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Para conservar ex situ, promover el uso y la potenciación de germoplasma nativo de interés ornamental como T. viereckii subsp. major una especie en estatus de riesgo Pr, se planteó la presente investigación con el objetivo de regenerar esta especie en el laboratorio de cultivo de tejidos vegetales (LCTV) del Campo Experimental Saltillo CIRNE-INIFAP considerando la estabilidad del explante durante subcultivos subsecuentes, determinar el tipo y la concentración de fitohormonas y la mejor relación citocinina-auxina que más influyen en la etapa de multiplicación in vitro. El segmento intermedio del tallo (SIT) obtenido a partir de vitroplantas se usó como explante. De 2017 a 2019 se evaluó la etapa de multiplicación utilizando el medio Murashige-Skoog al 50% de sus macrosales. Un diseño experimental completamente al azar con arreglo factorial, se usó para evaluar dos citocininas: 6-bencil aminopurina (BAP) y 6-furfuryl aminopurina (KIN) en cuatro concentraciones 2.5, 5, 7.5 y 10 mg L-1 en interacción con dos auxinas: ácido naftalenacético (ANA) y ácido indolbutírico (AIB) en una relación citocinina-auxina de 10:1. Se evaluaron 16 tratamientos estableciendo cinco SIT/frasco con 10 repeticiones/tratamiento. Esta evaluación se repitió cinco veces mediante subcultivos, evaluando cada diez semanas el número de brotes/explante (Nb) y la altura del brote (Ab, mm). El análisis de varianza (Anova) demostró que hubo estabilidad del explante durante los subcultivos manteniendo una tasa de multiplicación semejante por más de tres años, efecto importante para una multiplicación intensiva. Al analizar los tratamientos como efectos independientes en la prueba de medias de Tukey (p≤ 0.05), se seleccionó la interacción BAP: AIB y KIN: AIB con las concentraciones de 5 mg L-1 de BAP + 0.5 mg L-1 de AIB y 2.5 mg L-1 de KIN + 0.25 mg L-1 de AIB como los tratamientos que inducen brotes con una tasa de multiplicación de 9.25 brotes/explante con una Ab de 6.73 mm.

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Introduction: Mexican artisans use the linaloe tree for the production of handcrafts. The extracted oil from the endangered Mexican tree Bursera linanoe which main components are the terpenes linalol and linalyl acetate is protected because of its excessive exploitation. An alternative to mitigate the deforestation of the linaloe tree is the use of somatic embryos, which can be cultured in vitro. Objectives: In this study, we quantify the yield of linaloe oil extracted from three different linaloe embryogenic lines (LEL) B5, 54, and 2011 cultured in different micropropagation systems. Materials and Methods: Using a microwave technique extraction coupled with a Cleavenger device, it was possible to obtain the essential oil from the somatic embryos of B. linanoe. Results: This study suggest that the tested clones have different proliferation responses, depending on the propagation system culture. The LEL B5 harvested in a permanent immersion system showed the highest growth index (GI= 4.23) as well as the highest concentration of linalol and linalyl acetate with 0.1439 mg/mL and 0.5391 mg/mL respectively, while the LEL 54 harvested in a permanent immersion system and semi-solid, produced the lowest concentration of linalol and linalyl acetate with 0.0090 mg/mL and 0.0923 mg/mL respectively. Conclusion: The proliferation and oil yield varied according to the LEL's. However, the highest production of the biomass was measured under the TI system type RITA ® .

Objective: To induce in vitro flowering of vanilla (Vanilla planifolia) with different plant growth regulators (PGRs) using the double-layer technique. Design/methodology/approach: A layer of semi-solid Knudson C (KC) medium, added with 40 g L-1 sucrose, 15% coconut water (CW; v/v) and 7 g L-1 agar, was placed in 100 mL flasks. A liquid layer of the same composition without agar was placed on top. It was supplemented with different doses (mg L-1) of PGRs: 6-benzyladenine (BA) (7), thidiazuron (TDZ) (6), paclobutrazol (PBZ) (0.5) and gibberellic acid (AG3) (2). Plus two controls, C1: no PGRs + no CW; C2: no PGRs + CW. Vanilla shoots of 2 cm in length and with at least one axillary shoot were placed. They were incubated at a temperature of 26±2 °C day and 18 °C darkness, with light intensity of 55 µmol m-2 s-1 during 13 weeks. The number of shoots, leaves and roots was evaluated, as well as the length of shoots and fresh weight. Floral differentiation was evaluated at the tenth week by conventional microtechnique. Results: The number shoots and leaves and shoot length were significantly higher in C2. The number of roots increased with PBZ 0.5 mgL-1. C1 and C2 promoted higher fresh weight. Floral differentiation was observed with AG3 2 and PBZ 0.5 mg L-1 treatments. Limitations on study/implications: Further evaluation of other PGR doses and environmental conditions is required to achieve full floral differentiation of vanilla. Findings/conclusions: CW increased vegetative growth. AG3 and PBZ showed early floral differentiation in Vanilla planifolia, which is the first report of this phenomenon for the species.