Seeds from Tabebuia roseo-alba lose viability very fast. Moreover, the seed germination rate is very low, reaching approximately 40%. This study aimed at the in vitro induction of embryogenic callus. This technology a...Seeds from Tabebuia roseo-alba lose viability very fast. Moreover, the seed germination rate is very low, reaching approximately 40%. This study aimed at the in vitro induction of embryogenic callus. This technology allows subsequent plant regeneration as an alternative for the production of T. roseo-alba seedlings. Seeds were germinated in vitro and after 20 days, cotyledonary leaves, hypocotyls and root segments excised from these seedlings were used as explants. They were inoculated on MS medium supplemented with sucrose （30 g/L）, agar （5.0 g/L） and different auxins. The effect of 2,4-D, picloram and NAA at concentrations 0.0, 0.5, 1.0, 2.0 and 4.0 mg/L was evaluated. For the analysis of callus with embryogenic characteristics, ultra-structural study by scanning electron microscopy and cytochemical test with carmine were performed. The results showed that the culture medium supplemented with 4 mg/L NAA presented induction of callus with embryogenic characteristics in all explants used, with cotyledonary leaves showing the highest percentage （70% of explants with embryogenic characteristics）. The use of 2, 4-D and picloram was efficient for callus formation in different explants, but no embryogenic characteristics were observed. From the ultra-structural analysis of callus with embryogenic characteristics, it was found that cells from different explant sources had isodiametric format. This format is similar to somatic embryos in globular stage. The cytochemical analysis confirmed the presence of pro-embryogenic cells in callus mass. Callus induced from cotyledonary leaves presented 46% positive reaction to carmine acetic.展开更多
Byrsonima intermedia A. Juss. is a species from the Brazilian Cerrado that produces edible fruits and, in common with other species from the Byrsonima genus, has pharmacological potential. Previous attempts to propaga...Byrsonima intermedia A. Juss. is a species from the Brazilian Cerrado that produces edible fruits and, in common with other species from the Byrsonima genus, has pharmacological potential. Previous attempts to propagate the species through conventional methods showed difficulties. Thus, the purpose of this work was to characterize pro-embryogenic masses of Byrsonima intermedia callus, aiming for their in vitro propagation through somatic embryogenesis. Leaf segments from in vitro germinated seedlings were employed as explants for callus production. The calli were then subcultured and exposed to dyes to fulfill their embryogenic potential. Digitalizations of the cytological preparations were made in order to measure the area that was stained by both Aceto-Carmine and Evans-Blue, using image tool software. Somatic embryos were induced after treatments with l-naphthaleneacetic acid （NAA）. The percentages of double-colored areas （by Aceto-Carmine and Evans-Blue） were calculated and the data were analyzed by using the Skott-Knott test （P ≤ 0.05） and, the embryogenic callus, as well as the formation of somatic embryos were analyzed by using the Krsuskal-Wallis rank test （P ≤0.05）. The results show that double coloration is effective at identifying cells showing embryogenic potential. Early callus subculture phases show a larger percentage ofembryogenic area （83%） Somatic embryos were induced by using high auxin level.展开更多
文摘Seeds from Tabebuia roseo-alba lose viability very fast. Moreover, the seed germination rate is very low, reaching approximately 40%. This study aimed at the in vitro induction of embryogenic callus. This technology allows subsequent plant regeneration as an alternative for the production of T. roseo-alba seedlings. Seeds were germinated in vitro and after 20 days, cotyledonary leaves, hypocotyls and root segments excised from these seedlings were used as explants. They were inoculated on MS medium supplemented with sucrose （30 g/L）, agar （5.0 g/L） and different auxins. The effect of 2,4-D, picloram and NAA at concentrations 0.0, 0.5, 1.0, 2.0 and 4.0 mg/L was evaluated. For the analysis of callus with embryogenic characteristics, ultra-structural study by scanning electron microscopy and cytochemical test with carmine were performed. The results showed that the culture medium supplemented with 4 mg/L NAA presented induction of callus with embryogenic characteristics in all explants used, with cotyledonary leaves showing the highest percentage （70% of explants with embryogenic characteristics）. The use of 2, 4-D and picloram was efficient for callus formation in different explants, but no embryogenic characteristics were observed. From the ultra-structural analysis of callus with embryogenic characteristics, it was found that cells from different explant sources had isodiametric format. This format is similar to somatic embryos in globular stage. The cytochemical analysis confirmed the presence of pro-embryogenic cells in callus mass. Callus induced from cotyledonary leaves presented 46% positive reaction to carmine acetic.
文摘Byrsonima intermedia A. Juss. is a species from the Brazilian Cerrado that produces edible fruits and, in common with other species from the Byrsonima genus, has pharmacological potential. Previous attempts to propagate the species through conventional methods showed difficulties. Thus, the purpose of this work was to characterize pro-embryogenic masses of Byrsonima intermedia callus, aiming for their in vitro propagation through somatic embryogenesis. Leaf segments from in vitro germinated seedlings were employed as explants for callus production. The calli were then subcultured and exposed to dyes to fulfill their embryogenic potential. Digitalizations of the cytological preparations were made in order to measure the area that was stained by both Aceto-Carmine and Evans-Blue, using image tool software. Somatic embryos were induced after treatments with l-naphthaleneacetic acid （NAA）. The percentages of double-colored areas （by Aceto-Carmine and Evans-Blue） were calculated and the data were analyzed by using the Skott-Knott test （P ≤ 0.05） and, the embryogenic callus, as well as the formation of somatic embryos were analyzed by using the Krsuskal-Wallis rank test （P ≤0.05）. The results show that double coloration is effective at identifying cells showing embryogenic potential. Early callus subculture phases show a larger percentage ofembryogenic area （83%） Somatic embryos were induced by using high auxin level.
