Acclimatization Of Plantlets Research Articles

Integrative approach reveals new insights into photosynthetic and redox protection in ex vitro tobacco plantlets acclimatization to increasing light intensity

Integrative mechanisms involving photosynthetic and antioxidant protection regulated by light intensity during in vitro and ex vitro plantlets acclimatization are poorly understood. Tobacco plantlets grown under in vitro and ex vitro environments were exposed to different light regimes to evaluate the role of photosynthesis and antioxidant protection. In vitro plantlets displayed a narrow photosynthetic capacity to cope with light as revealed by low net CO2 assimilation (PN), decreased actual quantum efficiency of photosystem II (ΦPSII) associated with non-induction of non-photochemical quenching (NPQ). In contrast, acclimated ex vitro plants showed strong stimulation in PN whereas ΦPSII and NPQ remained at high levels. In vitro plantlets exposed to moderate light suffered strong oxidative stress associated with increased activities of superoxide dismutases, catalases and ascorbate peroxidases, revealing an ineffective antioxidant system. In contrast, ex vitro plants presented lower oxidative damage in parallel to unchanged enzymatic activities, indicating an efficient antioxidant steady state. The levels of reduced ascorbate (ASC) and glutathione (GSH) were also increased only in ex vitro plants in response to excess light. An integrative study based on correlation networks and principal component analyses (PCA) corroborate that the two plant groups indeed displayed contrasting acclimation processes. In conclusion, during in vitro to ex vitro transition, tobacco plantlets exposed to increasing light display physiological adjustments involving photosynthesis and improvement of the enzymatic and non-enzymatic antioxidant systems. These findings highlight the importance of integrative approaches to understand ex vitro acclimatization to environmental stimuli.

Plantlets Regeneration from Crown Bud Slicing of Pineapple (Ananas comosus)

Pineapple propagation by lateral shoots, suckers or crowns is often confronted with limited number of regenerated seedlings and high diversity in flowering and fruit formation. In order to solve this problem, this study offer an alternative method by using tissue culture techniques. This study aimed to determine the effect of growth regulators on plantlet regeneration from bud slicing of pineapple cv. Tangkit. Four levels of 2.4-D (0.0, 0.001, 0.01 and 0.1 ppm) in combination with BA (0.0, 0.1, 1.0 and 10.0 ppm) were tested on solid MS medium. Cultures were incubated in total darkness for a week followed by transfer to 16-hour photoperiod. Results showed that explants treated with 2,4-D and/or BA succeeded in regenerating adventitious shoots. Average leaf number did not differ significantly among treatments (P = 0.60). Highest leaf number (2.99 ± 0.23) was obtained on medium with 0.01 ppm 2,4-D without BA, followed by 0.1 ppm 2,4-D without BA (2.85 ± 0.33). Meanwhile, roots were only formed on medium with 0.1 ppm 2.4-D without BA (4.2 ± 0.37 per shoot). Thus, complete plantlets were regenerated only on medium supplemented with 0.1 ppm 2,4-D without BA. The growth of plantlets was relatively uniform, and plantlet acclimatization succeeded 100% on Jiffy pots. The finding of optimum concentration of 2.4-D and BA in this study is important to develop standard protocol for in vitro propagation of pineapple cv. Tangkit. Thus, the benefit of producing seeds in large quantities and relatively uniform in growth is made possible through tissue culture technique.

Penggunaan Adenin Sulfat Pada Perbanyakan Mikro Talas Jepang

Taro is a staple food source in several regions of Indonesia. One type of this crop, namely Japanese taro or satoimo [Colocasia esculenta (L.) Schott var. antiquorum], is widely consumed in Japan so that there are export opportunities into the country. To overcome the problem of lack of propagules in the cultivation of taro, quality seed production can be done with micro propagation. This study aimed to obtain MS tissue culture media with the right concentration of adenine sulfate for Japanese taro micro propagation. The study was designed as a single factor experiment with a Completely Randomized Design, with an experimental factors of adenine sulfate concentration consisting of 5 levels, namely: A0 (control, 0 mg / l), A1 (10 mg / l), A2 (60 mg / l ), A3 (110 mg / l), A4 (160 mg / l), and with 5 replications. The use of MS media with BAP 0.5 mg /l + adenine sulfate 160 mg/l gave the best results for shoot multiplication with an average number of shoots produced 21.40 per culture bottle, at 12 weeks after culturing. The success percentage of plantlet acclimatization was 86%, and tissue cultur propagules subsequently was able to grow normally under ex vitro conditions.

