Badania nad biochemicznym podłożem molekularnej adaptacji aparatu fotosyntetycznego do suszy glebowej w różnych fazach wzrostu pszenżyta
Kierownik projektu: dr hab. Tomasz Hura (Zakład Ekofizjologii)
Wykonawcy: dr inż. Agnieszka Ostrowska (Zaklad Biologii Rozwoju); dr Michał Dziurka (Zakład Biologii Rozwoju)
SUMMARY OF RESULTS 1
Long-stemmed and semi-dwarf cultivars of triticale were exposed to water stress at tillering, heading and anthesis stage. Quantitative determination of free and cell wall-bound polyamines, i.e. agmatine, cadaverine, putrescine, spermidine and spermine, was supplemented with an analysis of quantitative relationships between free and cell wall-bound polyamines.
The content of free and cell wall-bound polyamines varied depending on the development stage, both under optimal and water stress conditions. Drought-induced increase in free agmatine content was observed at all developmental stages in long-stemmed cultivar. A depletion of spermidine and putrescine was also reported in this cultivar, and spermidine was less abundant in semi-dwarf cultivar exposed to drought stress at the three analyzed developmental stages. Changes in the content of the other free polyamines did not follow a steady pattern reflecting the developmental stages. On the contrary, the content of cell wall-bound polyamines gradually increased from tillering, through heading and until anthesis period. Water stress seemed to induce a progressive decrease in the content of free polyamines and an accumulation of cell wall-bound polyamines. An increase in cell wall-bound polyamines in semi-dwarf cultivar and their decline in long-stemmed cultivar may be a specific biochemical marker for the investigated types of triticale.
SUMMARY OF RESULTS 2
Primary carbohydrate metabolism is the basis for plant growth processes, osmotic regulation and secondary metabolism of phenolic compounds. Therefore, the aim of the study was to determine the metabolic pathways of carbohydrates and phenolic compounds during triticale acclimation to soil drought stress applied at tillering, heading and anthesis stage. The study included a semi-dwarf cultivar 'Woltario' and a long-stemmed cultivar 'Moderato', differing in the activity of photosynthetic apparatus under optimum growth conditions. Differences were found in quantitative and qualitative composition of individual carbohydrates and phenolic compounds, depending on the developmental stage and water availability. Dominant pathways of soluble carbohydrate utilization in the semi-dwarf 'Woltario' cv. under soil drought included a synthesis of starch and soluble phenolic compounds and an accumulation of cell wall carbohydrates. In the typical 'Moderato' cv., soluble carbohydrates were primarily used for the synthesis of phenolic compounds that were then incorporated into cell wall structures. Increased content of cell wall-bound phenolics in 'Moderato' cv. improved the cell wall tightness and reduced the rate of leaf water loss. In 'Woltario' cv., the increase in cell sap osmotic potential due to enhanced concentration of carbohydrates and proline was insufficient to slow down the rate of leaf water loss.