Effects of light on somatic embryo development and abscisic levels in carrot suspension cultures

Abstract

Carrot cells were cultured under various light spectra and intensities at different times following the initiation of suspension cultures from callus. The highest intensity white and blue light treatments were inhibitory to growth and somatic embryogenesis. Red and green light were not different from dark treatments which produced the highest total number of embryoids. After extended time in culture, carrot cells in blue light produced secondary embryoids and anthocyanin. Cultures in red light had multiple cotyledons and orangepigmented radicles. Leafy cotyledons occurred in all light treatments. Abscisic acid production peaked at the heart stage of embryogenesis and synthesis was most pronounced in blue light. Red light enhanced development to the heart stage. Both the red and blue light spectra may be used to manipulate carrot cell cultures to optimize growth.

Seasonal effect on tissue culture response and plant regeneration frequency from non-bombarded and bombarded immature scutella of barley (Hordeum vulgare) harvested from controlled environment

“…Taking into account that the high embryogenic competence in maize and wheat immature embryos correlated with a low IAA content (Carnes and Wright, 1988;Hess and Carman, 1998), it could be possible that the higher embryogenic reactivity of barley that we observed between February and June is connected with the higher amount of red light at that time. This hypothesis is consistent with observations of a promoting influence of red light on embryogenic callus formation whereas white to blue light treatments were inhibitory to somatic embryogenesis in different plant species (Michler and Lineberger, 1987;D'Onofrio et al, 1998;Karnachuk and Gyozdeva, 1998;Bach and Krol, 2001). …”

Morphogenic Aspects of Somatic Embryogenesis

“…Although somatic embryo maturation has been reported in both the dark and the light, the maturation of spruce embryos in the dark reduced the total number of mature embryos, and the number that eventually germinated, when compared to maturation using a 16-h photoperiod [75]. Furthermore, during carrot somatic embryo development, light quality and quantity affected both the total number of developing embryos, as well as their endogenous ABA content [88]. Hence, alterations in light spectra may be used to optimize maturation protocols.…”

“…Red light enhanced while blue light decreased the induction of date palm [87] somatic embryos. Green light, red light, or darkness were equally effective, while blue light or white light at higher intensities were inhibitory for induction of carrot somatic embryos [88]. Darkness, or white light from fluorescent tubes (75 J.tE m -2 s-I), tended to lower somatic embryogenesis of soybean, while lower light intensities (10 J.tE m -2 s-I), or light provided by Grolux® fluorescent tubes, which provide more light in the red spectrum, resulted in higher frequencies of embryogenesis [89].…”

Induction mechanism of adventitious root from leaf explants of Morinda citrifolia as affected by auxin and light quality

“…This suggests the involvement of the blue absorbing photoreceptor system in the callus formation process and for root regeneration; phytochrome seemed to be the only photoreceptor involved. In the case of wild carrot, callus production increased with decreasing embryo production under light other than red and green (Michler and Lineberger 1987). In our present work, we observed that NAA and dark environment have a marked effect on the callusing process.…”