A submerged culture system for rapid micropropagation of the commercially important aquarium plant, ‘Amazon sword’ (Echinodorus ‘Indian Red’)

Echinodorus ‘Indian Red’ is an underwater plant, used worldwide for aquarium ornamentation. An efficient method for in vitro propagation and plantlet acclimatization of this popular aquarium plant was standardized. Surface-disinfected shoot-tips were cultured in submerged conditions in a solid–liquid bilayer medium, consisting of an upper, liquid layer (sterile distilled water) and a lower, solid layer Murashige and Skoog (MS) basal medium supplemented with 3.0% (w/v) sucrose, 0.8% (w/v) agar-agar, and plant growth regulators (PGRs) in different combinations and concentrations. The combination of 2.5 mg L−1 6-benzylaminopurine and 1.0 mg L−1 α-naphthaleneacetic acid improved the multiplication rate to a maximum of 26.8 ± 0.51 shoots per explant after 60 d of culture. The number of multiplied shoots increased with each regeneration cycle, thus from only 26.8 ± 0.51 shoots per explant (first regeneration cycle), this number increased to 33.5 ± 0.58 (second regeneration cycle), and to 38.3 ± 0.62 for the third regeneration cycle with the same medium composition. The highest number of roots (8.3 ± 0.28) per shoot was induced in the presence of 1.0 mg L−1 indole-3-butyric acid, but further growth of these roots was stunted. The best rooting was achieved on PGR-free ½-strength MS medium, where 6.1 ± 0.21 roots per shoot were induced with 5.8 ± 0.35 cm length after 30 d of culture. The regenerated plantlets were successfully acclimatized to submerged underwater conditions, with 100% survival rate. The present protocol is suitable for the commercial propagation of Echinodorus ‘Indian Red’ for aquarium-industries.

Effect of jasmonic acid on cold-storage of Taraxacum pieninicum encapsulated shoot tips

Jasmonic acid is involved in plants response to various abiotic and biotic stresses. The aim of this study was to examine physiological response of Taraxacum pieninicum to JA-treatments during shoots micropropagation and during cold storage at 4 °C under reduced light or in the darkness. Obtained results indicated that JA during preculture reduced significantly growth of shoots without impact on proliferation rate. During cold storage JA (24–72 µM) limited effect of cold stress what was manifested by reduced accumulation of proline and TBARS. Growth inhibition of the stored tissue was more effective when JA was inside synthetic seeds structure than after preculture on medium supplemented with JA. Shoot proliferation and rooting were effective during regrowth after cold storage combined with JA exposure. Only elongation of roots was inhibited after storage in this conditions. However, length of roots did not affect acclimatization of plantlets to ex vitro conditions.

English

Humic acid and brassinosteroid applications may be an alternative to decrease the pineapple plantlet acclimatization in in vitro cultivation, since promising results have been observed when these substances were independently applied in other propagation methods. In this sense, the aim of the present study was to evaluate the effects of humic acids and brassinosteroid application on 'BRS Vitoria' pineapple plantlets grown from in vitro cultivation during acclimatization. A randomized block design was used in a 5x2x4 factorial scheme, at five brassinosteroid doses (0, 0.25, 0.50, 0.75, 1.0 mg L-1) in the presence and absence of humic acids during four sampling periods (60, 90, 120 and 150 days after transplanting), with five replicates for each treatment. BIOBRAS-16 was used as the brassinosteroid source, and the organic soil conditioner Agrolmin HF® was used as the humic acid source. Plantlets were collected for evaluation every 30 days from 60 days after transplanting. The number of plantlet leaves, length and root mass were higher in the humic acid treatment without brassinosteroid application. Leaf, nitrogen, phosphorus, potassium, calcium and magnesium contents were of 13.04, 1.77, 40.2, 8.79 and 3.17 mg kg-1, respectively. Nitrogen and potassium contents in the plantlets decreased, while phosphorus contents increased as a function of acclimatization time, regardless of treatment. Key words: Ananas comosus var. comosus, propagation, in vitro.

