Water relations of crok-oak (Quercus suber L.) under natural conditions

Vegetatio ◽  
1992 ◽  
Vol 99-100 (1) ◽  
pp. 199-208 ◽  
Author(s):  
G. Oliveira ◽  
O. A. Correia ◽  
M. A. Martins-Lou��o ◽  
F. M. Catarino
Keyword(s):  
Water Relations ◽  
Quercus Suber ◽  
Natural Conditions

Water relations of cork-oak (Quercus suber L.) under natural conditions

1992 ◽  
pp. 199-208 ◽  
Author(s):  
G. Oliveira ◽  
O. A. Correia ◽  
M. A. Martins-Loução ◽  
F. M. Catarino
Keyword(s):  
Water Relations ◽  
Quercus Suber ◽  
Cork Oak ◽  
Natural Conditions

Lichen carbon gain under tropical conditions: water relations and CO2 exchange of Lobariaceae species of a lower montane rainforest in Panama

2004 ◽  
Vol 36 (5) ◽  
pp. 329-342 ◽  
Author(s):  
Otto L. LANGE ◽  
Burkhard BÜDEL ◽  
Angelika MEYER ◽  
Hans ZELLNER ◽  
Gerhard ZOTZ
Keyword(s):  
Water Relations ◽  
Carbon Fixation ◽  
Nitrogen Concentration ◽  
Carbon Gain ◽  
Carbon Loss ◽  
Natural Conditions ◽  
Low Light ◽  
Green Algal ◽  
Tropical Conditions ◽  
Montane Rainforest

Diel (24-h) time courses of microclimate, water relations, and CO2 exchange were measured under quasi-natural conditions at a forest edge in a lower montane, tropical rainforest in Panama for six Lobariaceae (Lobaria crenulata, L. dissecta, Pseudocyphellaria aurata, P. intricata, Sticta sublimbata, S. weigelii). Responses to experimentally controlled water content (WC), photosynthetic photon fluence rate (PPFR), and temperature were studied in most detail with P. aurata.Photosynthesis was well adapted to high temperatures, and all species exhibited ‘shade plant’ characteristics with low light compensation points and low light saturation. Lobaria and Pseudocyphellaria species suffered from a strong depression of net photosynthesis (NP) at suprasaturating WC; suprasaturation depression was less in cyphellate Sticta species.Photosynthetic capacity correlated with thallus nitrogen concentration, and maximal NP rates of the cyanobacterial Sticta species was 4 to 5 times higher than that of the green algal Lobaria species. However, high rates of NP were uncommon and brief events under natural conditions; the different environmental factors were rarely optimal simultaneously. Similar to earlier observations with other rainforest lichens, NP ceased during the period of highest irradiation on most days due to desiccation. During moist periods low light often limited carbon fixation, and high thallus hydration was often detrimental to NP. In spite of these limitations the maximal daily integrated net photosynthetic carbon income (ΣNP) was quite high especially for the Sticta species [17·3 and 24·1 mgC (gC)−1 day−1 for S. sublimbata and S. weigelii, respectively]. High nocturnal carbon loss, due to high night temperatures and continuous hydration, resulted in frequent negative diel carbon balances (ΣC) in all species. The average nocturnal carbon loss amounted to 83 and 70% ΣNP for P. aurata and P. intricata, respectively and to 64 and 59% of ΣNP for S. sublimbata and S. weigelii, respectively. Their average diel ΣC was as high as 3·7 and 5·3 mgC (gC)−1 day−1. In contrast, ΣC was much lower for the other species, it amounted to only 0·18 mgC (gC)−1 day−1 for L. crenulata. Thus, the Sticta species stood out amongst the species studied for their most successful adaptation of photosynthetic productivity to the habitat conditions in the lower montane rainforest.

scholarly journals A Cork Cell Wall Approach To Swelling And Boiling

2021 ◽  
Author(s):  
Ana Patrícia Poeiras ◽  
Cordula Voguel ◽  
Björn Günther ◽  
Constança Camilo-Alves ◽  
Peter Surový ◽  
...  
Keyword(s):  
Cell Wall ◽  
Water Availability ◽  
Cell Walls ◽  
Quercus Suber ◽  
Cork Oak ◽  
Cork Stopper ◽  
Natural Conditions ◽  
Cork Cell ◽  
Insight Into ◽  
Cell Wall Expansion

