Effect of abscisic acid, osmolarity and temperature onin vitro development of recalcitrant mango nucellar embryos

Abstract

Development of cotyledonary-stage nucellar embryos of mango was arrested in vitro by exposure to 750-1750 #M ABA. The enlargement and germination of nucellar embryos was inhibited for as long as 4 weeks after subculture from ABA-containing medium. Mannitol at concentrations between 7.5 and 12.5% inhibited nucellar embryo development, presumably due to osmotic effects; however, there was no residual effect after subculture of somatic embryos onto medium without mannitol. Temperatures between 22.5 and 37.5 °C stimulated embryo development, whereas lower temperatures (7.5 and 15 °C) delayed germination. There was no germination 1 month after somatic embryos, pulsed for 8 weeks at 7.5 °C, were transferred to 22.5 °C; however, after 2 months, 86% of these somatic embryos germinated. These results indicate that it is possible to induce developmental arrest in recalcitrant mango embryos with high concentrations of ABA, mannitol or low temperature (7.5 °C).Abbreviations: ABA -Abscisic acid; MM1 -Mango maturation medium

In vitroregeneration and transient gene expression in mango cv. ‘Vellaikolumban’

“…Thomas (1999) also recommended the use of thidiazuron (TDZ) to promote shoot growth. The highest percentage germination (33.3%) reported here was a little more than in earlier reports (Dewald et al, 1989b;Pliego-Alfaro et al, 1996;Thomas, 1999). These workers reported leaf necrosis on in vitro-grown mango seedlings.…”

Physiological and morphological characteristics during development of pedunculate oak (Quercus robur L.) zygotic embryos

“…The species Quercus robur L. has desiccation-sensitive (recalcitrant) seeds, which cannot be stored for long periods without serious loss of viability (Roberts 1973). In contrast to orthodox seeds, recalcitrant species do not undergo a period of drying on the mother plant; rather maturation and growth represent a continuous process (Pliego-Alfaro et al 1996). Similar to dormant seeds, the concentration of abscisic acid (ABA) in recalcitrant seeds increases toward the end of embryogenesis and reaches its maximum during the maturation phase just before shedding (Finch-Savage and Clay 1994;Marion-Poll 1997).…”

Histological aspects of avocado embryo development and effect of developmental stages on germination

“…Avocado embryos are considered to be recalcitrant. Recalcitrant embryos are larger and fleshier (Pliego-Alfaro et al, 1996), and have a more prolonged maturation period (Whiley, 1992), than embryos of the orthodox type. Moreover, recalcitrant seeds cannot tolerate maturation drying, generally lack dormancy (Pence, 1992), and reserve accumulation appears to be controlled differently (Alemanno et al, 1997).…”