Novel Insights into Floral Thermogenesis: In Vivo Analyses of Mitochondrial Dynamics in Nelumbo nucifera Flowers

Abstract

Animal-like thermogenic (TM) activities in flowers have been reported in several families of seed plants. While an association of mitochondria with floral thermogenesis has been described, how mitochondrial dynamics are involved in the regulation of floral thermogenesis is unclear. In this study, the morphological and functional dynamics of mitochondria in vivo were assessed in Nelumbo nucifera Gaertn. flowers during floral thermogenesis. The results showed that mitochondrial biogenesis increased considerably in N. nucifera flowers during thermogenesis, accompanied by notable morphological changes in the mitochondria, including long elliptical, rod-shaped, and dumbbell-shaped morphologies, as well as increased mitochondrial reactive oxygen species (ROS) levels in TM cells. An increase in the expression of alternative oxidase (AOX) during the thermogenesis of N. nucifera flowers was also observed. These observations suggested the rapid change in mitochondrial morphology and increased density during thermogenesis implied activation of mitochondrial fission, which combined with elevated levels of mitochondrial ROS trigger a substantial increase in AOX within the respiratory pathway of TM N. nucifera.

Nepenthespitchersversusthermogenic flowers: Thermal patterns and their role in prey capture and pollination

“…One wild flower of N. nucifera produces around 1 million pollen grains, which is an exceptionally high number for a bee-pollinated species (Li and Huang 2009). N. nucifera is known to regulate flower temperatures between 30 and 36°C for up to 4 days in environments between 10 and 45°C (Lamprecht et al 1998; Seymour 1997; Seymour and Schultze-Motel 1998; Li et al 2022). In this study (Figs.…”