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Somatic embryogenesis (SE) in the tree fern Cyathea delgadii was first described in 2015 and since then has been used to exploration of this phenomenon in cryptogamic plants. To deepen the knowledge about the hormonal control of SE, stipe explants were cultured on media supplemented with hormone biosynthesis and transport inhibitors (HBTIs). In the presence of 30 µM 2,3,5-triiodobenzoic acid (TIBA), or 40 µM fluridone or 125 µM salicylic acid (SA), somatic embryo production was totally inhibited. The quantitative analysis of the changes in endogenous hormone and sugar contents was conducted every 2 days within 10-day-long initial culture. The results showed that the concentrations of endogenous indole-3-acetic acid (IAA), abscisic acid (ABA), cytokinins (CKs) and soluble sugars were strongly modified either by TIBA and fluridone. Under their influence, the contents of cytokinins such as c-Z, c-ZR, t-Z, t-ZR, KinR were reduced to barely detectable levels. Treatment with SA results in the changes in endogenous IAA and sugar contents. It also modifies the IAA/CKs ratio; however, excluding the first 2 days of culture, the concentrations of ABA and cytokinins were kept on the control level. All HBTIs significantly increased the kinetin (Kin) content. Our work sheds new light on the relationships between the biosynthetic inhibitors and phytohormones and sugars in the process of early SE. It can be helpful to study the role of hormones in acquisition of embryogenic competence.
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Laki i lasy w dolinach - nowe zagrozenia i szanse

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The main goal of the EU agro-environmental programmes implemented in Poland in 2001 is to protect the low-productive agricultural areas of high natural values. The main goal of the parallely introduced „Law on farmlands foreseen for afforestation" is to establish the forests on lands yielding low income. To avoid afforestation of particularly valuable open areas the synchronization of the both above mentioned documents and relevant activities is required. The priority should be given to the expert's studies supplementing management plans for rural areas in order to create optimal structure of the meadow-forest landscape. Forest should not be planted in habitats in which species composition is not adjusted to habitat conditions. Restoration of the original water conditions which reduces losses of the organic matter in soils is essential before afforestation operations are started. Identification of key habitats being of high significance for biological diversity prior to the afforestation seems to be crucial - as it was done for the non-forest habitats in the agro-environmental programmes. The genetic relationships between grasslands and forest habitats together with the variety of plant species and communities presented in the paper illustrate the complexity of the afforestation issue.
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