Browsing by Author "GAJARDO, G"

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    ALLELOPATHIC EFFECTS OF THE CHILEAN MATORRAL SHRUB FLOURENSIA-THURIFERA
    (1987) FUENTES, ER; ESPINOZA, GA; GAJARDO, G
    This paper reports 4 types of evidence of the allelopathic effect of the drought-deciduous shrub Flourensia thurifera (Compositae) on forbs and shrubs. Field evidences include: (1) observed differences in grass abundances at neighboring sites with and without (removed) F. thurifera; (2) measured grass abundances at various distances and directions from isolated F. thurifera shrubs; and (3) the results of experiments in which F. thurifera was cut and the ensuing increment in the relative grass densities monitored. Laboratory evidences pertain to relative germination rates of rye and shrub seeds when irrigated with water in which shrub leaves had been soaked. All four evidences point in the same direction, namely, that F. thurifera produces water-soluble chemical substances capable of inhibiting the germination of other plant species. In addition, the paper supports previous results regarding the lack of demonstrable allelopathic effects in some evergreen species of shrubs. Finally, the ecological significance of these results is discussed.
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    EFFECT OF SALT CONCENTRATION ON THE SYNTHESIS OF SULFATED MACROMOLECULES IN THE BRINE SHRIMP (ARTEMIA-FRANCISCANA) - CHANGES OF SULFATION RATE DURING DEVELOPMENT
    (1993) BRANDAN, E; URREA, R; GAJARDO, G
    1. The effect of sodium chloride and sulphate concentrations on the rate of sulphation was evaluated in four developmental stages of the brine shrimp Artemia franciscana, a crustacean inhabiting extreme hypersaline environments.
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    SPERM MIGRATION THROUGH THE FEMALE GENITAL-TRACT OF THE NEW-WORLD MONKEY CEBUS-APELLA
    (1995) ORTIZ, ME; GAJARDO, G; LEON, CG; HERRERA, E; VALDEZ, E; CROXATTO, HB
    This study was designed to characterize sperm migration in the female genital tract of Cebus apella. Forty-eight cycles of eighteen females mated during the periovulatory period were studied. Eggs were searched for and spermatozoa were counted in segmental flushings of the genital tract performed in situ 1-7 h, 19-31 h, or 45-56 h after coitus. Of 14 eggs recovered, 8 were fertilized, thus assuring a reasonable normality of prefertilization phenomena in both males and females.