The LEAFY COTYLEDON2 (LEC2) transcription factor with a plant-specific B3 domain plays a central role in zygotic and somatic embryogenesis (SE). LEC2 overexpression induced in planta leads to spontaneous somatic embryo formation, but impairs the embryogenic response of explants cultured in vitro under auxin treatment. The auxin-related functions of LEC2 appear during SE induction, and the aim of the present study was to gain further insights into this phenomenon. To this end, the effect of LEC2 overexpression on the morphogenic responses of Arabidopsis explants cultured in vitro under different auxin treatments was evaluated. The expression profiles of the auxin biosynthesis genes were analysed in embryogenic cultures with respect to LEC2 activity. The results showed that LEC2 overexpression severely modifies the requirement of cultured explants for an exogenous auxin concentration at a level that is effective in SE induction and suggested an increase in the auxin content in 35S::LEC2-GR transgenic explants. The assumption of an LEC2 promoted increase in endogenous auxin in cultured explants was further supported by the expression profiling of the genes involved in auxin biosynthesis. The analysis indicated that YUCCAs and TAA1, working in the IPA-YUC auxin biosynthesis pathway, are associated with SE induction, and that the expression of three YUCCA genes (YUC1, YUC4 and YUC10) is associated with LEC2 activity. The results also suggest that the IAOx-mediated auxin biosynthesis pathway involving ATR1/MYB34 and CYP79B2 does not seem to be involved in SE induction. We conclude that de novo auxin production via the tryptophan-dependent IPA-YUC auxin biosynthesis pathway is implicated in SE induction, and that LEC2 plays a key role in this mechanism.Electronic supplementary materialThe online version of this article (doi:10.1007/s00425-013-1892-2) contains supplementary material, which is available to authorized users.
In this article, I analyze the social determinants of the development of creative imagination. Due to its importance, this phenomenon is one of the main areas of research in pedagogy and psychology, which, however, despite numerous analyzes, has not been sufficiently explained. One interpretation of the understanding of imagination as a social mental activity is outlined here. This approach is presented mainly in the works of L.S. Vygotski and his students. Their analyses go beyond the mechanical understanding of the imagination and the dualistic division of the imagined and real worlds. The cultural-historical theory of the development of creative imagination describes it as an internalized system of social relations. The development of this form of imagination, according to Vygotsky, is the main goal of human development. The most effective way to achieve it is education, which “nurtures” in the child all manifestations of a socially creative imagination.
This study describes the issue of maladaptive daydreaming. This phenomenon is becoming a contemporary educational problem because it limits the development potential of children and adolescents as well as their interpersonal relations. The field of possible understanding of maladaptive daydreamingin relation to terms related in meaning was outlined, as well as the current attempts at its scientific conceptualization. In my analysis, I go beyond the dualistic understanding of the children’s real and imaginary world, referring to the cultural-historical theory of the development of creative imagination as a higher mental function as an internalized system of social relations. From this perspective, the phenomenon of daydreaming in children and adolescents, in relation to reality, is not treated in a dichotomous way, but as a social development situation.
In this article, we discuss the issues of motivation and motive in education in the context of the zombie culture that permeates school life, where engagement in achieving goals is an action devoid of interpersonal relations. In the analysis, we go beyond the dualistic understanding of motive, which is construed as either inside or outside the subject. We refer to the proposal of cultural-historical theory of action, in which motive is understood as a system of social relations. From this perspective, understanding a child’s motive requires a methodological grasp of the dynamics and complexity of the relationship: the social situation of the child’s development and institutional values, goals, and demands. Recalling examples from studies on school practice, we show the significance of interactions based on the student’s and teacher’s mutual interest in each other’s activities, and we defy the common belief equating learning with development.
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