To induce somatic embryogenesis in habanero pepper (Capsicum chinense Jacq.), the cultivar BVll-03, belonging to the red type, was used. Different explants were evaluated, as were different culture media, the composition of which varied in the content of plant growth regulators. Results showed the formation of somatic embryos from cotyledons, zygotic embryos, germinated zygotic embryos, hypocotyls, and cotyledonary leaves. Explants were cultured on Murashige and Skoog medium supplemented with 2,4-D (9.05 μm). The somatic embryos always formed directly from the explant, without callus formation, and the greatest efficiency was obtained when segments of hypocotyls were cultured, obtaining 175 ± 20 somatic embryos per explant. Only the somatic embryos obtained on Murashige and Skoog medium containing 2,4-D (9.05 μm) and treated with abscisic acid (ABA) (1.89 μm) before their transfer to the germination media (Murashige and Skoog + 1.1 μm GA3) emitted their radicule and expanded their cotyledonary leaves (60%), whereas the remaining embryos did not achieve germination because of different causes (abnormalities, delayed development). Not only is this protocol of somatic embryogenesis the first to be reported for this species (C. chinense Jacq.), but it is also the most efficient reported so far, within the Capsicum genus.
Guadalupe López-Puc, Adriana Canto-Flick, Felipe Barredo-Pool, Patricia Zapata-Castillo, María del C. Montalvo-Peniche, Felipe Barahona-Pérez, Nancy Santana-Buzzy and Lourdes Iglesias-Andreu
María del C. Montalvo-Peniche, Lourdes G. Iglesias-Andreu, Javier O. Mijangos-Cortés, Sara L. Nahuat-Dzib, Felipe Barahona-Pérez, Adriana Canto-Flick and Nancy Santana-Buzzy
To determine the effect of different nitrogen sources and osmotic regulators on minimal growth of Habanero pepper (Capsicum chinense Jacq.) germplasm for in vitro conservation, different concentrations of nitrate, sucrose, mannitol, and sorbitol were evaluated. The micropropagation system based on Santana-Buzzy et al. (2006) culture medium was modified in its nitrate concentrations: reduced to 50% and increased to 150%, and osmoregulators were added to the basal culture media: sucrose (6% and 8%), mannitol (2%, 4%, and 8%), or sorbitol (2%, 4%, and 8%). The apical meristems of germinated plants were cultivated in the different treatments for 35 weeks without subculture. Results have demonstrated that mannitol at 2% had the better effect on minimal growth of the plantlets and did not affect the plant physiology and quality. The plantlets remained small in size, turgent, with green leaves and stems and looked like normal plants until to the end of the evaluation period. Changes in nitrogen media concentration did not prove to be adequate for conserving because they affected the plantlet quality (they became chlorotic). The presence of sorbitol and high osmolite concentrations induced minimal growth but reduced the plant quality. Sucrose at mid or low concentrations did not induce minimal growth.
Patricia Yolanda Zapata-Castillo, Adriana-Canto Flick, Guadalupe López-Puc, Anabel Solís-Ruiz, Felipe Barahona-Pérez, Nancy Santana-Buzzy and Lourdes Iglesias-Andreu
To induce the somatic embryogenesis of Habanero pepper, different culture media and different types of explants (node, internode, hypocotyl, half seeds, and fruit segments) were evaluated. For the induction of embryogenic callus, 9.05 μm of 2,4-dichlorofenoxiacetic acid, 3% sucrose, and 0.8% gelrite were added to the basic MS medium over a period of 30 days at 25 ± 2 °C under continuous light (40–50 μmol·m2·s−1). Once the callus formed, they were transferred to liquid medium using the same induction formulation. Somatic embryogenesis only occurred from explants of hypocotyl and in the presence of 3.4 μm thidiazuron. This constitutes the first proposal of a protocol for the “induction of somatic embryogenesis in Habanero pepper (Capsicum chinense Jacq.) from cell suspensions.”
Nancy Santana-Buzzy, Adriana Canto-Flick, Lourdes G. Iglesias-Andreu, María del C. Montalvo-Peniche, Guadalupe López-Puc and Felipe Barahona-Pérez
The in vitro production of ethylene and its effects on the development of Habanero pepper (Capsicum chinense Jacq.) plantlets were evaluated using nonventilated containers (NVCs) and ventilated containers (VCs). Shoots of Habanero pepper between 0.5 and 1.0 cm of height were cultivated in Magenta culture boxes and samples of the headspace atmosphere were taken every four days during the previously established culturing time of 40 days. The presence of ethylene was detected in the NVCs and produced a negative effect on the development of plantlets. In a second phase of this work, the effect of silver nitrate (AgNO3) and cobalt chloride (CoCl2) on ethylene production was evaluated during in vitro development of Habanero pepper plantlets. Concentrations of 50, 300, and 500 μm of each ethylene inhibitor were used in the culture medium. Although cobalt chloride partially inhibited the production of ethylene during in vitro culture of this species, at low concentrations the plantlets presented some degree of vitrification and the highest concentration proved to be toxic for the plantlets. Silver nitrate added to the culture medium did not inhibit ethylene production, however, it did inhibit the effect of this hormone on the plantlets. In fact, when high concentrations of silver nitrate were used (300 μm), high amounts of ethylene were detected in the headspace of the vessels and plantlets were actually healthier.
Nancy Santana-Buzzy, Adriana Canto-Flick, Felipe Barahona-Pérez, María del Carmen Montalvo-Peniche, Patricia Yolanda Zapata-Castillo, Anabel Solís-Ruiz, Amílcar Zaldívar-Collí, Omar Gutiérrez-Alonso and María de Lourdes Miranda-Ham
To induce multiple shoots from habanero pepper (Capsicum chinense Jacq.), nodes and stem segments were cultivated in MS medium supplemented with varying concentrations of kinetin, benzyladenine, and thidiazuron. The effect of the age of the explant in the medium on shoot formation and their latter development into plants was assessed. Ethylene concentration was measured along the experiments. Thidiazuron was the key growth regulator in the process, which at 3.4 μm induced seven to eight shoots that developed into healthy plants per explant. Plantlets in nonventilated vessels, where ethylene concentration was 0.25 ± 0.1102 μL·L–1, showed early defoliation and the formation of calli on the leaves and stems.