ABSTRACT
En este trabajo de investigación se propagaron, bajo condiciones in vitro, propágulos de Marchantia polymorpha evaluando su desarrollo vegetativo mediante observaciones y registros semanales a cada cultivo por tratamiento en función del tiempo de desarrollo. En este contexto, se evaluó cualitativamente la forma y las características del talo, las cuales se valoraron mediante observaciones y registros semanales. Se analizaron los resultados cuantitativos mediante un análisis de varianza con diseño al azar y arreglo factorial 4 x 2, mediante la prueba estadística de Fisher. Las condiciones apropiadas de cultivo para propágulos de M. polymorpha se establecieron en una concentración de 25% de sales minerales Murashige y Skoog (1962), incubados a una temperatura de 25 ± 1 ºC. Luego de 13 semanas de desarrollo bajo condiciones in vitro, se adaptaron a condiciones naturales mediante un cambio de sustrato, y controlando la temperatura y humedad en el lugar de desarrollo. En esta etapa se evaluó la sobrevivencia de plantas durante 10 semanas; posteriormente al cambio de condiciones, y como característica cualitativa, se tuvo en cuenta el vigor del talo. Este protocolo de propagación de M. polymorpha, pionero en Colombia, es un modelo que permite conservar y cultivar de manera masiva diferentes especies de briófitos, especialmente aquellos que se encuentran en vías de extinción en nuestro país.
Marchantia polymorpha propagules were propagated in this research in in vitro conditions to assess their growth in terms of development time. Development rate and contamination regarding each treatment were also evaluated by weekly observations and crop records for each experimental unit per treatment. Talus shape and characteristics were also qualitatively evaluated by weekly observations and records. Fishers statistical test was used for analysing quantitative results by variance analysis with random design and 4 x 2 factorial arrangement. Appropriate conditions for cultivating M. polymorpha propagules were established at 25% Murashige and Skoog mineral salt concentration (1962), incubated at 25ºC ± 1ºC. After 13 weeks development in in vitro conditions, they were adapted to natural conditions by changing development site substrate and controlling temperature and humidity. Plant survival was evaluated for 10 weeks during this stage. Conditions were then changed and (as qualitative characteristic) talus vigour was taken into account. In was also determined that the ex vitro cultivation level should allow for gradual adjustment to new humidity, temperature and substrate conditions, taking special care that these conditions were not so altered as to become insurmountable. This pioneering M. polymorpha propagation protocol in Colombia is a model for the future maintenance and mass development of different bryophyte species, especially those which are endangered in our country.
Subject(s)
Crop Production , Culture Media/analysis , Culture Media/classification , Culture Media/adverse effects , Culture Media/chemistry , Virus CultivationABSTRACT
OBJECTIVES: To investigate the effect of preimplantation exposure to 0.6 mM ammonium chloride on both preimplantation and postimplantation development of (F1 x F1) strain mouse embryos. METHOD: Two-cell stage mouse embryos were randomly allocated to culture in either M16 medium or M16 added with 0.6 mM ammonium chloride for 2 days before being transferred to 2.5 day pseudopregnant recipients. Embryo morphology was assessed after 1 and 2 days of culture. The recipient females were sacrificed on day 15.5 of gestation. The number of implantation sites, fetuses, moles and any gross abnormalities found were noted. RESULTS: There was no significant difference in the number of embryos reaching morula stage after two days of culture between the two groups (chi2=0.86, P>0.05). Implantation and pregnancy loss rates between the two groups were within comparable ranges. Crown-rump length was significantly higher in the group of embryos exposed to ammonium chloride (t=2.46, P<0.05). There was one gross abnormality, exencephaly, detected in the experimental group (4.35% per fetus obtained). CONCLUSIONS: Besides the abnormal increase in fetal size, preimplantation exposure to ammonium chloride also resulted in gross abnormality, exencephaly. If such effects occurred in the course of human in vitro fertilization, it could be devastating. Further study in this aspect is, therefore, clinically very important in preventing unwanted abnormalities that could arise from human in vitro fertilization.