Rooting of Pinus radiata somatic embryos: factors involved in the success of the process

In vitro conditions of the culture media, plant growth regulators and culture containers may cause anatomical and physiological changes that have negative effects on rooting and ex vitro acclimatization of somatic plantlets. The control of these factors could contribute to the improvement of somatic embryogenesis systems in conifers, especially in pines. The influence of macronutrient concentrations, explant type and culture containers in Pinus radiata D. Don in vitro somatic embryo rooting were analyzed. The highest rooting percentage was observed using half-strength macronutrient concentrations, complete micronutrients and vitamins of Quoirin and Lepoivre medium. Although the use of glass culture vessels was the best to increase the efficiency of the somatic embryogenesis process in terms of rooting, the use of ventilated containers resulted in a significant increase in the percentage of plants able to be planted in the field.

In vitro effects of GA3 on morphogenesis of CIP potato explants and acclimatization of plantlets in field

Improvement of potato has been accomplished using conventional and non-conventional approaches coupled with numerous tissue culture procedures. The aim of the present study was to assess the efficacy of gibberellic acid (GA3) on the morphogenesis of International Potato Center (CIP) potato explants and acclimatization of plantlets in the field. Nodal segments as an explant source (1–1.5 cm) were isolated from 31 CIP potato plantlets and were inoculated into Murashige and Skoog (MS) medium supplemented with 0.0 (control), 0.1, 0.5, or 1.0 mg L−1of GA3. The variation in growth parameters of the cultivars was then observed. The highest shoot induction occurred in MS medium containing 1.0 mg L−1 GA3 with an increase in the inter-nodal distance between nodes as compared to other treatments. Higher concentration (1.0 mg L−1) of GA3 significantly increased plant height and root length in the treated germplasm however; this concentration was inhibitory to the number of nodes and roots per plant. The number of leaves was significantly increased in plants receiving GA3 treatment at lower concentration (0.1 mg L−1). The 31 CIP genotypes were transplanted to the field and checked for yield quality traits. It was concluded from the results that GA3 had significant effects on morphogenesis and was effective in the acclimatization of CIP potato plantlets in field.

Improvement ofex vitroacclimatization of mulberry plantlets by supplement of abscisic acid to the last subculture medium

Other SectionsAbstractIntroductionMaterials and MethodsResults and DiscussionEffect of ABA on proline content during acclimatization of in vitro cultured mulberry plantletsAcknowledgementReference

In vitro photoautotrophic acclimatization, direct transplantation and ex vitro adaptation of rubber tree (Hevea brasiliensis)

We investigated the effect of carbon dioxide (CO2)-ambient (350 µmol CO2 mol−1) and CO2-enriched (1500 µmol CO2 mol−1) conditions of in vitro photoautotrophic system on two cultivars, ‘RRIM600’ and ‘RRIT413’ of rubber tree (Hevea brasiliensis) in an acclimatization process of 45 days. Survival percentage of in vitro rubber tree plantlets derived from somatic embryos under ambient CO2 was better than those under CO2-enriched conditions, especially in cv. ‘RRIT413’. Subsequently, the survival rate of ex vitro transplanted plantlets was similar to the in vitro plantlets and abnormal morphological characters such as light-green leaves (SPAD), small leaves in cv. ‘RRIT413’ acclimatized under CO2-enriched conditions were demonstrated 30 days after the plantlets were transferred into the soil. Maximum quantum yield of PSII, photon yield of PSII, stomatal conductance and transpiration rate in cv. ‘RRIT413’ acclimatized under CO2-enriched conditions were sharply declined by 39.0, 50.6, 47.1 and 45.8%, respectively as compared to those acclimatized under ambient CO2 conditions. In contrast, the in vitro acclimatized plantlets of cv. ‘RRIM600’ were un-responsive under both ambient- and enriched-CO2 conditions. In conclusion, genotypic dependent in response to CO2 enriched conditions in in-vitro acclimatization of rubber tree plantlets was evidently demonstrated as a key result to regulate plant growth and development in ex vitro environments. Interestingly, soluble sugar contents (sucrose, glucose and fructose) were increased after transplanting the plantlets of cv. ‘RRIM600’ acclimatized under CO2-enriched condition into the soil and thus, can be considered as an adaptive indicator of ex vitro adaptation.

