Abstract
Plants are constantly subjected to environmental stresses, among which flooding is one of the most severe due to its increasing occurrence and the increasingly large area affected. Flooding causes devastating damage to global agricultural production. Therefore, it is of great practical significance to understand plant response to flooding, with the hope to provide useful insights for breeders and maintain crop performance under less predictable climatic conditions.
Adventitious root (AR) formation is a characteristic adaptation to flooding. These de-novo formed roots can sustain plants with nutrients, water and oxygen supply, therefore enabling them to survive under flooding. In this thesis, we build hormonal signaling models which regulate AR formation under two different water regimes, partial and complete submergence in Solanum dulcamara. Evidences from both physiological and molecular analysis revealed that ethylene and abscisic acid (ABA) are antagonistically involved in the biological processes related partial-flooding induced AR formation. ABA INSENSITIVE5 (ABI5), a core transcription factor in ABA signaling pathway, was found to negatively modulate AR outgrowth, possibly by mediating plants’ hypoxia response. Auxin presence and proper signaling are necessary for AR outgrowth in both partially and completely submerged S. dulcamara plants.
Overall, These results provides novel insights to understand plant responses to environmental factors.
