Effect of Mid-day Shading on Stem Diameter, Xylem Pressure Potential, Leaf Surface Resistance, and Net Assimilation Rate in a White Oak Sapling

1974 ◽  
Vol 4 (3) ◽  
pp. 296-300 ◽  
Author(s):  
T. M. Hinckley ◽  
J. L. Chambers ◽  
D. N. Bruckerhoff ◽  
J. E. Roberts ◽  
J. Turner
Keyword(s):  
Surface Resistance ◽  
Leaf Surface ◽  
Stem Diameter ◽  
Net Assimilation Rate ◽  
Assimilation Rate ◽  
White Oak ◽  
Pressure Potential ◽  
Xylem Pressure ◽  
Xylem Pressure Potential ◽  
Net Assimilation

The diurnal relationship between xylem pressure potential and stem diameter in white oak (Quercusalba L.) resulted in a hysteresis loop on clear days where, for a given level of xylem pressure potential, the stem was thinner upon rehydration than during dehydration. Cloudy days complicated this pattern by forming a loop within the main loop. This additional loop was caused by the same factor which caused the main loop, the delayed reaction or lag between changes in stem diameter and xylem pressure potential. Both net assimilation rate and leaf surface resistance were closely linked and responded rapidly to changes in radiation. Hydroactive increases in leaf surface resistance were observed as xylem pressure potential decreased below −23 bars. A discussion of the relationship between stem diameter, radiation, leaf surface resistance, and xylem pressure potential is presented.

A simulation of water relations of white oak based on soil moisture and atmospheric evaporative demand

1977 ◽  
Vol 7 (2) ◽  
pp. 400-409 ◽  
Author(s):  
D. R. Thompson ◽  
T. M. Hinckley
Keyword(s):  
Soil Moisture ◽  
Surface Resistance ◽  
Vapor Pressure Deficit ◽  
Leaf Surface ◽  
White Oak ◽  
Pressure Potential ◽  
Evaporative Demand ◽  
Xylem Pressure ◽  
Xylem Pressure Potential ◽  
Predicted Values

A model was described which simulated xylem pressure potential and leaf surface resistance for a white oak (Quercusalba L.) tree and several saplings in central Missouri. The simulation was accomplished using a deterministic approach and was applicable from after leaf maturation in the spring to leaf senescence in the fall. Soil moisture content, vapor pressure deficit, and solar radiation were the required driving variables. The Ohm's law analogy describing water potentials and fluxes in the soil–plant–atmospheric continuum served as the basis for the model. The model was tested with data not used in the original parameter estimation, and very close agreement between observed and predicted values was found. The patterns of xylem pressure potential and leaf surface resistance obtained from simulation runs imply that white oak has a significant amount of stress tolerance and an ability to avoid severe dehydration.

Water deficits and root growth of ectomycorrhizal white oak seedlings

1980 ◽  
Vol 10 (4) ◽  
pp. 545-548 ◽  
Author(s):  
R. K. Dixon ◽  
G. M. Wright ◽  
G. T. Behrns ◽  
R. O. Teskey ◽  
T. M. Hinckley
Keyword(s):  
Leaf Surface ◽  
Soil Water Potential ◽  
Leaf Conductance ◽  
Silt Loam ◽  
White Oak ◽  
Pressure Potential ◽  
Xylem Pressure ◽  
Xylem Pressure Potential ◽  
Leaf Surface Area ◽  
Loam Soil

White oak (Quercusalba L.) seedlings grown in a silt loam soil inoculated with Pisolithustinctorius (Pers.) Coker and Couch exhibited 80% ectomycorrhizal development after a 6-month establishment period whereas the noninoculated controls exhibited less than 5%.When water was withheld and soil water potential decreased as the soil dried, xylem pressure potential and leaf conductance of both the inoculated and noninoculated seedlings declined gradually. At the peak of the drying cycle, the inoculated seedlings exhibited mean prelight and midlight xylem pressure potential values which were 0.2 MPa and 0.15 MPa, respectively, more negative than the noninoculated seedlings. Although the inoculated seedlings had a mean leaf surface area 1.5 times larger than that of the noninoculated seedlings, there were no significant differences in leaf conductance at the peak of the dehydration cycle. Mean rates of root elongation were greater among the inoculated seedlings during the drying cycle. Following reirrigation of the soil, the inoculated seedlings yielded significantly less negative values of prelight and midlight xylem pressure potential and greater leaf conductance when compared to the noninoculated seedlings.