English

Seedling production of canjerana (Cabralea canjerana (Vell.) Martius) has been limited by difficulty in germination, caused by recalcitrant behavior of their seeds. The objective of this study was to develop an efficient protocol for conservation and production of canjerana micropropagated plantlets. Seeds of canjerana were disinfected with 0, 2.5, 5.0, 7.5 and 10% of NaOCl solution, at immersion times of 10, 20 and 30 min to produce aseptic seedlings, which were cultivated on Murashige and Skoog (MS) and Woody Plant Medium (WPM) media. Nodal segments were cultivated in WPM medium supplemented with 0 and 2.5 µM of 6-benzylamine purine (BAP), kinetin (KIN) and thidiazuron (TDZ) or with 0, 1, 3, 6, 9 and 12 µM of BAP. Micro-cuttings were cultivated in MS and WPM media with 0 and 5.0 µM of indole-3-butyric acid (IBA) and naphthaleneacetic acid (NAA). The rooted micro-cuttings were acclimatized in a humid chamber in a greenhouse. The highest percentage of aseptic seedlings was produced with a solution of 7.5% of NaOCl and immersion times of 20 and 30 min. Adding BAP, KIN and TDZ or increasing concentrations of BAP to the WPM medium did not increase shoot number and length. Neither the base medium nor the auxin (IBA and NAA) had a significant effect on the survival of micro-cuttings after 60 days of cultivation, but the addition of 5.0 µM of NAA did increase the percentage of rooting and survival during the acclimatization. Both nodal segments and micro-stumps of canjerana have showed a low rate of multiplication. The addition of 5.0 µM of NAA to the basal medium increased the percentage of in vitro rooting and the percentage of survival during acclimatization of canjerana plantlets. Key words: In vitro propagation, in vitro multiplication, in vitro rooting, acclimatization, microclonal hedge.

Sucker multiplication in plantain using chicken manure as a substrate supplement

This study was carried out to evaluate the response of chicken manure (CM) as a substrate supplement for sucker multiplication and its effect on varietal differences in two subgroups of plantain (Apantu, a False Horn and Apem, a French plantain), using well-developed sword suckers. The research was laid out in a 2 x 2 factorial randomized complete block design with two substrates (chicken manure/sawdust mix and sole sawdust substrate) and the two groups of plantain with three replications. Data were collected on temperature changes within the substrates, number of plantlets sprouted, physical growth of the plantlets, root formation of plantlets and their correlation with plantlet establishment in the nursery. It was observed that plantlet/substrate-types had no significant effect on number of plantlets sprouted. The corms of Apantu showed a higher positive response to all the treatments applied than those of Apem. Plantlets from CM/SD mix recorded better physical parameters but had lower survival rate as compared to the SD treatments. There was low positive correlation (26.79%) between rooted sprouts and survival rates of regenerated plantlets, which might be due to differences in environmental conditions. Generally, Apantu produced more vigorous sprouts than Apem, which may be due to differences in maturity period and varietal effect. Planting-material-type did not have any effect on plantlet acclimatization, while media-type showed greater impact on number of plantlets and acclimatization. CM/SD mix influenced higher sprouts but plantlets were poorly acclimatized to the environment. Key words: Chicken manure, sawdust, ‘Apantu’ (False horn), ‘Apem’ (French plantain), cultivar, media, plantlets.

