Morphological Plasticity and Reproductive Strategies of Kalanchoe Species in Invasive Spread

Kalanchoe species, originally introduced worldwide as ornamentals, are now reported to be spreading in many regions, including China. It is hypothesized that morphological plasticity and the production of asexual plantlets contribute to their successful invasion. To address the hypothesis, four species - Kalanchoe delagoensis Eckl. & Zeyh., Kalanchoe × houghtonii D. B. Ward, Kalanchoe laetivirens Desc. and Kalanchoe daigremontiana Raym. - Hamet & H. Perrier - were cultivated under contrasting light and water conditions, and their reproductive and vegetative traits were examined. 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, whereas K. daigremontiana and K. laetivirens enhanced the fresh weight of individual plantlets without altering the total number produced. These results highlight the high plasticity of vegetative and reproductive growth in response to light and water availability. The increased production of plantlets may contribute to the widespread occurrence of Kalanchoe species in open fields.