Oxytropism: a new twist in pollen tube orientation.

摘要: Chemical gradients and structural features within the pistil have been previously proposed as factors determining directionality of pollen tube growth. In this study, we examine behavior eight species germinated in a dynamic oxygen gradient. While germination rates some decreased directly with decreasing tension, other showed no decrease at tensions low 2 kPa. one species, was consistently greater than ambient atmospheric levels. three tested, developing clear directional growth away from more-oxygenated regions medium, while towards region. The remaining four random pattern oxytropic responses among taxa suggests that tropic is both widespread phylogenetically unpredictable.