In Norway spruce, as in many other conifers, the germination capacity of somatic embryos is strongly influenced by the desiccation phase inserted after maturation. The intensity of drying during desiccation eminently affected the formation of emblings (i.e., seedlings developed from somatic embryos). Compared to non-desiccated embryos, the germination capacity of embryos desiccated at 100% relative humidity was about three times higher, but the reduction of relative humidity to 95% and 90% had a negative effect on the subsequent embryo development.
Desiccation as a post-maturation treatment helps complete maturation of Norway spruce somatic embryos: carbohydrates, phytohormones and proteomic status
Exposure of Norway spruce (Picea abies) somatic embryos and those of many other conifers to post-maturation desiccation treatment significantly improves their germination. An integration analysis was conducted to understand the underlying processes induced during the desiccation phase at the molecular level. Carbohydrate, protein and phytohormone assays associated with histological and proteomic studies were performed for the evaluation of markers and actors in this phase.
The effect of different air humidity during desiccation on the development of Norway spruce somatic embryos
The objective of the study was to follow morphological, selected biochemical and transcriptional characteristics induced by various air humidity during desiccation of Norway spruce somatic embryos. The level of free polyamines lowered, higher forms of polyamines were favoured. Expression profiles of monitored genes were variously influenced by different relative air humidity. Our data proved, that desiccation of somatic embryos is metabolically active process highly affected by relative air humidity.
Somatic embryogenesis is a developmental process where a plant somatic cell dedifferentiate to a totipotent embryonic stem cell that has the ability to give rise to an embryo under appropriate conditions. Desiccation is the final phase of normal embryonic development in most angiosperms and appears to be important in the transition from embryogeny to the ability to germinate and form normal seedlings.