Morphological plasticity and reproductive strategies of Kalanchoe species in invasive spread.

Kalanchoe species, originally introduced worldwide as ornamentals, are now reported to be globally spreading in many regions, including China. It is hypothesized that the morphological plasticity and asexual plantlet production of these species contribute to their rapid invasive spread. To address this hypothesis, an experiment was conducted using four Kalanchoe species: Kalanchoe delagoensis Eckl. & Zeyh., Kalanchoe × houghtonii D. B. Ward, Kalanchoe laetivirens Desc. and Kalanchoe daigremontiana Raym.-Hamet & H. Perrier. The reproductive and vegetative traits of these four species were evaluated under contrasting light and water conditions. The plants subjected to high light tended to prioritize plantlet production, accompanied by a reduction in vegetative growth. Two distinct reproductive strategies were observed. K. delagoensis and K. × houghtonii significantly increased plantlet production under high light conditions. In contrast, K. daigremontiana and K. laetivirens enhanced the fresh weight of individual plantlets without altering the total number produced. These results demonstrate the high plasticity of vegetative and reproductive growth in response to light and water availability. The increased production of plantlets may contribute to the invasive spread of Kalanchoe species in open fields.