RESUMEN
BACKGROUND: Tissue culture and rapid propagation technology is an important way to solve the difficulties of plant propagation. This experiment aims to explore the appropriate conditions at each stage of the red maple's tissue culture process and to obtain plantlets, thus providing a theoretical basis for the establishment of the red maple's tissue culture system. RESULTS: The results showed that the stem segment is the most suitable explant for inducing embryogenic callus. The MS (Murashige&Skoog) + 0.8 mg/L TDZ (Thidiazuron) + 1.0 mg/L 6-BA (6-Benzylaminopurine) + 0.5 mg/L IAA(Indole-3-acetic acid) + 35 g/L sucrose+ 7.5 g/L semi-fixed medium was the best for callus formation. When selecting type VI callus as embryonic callus induction material, MS + 0.6 mg/L TDZ + 0.5 mg/L 6-BA + 2.0 mg/L IAA + 35 g/L sucrose+ 7.5 g/L semi-fixed medium can get embryonic callus. The optimal medium for adventitious bud induction is MS + 1.0 mg/L TDZ + 3.0 mg/L 6-BA+ 0.2 mg/L NAA (1-Naphthaleneacetic acid) + 1.2 mg/L IAA + 35 g/L sucrose+ 7.5 g/L semi-fixed medium. The induction rate of adventitious roots in MS + 0.6 mg/L TDZ + 1.0 mg/L 6-BA+ 3 mg/L NAA + 35 g/L sucrose+ 7.5 g/L semi-fixed medium was the highest, reaching 76%. CONCLUSIONS: In the course of our research, we found that PGRs play an important role in the callus induction stage, and the effect of TDZ is particularly obvious; The callus cells grow and proliferate according to the "S" growth curve, and can be sub-cultured when the highest growth point is reached to maintain the rapid proliferation of the callus cells and to avoid inactivation of callus caused by tight niche.
Asunto(s)
Acer/crecimiento & desarrollo , Cámbium/embriología , Brotes de la Planta/crecimiento & desarrollo , Acer/embriología , Raíces de Plantas/crecimiento & desarrollo , Brotes de la Planta/embriología , RegeneraciónRESUMEN
The haustorium in parasitic plants is an organ specialized for invasion and nutrient uptake from host plant tissues. Despite its importance, the developmental processes of haustoria are mostly unknown. To understand the dynamics of cell fate change and cellular lineage during haustorium development, we performed live imaging-based marker expression analysis and cell-lineage tracing during haustorium formation in the model facultative root parasite Phtheirospermum japonicum Our live-imaging analysis revealed that haustorium formation was associated with induction of simultaneous cell division in multiple cellular layers, such as epidermis, cortex and endodermis. In addition, we found that procambium-like cells, monitored by cell type-specific markers, emerged within the central region of the haustorium before xylem connection to the host plant. Our clonal analysis of cell lineages showed that cells in multiple cellular layers differentiated into procambium-like cells, whereas epidermal cells eventually transitioned into specialized cells interfacing with the host plant. Thus, our data provide a cell fate transition map during de novo haustorium organogenesis in parasitic plants.
Asunto(s)
Cámbium , Modelos Biológicos , Orobanchaceae , Epidermis de la Planta , Xilema , Cámbium/citología , Cámbium/embriología , Orobanchaceae/citología , Orobanchaceae/embriología , Epidermis de la Planta/citología , Epidermis de la Planta/embriología , Xilema/citología , Xilema/embriologíaRESUMEN
The secondary growth of a woody stem requires the formation of a vascular cambium at an appropriate position and proper patterning of the vascular tissues derived from the cambium. Class III homeodomain-leucine zipper (HD ZIP) transcription factors have been implicated in polarity determination and patterning in lateral organs and primary vascular tissues and in the initiation and function of shoot apical meristems. We report here the functional characterization of a Populus class III HD ZIP gene, popREVOLUTA (PRE), that demonstrates another role for class III HD ZIPs in regulating the development of cambia and secondary vascular tissues. PRE is orthologous to Arabidopsis (Arabidopsis thaliana) REVOLUTA and is expressed in both the shoot apical meristem and in the cambial zone and secondary vascular tissues. Transgenic Populus expressing a microRNA-resistant form of PRE presents unstable phenotypic abnormalities affecting both primary and secondary growth. Surprisingly, phenotypic changes include abnormal formation of cambia within cortical parenchyma that can produce secondary vascular tissues in reverse polarity. Genes misexpressed in PRE mutants include transcription factors and auxin-related genes previously implicated in class III HD ZIP functions during primary growth. Together, these results suggest that PRE plays a fundamental role in the initiation of the cambium and in regulating the patterning of secondary vascular tissues.
Asunto(s)
Tipificación del Cuerpo , Cámbium/embriología , Proteínas de Homeodominio/metabolismo , Leucina Zippers/genética , Proteínas de Plantas/metabolismo , Tallos de la Planta/embriología , Populus/embriología , Cámbium/citología , Cámbium/genética , Cámbium/crecimiento & desarrollo , Diferenciación Celular/genética , Regulación del Desarrollo de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Genes de Plantas/genética , Proteínas de Homeodominio/genética , MicroARNs/metabolismo , Mutación/genética , Especificidad de Órganos , Fenotipo , Filogenia , Reguladores del Crecimiento de las Plantas/genética , Proteínas de Plantas/genética , Tallos de la Planta/citología , Tallos de la Planta/genética , Haz Vascular de Plantas/genética , Haz Vascular de Plantas/crecimiento & desarrollo , Plantas Modificadas Genéticamente , Populus/citología , Populus/genética , Homología de Secuencia de Aminoácido , Madera/citología , Madera/genética , Madera/crecimiento & desarrolloRESUMEN
The processes underlying the formation of leaf vascular networks have long captured the attention of developmental biologists, especially because files of elongated vascular-precursor procambial cells seem to differentiate from apparently equivalent, isodiametric ground cells. In Arabidopsis leaves, ground cells that have been specified to vascular fate engage expression of ARABIDOPSIS THALIANA HOMEOBOX8 (ATHB8). While definition of the transcriptional state of ATHB8-expressing ground cells would be particularly informative, no other genes have been identified whose expression is initiated at this stage. Here we show that expression of SHORT-ROOT (SHR) is activated simultaneously with that of ATHB8 in leaf development. Congruence between SHR and ATHB8 expression domains persists under conditions of manipulated vein patterning, suggesting that inception of expression of SHR and ATHB8 identifies transition to a preprocambial cell state that presages vein formation. Our observations further characterize the molecular identity of cells at anatomically inconspicuous stages of leaf vein development.