Shoot tips excised from shoot culture of Salvia officinalis were encapsulated in 2% or 3% (w/v) sodium alginate and exposed to 50 mM calcium chloride for complexation. Immediately or after 6, 12 or 24 weeks of storage at 4°C, the synthetic seeds were cultured for 6 weeks on half-strength MS medium supplemented with indole-3-acetic acid (IAA) (0.1 mg/l) and solidified with 0.7% agar. The frequency of shoot and root emergence from encapsulated shoot tips was affected by the concentrations of sodium alginate and additives in the gel matrix (sucrose, gibberellic acid, MS nutrient medium) as well as duration of storage. The frequency of shoot and root induction of non-stored synthetic seeds was highest with shoot tips encapsulated with 2% sodium alginate containing 1.5% sucrose and 0.5 mg/l gibberellic acid (GA3). Shoot tips maintained their viability and ability to develop shoots even after 24 weeks of storage when they were encapsulated in 3% alginate with 1/3 MS medium, sucrose (1.5%) and GA3 (0.25 mg/l). Root formation tended to decrease with storage time. Overall, 90% of the plantlets derived from stored and non-stored synthetic seeds survived in the greenhouse and grew to phenotypically normal plants. This procedure can enable the use of synthetic seed technology for germplasm conservation of S. officinalis, a plant species of high medical and commercial value.

Roots of Codonopsis pilosula (Franch.) Nannf. are among the most popular Chinese herbal medicines, exhibiting various beneficial activities which support immunity and stress resistance. The plant shows high intraspecific genetic variation. There is a need for effective vegetative propagation methods yielding high and sustainable quality. Here we report a micropropagation method using axillary shoot proliferation. Nodal segments from aseptically germinated plants were inoculated on modified MS media enriched with different concentrations of cytokinins: benzyladenine, kinetin (1, 4, 10 or 20 μM) or thidiazuron (1, 4 or 8 μM), with or without the auxin NAA (1 μM). Axillary bud break was initiated most efficiently on media with 1 or 4 μM BA and 1μM NAA. Shoot number increased markedly in subsequent cycles of harvesting and transfer to fresh 1 μM BA and NAA medium, leading to the maximum 69 shoots (mean 38.16±4.35) from a single nodal explant in the fourth harvest. The shoots were successfully (>98% efficiency) rooted in MS medium containing high sucrose (60 g/L) and 5 μM IAA, and acclimatized to soil cultivation with a survival rate of 90%. These results can be used to establish a simple and commercially viable protocol for mass propagation of C. pilosula for plantations or breeding.

Abstract The aim of the study was to determine the effect of exogenous sucrose and cytokinin on ethylene production and responsiveness in relation to the shoot formation of Pelargonium × hortorum ‘Bergpalais’ in vitro. Increasing the concentration of sucrose from 15 to 40 g L−1 in medium containing meta-topolin (mT) resulted in a two-fold decrease in the number of shoots and leaves as well as a reduction in ethylene production. The addition of ethylene synthesis inhibitor (AVG) to mT-medium significantly reduced the ethylene production and the shoot growth, but it had no significant influence on the shoot formation. The mT-induced shoot formation was, however, significantly reduced in the presence of ethylene action inhibitor (AgNO3), in a manner dependent on sucrose levels. At the end of the subculture period, increased sucrose concentrations (15–40 g L−1) in the presence of mT and AgNO3 resulted in a 3.7-fold increase in ethylene emission. At the same time, the supply of sucrose caused a 2.8-fold increase in the level of endogenous abscisic acid (ABA). Our results may suggest that the inhibitory effect of high sucrose concentration (30 and 40 g L−1) may depend on its influence on ethylene sensitivity. It also suggests that sucrose-regulation of the shoot formation of Pelargonium in vitro is mediated by ABA.

Abstract The present study was conducted to determine the effect of the D genome on embryoid induction and green plant regeneration in wheat anther culture and how it is influenced by low temperature and mannitol treatment. For this reason, the anther culture response of two Canadian bread wheat cultivars and their extracted tetraploids (AABB) was studied. As controls two cultivars well responding to anther-culture (i.e. cvs. Kavkaz/Cgn and Acheron) and a no-responding cultivar (cv. Vergina) were used. Approximately 3000 anthers of these cultivars were cultured and three pre-treatments were applied: cold pre-treatment for 7 and 18 days at 4°C, and 0.3M mannitol for seven days at 4°C. W14 and 190-2 were used as induction and regeneration media, respectively, and the basic MS medium as the rooting medium. No green plants were produced from the tetraploids, which supports the view that the D-genome chromosomes are necessary for androgenic response in wheat. Furthermore, the Canadian cultivars performed better after 18-day pre-treatment at 4°C. The extracted tetraploids produced fewer embryoids and performed better after seven days of cold pre-treatment. The controls well responding to anther culture performed better than the Canadian cultivars, although their best response was recorded after seven-day cold pre-treatment. Cultivar Vergina produced no green plants. The presence of mannitol influenced negatively both embryoid and green plant production. It was concluded that the D genome plays a crucial role in anther culture response of wheat and that this response is influenced by both the genotype and the duration of cold pre-treatment.

Abstract The total soluble sugar content and antioxidant enzyme activities were studied for the first time during axillary shoot formation in Magnolia × ‘Spectrum’ in vitro in response to BAP (0.3 mg l−1), different levels of gibberellic acid (GA3; 0.0, 0.1, 0.5, 1.0 mg l−1), sucrose (20 and 30 g l−1) and nitrogen salts (KNO3/NH4NO3; 100/100% and 75/50% relative to MS medium). Among various GA3 and sucrose/nitrogen salts ratios, the most effective axillary multiplication (5.9 shoots/explant) and leaf formation (25.7 leaves per multiplied clumps) were obtained after addition of GA3 at 0.1 mg l−1 to a BAP medium containing 20 g l−1 sucrose and reduced levels of nitrogen salts (75% KNO3 and 50% NH4NO3). The addition of GA3 to the BAP medium enhanced shoot formation by 36% and leaf formation by 27%. The highest shoot formation capacity of M. × ‘Spectrum’ in vitro coincided with enhanced levels of soluble sugar and peroxidase (POD) activity. Increasing GA3 concentration from 0.1 to 1.0 mg l−1 in the above medium resulted in inhibition of shoot and leaf formation and a decrease in the soluble sugar content. The influence of GA3 on the activities of catalase (CAT) and POD depended on its concentration and the levels of sucrose and nitrogen salts in the medium. The highest increase in CAT and POD activities, that coincided with the enhanced shoot formation capacity of M. × ‘Spectrum’ in vitro, was observed after addition of GA3 to the medium containing high levels of sucrose and nitrogen salts.