Dehydration, Water Fluxes, and Permeability of Tobacco Leaf Tissue

Dehydration, water fluxes, and permeability of tobacco leaf tissue.

Removal of the lower epidermis from a tobacco leaf allows a faster and wider range of water fluxes, without damaging the mesophyll. It also permits a more direct examination of the photosynthetic potential of the tissue at various levels of hydration.The rehydration rate of leaf discs is essentially linear. It decreases with leaf age and is correlated with the rate of dehydration, but it is ind...

Effects of water vapor pressure deficit on photochemical and fluorescence yields in tobacco leaf tissue.

The relationship between photochemical quantum yield (phi(s)) and fluorescence yield have been investigated in leaf tissue from Nicotiana tabacum using CO(2) exchange and a modulated fluorescence measuring system. The quantum yield of CO(2) fixation at 1.6% (v/v) O(2) and limiting irradiance was reduced 20% by increasing the mean H(2)O vapor pressure deficit (VPD) from 9.2 to 18.6 mbars. As [CO...

Lethal freeze-dehydration injury of dogwood stem tissue does not change the activation energy of water permeability.

The Arrhenius activation energy for water permeability, (DeltaE(a,H(2)O)) through stem cortical tissue of red osier dogwood (Cornus sericea L.) was determined after treatments which cause membrane rupture as well as after a lethal slow freeze and subsequent slow rewarming. The latter value was higher than the former, but was indistinguishable from the DeltaE(a,H(2)O) found for healthy tissue. I...

Tissue dehydration and embedment

Biological specimens contain up to 80% or more water which must be substituted in fixed cells (with the exception of special cryo-techniques) by some kind of embedding media to allow mechanical support for the sectioning process. Usually, embedding media cannot directly replace water, and fixation is followed by a sequence of dehydrating solutions from which the last must be miscible with the e...

Influence of salinity on co2 fluxes stomatal conductance and specific leaf eeight of jojoba