Tissue- and cell-specific cytokinin activity in poplar under drought

Climate change with increasing periods of drought is expected to reduce the yield of biomass crops such as poplars. To combat yield loss it is important to better understand the molecular mechanisms that control growth under drought. Cytokinins are important phytohormones that regulate plant growth. In a recent study published in AoB PLANTS, Paul et al. localized cytokinin activities in poplar trees, and demonstrated that even mild drought stress strongly suppresses cytokinin activities in the cambium, the “stem cells” of trees, resulting in loss in productivity and reduced wood formation. Cytokinin activities also decline in the leaf stalks before shedding. Their results identify critical tissues for drought acclimation in the woody biomass crop poplar, and provide a basis for selection of climate-smart trees.