Growth media and mycorrhizal species effect on acclimatization and nutrient uptake of banana plantlets

The objective of this study was to investigate the acclimatization and performance of banana (Dwarf Cavendish) in two substrates inoculated with different AM fungi (Glomus. caledonium and G. macrocarpun) and assess the plantlets dependency on inoculation for phosphorus (P) and zinc (Zn) uptake along with biomass development. In addition, to investigate the role of mycorrhizal fungi in supporting acclimatization phase, a plant growth promotion study was set-up in greenhouse using micropropagated plantlets. Two growth media, as GM-I and GM-II were used accompanied by G. caledonium and G. macrocarpum. In first phase, 9 weeks acclimatization study was conducted and in second phase, acclimatized plants were propagated for 16 weeks in both inoculated and non-inoculated conditions. Plantlets acclimatization and nutrient uptake were recorded along with other parameters. Mycorrhizal inoculation significantly increased banana plantlets growth, root infection and P uptake. Plantlets inoculated with G. caledonium exhibited increase in shoot and root dry mass, P and Zn concentration, and root infection in the GM-I. The shoot and root dry mass, P and Zn concentration, and root infection were higher in GM-I than Konaktas soil series. Banana plantlets are mycorrhizal dependent (MD) and soil-grown banana plantlets are more MD than plants grown in the GM-I. Mycorrhizal inoculation seems to be a significant factor in decreasing mortality and increasing production of high-quality banana plantlets under micropropagation conditions.

Plant Regeneration from Somatic Embryogenic Suspension Cultures of Date Palm.

Somatic embryogenesis is one of the most important technologies for plant regeneration of elite date palm cultivars. Recently, considerable progress has been made in the development and optimization of this technique from embryogenic cell suspension cultures. This chapter describes a procedure for the rapid development of a large number of somatic embryos from embryogenic cell suspension cultures. An efficient plant regeneration protocol via somatic embryogenesis from cell suspension cultures starting with shoot-tip explants to plantlet acclimatization also is fully described. Low concentrations of 6-benzylaminopurine (BAP) to 0.3mg/L and high rate of subcultures each 7 days lead to improve the establishment and multiplication of somatic embryos in suspension cultures by limiting oxidative browning, associated with high total phenols and peroxidase activities. The detailed morphological observations have revealed the cells destined to become somatic embryos. Activated charcoal (AC) at 0.15g/L has a positive effect on growth rate of somatic embryos by reducing tissue and medium browning, phenolics, and peroxidase activity.

Improvement of In Vitro Date Palm Plantlet Acclimatization Rate with Kinetin and Hoagland Solution.

In vitro propagation of date palm Phoenix dactylifera L. is an ideal method to produce large numbers of healthy plants with specific characteristics and has the ability to transfer plantlets to ex vitro conditions at low cost and with a high survival rate. This chapter describes optimized acclimatization procedures for in vitro date palm plantlets. Primarily, the protocol presents the use of kinetin and Hoagland solution to enhance the growth of Barhee cv. plantlets in the greenhouse at two stages of acclimatization and the appropriate planting medium under shade and sunlight in the nursery. Foliar application of kinetin (20mg/L) is recommended at the first stage. A combination between soil and foliar application of 50% Hoagland solution is favorable to plant growth and developmental parameters including plant height, leaf width, stem base diameter, chlorophyll A and B, carotenoids, and indoles. The optimum values of vegetative growth parameters during the adaptation stage in a shaded nursery are achieved using planting medium containing peat moss/perlite 2:1 (v/v), while in a sunlight nursery, clay/perlite/compost at equal ratio is the best. This protocol is suitable for large-scale production of micropropagated date palm plantlets.

