Photosynthetic pathway alters xylem structure and hydraulic function in herbaceous plants

Xylem Structure and Function

The earliest land plants were short, herbaceous plants that evolved from primitive, water-living ancestors. For these plants, the change from a predominantly aquatic to a terrestrial environment was accompanied by the need for additional structural support to keep the plants upright and the need for more efficient transport of water to the aboveground parts of the plants. Larger plant sizes als...

Hydrogel control of xylem hydraulic resistance in plants.

Increasing concentrations of ions flowing through the xylem of plants produce rapid, substantial, and reversible decreases in hydraulic resistance. Changes in hydraulic resistance in response to solution ion concentration, pH, and nonpolar solvents are consistent with this process being mediated by hydrogels. The effect is localized to intervessel bordered pits, suggesting that microchannels in...

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 ...

Getting variable xylem hydraulic resistance under control: interplay of structure and function.

The Structure and Function of Xylem in Seed- Free Vascular Plants: An Evolutionary Perspective

The evolution of xylem was critical to the success of embryophytic land plants. According to the fossil record, the earliest terrestrial autotrophs were algae followed by bryophytes, simple organisms that lacked the ability to effi ciently transport water (Raven 1984 ; Sperry 2003 ; Taylor et al. 2009 ; Pittermann 2010 ). Like their ancestors, today’s non-vascular plants have essentially two op...