Light sensitivity of shoot hydraulic conductance in five temperate deciduous tree species

2012 ◽  
Vol 39 (8) ◽  
pp. 661 ◽  
Author(s):  
Krõõt Aasamaa ◽  
Anu Sõber
Keyword(s):  
Stomatal Conductance ◽  
Water Potential ◽  
Water Use ◽  
Tree Species ◽  
Light Sensitivity ◽  
Hydraulic Conductance ◽  
Leaf Water ◽  
Deciduous Tree ◽  
Temperate Deciduous ◽  
Shoot Hydraulic Conductance

The light sensitivity of the shoot hydraulic conductance in five temperate deciduous tree species was measured using two methods to clarify the role of light sensitivity and the suitability of the methods used to study it. The light sensitivity measured using a method that included an interruption of ≤10 min in shoot light acclimation did not differ from that measured using a method with continuous illumination. The ‘noncontinuous light’ methods are suitable for measuring hydraulic conductance and its light response. Light sensitivity correlated with other leaf water traits as follows: positively with the ion-mediated increase in xylem hydraulic conductance; a relative decrease in the hydraulic conductance of the laminae in response to HgCl2; a relative change in stomatal conductance in response to changes in PAR intensity or atmospheric CO2 concentration, or to a decrease in air humidity or leaf water potential; and with instantaneous water use efficiency. The traits correlated negatively with shoot hydraulic conductance, stomatal conductance and relative increases in stomatal conductance in response to increases in leaf water potential. We suggest that high light sensitivity should be considered as one of the characteristics of conservative water use in trees. Low blue light increased shoot hydraulic conductance to a similar extent to moderate white light and twice as much as moderate red light. Blue light perception is important in the light sensitivity mechanism.

Leaf anatomical characteristics associated with shoot hydraulic conductance, stomatal conductance and stomatal sensitivity to changes of leaf water status in temperate deciduous trees

2001 ◽  
Vol 28 (8) ◽  
pp. 765 ◽  
Author(s):  
Krõõt Aasamaa ◽  
Anu Sõber ◽  
Märt Rahi
Keyword(s):  
Stomatal Conductance ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Hydraulic Conductance ◽  
Leaf Water ◽  
Fourth Power ◽  
Anatomical Characteristics ◽  
Temperate Deciduous ◽  
Stomatal Sensitivity ◽  
Shoot Hydraulic Conductance

Some anatomical characteristics in leaves relating to hydraulic conductance and stomatal conductance were examined in six temperate deciduous tree species. The fourth power of the radius of the conducting elements in xylem (r4) and the area of mesophyll and epidermal cells per unit length of leaf cross-section (u) were high in leaves with high hydraulic conductance (L). Stomatal conductance (gs) and stomatal sensitivity to an increase in leaf water potential (si) correlated positively with the length of stomatal pore (l), but negatively with the guard cell width (z) and the length of the dorsal side of the guard cells (ld). Stomatal sensitivity to a decrease in leaf water potential (sd) correlated negatively with l and positively with z and ld. The anatomical characteristics associated with hydraulic conductance (r4 and u) and those associated with stomatal conductance and sensitivity to changes of leaf water potential (l, z and ld) were correlated. We conclude that hydraulic conductance may depend on anatomical characteristics of xylem, mesophyll and epidermis, and stomatal conductance and its sensitivity to changing water potential may depend on anatomical characteristics of stomata. The correlation of shoot hydraulic conductance with stomatal conductance and its sensitivity may be based largely on the correlation between the anatomical characteristics of the water conducting system and stomata in these trees.

Hydraulic limitations and water-use efficiency in Pinus pinaster along a chronosequence

2008 ◽  
Vol 38 (1) ◽  
pp. 73-81 ◽  
Author(s):  
Federico Magnani ◽  
Abdelkader Bensada ◽  
Sergio Cinnirella ◽  
Francesco Ripullone ◽  
Marco Borghetti
Keyword(s):  
Stomatal Conductance ◽  
Water Use Efficiency ◽  
Water Potential ◽  
Water Use ◽  
Leaf Water Potential ◽  
Pinus Pinaster ◽  
Hydraulic Conductance ◽  
Leaf Water ◽  
Stand Development ◽  
Use Efficiency

