Diurnal cycles in sap flow and leaf water potential: do leaf height - - PowerPoint PPT Presentation

Diurnal cycles in sap flow and leaf water potential: do leaf height and species identity matter?

Adarsh U.G., College of Forestry-Sirsi Akshay Surendra, NCBS-Bangalore Rishiddh Jhaveri, IISER-Pune

Flow of water in a tree: potential gradient

Choat et al., 2018

Model

Sperry et al., 2017

Hypotheses

Diurnal cycle in sap flow and leaf-water potential There is a lag in leaf-water potential between bottom leaves and top leaves

Methods

Turner 1988; Lu 1988

Trees of interest

Terminalia paniculata Canopy species, tree height: 18.9 m Bottom measurement: at 1.6 m Top measurement: at 6 m Careya arborea Middle-storey species, tree height: 7m Bottom measurement: at 3.5 m Top measurement: at 7 m

Diurnal cycle of leaf water potential for two species

Diurnal cycle of leaf water potential at two heights

Comparing temperature, sap flow and leaf water potential

Key-takeways

• Diurnal pattern of a hump-shaped curve (with mid-day

peak) for temperature, sap flow (2 species, 3 days) and leaf-water potential (2 species, 2 heights)

• Sap flow picks up later than leaf-water potential (sap flow

follows leaf water conductance)

• Sap flow and leaf-water potential do no go to ‘zero’ by dusk

(~7pm)

• Higher (negative) leaf water potential at greater height-of-

leaf (terpan, cararb)

Thank you