The effects of drought on water relations and stem shrinkage of Quercus alba

1975 ◽  
Vol 53 (1) ◽  
pp. 62-72 ◽  
Author(s):  
Thomas M. Hinckley ◽  
David N. Bruckerhoff
Keyword(s):  
Soil Moisture ◽  
Surface Resistance ◽  
Leaf Surface ◽  
Stomatal Closure ◽  
Quercus Alba ◽  
Plant Water ◽  
White Oak ◽  
Water Deficits ◽  
Xylem Pressure Potential ◽  
Diurnal Fluctuations

Stem circumference, xylem pressure potential (P), and leaf surface resistance were measured in a dominant forest-grown white oak (Quercus alba L.) tree from the beginning of, through the development of, and to recovery from a major drought in mid-Missouri. Continuous recording of several environmental variables and periodic measurements of soil moisture were made in coordination with the above plant variables. As base P(P measured just before sunrise) and soil moisture decreased, net day-to-day and even week-to-week stem shrinkage was observed. Periodic thunderstorms alleviated soil and plant water deficits and stem circumference recovered. Excellent relationships were noted between soil moisture in the upper 30 cm of a 107-cm profile and either base P or stem circumference.Four clear and 2 cloudy days with rain are presented to illustrate diurnal patterns in the aforementioned variables. The generalized pattern of diurnal fluctuations in stem circumference consisted of early morning shrinkage, which continued to a 1500- to 1700-h. (true solar time) minimum, and subsequent recovery. Hysteresis loops resulted when stem circumference was plotted against P. Maximum diurnal fluctuations in stem circumference were greatest when soil moisture had been depleted slightly below field capacity. Further depletion led to lower values of P, stomatal closure, restricted plant water loss, and reduced stem shrinkage. The relationship between flux (vapor pressure deficit – leaf surface resistance) and P is also described and it provided a possible means of modeling P in plants. The possible role of the stem reservoir in augmenting foliar water deficits is presented and discussed.

Effects of Temperature and CO2Concentration on the Growth of Cotton (Gossypium hirsutum), Spurred Anoda (Anoda cristata), and Velvetleaf (Abutilon theophrasti)

Weed Science ◽  
1988 ◽  
Vol 36 (6) ◽  
pp. 751-757 ◽  
Author(s):  
David T. Patterson ◽  
Maxine T. Highsmith ◽  
Elizabeth P. Flint
Keyword(s):  
Dry Matter ◽  
Dry Weight ◽  
Net Assimilation Rate ◽  
Assimilation Rate ◽  
Short Term ◽  
Leaf Weight ◽  
Matter Production ◽  
Total Plant ◽  
Net Assimilation ◽  
Total Dry Weight

Cotton, spurred anoda, and velvetleaf were grown in controlled-environment chambers at day/night temperatures of 32/23 or 26/17 C and CO2concentrations of 350 or 700 ppm. After 5 weeks, CO2enrichment to 700 ppm increased dry matter accumulation by 38, 26, and 29% in cotton, spurred anoda, and velvetleaf, respectively, at 26/17 C and by 61, 41, and 29% at 32/23 C. Increases in leaf weight accounted for over 80% of the increase in total plant weight in cotton and spurred anoda in both temperature regimes. Leaf area was not increased by CO2enrichment. The observed increases in dry matter production with CO2enrichment were caused by increased net assimilation rate. In a second experiment, plants were grown at 350 ppm CO2and 29/23 C day/night for 17 days before exposure to 700 ppm CO2at 26/17 C for 1 week. Short-term exposure to high CO2significantly increased net assimilation rate, dry matter production, total dry weight, leaf dry weight, and specific leaf weight in comparison with plants maintained at 350 ppm CO2at 26/17 C. Increases in leaf weight in response to short-term CO2enrichment accounted for 100, 87, and 68% of the observed increase in total plant dry weight of cotton, spurred anoda, and velvetleaf, respectively. Comparisons among the species showed that CO2enrichment decreased the weed/crop ratio for total dry weight, possibly indicating a potential competitive advantage for cotton under elevated CO2, even at suboptimum temperatures.

