Variation in the amount of foliage on woody shoots and its effects on water relations parameters derived from pressure–volume curves

1986 ◽  
Vol 16 (2) ◽  
pp. 239-243 ◽  
Author(s):  
Howard S. Neufeld ◽  
Robert O. Teskey
Keyword(s):  
Water Content ◽  
Water Relations ◽  
Loblolly Pine ◽  
Woody Plant ◽  
Parameter Estimates ◽  
Relative Water ◽  
Degree Of Confidence ◽  
The Mean ◽  
Foliage Weight ◽  
Water Contents

The interpretation of pressure–volume curves for woody plant material is complicated by the use of foliated twigs to derive estimates of the water relations parameters of just the foliage. In this study, the ratio of foliage to twig water in shoots of loblolly pine (Pinustaeda) was varied systematically by defoliating twigs to varying degrees prior to constructing pressure–volume curves. Results show that variation in the ratio of foliage to twig water can influence interpretation of the curves. Reducing the amount of foliage causes decreases in the estimates of apoplasmic water content. Estimates of osmotic potential at full turgor and water potential at turgor loss were less affected. When foliated and fully defoliated twigs were compared, foliated twigs had lower water potentials at the same relative water contents. This may partially explain some of the differences in the parameter estimates among the treatments. If care is taken to avoid large differences in relative foliage weight, twigs can be used to estimate water relations characteristics of the foliage. For loblolly pine though, estimates of apoplasmic water content in twigs will be lower than in single fascicles. If single fascicles are used, more samples will have to be taken to obtain the same degree of confidence about the mean as for twigs, since the coefficient of variation is higher.

scholarly journals Capillary Mats Alter the Water Content in Medium during Mist Propagation of Dendranthema

HortScience ◽  
2004 ◽  
Vol 39 (3) ◽  
pp. 584-587 ◽  
Author(s):  
R.L. Geneve ◽  
S.T. Kester ◽  
J.W. Buxton
Keyword(s):  
Water Content ◽  
Water Table ◽  
Relative Water Content ◽  
Water Status ◽  
Internal Water ◽  
Relative Water ◽  
Reduced Water ◽  
Water Contents

A capillary mat-mist system was developed to provide near constant media water contents at differing quantities of mist. Media water contents were reduced by increasing the capillary mat height above a constant water table maintained at bench level. Increased tensions from 0 to 10 cm above the water table reduced water content in Oasis, rockwool, and peat-perlite by 35.4%, 27.6%, and 17.4%, respectively. There was no difference in water content for each medium when the mist quantity ranged between 600 and 1800 mL·m-2·h-1, except when the capillary mat was at 9 cm above the water table and mist volume was 300 mL·m-2·h-1. Chrysanthemum cuttings rooted best when water content was highest regardless of media. Using the peat-perlite medium, water content had the greatest impact on rooting when the mist volume was low (600 mL·m-2·h-1). Relative water content of cuttings was lowest during the first 5 days of sticking and both reduced media water content and mist quantity resulted in the lowest internal water status for the cuttings.

Water relations of temperate mistletoes on various hosts

2002 ◽  
Vol 29 (1) ◽  
pp. 89 ◽  
Author(s):  
Graham L. Strong ◽  
Peter Bannister
Keyword(s):  
New Zealand ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Water Relations ◽  
Daily Minimum ◽  
Relative Water ◽  
Artificial Shading ◽  
Osmotic Potentials ◽  
Moduli Of Elasticity ◽  
Water Contents

The daily field water relations and gas exchange of the temperate mistletoes Ileostylus micranthus (Hook.f.) Tiegh. and Tupeia antarctica Cham. et Schlecht. on various hosts were examined seasonally in Dunedin, New Zealand during 1996–1998. Mistletoes commonly have higher transpiration rates (E) than their hosts, and this is generally cited as the reason why mistletoes develop lower water potentials (ψ) than their hosts. The mistletoe-host pairs that we examined showed no significant overall differences in E and stomatal conductance (g), and we used them to test the hypothesis that lowered ψ in mistletoes result from higher E. Despite the lack of differences in E and g, osmotic potentials, predawn and daily minimum ψ (ψmin) were significantly more negative in mistletoes, although differences between host and mistletoe ψ were less on hosts with low osmotic potentials and ψ. Mistletoes maintained lower ψ than their hosts both when unshaded and under artificial shading, had lower ψ than hosts at equal E, but had shoot hydraulic resistances similar to that of their hosts. E and ψ of hosts and mistletoes tended to be coordinated only in summer, when hosts were most water-stressed. Mistletoes maintained higher relative water contents at turgor loss, symplastic water contents, and bulk moduli of elasticity (ε) than their hosts. We conclude that the lower ψ in these temperate mistletoes are a consequence of greater mistletoe E only when host ψ are low, but are otherwise maintained by greater succulence and higher ε than in their hosts.

