Hydraulic Anatomy and Function of Trees—Basics and Critical Developments

Abstract

The study of hydraulic anatomy and function of trees has a long tradition. Motivated by current and projected changes in water availability, the field of tree hydraulics is experiencing a bout of activity. Significant progress has been made in understanding how water transport in trees is organized, how it integrates with other physiological processes, and what it takes for it to malfunction. Many of these advances have been possible, as fields of research that have traditionally been separate are merging, for example, wood anatomy and plant ecophysiology. These developments have led to the creation of powerful and novel approaches that help to answer longstanding questions relating to fundamental aspects of fluid transport in plants and how plants survive in the face of environmental stresses such as drought and freezing. The increased capacities to visualize the ultrastructures of wood in ever-greater detail and the ability for in-situ visualization of long-distance fluid transport have contributed to this progress. This review provides an entry point to the vast and continuously increasing knowledge of how water transport in trees is organized. It scales from cells to tissue anatomy to whole-tree physiology and landscape ecology. Known mechanisms and novel conceptual theories around how trees die as well as ways to prevent this fate are summarized. High-priority research questions for the coming years are formulated.

Grand Challenges: Forests and Global Change

“…Perhaps most famously described for trees by Leonardo da Vinci more than 500 years ago (see Minamino and Tateno, 2014), the role of structure in water transportone of the most important of all tree functions-remains a research field that engages hundreds of forest scientists (see Pfautsch, 2016;Landsberg et al, 2017;Venturas et al, 2017, for just three examples of many recent reviews and updates).…”

Characterising the water use and hydraulic properties of riparian tree invasions: A case study of Populus canescens in South Africa

“…This suggests that although the trees had ready access to water, the hydraulic system likely limited the volumes of water that could be transported through the transpiration stream at a given time. The difference in the hydraulic resistances was probably due to climatic differences between the sites, as suggested by Pfautsch et al (2016), and possibly differences in the wood anatomy. As a result of the high hydraulic resistances, the time lags between water uptake by the roots and transpiration by the small trees was around 1 h while it was between 1 and 2 h for the large trees (Fig.…”

“…Hydraulic capacitance, on the other hand, gives an indication of the ability of trees to store water for later use, e.g., when water supply does not match demand (Steppe et al, 2006). A recent study by Pfautsch et al (2016) suggests that prevailing climatic conditions play a critical role in the hydraulic properties of species and this, in turn, determines the volumes of water used by the plants.…”

Crescimento, anatomia, microdensidade e propriedades hidráulicas do lenho de árvores de >i<Eucalyptus grandis>/i< ao longo de uma rotação de 8 anos: correlações com o clima e ciclos do carbono e da água

“…É através delas que o equilíbrio entre eficiência/segurança no transporte de nutrientes e água ocorre , formando assim, um xilema e sistema hidráulico (densidade, arranjo e tamanho do vaso) com maior, ou menor riscos de cavitação e embolismo Gleason et al, 2016). E, ainda, se esses ajustes são suficientes quando ocorrem eventos extremos e se as falhas hidráulicas resultantes, podem alterar a mortalidade natural das árvores (Blackman et al, 2016; bem como a composição dos biomas onde ocorrem Pfautsch, 2016).…”

“…xilema das árvores sob a dinâmica dos ciclos biogeoquímicos ainda não é clara, dessa forma, seu estudo é fundamental (Pfautsch, 2016). Avanços nesse sentido possibilitam antecipar e mitigar, ao menos em parte, as consequências das mudanças climáticas no funcionamento das plantações .…”