Varietal differences in growth characteristics in sugar cane

1987 ◽  
Vol 108 (1) ◽  
pp. 245-247 ◽  
Author(s):  
S. Singh ◽  
P. N. Gururaja Rao
Keyword(s):  
Growth Rate ◽  
Sugar Cane ◽  
Growth Characteristics ◽  
Net Assimilation Rate ◽  
Assimilation Rate ◽  
Area Index ◽  
Relative Growth ◽  
Varietal Differences ◽  
Net Assimilation ◽  
High Yielding Varieties

In sugar cane, investigations made earlier (Singh & Gururaja Rao, 1985) have shown that high-yielding varieties have higher net assimilation rate than low-yielding types. Similarly, differences in progeny means for relative growth rate and net assimilation rate have been reported by George (1965). In other crops also, varietal differences in leaf area index and net assimilation rate have been reported (Watson, 1947). It appears that in this crop, limited attempts have been made to study all the growth characteristics. This paper describes the differences in most of the growth characteristics in six sugar-cane varieties.

Critical Period of Weed Interference in Transplanted Tomatoes (Lycopersicon esculentum): Growth Analysis

Weed Science ◽  
1983 ◽  
Vol 31 (4) ◽  
pp. 476-481 ◽  
Author(s):  
Susan E. Weaver ◽  
Chin S. Tan
Keyword(s):  
Lycopersicon Esculentum ◽  
Critical Period ◽  
Growth Analysis ◽  
Canopy Temperature ◽  
Dry Weight ◽  
Pressure Potential ◽  
Xylem Pressure ◽  
Fruit Number ◽  
Weed Interference ◽  
Xylem Pressure Potential

The critical period of weed interference in transplanted tomatoes (Lycopersicon esculentumMill. 'Springset’) was from 28 to 35 days after transplanting. A single weeding during this period was sufficient to prevent yield reductions. A growth analysis revealed that significant differences in plant dry weight and fruit number between tomatoes from weed-free and weed-infested plots were not apparent until 56 to 70 days after transplanting. The shorter the initial weed-free period, or the longer weeds were allowed to remain in the plots before removal, the earlier reductions in tomato dry weight and fruit number appeared. Weed interference was due primarily to shading rather than water stress. Tomatoes from weed-infested plots had significantly lower stomatal conductances than those from weed-free plots, but did not differ in xylem-pressure potential or in canopy temperature. If tomatoes were kept weed-free for more than 28 days, or when weeds were present for less than 28 days after transplanting, stomatal conductances were not significantly reduced.

scholarly journals Wplyw stopnia krzewienia się roślin na akumulacje biomasy organicznej u niektórych odmian zwyczajnej pszenicy ozimej [Influence of tillering degree on the accumulation of dry matter of some winter wheat varieties]

2015 ◽  
Vol 28 (2) ◽  
pp. 155-175
Author(s):  
Witold Drezner
Keyword(s):  
Winter Wheat ◽  
Dry Matter ◽  
Net Assimilation Rate ◽  
Assimilation Rate ◽  
Wheat Varieties ◽  
H Index ◽  
Net Assimilation ◽  
Winter Wheat Varieties

The correlation between the net assimilation rate and the degree of plant tillering are investigated for several varieties of simple winter wheat. The net assimilation rate (E, NAR, An) of the studied varieties for different degrees of tillering, individual shoots and individual plants is described according to the units mg/cm<sup>2</sup> • 24 h. Index of efficiency of assimilation surface (F, LAR, I<sub>S</sub>) is determined in units cm<sup>2</sup>/mg. The tillering ability of vegetative shoots in plaints is a very important factor which increases the total assimilate stirfaice value and the assimilation effectivity of the plant's biomass.

Studies on the productivity of tropical pasture plants. V.* Effect of shading on growth, photosynthesis and respiration in two grasses and two legumes

1974 ◽  
Vol 25 (3) ◽  
pp. 425 ◽  
Author(s):  
MM Ludlow ◽  
GL Wilson ◽  
MR Heslehurst
Keyword(s):  
Radiant Energy ◽  
Net Assimilation Rate ◽  
Assimilation Rate ◽  
Pasture Production ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Analysis Techniques ◽  
Net Assimilation ◽  
Photosynthesis And Respiration ◽  
Pasture Plants

Two grasses and two legumes were grown at three illuminances: one grass and one legume in a growth cabinet (100, 50 and 34% relative illuminance) and one of each in a glasshouse (100, 30 and 10% relative illuminance). The response to shading was investigated by using classical growth analysis techniques, and the photosynthesis-respiration balance obtained by Watson and Hayashi's method. Shading caused a reduction in the proportion of root and a corresponding increase in the proportion of leaf, and an increase in the shoot/root ratio in all species except green panic. The relative growth rates of grasses (which were only clearly superior at the highest illuminance) were affected more by shading than were those of legumes, and the greater shading effect resulted from a greater decrease in net assimilation rate, and to a lesser extent, from a smaller compensatory increase in leaf area ratio in the grasses than in the legumes. The greater sensitivity of net assimilation rate of grasses to shading arose from a stronger dependence of the photosynthetic rate on illuminance. The significance of these findings for pasture production is discussed. Both tiller and runner production were dependent upon the total amount of radiant energy received by the plant, and in the growth cabinet, at least, were independent of its intensity, duration and sequence. ______________________ *Part IV, Aust. J. Agric. Res., 25: 415 (1974).