Water relations and yield inAzospirillum-inoculated wheat exposed to drought in the field

2004 ◽  
Vol 82 (2) ◽  
pp. 273-281 ◽  
Author(s):  
Cecilia M Creus ◽  
Rolando J Sueldo ◽  
Carlos A Barassi
Keyword(s):  
Grain Yield ◽  
Water Potential ◽  
Water Content ◽  
Water Relations ◽  
Relative Water Content ◽  
Mineral Content ◽  
Water Status ◽  
Water Fraction ◽  
Relative Water ◽  
And Control

There are scarce data connecting water relations in Azospirillum-inoculated wheat suffering drought during anthesis with the yield and mineral content of grains. Azospirillum brasilense Sp245-inoculated seeds of Triticum aestivum 'Pro INTA Oasis' were sown in nonirrigated and control plots. Water potential, water content, and relative water content were determined on flag leaves. Plant water status was calculated from pressure–volume curves. At maturity, grain yield and its components were determined. P, Ca, Mg, K, Fe, Cu, and Zn were determined in dried grains. Even though the cultivar underwent osmotic adjustment, significantly higher water content, relative water content, water potential, apoplastic water fraction, and lower cell wall modulus of elasticity values were obtained in Azospirillum-inoculated plants suffering drought. Grain yield loss to drought was 26.5% and 14.1% in noninoculated and Azospirillum-inoculated plants, respectively. Grain Mg and K diminished in nonirrigated, noninoculated plots. However, grains harvested from Azospirillum-inoculated plants had significantly higher Mg, K, and Ca than noninoculated plants. Neither drought nor inoculation changed grain P, Cu, Fe, and Zn contents. A better water status and an additional "elastic adjustment" in Azospirillum-inoculated wheat plants could be crucial in promoting higher grain yield and mineral quality at harvest, particularly when drought strikes during anthesis.Key words: Azospirillum, wheat, drought, pressure–volume curves, yield, mineral content.

Pressure–volume curves of shoots and roots of normal and drought conditioned western hemlock seedlings

1980 ◽  
Vol 10 (1) ◽  
pp. 10-16 ◽  
Author(s):  
R. A. Kandiko ◽  
R. Timmis ◽  
J. Worrall
Keyword(s):  
Drought Stress ◽  
Water Content ◽  
Water Deficit ◽  
Western Hemlock ◽  
Relative Water ◽  
Osmotic Potentials ◽  
Water Contents

Pressure–volume curves for western hemlock (Tsugaheterophylla (Raf.) Sarg.) seedlings showed roots to have lower osmotic potentials, at both full turgor and incipient plasmolysis, and lower relative water contents at incipient plasmolysis than shoots. Roots remained turgid under mild water deficit, whereas shoots lost turgor exponentially with water content. Shoots of seedlings given a 2-week drought stress had lower osmotic potentials at full turgor and incipient plasmolysis than shoots of unstressed seedlings; roots showed a similar trend.

scholarly journals THE EFFECTS OF FILM-FORMING ANTITRANSPIRANTS ON LEAF WATER RELATIONS OF BEDDING PLANTS

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1086e-1086
Author(s):  
Cynthia B. McKenney ◽  
Marihelen Kamp-Glass
Keyword(s):  
Stomatal Conductance ◽  
Water Content ◽  
Water Relations ◽  
Relative Water Content ◽  
Leaf Water ◽  
Leaf Water Relations ◽  
Bedding Plants ◽  
Film Forming ◽  
Significant Difference ◽  
Relative Water

The effectiveness of antitranspirant type and concentration on the leaf water relations of Saliva splendens F. `Firebird and Petunia × hybrida Juss. `Comanche'. Two film-forming antitranspirants, Cloud Cover and Folicote, were tested at three different concentrations in two different environments. The leaf water potential, stomatal conductance, and relative water content were evaluated. Transpiration per unit vapor pressure deficit and stomatal conductance for both crops decrease slightly but there was no trend with respect to the film type, environment or concentration rate. The leaf water potentials and relative water content did not show significant difference after antitranspirant application. In order for antitranspirant application to be of benefit to the growth of herbaceous plants, a more durable coating that remains semipermeable would have to be utilized.