Diazotrophic bacteria and nitrogen fertilization on the growth of micropropagated pineapple plantlets during acclimatization

ABSTRACT: This study examines the effect of inoculation with diazotrophic bacteria and nitrogen fertilization on the growth of micropropagated pineapple cv. 'Vitória' plantlets during the acclimatization period. The experiment was carried out in a greenhouse in Campos dos Goytacazes, in randomized blocks, using a 2x5x5 factorial scheme, with the factors being two types of inocula (absence or presence of a mixture of diazotrophic bacteria that contained Burkholderia sp. UENF 114111, Burkholderia silvatlantica UENF 11711, and Herbaspirillum seropedicae HRC 54), five levels of urea (0, 2, 5, 7, and 10g L-1), and five evaluation periods (30, 60, 90, 120, and 150 days following the planting of plantlets in trays), and with four replications of each treatment. An increase in the dried weight of shoots and roots of micropropagated pineapple cv. 'Vitória' plants depended on inoculation with diazotrophic bacteria, and plantlets acclimatization could be reduced by up to 57 days, depending on the concentration of urea fertilizer.

Kultur Apeks untuk Penyediaan Bibit Unggul Tebu Varietas PS864 dan PS881

<p>In vitro culture<br />techniques have become alternative to help overcome the<br />problems those are often encountered in the provision of<br />seeds through conventional means. Micropropagation<br />through apex culture in sugarcane has several advantages,<br />such as the produced plants have higher genetic stability,<br />high multiplication rate, and more healthy seeds (especially<br />virus-free)., The aims of the the research were to produce<br />seeds of two varieties of sugarcane, namely PS864 and<br />PS881, through apex culture. Laboratory-scale research was<br />conducted at the Indonesian Center for Agricultural<br />Biotechnology and Genetic Resources Research and<br />Development (ICABIOGRAD), Bogor, while sowing seeds<br />nursery was done in the Experimental Station of Gowa,<br />South Sulawesi Assessment Institute for Agricultural<br />Technology. The experiments consisted of initiation and<br />regeneration of apexes, shoots multiplication, rooting<br />induction, and acclimatization of plantlets. Research results<br />showed the initiation and regeneration of PS864 and PS881<br />through apex culture could be done on MS basic medium<br />containing 0.5 mg/l BAP. Shoot proliferation of both varieties<br />increased in the second subculture. Addition of 1 mg/l BAP<br />into medium in the second subculture resulted in higher<br />average number of shoots than that of 5 mg/l BAP, both for<br />PS864 and PS881. Addition of 1 mg/l and 5 mg/l kinetin<br />showed no significant differences for shoot numbers<br />compared to that of PS864 in medium containing 1 mg/l<br />BAP. The average number of PS881 shoots in multiplication<br />media containing 5 mg/l kinetin was higher than that of 1<br />mg/l kinetin. Increased concentrations of NAA and IBA from<br />0.1 mg/l to 0.5 mg/l in the MS medium were correlated to the<br />increased number of roots in PS864 shoots. Meanwhile, only<br />increased concentration of NAA that affected rooting percentage<br />of PS881. Acclimatization showed the percentage of<br />the plantlets grown in polybags was higher than that directly<br />grown in planting bed. The primary seeds (G0) produced in<br />these experiments were ready to be reproduced again to<br />obtain further stages.</p>

In vitro propagation, micromorphological studies and ex vitro rooting of Alternanthera philoxeroides (Mart.) Griseb.: an important aquatic plant

In vitro propagation methods using ex vitro rooting were developed for Alternanthera philoxeroides using nodal segments procured from mature plants. The explants were surface sterilized with 0.1 % HgCl2 solution and inoculated on semisolid Murashige and Skoog (MS) medium containing various concentrations and combinations of plant growth regulators. All the explants responded, and maximum 8.0 ± 0.4 shoots per node with 4.7 ± 0.7 cm average length were induced from nodal meristems on MS medium supplemented with 2.0 mg/L 6-benzylaminopurine (BAP). The shoots were further multiplied (23.8 ± 1.9 shoots per explant) by repeated subculture of freshly induced shoots on MS medium augmented with 1.0 mg/L each of BAP and Kinetin, 0.1 mg/L indole-3-acetic acid (IAA) and additives. About 85 % shoots were rooted (18.0 ± 0.8 roots per shoot) in vitro on half-strength MS medium fortified with 1.5 mg/L indole-3-butyric acid (IBA). Maximum 96 % shoots were rooted using ex vitro methods, and 7.3 ± 1.0 roots per shoot induced with IBA (300 mg/L). The in vitro as well as ex vitro rooted plantlets were acclimatized successfully in the greenhouse. Biologically significant developmental changes were observed during acclimatization of plantlets, particularly in leaf micromorphology in terms of changes in stomatal frequency and stomatal index. This knowledge helps in understanding the response of the plants toward changed environmental conditions during hardening process. This is the first report on micropropagation of A. philoxeroides using ex vitro rooting method which can be used for the large-scale multiplication of this medicinally important aquatic plant.