Hydraulic constraints to water transport and water-use efficiency were studied in a Pinus pinaster Ait. chronosequence in Italy, consisting of four even-aged stands ranging from young (10 years old) to mature (75 years old), to explore the mechanisms involved in the decline of stand productivity as tree grow taller. Leaf-specific transpiration was estimated from sapflow rates measured by the heat dissipation technique, leaf-specific hydraulic conductance was computed from the slope of the relationship between transpiration and leaf water potential, long-term water-use efficiency was estimated from carbon isotope discrimination (Δ13C) in xylem cores, and photosynthetic capacity was assessed from CO2 assimilation/CO2 intercellular concentration curves. Leaf-specific transpiration decreased with stand development, suggesting a reduction in stomatal conductance, and a negative relationship was found between leaf-specific hydraulic conductance and tree height, suggesting a role of hydraulic constraints in the decline of current annual increment. Minimum daily leaf water potential did not change with stand height, suggesting that homeostasis in leaf water potential is achieved through a reduction in leaf transpiration. The Δ13C values increased with stand development, indicating a decline of water-use efficiency. Leaf level stomatal conductance was higher in the younger stand; no significant difference in maximum carboxylation rate was found among stands.

scholarly journals Stomatal conductance and root-to-shoot signalling in chestnut saplings exposed to Phytophthora cinnamomi or partial soil drying

2004 ◽  
Vol 31 (1) ◽  
pp. 41 ◽  
Author(s):  
Marion Maurel ◽  
Cécile Robin ◽  
Thierry Simonneau ◽  
Denis Loustau ◽  
Erwin Dreyer ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Potential Role ◽  
Phytophthora Cinnamomi ◽  
Castanea Sativa ◽  
Hydraulic Conductance ◽  
Leaf Water ◽  
Split Root

The effects of root infection by Phytophthora cinnamomi on stomatal conductance in Castanea sativa L. saplings were investigated to determine the potential role of root-derived chemical signals. A split-root experiment was carried out, in which inoculation of the pathogen or drought was applied to the root systems in either one or both compartments. At the end of the experiment plant sap extracts were collected and their effects on stomatal conductance were determined by leaf bioassay. Inoculation or drought imposed in both compartments resulted in decreases in stomatal conductance (gs), transpiration rate, soil-to-leaf specific hydraulic conductance, leaf water potential, xylem [ABA] and root biomass, but not in the ratio of root-to-leaf mass in inoculated plants. Conversely, only gs and xylem [ABA] were affected in plants inoculated or droughted in one compartment, and no changes were detectable in leaf water potential and soil-to-leaf specific hydraulic conductance. The leaf bioassay showed that gs in chestnut was sensitive to ABA but not to Phytophthora elicitins. Stomatal conductance was reduced by some sap extracts, both from control and inoculated plants. Our results suggest the involvement of different signals, chemical and hydraulic, in regulating stomatal conductance of chestnut at different stages of stress.

Relationship Between Root/Soil Hydraulic Properties and Stomatal Behaviour in Sugarcane

1989 ◽  
Vol 16 (3) ◽  
pp. 241 ◽  
Author(s):  
NZ Saliendra ◽  
FC Meinzer
Keyword(s):  
Stomatal Conductance ◽  
Water Potential ◽  
Soil Water ◽  
Leaf Water Potential ◽  
Water Status ◽  
Hydraulic Conductance ◽  
Leaf Water ◽  
Soil Drying ◽  
Root Hydraulic Conductance ◽  
High Soil Moisture

Stomatal conductance, leaf and soil water status, transpiration, and apparent root hydraulic conductance were measured during soil drying cycles for three sugarcane cultivars growing in containers in a greenhouse. At high soil moisture, transpiration and apparent root hydraulic conductance differed considerably among cultivars and were positively correlated, whereas leaf water potential was similar among cultivars. In drying soil, stomatal and apparent root hydraulic conductance approached zero over a narrow (0.1 MPa) range of soil water suction. Leaf water potential remained nearly constant during soil drying because the vapor phase conductance of the leaves and the apparent liquid phase conductance of the root system declined in parallel. The decline in apparent root hydraulic conductance with soil drying was manifested as a large increase in the hydrostatic pressure gradient between the soil and the root xylem. These results suggested that control of stomatal conductance in sugarcane plants exposed to drying soil was exerted primarily at the root rather than at the leaf level.

Stomatal conductance and leaf water potential responses to hydraulic conductance variation in Pinus pinaster seedlings

Trees ◽  
2007 ◽  
Vol 21 (3) ◽  
pp. 371-378 ◽  
Author(s):  
Francesco Ripullone ◽  
Maria Rosa Guerrieri ◽  
Angelo Nole’ ◽  
Federico Magnani ◽  
Marco Borghetti
Keyword(s):  
Stomatal Conductance ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Pinus Pinaster ◽  
Hydraulic Conductance ◽  
Leaf Water
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