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Regulation of potato tuber onset: the role of auxin
Myslivcová, Jitka ; Mašková, Petra (advisor) ; Havelková, Lenka (referee)
Potato (Solanum tuberosum) is an essential component of food worldwide. The process of tuber formation is controlled by the interplay of external and internal conditions. Understanding of the molecular basis of tuberization, including the effect of photoperiod, pointed to a key role of mobile signals. Among these morphogenic signals StBEL5 and POTH1 transcripts are involved, which are translated in the stolon and form a heterodimer regulating target genes with TTGAC tandem motifs, further an FT homologue, StSP6A, mobile from leaves to stolons as a protein. BEL5/POTH1 and StP6A signaling pathways seem to overlap. Phytohormones also play an important signaling role, i.a. auxins. During tuber initiation, IAA levels in stolon tissues increase. PIN transporters are likely to be involved in the redistribution of auxin in the stolon, but also LAX and ABCB transporters and components of auxin signaling pathway, Aux/IAAs and ARFs are also involved in the process. Although auxins are proved to play an important role during stolon-to-tuber transition, their exact role in the process is not sufficiently clarified. Auxin signaling is interconnected with BEL5/POTH1 and SP6A-mediated tuber signaling, as its target genes in the stolon include those that encode proteins involved in auxin biosynthesis (YUCCA1),...
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Faktory indukce tvorby hlíz lilku bramboru (Solanum tuberosum L.) v in vitro podmínkách
Kůrková, Jana
This thesis deals with the factors responsible for induction of the formation of tuber potato (Solanum tuberosum L.) in in vitro conditions. The aim was to observe cultivation of the nodal segments of stems on the induction medium with reduced content of inorganic nitrogen 12 umol, 80 g/l sucrose and the addition of 10 mg/l BA for the for-mation of tubers. The frequency of tuberisation was evaluated, as well as morfological changes, size and weight of the tubers. Three groups of explants were established diffe-ring in lenght of cultivation on the induction medium. These were monitored for chan-ges in the content of endogenous ABA in the nodal segments of stem and stolon. Moni-toring of the changes in content of endogenous cytokinin, nitrogen content, production of ethylene, ethane and CO2 was performed as well. Permanent microscopic preparations were prepared to detect transformation of the axillary bud into stolon, resp. tuber. Increased content of ABA during the tuber formation demonstrates its effect on tuberi-zation. Amongs cytokinins, the biggest effect of cytokinins on tuberization has BA, iP and iPR. Conversely, Z and ZR had no influence. Contents of ethylene, ethane,CO2 and nitrogen are related to the lenght of culturing on the induction medium.
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Morfogenetické změny v procesu tvorby hlíz lilku bramboru (Solanum tuberosum L.) v in vitro podmínkách
Kůrková, Jana
This work deals with the morphogenetic changes in the process of formation potato tubers (Solanum tuberosum L.) in vitro conditions. The aim was to determine the optimal length of the cultivation the nodal segments of stems on the induction medium with reduced content of inorganic nitrogen 12 micromolar, 80 g/l sucrose and the addition 10 mg/l BA for the formation of tubers. And to confirm the assumption that reduced the amount of inorganic nitrogen in the medium generally leads to a significant induction of tuberization potato (Solanum tuberosum L.). Morphological changes were observed during tuberization and recorded the frequency of tuberization. It was founded the four variants and the control variant was differing length cultivation on the induction medium. It was watched the changes in the content of endogenous ABA in the nodal segment of stem, leaf, stem and tuber during tuberization. It was found that a longer period cultivation on induction medium with a reduced content of inorganic nitrogen in the nitrate form leads to a higher and earlier tuberization of potato (Solanum tuberosum L.). By measuring the content of ABA, it was found that the content of ABA increases with the time during which explants are subjected to stress. Increased content of ABA at the time the tubers illustrates the effect of ABA on the induction of tuberization in potato (Solanum tuberosum L.).
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