palms thereby enhancing the possibility of conservation of the endangered palm.