Abstract The bark of cork oak (Quercus suber L.) is mostly used for cork stopper production, whereas bark is undergoing a series of industrial procedures, boiling usually leading to changes in the characteristics of the tissue. Trees are traditionally grown under natural conditions; however, irrigation is now being used in plantations. These permanent water availability affects cork-oak development, while its effects on industrial procedures is unknown. This study provides a first insight into the behaviour of the cell walls of cork during the process of swelling and boiling when trees have been grown under irrigation, subject to a specific water regime. Cork tissue was analysed using environmental and scanning electron microscopy under three regimes: raw conditions; following immersion in water; and after boiling. Additionally, the radial expansion of samples was determined. The results showed greater cell-wall expansion in cork from the irrigated site than cork from the traditional rainfed plot, when hydrated for 24h. After boiling, the cell walls of the rainfed site were thinner than in the raw stage, in contrast to the irrigated cork. This study suggests that irrigation during cork-oak growth produces a higher capacity for adsorption, increasing cell-wall thickness from the raw stage to the boiling stage.

scholarly journals WATER RELATIONS IN THE CELL

1945 ◽  
Vol 29 (2) ◽  
pp. 73-78 ◽  
Author(s):  
W. J. V. Osterhout
Keyword(s):  
Water Relations ◽  
Ferric Chloride ◽  
Lead Acetate ◽  
Lead Nitrate ◽  
Inorganic Salts ◽  
Natural Conditions ◽  
Ellipsoid Bodies ◽  
Straight Rod

Chloroplasts may contract under natural conditions and give up water to the rest of the cell, thus indicating changes in metabolism or constitution. Such contractions may be produced experimentally. In Nitella the chloroplasts are ellipsoid bodies which, under natural conditions, may contract to spheres with a loss of volume. This may be brought about by lead acetate, ferric chloride, and digitonin: the contraction may occur while the cell is alive. The contraction in lead acetate is reversible (in lead nitrate little or no contraction occurs). In Spirogyra the chloroplast is a long, spirally coiled ribbon which may contract under natural conditions to a short nearly straight rod with a loss of volume. This can be brought about by inorganic salts and in other ways while the cell is still alive.

Azimuthal variations in xylem structure and water relations in cork oak (Quercus suber)

IAWA Journal ◽  
2011 ◽  
Vol 32 (1) ◽  
pp. 25-40 ◽  
Author(s):  
Nadia Barij ◽  
Jan Čermák ◽  
Alexia Stokes
Keyword(s):  
Moisture Content ◽  
Water Relations ◽  
Sap Flow ◽  
Quercus Suber ◽  
Cork Oak ◽  
Wood Moisture Content ◽  
Wood Moisture ◽  
Vessel Size ◽  
Xylem Structure ◽  
Crown Size

Azimuthal variations in xylem conductivity and transpiration can occur in trees and may be due to heterogeneity in environmental factors. In cork oak (Quercus suber L.), it can be hypothesized that such modifications may be more pronounced because the insulating layer of bark is harvested every 9–10 years, thus cambial cells will be exposed to fluctuations in the microenvironment. To investigate whether xylem structure and water relations differed around the stems of mature cork oak, sap flow per section and xylem structure were measured on the northern (N) and southern (S) sides of nine trees during three months in Portugal, using the Trunk Sector Heat Balance method. Crown size was measured on both sides of each tree and increment wood cores were extracted from the sites where sap flow was measured in five trees. Wood moisture content, earlywood (EW) vessel size and density were measured and theoretical hydraulic conductivity for individual vessels (Lth) was calculated along the N and S stem radial profiles. No significant differences in crown size between the two sides of the tree were found, but sap flow was higher on the S side of the tree in May only. No differences in wood moisture content were observed along the length of each wood core throughout the heartwood. Significant differences in vessel size occurred, with a greater diameter and surface area on the N side of the tree, and consequently Lth was significantly greater. These conduit diameters on the S facing side of the tree may be smaller in response to a combination of signals and trade-offs due to the heterogeneous air and soil environment around the tree.

scholarly journals Water relations of cork oak (Quercus suber L.) seedlings in response to shading and moderate drought

2005 ◽  
Vol 62 (5) ◽  
pp. 377-384 ◽  
Author(s):  
Marta Pardos ◽  
M. Dolores Jiménez ◽  
Ismael Aranda ◽  
Jaime Puértolas ◽  
José A. Pardos
Keyword(s):  
Water Relations ◽  
Quercus Suber ◽  
Cork Oak ◽  
Moderate Drought

scholarly journals Effects of three fungal pathogens on water relations, chlorophyll fluorescence and growth of Quercus suber L

1999 ◽  
Vol 56 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Jordi Luque ◽  
Moshe Cohen ◽  
Robert Savé ◽  
Carmen Biel ◽  
Isabel F. Álvarez
Keyword(s):  
Chlorophyll Fluorescence ◽  
Water Relations ◽  
Fungal Pathogens ◽  
Quercus Suber
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