El carbón activado y las condiciones de oscuridad en la micropropagación de banana variedad Nanicão

El objetivo del trabajo fue evaluar los efectos del carbón activado y las condiciones de oscuridad inicial sobre la propagación in vitro de banana (Musa spp.) variedad Nanicão. Fueron empleados 64 ápices provenientes de hijuelos de 20 - 30 cm. Los tratamientos consistieron en la combinación de dos concentraciones de carbón activado (2 y 3 g/l) y dos condiciones de oscuridad inicial (15 y 30 días). El diseño experimental utilizado fue completamente al azar con arreglo factorial 2 x 2 y cuatro repeticiones. Cada unidad experimental estuvo constituida por cuatro ápices. Las variables evaluadas fueron la tasa media de multiplicación, el porcentaje de supervivencia, oxidación, contaminación y aclimatización de plántulas. El análisis estadístico consistió en el ANAVA con un nivel de significancia del 5 %. Las medias fueron comparadas a través del test de Tukey al 5 % de probabilidad. Los resultados mostraron que la combinación de 2 g/l de carbón activado y 15 días de oscuridad inicial promovió el mayor porcentaje de supervivencia del primer subcultivo que alcanzo 57,30 %. En la fase de establecimiento el porcentaje de contaminación de los ápices de 39,06 % mientras que en el primer subcultivo de 22,39 %. La oxidación en la fase de establecimiento fue de 9,37 % y en el primer subcultivo fue de 8,85 %. Se concluye que la combinación entre la concentración de 2 g/l de carbón activado y 15 días de período de incubación inicial resulta efectiva en el aumento de la supervivencia de los ápices. Palabras clave: Musa spp, banana, supervivencia, multiplicación in vitro.

In vitro Propagation and Ex vitro Acclimatization of Potato (Solanum tuberosum L.) Using Nodal Cutting Explants

Potato (Solanum tuberosum L.) is an economic tuberous crop cultivated worldwide in the temperate, tropical and subtropical zones. It occupies the fourth largest food crop following wheat, rice and maize. The aim of this study is to establish a protocol for in vitro initiation, multiplication, rooting and ex vitro acclimatization of potato plants (Solanum tuberosum L.) cultivars Lady Balfour and Bellini. This study was carried out in the plant tissue culture laboratory, the Faculty of Agriculture, Saba basha, Alexandria University, Egypt during the period from 2013 to 2016. An efficient and reliable protocol for in vitro propagation and ex vitro acclimatization of potato (Solanum tuberosum L.) was optimized. Nodal cutting explants were inoculated on various initiation or establishment media with different combinations of NAA and KIN and the neoformed shoots were cultured on proliferation (multiplication) media with different combinations of NAA and BAP for the development of multiple shoots, and the elongation media to elongate of the neoformed shoot. The subsequent elongated shoots were rooted, and acclimatized ex vitro, successfully. The best medium for shoot initiation was MS medium supplemented with 1.0 mg/l KIN. The favorable medium for multiplication was the tested medium augmented with 2.0 mg/l BA and 0.250 mg/l NAA. In addition, the most effective medium for elongation was the used medium enriched with 0.250 mg/l NAA. Furthermore, in vitro the shoots showed healthy root development when the tested medium was supplemented with combination of 1.0 mg/l IBA and 0.50 mg/l NAA (rooting stage).The combination of sand:perlite:peatmoss (1:3:3, v:v:v) was used as substrates for the hardening of the in vitro plantlets, as a potting mix, was the best suited mix for the acclimatization of plantlets ex vitro.