The role of leaf water potential in controlling stomatal conductance (gs)

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叶片水势在控制气孔导度（gs）中的作用

O papel do potencial hídrico das folhas no controle da condutância estomática (gs).

El papel del potencial hídrico de las hojas en el control de la conductancia estomática (gs).

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Control of stomatal conductance by leaf water potential in Hymenoclea salsola (T. & G.), a desert subshrub

Comstock J., Mencuccini M. (1998)

Plant Cell Environ. 21(10): 1029–1038 –

https://doi.org/10.1046/j.1365-3040.1998.00353.x –

https://onlinelibrary.wiley.com/doi/10.1046/j.1365-3040.1998.00353.x

Abstract

The role of leaf water potential in controlling stomatal conductance (g_s) was examined in the desert subshrub Hymenoclea salsola. For plants operating at high irradiance, stomatal closure in response to high leaf-air humidity gradient (D) was largely reversed by soil pressurization. Stomatal re-opening eliminated, on average, 89% of the closure normally induced by high D. Transpiration rates (E) reached under these conditions were far higher than maximal rates normally observed at any point of the D response. In situ stem psychrometry indicated that water flux at all times conformed to a simple Ohm’s-law analogy. Under conditions of high D, E increased substantially in response to soil pressurization. Stomatal regulation did not constrain E during this treatment, but did result in nearly constant minimum leaf water potentials.

Control of stomatal conductance

 

 

Control of stomatal conductance by leaf water potential in Hymenoclea salsola (T. & G.), a desert subshrub.

by Comstock J., Mencuccini M. (1998)

in Plant, Cell & Environment 21: 1029–1038. –

Wiley Online Library |PubMed |

http://onlinelibrary.wiley.com/doi/10.1046/j.1365-3040.1998.00353.x/full

Schematic of the whole-plant photosynthesis cuvette with root pressure chamber. The cuvette was constructed of acrylic plastic lined with Teflon film. Internal mixing fans generated air movement 10–100 times the rate of air flow through the cuvette for gas exchange measurements. Temperature control was achieved by both water channels in the acrylic chamber walls and small radiators in the internal air flow pathway. The root pressure chamber was made of carbon steel and rated for pressures up to 4·0 MPa. The pressure chamber lid and the compression plate were formed by two steel half-circles which could be fitted around the intact plant stem to compress a neoprene gasket. – http://api.onlinelibrary.wiley.com/asset/v1/doi/10.1046%2Fj.1365-3040.1998.00353.x/asset/image_n%2FPCE_353_f1.gif?l=q8hDySOaNttEIdDP9D42UhSPCn%2BHKzXqYVuA9SabmExnDhSJcb7YXXRak4%2FJruKxT60H5vf%2BOJL1eC1RUWKaBg%3D%3D&s=%22d695782fa0f9473cbd5dea6c705f7155%22&a=wol

Abstract

The role of leaf water potential in controlling stomatal conductance (g_s) was examined in the desert subshrub Hymenoclea salsola. For plants operating at high irradiance, stomatal closure in response to high leaf-air humidity gradient (D) was largely reversed by soil pressurization.

Stomatal re-opening eliminated, on average, 89% of the closure normally induced by high D. Transpiration rates (E) reached under these conditions were far higher than maximal rates normally observed at any point of the D response. In situ stem psychrometry indicated that water flux at all times conformed to a simple Ohm’s-law analogy.

Under conditions of high D, E increased substantially in response to soil pressurization.

Stomatal regulation did not constrain E during this treatment, but did result in nearly constant minimum leaf water potentials.

Read the full text: Wiley Online Library

Leaf water potential and stomatal conductance (gs)

Photo credit: Google

Control of stomatal conductance by leaf water potential in Hymenoclea salsola (T. & G.), a desert subshrub

by Comstock J. P., Mencuccini M. (1998)

in Plant, Cell & Environment 21: 1029–1038. – 

Abstract, Full Article (HTML), PDF(594K), References, Web of Science® Times Cited: 64.

(a) Stomata usually open in response to the blue light of sunlight. (b) Stomata usually close in response to lack of sunlight. They can also close during the day under conditions of water stress, which induces plants to produce more of the hormone abscisic acid (ABA). Stomatal guard cell plasma membranes possess ABA receptors, which receive the drought signal. – http://biology-forums.com/gallery/33_25_07_11_12_56_44.jpeg

Abstract

The role of leaf water potential in controlling stomatal conductance (g_s) was examined in the desert subshrub Hymenoclea salsola. For plants operating at high irradiance, stomatal closure in response to high leaf-air humidity gradient (D) was largely reversed by soil pressurization.

Stomatal re-opening eliminated, on average, 89% of the closure normally induced by high D. Transpiration rates (E) reached under these conditions were far higher than maximal rates normally observed at any point of the D response.

In situ stem psychrometry indicated that water flux at all times conformed to a simple Ohm’s-law analogy. Under conditions of high D, Eincreased substantially in response to soil pressurization. Stomatal regulation did not constrain E during this treatment, but did result in nearly constant minimum leaf water potentials.