Plant in situ tissue regeneration: dynamics, mechanisms and implications for forestry research

Plants possess remarkable developmental plasticity and regenerative ability to reshape themselves in response to external stimulations. After localised injuries, they can initiate cellular reprogramming at the wound sites to repair or regrow structures that could substitute the functionality of the damaged or lost parts. This way of regeneration in plants is called plant in situ tissue regeneration. Upon wounding like excision, incision or girdling, the original tissue patterns are completely or partially destroyed, the remanent tissues could perceive the wounding signals and thereby initiate cell de-differentiation, trans-differentiation or re-differentiation to reconstruct the lost or damaged tissues. In this review, we summarize the regenerative dynamics and regulatory mechanisms during the major in situ tissue regeneration processes in plants, including secondary vascular tissue (SVT) regeneration after girdling, apex regeneration after excision and tissue reunion after incision. In addition, we compare the features of SVT regeneration, the most relevant system for forestry, with other plant in situ tissue regeneration systems. We further discuss the unsolved issues and the potential applications of plant in situ regeneration for forestry research, aiming to provide new insights for the study of woody plant development.