Genetic Variation in the Effects of Root Impedance on Growth and Transpiration Rates of Wheat and Barley

1992 ◽  
Vol 19 (2) ◽  
pp. 109 ◽  
Author(s):  
J Masle
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Time Course ◽  
Net Assimilation Rate ◽  
Root Penetration ◽  
Lower Sensitivity ◽  
Soil Resistance ◽  
Assimilation Rate ◽  
Relative Growth ◽  
Net Assimilation

Genotypes of wheat and barley, including modern and landrace lines, were compared in their response to soil resistance to root penetration during the early vegetative phase (up to 5 leaf stage). All genotypes exhibited reduced growth and transpiration rates at high soil resistance, but there was large variation in the magnitude and time course of these effects and in the mechanisms underlying the growth reduction (changes in net assimilation rate, carbon partitioning within the plant, relative effects of leaf primordia development, versus growth of expanding leaves). Similar wide ranges of responses were observed among landrace and modern wheats. In both wheat and barley, the genotypes with lower sensitivity to soil resistance, in terms of relative growth rate, were those with the slowest net assimilation rate and root growth rate at low soil resistance, and those for which carbon allocation to the impeded roots, relative to the shoot, was significantly increased, to the extent that root relative growth rate even became greater (in terms of mass, not of length) than on loose soil. For a number of genotypes, growth was slowed down throughout the experiment whereas for others it was reduced only during the first few days following germination. In contrast, transpiration rate was at all stages lower at high than at low soil resistance. This indicates that the effects of soil resistance to root penetration on stomatal conductance involve different controls - or different sensitivities to a common signal - from those operating on cell division and expansion.

The growth of maize

1978 ◽  
Vol 90 (3) ◽  
pp. 569-577 ◽  
Author(s):  
G. O. Iremiren ◽  
G. M. Milbourn
Keyword(s):  
Leaf Area ◽  
Dry Matter ◽  
Matter Content ◽  
Net Assimilation Rate ◽  
Dry Matter Content ◽  
Dry Matter Yield ◽  
Assimilation Rate ◽  
Maize Silage ◽  
Area Index ◽  
Net Assimilation

SummaryTotal dry-matter yield of maize silage rose asymptotically as density was increased up to 17 plants/m2. Over the range 11–17 plants/m2, which is generally higher than is used in the U.K., the increase in yield was 1–1·6 t dry matter/ha which can justify the higher seed cost and although there was no adverse affect on time of maturity the risk of lodging increased at the highest density. During the harvest period whilst whole crop dry-matter percentage was rising from 23 to 28%, the ear dry-matter content rose steadily from 29 to 35%, whereas the leaf and stem dry-matter content remained essentially constant and only dried out at a later stage after a frost.Caldera 535 had a higher leaf area index and net assimilation rate than the earlier variety Julia which it outyielded by 15%. The additional yield was mainly stem tissue and the greater vegetative production caused an 11-day delay in reaching the silage stage of maturity (25% crop D.M.). NO differences occurred between density treatments and varieties in the forage quality components considered, namely percentage drymatter digestibility, modified acid-detergent fibre, crude protein and ash. Thus in U.K. conditions, total dry-matter yield exerts an overriding influence on the yields per unit area of these quality constituents. This contrasts with reports from the U.S.A. in which a reduced grain/stover ratio adversely influences silage quality.Removal of the whole ear (including husk and rachis) at an early stage in ear development resulted in a 50% reduction in the final dry-matter yield. In the earless plants, leaf area and net assimilation rate was lower, but the dry-matter content of the leaves and stem was considerably higher, and a marked purple coloration developed indicative of excess starch concentration. These results emphasize the need in maize silage not only for an adequate leaf canopy, best obtained early in the growing season by using high planting density and subsequently by using late maturing varieties, but also for sufficient sink capacity in the ear as well as in the stem fraction.

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