Hydathodal leaf teeth of Chloranthus japonicus (Chloranthaceae) prevent guttation‐induced flooding of the mesophyll

摘要: Why the leaves of cold temperate deciduous and moisture-loving angiosperms are so often toothed has long puzzled biologists because functional consequences teeth remain poorly understood. Here we provide structural evidence that marginal leaf Chloranthus japonicus, an understory herb, enable release guttation sap during root pressure. When from hydathodes was experimentally blocked, found intercellular airspaces became flooded. Measurements chlorophyll a fluorescence revealed internal flooding resulted in inhibition photosynthesis, most likely through formation film water within reduced CO2 diffusion. Comparing developmental series with without covered wax, did not affect overall stomatal conductance uptake. However, maximal effective light-saturation PSII quantum yields were to be lower or equal surrounding lamina throughout ontogeny. Collectively, our results suggest their development on apices avoidance mesophyll by We discuss how these new findings bear potential physiological interpretations models apply traits infer ancient climates.