Factors of regulating internode elongation during sprouting of tubers in Sagittaria trifolia and S. pygmaea

无论是覆土还是玻璃珠，淹水都能诱导慈姑的节间伸长。pygmaea植物依赖于覆盖土壤或玻璃珠的存在。我们研究了负责增强节间伸长在这些物种的气体因素，因为气体积累容易发生在沉水植物组织。处理的植物激素乙烯，这是已知的，以提高伸长生长在许多水生植物物种，确实刺激叶伸长，但未能促进节间伸长慈姑属物种。我们发现，淹水引起的低氧或缺氧是S. trifolia和淹水过程中积累的CO2触发了S.侏儒。

Internode elongation of Sagittaria trifolia plants was induced by submergence irrespective of cover soil or glass beads.On the other hand, submergence-induced internode elongation of S. pygmaea plants was dependent on the presence of cover soil or glass beads. We examined gaseous factors responsible for the enhanced internode elongation in these species, because gas accumulation easily occurs in submerged plant tissues. Treatment of the plant hormone ethylene, which is known to enhance elongation growth in many aquatic plant species, indeed stimulated leaf elongation but failed to promote internode elongation in both Sagittaria species. We found that hypoxia or anoxia generated by submergence serves as an initial growth-promoting factor for internode elongation in S. trifolia, and carbon dioxide accumulated during submergence trigger internode elongation in S. pygmaea.