The influence of growth regulators and explant position on the growth and development of Mandevilla sanderi (Hemsl.) Woodson in vitro

Mandevilla is a valuable ornamental pot vine. However, due to a low propagation rate, it is difficult to keep up with the demand. Micropropagation would allow to produce lots of plants for the market. The aim of the study was to determine the effect of the growth regulators addition to the media and explants orientation on multiplication of Mandevilla sanderi, an exotic, ornamental pot plant. The shoot tips were placed vertically or horizontally on the Murashige and Skoog medium supplemented with benzyladenine (BA) or isopentenyladenine (2iP), at concentrations of 1, 2.5 or 5 mg·dm–3 singly or in combination with thidiazuron (TDZ) at concentrations of 0.01, 0.025 or 0.05 mg·dm–3. Maximum multiplication rate was noted on the media supplemented with 2.5 mg·dm–3 2iP + 0.025 mg·dm–3 TDZ or 5 mg·dm–3 2iP, when explants were placed horizontally. All the treatments resulted in callus formation. Medium supplemented with the highest concentration of BA combined with TDZ was the most active in callus growth.

Effect of Hormonal Regime and Explant Type on Cell Clusters Expression of Maize Mutants (Zea Mays L) Derived from Gamma Irradiated Seeds of Ev8728 variety

Maize (Zea mays L.) seeds irradiated with gamma or not from the fourth self-fertilisation cycle were selected for tissue culture. For this purpose, MS medium supplemented with 30 g.L-1 sucrose, 100 mg.L-1 casein hydrolysate, 100 mg.L-1 myo-inositol and 6 g.L-1 agar was used. For this purpose, three auxins type (2.4-dichlorophenoxyacetic acid (2.4-D), 2-methoxy-3.6-dichlorobenzoic acid (Dicamba) and Indole-3-Acetic Acid (AIA)) and explants (root, epicotyl and leaf) were tested. The results showed that 2.4-D more precisely at 3.5 mg.L-1 was the best auxin for callus induction in the different maize mutants studied. The induction rate, dry matter weight and water content of callus varied according to the type, age, explant position and the maize mutants studied (control, 200 and 300 grays). Thus, the 7-day root and more precisely its basal part was better for callogenesis. In addition, mutants of the 200 grays dose were more expressive in the ability to induce callus in EV8728maize variety.

Effects of explant position and orientation, medium ph and nitrogen sources on micropropagation of blackberry

Composition of the medium and the explant origin are factors that interfere on success of micropropagation of Rubus species. For blackberry cultivar LochNess it was not investigated yet how the position and orientation of explant, pH levels and nitrogen source interfere on micropropagation. In this work, focused on the establishment of in vitro culture, variables were studied on R. fruticosus cv Loch Ness, such as the choice of the explants depending on their original position on the mother plant, pH level and nitrogen sources of the culture medium. For the first time in vitro on Rubus, the downward orientation (capogatto) of shoot tips explants was compared with the normal upward orientation. The highest weight and length values were recorded for the shoots proliferated from basal and nodal explants. For the initiation medium, the best multiplication rate were obtained in pH adjusted to 4.5. Shoot length was influenced by the nitrogen source; when associated with an increased light intensity, the complete substitution of ammonium by nitrate allowed results comparable with those obtained with the control medium containing both sources. The use of aminoacids did not improve the results. Apex orientation did not affect anatomical parameters or rooting rates of wild Rubus, but more efforts should be devoted on in vitro capogatto technique considering that advantages like reduction of plant growth regulators, cultivation on the same medium culture for more time and easily rooting can be established.

Evaluation of Factors Affecting Direct Organogenesis in a Somatic Tissue Culture of Sinningia speciosa (Lodd.) Hiern

In this study, the influence of genotype, concentration of thidiazuron (TDZ), and explant position on the culture medium in organogenesis in a somatic tissue culture of two gloxinia cultivars was investigated. Isolated explants cultured on the medium containing TDZ formed adventitious shoots directly without an intervening callus phase. Explant regeneration frequency varied depending on the genotype, TDZ concentration, and explant position on the medium. The analysis of variance revealed that cultivar (C), TDZ concentration (T), position of explant on culture medium (P), and the interaction of C × T, C × P, T × P, and C × T × P significantly influenced the frequency of shoot formation. However, the effect of interface C × P and C × T × P on the number of shoots per explant was not significant. “Snowy” leaf explants manifested a significantly higher mean shoot formation frequency (p ˂ 0.01) in comparison with the cultivar “Midnight Purple”. The medium enriched with 3.5 μM TDZ resulted in the highest organogenesis frequency, while the highest shoot number per explant was acquired on medium supplemented with 4.0 μM TDZ. The explants of the tested cultivars cultured on the medium with the adaxial side down showed a significantly higher (p ˂ 0.01) shoot formation frequency in comparison with explants cultured on the medium with the abaxial side, and they showed a higher mean number of shoots per explant. An effective method for in vitro organogenesis of Sinningia speciosa (Lodd.) Hiern without an intervening callus phase was established.

Studying on the in vitro shoot formation of Opuntia ficus – indica (L.) Mill.

This study presented the elimination of the glochids in the areoles of Opuntia ficus-indica cladode induced the shoot formation from the explants containing the shoot apical meristem (SAM) on Murashige and Skoog medium (MS) supplemented with 6-benzylaminopurine (BA) 5 mg/L. Morphological and physiological changes in shoot formation process were analyzed. This process involved the constant stages: activation of cell division, initiating of meristematic region; formation of shoot primordium and shoot with leaves. The SAM position in the upper front of the cladode gave the highest shoot productivity. This position had the photosynthesis rate, respiration rate, endogenous indole acetic acid (IAA) and zeatin activity higher than the others. Difference of auxin concentrations increased the amount of shoots and shoot height. The maximum number of shoots per explant was obtained on MS medium supplemented with BA 5 mg/L and 1-naphthalene acetic acid (NAA) 0.5 mg/L. The elimination of SAM by removing the surface of the shoot gave the highest number of the shoot. The correlation of the glochids in the areoles, explant position, plant hormones, photosynthesis rate respiration rate and shoot formation were discussed.

Pengaruh Letak Posisi Eksplan dan Sitokinin Pada Perkecambahan Biji Manggis (Garcinia mangostana L.) Lokal Aceh Secara in-Vitro

The application of modern biotechnology is needed in order to enhance the genetic diversity of mangosteens. The application of tissue culture on mangosteens is an important thing to do to support the biotechnology program of mangosteen plants. The purpose of this research is to reveal the influence of location of explants and Benzylaminopurine (BAP) concentration on germination of local Acehnese mangosteens in vitro. This research was conducted at the Laboratory of tissue culture of the Faculty of Agriculture, Malikussaleh University from March to May 2017. The study used an environmental design in the form of Completely Randomized Design (CRD) with two factors. The first factor is the location of explant position is abaxial (L1) and adaxial (L2). The second factor was the concentration of BAP 0 mg / L (B0), 2.5 mg / L (b1), and 5 mg / L (B2). The results showed that the position of eksplan gave an effect on mangosteen germination in vitro for its shoot length variables. The explant positions that had the best effect on the growth of in vitro mangosteen sprouts were adaxial. BAP concentration had an effect on germination of mangosteen in vitro for its bud growth and life percentage. 2.5 ppm of BAP concentration was the best concentration for mangosteen seed growth in vitro. There was no interaction between eksplan position and BAP concentration in all observed variables