Osmotic adjustment induced by elevated ozone: interactive effects of acid rain and ozone on water relations of field-grown seedlings and mature trees of Pinus ponderosa

1995 ◽  
Vol 15 (12) ◽  
pp. 799-805 ◽  
Author(s):  
B. Momen ◽  
J. A. Helms
Keyword(s):  
Acid Rain ◽  
Water Relations ◽  
Pinus Ponderosa ◽  
Osmotic Adjustment ◽  
Interactive Effects ◽  
Mature Trees ◽  
Elevated Ozone

Post-fire survival and flushing in three Sierra Nevada conifers with high initial crown scorch

2009 ◽  
Vol 18 (7) ◽  
pp. 857 ◽  
Author(s):  
Chad T. Hanson ◽  
Malcolm P. North
Keyword(s):  
Sierra Nevada ◽  
Pinus Ponderosa ◽  
Fire Severity ◽  
Conifer Species ◽  
Mature Trees ◽  
Salvage Logging ◽  
Abies Magnifica ◽  
Crown Scorch ◽  
Tree Survival ◽  
Large Trees

With growing debate over the impacts of post-fire salvage logging in conifer forests of the western USA, managers need accurate assessments of tree survival when significant proportions of the crown have been scorched. The accuracy of fire severity measurements will be affected if trees that initially appear to be fire-killed prove to be viable after longer observation. Our goal was to quantify the extent to which three common Sierra Nevada conifer species may ‘flush’ (produce new foliage in the year following a fire from scorched portions of the crown) and survive after fire, and to identify tree or burn characteristics associated with survival. We found that, among ponderosa pines (Pinus ponderosa Dougl. ex. Laws) and Jeffrey pines (Pinus jeffreyi Grev. & Balf) with 100% initial crown scorch (no green foliage following the fire), the majority of mature trees flushed, and survived. Red fir (Abies magnifica A. Murr.) with high crown scorch (mean = 90%) also flushed, and most large trees survived. Our results indicate that, if flushing is not taken into account, fire severity assessments will tend to overestimate mortality and post-fire salvage could remove many large trees that appear dead but are not.

scholarly journals Growth and Physiological Responses ofPhaseolusSpecies to Salinity Stress

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
J. S. Bayuelo-Jiménez ◽  
N. Jasso-Plata ◽  
I. Ochoa
Keyword(s):  
Salt Stress ◽  
Water Relations ◽  
Osmotic Adjustment ◽  
Soluble Carbohydrate ◽  
Salt Tolerant ◽  
Key Factors ◽  
Sensitive Species ◽  
Carbohydrate Accumulation ◽  
Unit Leaf ◽  
Salt Level

This paper reports the changes on growth, photosynthesis, water relations, soluble carbohydrate, and ion accumulation, for two salt-tolerant and two salt-sensitivePhaseolusspecies grown under increasing salinity (0, 60 and 90 mM NaCl). After 20 days exposure to salt, biomass was reduced in all species to a similar extent (about 56%), with the effect of salinity on relative growth rate (RGR) confined largely to the first week. RGR of salt-tolerant species was reduced by salinity due to leaf area ratio (LAR) reduction rather than a decline in photosynthetic capacity, whereas unit leaf rate and LAR were the key factors in determining RGR on salt-sensitive species. Photosynthetic rate and stomatal conductance decreased gradually with salinity, showing significant reductions only in salt-sensitive species at the highest salt level. There was little difference between species in the effect of salinity on water relations, as indicated by their positive turgor. Osmotic adjustment occurred in all species and depended on higher K+, Na+, and Cl−accumulation. Despite some changes in soluble carbohydrate accumulation induced by salt stress, no consistent contributions in osmotic adjustment could be found in this study. Therefore, we suggest that tolerance to salt stress is largely unrelated to carbohydrate accumulation inPhaseolusspecies.

Salinity‐Ozone Interactive Effects on Alfalfa Yield and Water Relations

1975 ◽  
Vol 4 (3) ◽  
pp. 326-331 ◽  
Author(s):  
G. J. Hoffman ◽  
E. V. Maas ◽  
S. L. Rawlins
Keyword(s):  
Water Relations ◽  
Interactive Effects

INTERNAL WATER RELATIONS OF YELLOW BIRCH AT CHALK RIVER

1959 ◽  
Vol 37 (5) ◽  
pp. 789-799 ◽  
Author(s):  
D. A. Fraser ◽  
H. T. Dirks
Keyword(s):  
Moisture Content ◽  
Water Relations ◽  
Field Capacity ◽  
Yellow Birch ◽  
Mature Trees ◽  
Wood Moisture ◽  
Moisture Contents ◽  
Internal Water ◽  
Birch Trees ◽  
Wilting Point

Wood moisture was measured in the butt of healthy and decadent yellow birch trees growing on various sites in the summers of 1950 and 1952. The moisture content decreased from almost 100% in May to about 60% in late June when the leaves were fully unfolded. Wood moisture was usually 5 to 15% higher in the butt of decadent trees than in healthy trees during the 2 years of investigations. It was higher in the trunk of trees on a dry site during a wet summer and on a wet site during a somewhat dry summer.Relative turgidity in leaves was measured in mature trees as well as in leaves of seedlings growing on soils with varied moisture contents. Relative turgidity was usually less during the day. During periods of drought it decreased even during the night. Exceptions observed may have been caused by leaf absorption of dew. In young birch seedlings relative turgidity values varied between 65 and 50% in soils ranging from 100 to 70% of field capacity. As the soil wilting point was approached, relative turgidity of leaves decreased to about 35%.

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