Tissue water relations for Brigalow and Mulga

1968 ◽  
Vol 16 (3) ◽  
pp. 487 ◽  
Author(s):  
DJ Connor ◽  
BR Tunstall
Keyword(s):  
Drought Tolerance ◽  
Water Potential ◽  
Water Content ◽  
Water Relations ◽  
Relative Water Content ◽  
Arid Zone ◽  
Tissue Water ◽  
Relative Water ◽  
The Relationship ◽  
Arid Zone Plants

The relationship between the relative water content and the water potential of the phyllodes in brigalow and mulga is compared. It is shown that brigalow phyllode tissue is more resistant to desiccation than that of mulga. This is of interest because mulga has previously been considered to represent an extreme in drought tolerance of Australian arid zone plants.

Leaf and root osmotic adjustment in drought-stressed Quercusalba, Q. macrocarpa, and Q. stellata seedlings

1988 ◽  
Vol 18 (1) ◽  
pp. 1-5 ◽  
Author(s):  
William C. Parker ◽  
Stephen G. Pallardy
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Water Relations ◽  
Osmotic Adjustment ◽  
Osmotic Potential ◽  
Root Tissue ◽  
Tissue Elasticity ◽  
Tissue Water ◽  
Before And After ◽  
Relative Water

The leaf and root tissue water relations of Quercusalba L., Quercusmacrocarpa Michx., and Quercusstellata Wang. seedlings before and after drought were examined to evaluate the occurrence and comparative extent of osmotic adjustment in seedlings of these species. Drought resulted in active osmotic adjustment in leaves of all three species, with decreases in osmotic potential at full tissue hydration and at the turgor loss point from 0.25 to 0.60 MPa. Active osmotic adjustment in Q. stellata, and increased root tissue elasticity in Q. macrocarpa and Q. alba, resulted in turgor loss of roots occurring at a water potential 0.36 to 0.66 MPa lower in drought-stressed than in well-watered seedlings. Species differed in tissue water relations only before drought, with Q. stellata exhibiting lower osmotic potentials than Q. alba and Q. macrocarpa. Estimates of the osmotic potential at full saturation were generally lower in leaves than in roots, but the osmotic potential at turgor loss was similar. Roots exhibited turgor loss at lower values of relative water content and experienced a more gradual decrease in water potential per unit water content during dehydration than did leaves. This response indicates greater relative tissue capacitance in roots than in leaves in these species.

scholarly journals Impact of Rice Husk Biochar on Growth, Water Relations and Yield of Maize (Zea mays L.) under Drought Condition

2018 ◽  
Vol 16 (02) ◽  
pp. 93-101 ◽  
Author(s):  
MA Shashi ◽  
MA Mannan ◽  
MM Islam ◽  
MM Rahman
Keyword(s):  
Water Content ◽  
Water Relations ◽  
Rice Husk ◽  
Water Relation ◽  
Leaf Water Content ◽  
Drought Condition ◽  
Relative Water ◽  
Rice Husk Biochar ◽  
The Impact ◽  
Different Doses

The present experiment was conducted to study the impact of rice husk biochar on growth, water relations and yield of maize (BARI Hybrid Bhutta- 9) under drought (60 and 40% of FC) conditions. Four doses of rice husk biochar @ 0, 5, 10 and 20 t/ha were applied as an amendment in soil before sowing of seeds. Results revealed that drought stress reduced plant height, relative water content and grain yield of maize. But rice husk biochar at different doses improved the above mentioned characters under drought conditions. Under 60% of FC, the highest plan height, leaf water content and yield were 196.67 cm, 79.86% and 89.75 g/plant, respectively when biochar was applied @ 20 t/ha but it was 173.33 cm, 78.32% and 84.57 g/plant, respectively under 40% of FC when biochar was applied at the same dose. It may be concluded that, rice husk biochar @ 20 t/ha showed the best result to promote growth, water relation traits and yield of maize under drought condition. The Agriculturists 2018; 16(2) 93-101

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