부산대학교 도서관

Xylem hydraulic failure has been recognized as a pervasive factor in the triggering of drought-induced tree mortality. However, foundational evidence of the mechanistic link connecting hydraulic failure with living cell damage and tree death has not been identified yet, compromising our ability to predict mortality events. Meristematic cells are involved in the recovery of trees from drought, and focusing on their vitality and functionality after a drought event could provide novel information on the mechanistic link between hydraulic failure and drought-induced tree mortality. In this Opinion, we focus on the cell's critical hydration status for tree recovery from drought and how it links with the membrane integrity of the meristems. Xylem hydraulic failure has been shown to be a ubiquitous factor in tree death from drought, but the mechanistic link between the two processes remains unclear. As meristematic cells are involved in the recovery of trees from drought, determining the damage they suffer during their progressive dehydration under water stress and its relationship to the loss of hydraulic function will provide new information on the mechanistic link between hydraulic failure and drought-induced mortality. The relative water content (RWC), altered redox status, and physical constraints that meristematic cells can support more accurately define meristem membrane integrity, and consequently meristem survival and tree recovery, than the P 50 and P 88 values used hitherto as thresholds for drought-induced tree mortality in mechanistic models. The capacity of trees to relocate stored water between tissues is crucial in buffering variation in the RWC and redox status of meristematic cells, determining the cell mortality timeline and therefore the resistance of different species to drought. [ABSTRACT FROM AUTHOR]