Do woody plants operate near the point of catastrophic xylem dysfunction caused by dynamic water stress? : answers from a model.

Hydraulic failure defines the recovery and point of death in water-stressed conifers.

This study combines existing hydraulic principles with recently developed methods for probing leaf hydraulic function to determine whether xylem physiology can explain the dynamic response of gas exchange both during drought and in the recovery phase after rewatering. Four conifer species from wet and dry forests were exposed to a range of water stresses by withholding water and then rewatering...

Hydraulic Efficiency and Safety of Xylem Sap Flow in Relation to Water Stress in Woody Plants

Xylem hydraulic safety margins in woody plants: coordination of stomatal control of xylem tension with hydraulic capacitance

1. The xylem pressure inducing 50% loss of hydraulic conductivity due to embolism (P50) is widely used for comparisons of xylem vulnerability among species and across aridity gradients. However, despite its utility as an index of resistance to catastrophic xylem failure under extreme drought, P50 may have no special physiological relevance in the context of stomatal regulation of daily minimum ...

Diurnal pattern of water potential in woody plants.

The dynamic relationship between the rates of water loss and uptake controls plant water status. Marked diurnal variations in water potential of both leaves and fruit occurred in all plants studied. Variations in water status during the day were most clearly related to changes in evaporative demand of the air and were different for the east and west sides of a tree. At night, the plant water po...

The dynamics of carbon stored in xylem sapwood to drought-induced hydraulic stress in mature trees

Climate-induced forest die-off is widespread in multiple biomes, strongly affecting the species composition, function and primary production in forest ecosystems. Hydraulic failure and carbon starvation in xylem sapwood are major hypotheses to explain drought-induced tree mortality. Because it is difficult to obtain enough field observations on drought-induced mortality in adult trees, the curr...