Search

Use of meta-topolin (mT) [6-(3-hydroxybenzylamino) purine] to scale up the plantain clone ‘CEMSA ¾’ in temporary immersion systems (TIS), when compared with conventional micropropagation protocols, has been shown to improve production and quality of microplants. To evaluate the impact of those innovations on plant field performance, in vitro plants of ‘CEMSA ¾’ were subjected to either an additional multiplication cycle using TIS or semi-solid medium (SS) in the presence of 4.44 μM mT or N 6 -benzyladenine (BA). Growth and yield components in the microplants grown in field – plant crop – and in the developed plants of the following field generation – first ratoon – were evaluated. Also (epi)genomic traits were studied by flow cytometry, fluorimetry-based AFLP and HPLC analyses of global genomic DNA methylation. Neither in vitro microprogation systems – TIS and SS – nor cytokinins – mT and BA – had any factorial effect on yield productivity of the plant crop. In the first ratoon, significant differences in yield appeared, with TIS-BA plants being more productive than those generated from TIS-mT. For most of the measured variables, the plant crop had higher values than the first ratoon, but true-to-type and each off-type phenotype of the plant crop was always inherited by their corresponding offspring of the first ratoon. The proportion of true-to-type plants was higher for SS-BA and TIS-mT culture conditions. Irrespective of micropropagation protocol and phenotype, in the plant crop, average genomic DNA content was maintained and global genomic methylation levels were similar. Nevertheless, dwarf individuals showed more AFLP polymorphisms with respect to mother plants than the rest of the micropropagated plants, and a dwarfism-related AFLP marker is proposed. On the basis of the results obtained and previous reports, the innovative TIS-mT protocol was deemed to be the most suitable plantain multiplication technique among those tested. more...

The positive effect of ventilation of the culture container on in vitro shoot proliferation and quality was already proven for different species. Hereafter we report on the evolution of the headspace during in vitro culture of plantain in a Temporary Immersion Bioreactor (TIB) on the one hand, and culture on semi-solid medium on the other hand. The CO2 and C2H4 concentration reached a maximum of 12% and 0.45 μl l−1, respectively in the control treatment on semi-solid medium, compared to 5.7% CO2 and 0.06 μl l−1 C2H4 in TIB. The minimal O2-concentration on semi-solid medium was 15.1%, compared to 19.3% in TIB. The multiplication rate was best in TIB, 6.4 compared to 4.3 in semi-solid conditions, and this was also the case for shoot height (4.3 cm compared to 3.3 cm), and leaf number (2.6 compared to 1.6). Moreover shoots produced on semi-solid medium showed distorted leaves. A typical day-night pattern in CO2 and O2 concentration was observed in TIB, as well as on semi-solid medium; this is illustrative for the photosynthetic capacity of the plant material produced in both systems. more...

The photosynthetic capacity changes and the main enzymatic systems related to carbon metabolism were investigated during the in vitro culture of plantain shoots (Musa AAB cv. CEMSA 3/4) in temporary immersion bioreactors (TIB) and their subsequent acclimatization. The maximal rate of photosynthesis (Pn), transpiration, and the activity of the carbon metabolism enzymes phosphoenolpyruvate carboxylase (PEPC), acid invertase (AI), pyruvate kinase (PK) and sucrose phosphate synthase (SPS) were measured every 7 d during the 21 d of elongation in TIB, and the following 42 d of acclimatization. Sucrose content in the liquid medium and in the leaves was also determined. The most significant changes in plant growth were observed during acclimatization. During the in vitro stage photosynthesis was limited (4–6 μmol CO2 m−2 s−1); the photosynthetic rate however increases rapidly and significantly as soon as in vitro culture is over during acclimatization. PEPC activity increased during the whole evaluation ... more...

The positive and reliable effect of temporary immersion systems on in vitroshoot proliferation was already proved for different plant genera and it is now presented as an alternative for plantain micropropagation. Some culture parameters affecting the efficiency of the twin flasks system or temporary immersion bioreactor (Escalona et al., 1999) were investigated. Three different cytokinins (benzyladenine, thidiazuron and meta-topolin) were added to the culture medium and meta-topolin at a concentration of 4.4 μM was proved to be the most efficient. Successive subcultures (28 days per subculture) were performed on medium supplemented with meta-topolin, revealing a decrease in multiplication after the 6th subculture. Multiplication rate was not changed within the ranges of immersion times (4, 12 or 22 min) and frequencies (every 3, 5 or 7 h) tested. The size of the bioreactor (250, 1,000, 5,000 or 10,000 ml) and the volume of medium per inoculum (10, 20 or 30 ml) were also evaluated and appeared to have an influence on the multiplication. A proportion of 25–100 ml of headspace per inoculum and 30 ml of medium per inoculum resulted in a multiplication rate > 13 in 28 days. more...

La automatización de la producción de plantas con el empleo de Biorreactores de Inmersión Temporal (BIT) constituye una herramienta eficaz para la propagación in vitro con la cual se elevan los coeficientes de multiplicación y se aumenta la calidad del material propagado. Algunos factores que influyen en este proceso son las características de los explantes que se emplean para inocular los BIT, la manipulación de los mismos y su estado fisiológico. Estos, aparejados a los indicadores de eficiencia del sistema, son elementos a tener en cuenta en el estudio de la morfogénesis de cultivos como el plátano, que presenta índices de proliferación bajos en medio semisólido. Con el objetivo de optimizar el protocolo descrito por Roels, et al. (2005), se evaluó el efecto del manejo del explante (con división y sin división), el volumen de medio de cultivo durante tres ciclos de proliferación de brotes de plátano cv. CEMSA ¾ sobre el coeficiente de multiplicación y la calidad de los mismos. El mayor coeficiente de multiplicación se logró con el tratamiento en el que se incrementó el volumen del medio de cultivo en función de la biomasa sin seccionar el explante durante los tres ciclos de propagación. Estas modificaciones al protocolo de Roels, et al. (2005), al reducir la manipulación de los explantes durante cada ciclo de cultivo y aumentar las tasas de multiplicación, lo hacen más eficiente y simple, y de esta manera más aplicable para la propagación de plátano a gran escala. The automation of the production of plants with the use of Temporary Immersion Bioreactors (TIB) is an effective tool for in vitro propagation, with which rates of multiplication and increases the quality of the material spread are increased. Some factors influencing this process are the characteristics of the explants used to inoculate the BIT, the manipulation of the data and the physiological state. These factors, coupled with efficiency indicators of the system, are elements to be considered in the study of morphogenesis in crops such as plantain, which has low growth rate in semisolid medium. In order to optimize the protocol described by Roels, et al. (2005), we evaluated the effect of management of the explants (with division and without division), thevolume of culture medium for three cycles of shoot proliferation of banana cv. ¾ CEMSA on the coefficient of multiplication and their quality. The highest multiplication rate was achieved with the treatment which increased the volume of culture medium in terms of biomass without severing the explants during the three cycles of propagation. Since they reduce the manipulation of the explants for each crop cycle, and they increase the multiplication rate making it more efficient and simple, these modifications to the protocol of Roels, et al. (2005), make more applicable the propagation of plantain on a large scale. more...