Plant Cell Culture & Micropropagation - ISSN 1808-9909

Establishment and clonal propagation of Lippia dulcis Trevir. through in vitro single node cultures

2023-01-26T15:00:30-03:00

Lippia dulcis Trevir. (Verbenaceae) is a species with medicinal potential that is used as a tranquilizer and to control diabetes in the western region of Pará, Brazil. The objective of this study was to determine the establishment and clonal propagation of Lippia dulcis through single nodal segments grown in different concentrations of salts in a MS (Murashige and Skoog) medium (MS, MS/2, MS/4) and determine the best period for subculturing the species. Nodal segments cultivated in the MS medium showed a higher survival percentage and better development than those grown in more dilute media (MS/2, MS/4). The concentration of the salts affected the dry weight gain of some plant parts. Plantlets cultivated in the MS medium obtained better leaf dry weight and total leaf area than plantlets cultivated in half-strength MS. The half-strength MS medium proved to be most effective for root length growth and root dry weight gainin vitro. The growth curve showed that day 30 was the time for subculturing the species. Starting with only one nodal segment, 3125 plantlets were obtained after sixth months of cultivation at a multiplication rate of five. The plantlets of Lippia dulcis were removed from the flasks and acclimatized with success in a greenhouse.
Index terms: Growth analysis; micropropagation; shoot proliferation; nodal segment.

Control of in vitro contamination during the establishment of Pyrus communis explants using Plant Preservative MixtureTM

2022-10-11T19:18:30-03:00

The presence of fungal and bacterial contamination in in vitro propagation is a determinant of the culture establishment. The biocide PPM (Plant Preservative Mixture™) has been utilized to control in vitro contamination. According to the manufacture’s label, it is a heat-stable, broad-spectrum product, non-selective, that affects directly microorganisms without causing damage to plant cells. The purpose of this study was to evaluate the influence of PPM asepsis on the control of contamination during the in vitro establishment and survival of Pyrus communis rootstock explants. Six compositions were tested for asepsis and explants from two locations (field and greenhouse). The results showed that asepsis with Alcohol 70% (1 minute) + NaOCl 2.5% + Tween 20 (15 minutes), plus 4.0 ml L-1 PPM added to media performed on explants from greenhouse plants and asepsis, with PPM 5% solution bath and PPM 5% solution bath plus 2.0 ml L-1 PPM added to media performed on explants from field-grown plants presented a good microbial control and good rate of survival.

Index terms: Biocide; tissue culture; micropropagation; pear tree; PPM.

In vitro culture of Stryphnodendron adstringens Mart. Coville

2023-03-30T20:52:30-03:00

Stryphnodendron adstringens (Mart.) Coville is a species native to Cerrado with high medicinal potential. It is an important
tannin source, is used mainly due to its healing, anti-inflammatory, and anti-septic activities. Due to the difficulties in
sexual propagation, the objective of this work was to study some aspects of its the in vitro culture. The concentration of
salts influenced the establishment of the initial explant in vitro, with a higher percentage of germination in the culture
medium without salts. The combination of concentrations of 1.0 mg L-1 BAP and 0.1 mg L-1 NAA promoted greater shoot
formation, and the concentration of 2.0 mg L -1 IBA promoted greater histogenesis. The composition of the culture medium influenced the establishment and development of S. adstringens.

Index terms: Native Brazilian tree; tissue culture; micropropagation; growth regulator

Tolerance to desiccation and production of encapsulated units of gabiroba (Campomanesia adamantium) seeds

2022-10-07T15:51:46-03:00

Campomanesia adamantium is a Brazilian Cerrado fruit crop species that presents a recalcitrant behavior, which compromises the viability of its seeds. Due to this seed feature, the objective of this study was to evaluate the preservation capacity of the species by the use of synthetic seeds. Two seed lots were maintained in a ventilation oven regulated at 30 °C for 30, 60, 120, 240 and 960 min, and then compared with the fresh seeds (control). After drying, the lots were evaluated according to the germination rate, emergence speed index (ESI), initial time, final time and mean time of germination, synchrony, relative frequency, germination speed and seed vigor. For the production of encapsulated units, 3 complexation times (15, 20 and 30 min) and 5 concentrations of sodium alginate (0, 1.5, 2, 2.5 and 3 g) were evaluated, with 3 replicates. For both experiments, Sisvar software was used, and the means were compared by Tukey test at 5%. Seed quality was compromised by desiccation, as the ESI decreases with increasing desiccation time. Regarding synchrony, there was no significant difference among the treatments, whereas for germination time, fresh seeds started and finished the process faster than the others, and the germination time increased as the drying treatments time increases. The emergence rate of fresh seeds was much higher than those exposed to desiccation. For synthetic seeds, the best complexation time was 20 min for 1.5, 2 and 3 g alginate, reaching 100% of the germinated encapsulated units.
Index terms: Cerrado fruit crop; recalcitrant seeds; seed germination; synthetic seeds.