Abstract:

During the life history of the heterophyllous plant Ottelia cordata, it undergoes the submerged-leaf and the floating-leaf phases, with dramatic changes in their surrounding environments. In the present study, we investigated the changes in morphology, anatomy, and inorganic carbon (Ci) utilization strategies in heterophyllous leaves of O. cordata. The results showed that the floating leaf was thicker and wider than the submerged leaf, and the floating leaf developed stomate that can use CO2 in the air which was absent in the submerged leaf. Both types of leaves could use HCO3- as an extra carbon source for photosynthesis, but it was stronger in submerged leaves. Another difference between floating and submerged leaves was in the Ci assimilation. Submerged leaves performed C4 metabolism, while the floating leaf only carried on C3 metabolism. Due to the floating and submerged habitat, the main Ci source was atmospheric CO2 and the free CO2 underwater for floating leaf and submerged leaf respectively. At the same time, the soluble HCO3- was another Ci source for submerged leaves, that could supply ~34% Ci during underwater photosynthesis. Our results indicated the heterophyllous plant responded in morphology, anatomy, and biochemistry to adapt to underwater and aerial environments.

全文链接：https://doi.org/10.1016/j.envexpbot.2022.104818