Hydraulic architecture of some diffuse-porous trees

1978 ◽  
Vol 56 (18) ◽  
pp. 2286-2295 ◽  
Author(s):  
Martin H. Zimmermann
Keyword(s):  
Water Stress ◽  
Specific Conductivity ◽  
Main Stem ◽  
Gravity Flow ◽  
Hydraulic Architecture ◽  
Fresh Weight ◽  
Leaf Specific Conductivity ◽  
Tree Stem ◽  
Diffuse Porous

The rate of flow of a dilute KCl solution through sections of stem, branches, and twigs was measured and expressed in microlitres per hour, under conditions of gravity flow, per gram fresh weight of leaves supplied by that section of xylem. This is called leaf-specific conductivity (LSC). It is not uniform throughout the tree, LSC of the stem being higher than that of branches. Furthermore, vascular junctions, such as the path from stem to branch, represent hydraulic constrictions. Distribution of LSC in the tree is primarily based on varying vessel diameters. Vessel diameters increase from top to bottom in the tree stem. They are smaller in branches than in the main stem, and there is a distinct constriction of diameters at the base of each branch. Functionally this means that when transpiration begins the pressure has to drop more rapidly in the xylem of lower lateral leaves than in those at the top of the tree. It also means that under conditions of water stress peripheral parts of the tree are more vulnerable than the trunk.

Effects of drought stress on hydraulic architecture of seedlings from five populations of green ash

1991 ◽  
Vol 69 (10) ◽  
pp. 2158-2164 ◽  
Author(s):  
Durland L. Shumway ◽  
Kim C. Steiner ◽  
Marc D. Abrams
Keyword(s):  
Flow Velocity ◽  
Leaf Area ◽  
Specific Conductivity ◽  
Control Plant ◽  
Population Variation ◽  
Precipitation Gradient ◽  
Green Ash ◽  
Hydraulic Architecture ◽  
Leaf Specific Conductivity ◽  
Plant Hydraulic Architecture

Two-year-old seedlings of green ash, Fraxinus pennsylvanica Marsh., representing five native populations from an east to west precipitation gradient, were grown under contrasting moisture regimes in the greenhouse. At midsummer and the end of the growing season, leaf areas, earlywood and latewood transverse areas, and several structural attributes of the xylem hydraulic system were compared between well-watered and drought-stressed seedlings. Xylem hydraulic capacity was essentially fixed by midsummer. Drought significantly reduced both earlywood and latewood production but had no significant effect on potentially functional xylem area (Apf) or flow velocity (v). The principal effect of drought on hydraulic architecture was a significant reduction in leaf area and therefore the ratios of potentially functional xylem area to unit leaf area (Apf to A1) and leaf specific conductivity (LSC). In contrast, populations differed significantly in all measured parameters, especially under drought conditions. Path analysis of LSC and its component variables revealed that treatment differences in LSC arose primarily through differences in A1; contributions from variation in Apf and especially flow velocity were relatively minor. In contrast, population variation in LSC could be attributed in roughly equal measure to variation in Apf and A1, and to a lesser degree to variation in flow velocity. The covariance between A1 and Apf was important for both treatment and population variation in LSC, suggesting a fundamental physiological linkage between these two aspects of plant hydraulic architecture. Among populations, high flow velocity tended to be associated with low Apf to A1 values, thereby minimizing population differences in the composite character LSC. Populations differed significantly in all attributes studied, in one environment or another, but those at either end of the precipitation gradient did not differ in several presumably important structural attributes. Although plant hydraulic architecture is genetically controlled and variable in green ash seedlings, its adaptive significance cannot be considered in isolation from other factors that control plant response to water stress. Key words: leaf specific conductivity, ecotypic variation, xylem structure.

RESPONSE OF PEAS TO ENVIRONMENT: IV. EFFECT OF FIVE SOIL WATER REGIMES ON GROWTH AND DEVELOPMENT OF PEAS

1968 ◽  
Vol 48 (2) ◽  
pp. 129-137 ◽  
Author(s):  
A. R. Maurer ◽  
H. F. Fletcher ◽  
D. P. Ormrod
Keyword(s):  
Water Stress ◽  
Soil Water ◽  
Growth And Development ◽  
Dry Matter ◽  
Fresh Weight ◽  
Water Regimes ◽  
Severe Water Stress ◽  
Water Conditions ◽  
Before And After ◽  
Soil Water Conditions

Pea plants growing in "weighing lysimeters" were subjected to five soil-water regimes to determine their response to varying conditions of soil water imposed at different stages of development. Plants subjected to a minimal water stress developed luxuriantly and continued to grow up to the harvest period. Pea yield and plant height were not reduced, but fresh weight and dry matter were less if irrigation was applied when soil water fell to 60% rather than 88% of that available. A severe water stress after blossom reduced pea yield, irrespective of soil-water conditions prior to blossom. Plants which had been given ample soil water before blossom wilted visibly when a severe stress was imposed in the post-blossom period, yet wilting did not occur in plants subjected to severe water stress both before and after blossom. Severe water stress prior to blossom did not cause a decrease in pea yield if ample soil moisture was made available after blossom.

scholarly journals Water Stress and Storage-protein Degradation during Germination of Impatiens Seed

1991 ◽  
Vol 116 (2) ◽  
pp. 302-306 ◽  
Author(s):  
Mehrassa Khademi ◽  
David S. Koranski ◽  
David J. Hannapel ◽  
Allen D. Knapp ◽  
Richard J. Gladon
Keyword(s):  
Water Stress ◽  
Storage Proteins ◽  
Dry Weight ◽  
Insoluble Fraction ◽  
Weight Basis ◽  
Optimum Conditions ◽  
Fresh Weight ◽  
Soluble Protein Fraction ◽  
Molecular Weights ◽  
And Storage

Water uptake by impatiens (Impatiens wallerana Hook. f. cv. Super Elfin Coral) seeds was measured as an increase in fresh weight every 24 hours during 144 hours of germination. Seeds absorbed most of the water required for germination within 3 hours of imbibition and germinated at 60% to 67% moisture on a dry-weight basis. Germination started at 48 hours and was complete by 96 hours at 25C. Water stress of -0.1, -0.2, -0.4, and -0.6 MPa, induced by polyethylene glycol 8000, reduced germination by 13%, 49%, 91%, and 100%, respectively, at 96 hours. Under the same water-stress conditions, increases in fresh weight were inhibited by 53%, 89%, 107%, and 106%, respectively. Three distinct groups of storage proteins were present in dry seed; their estimated molecular weights were 1) 35, 33, and 31 kDa; 2) 26, 23, and 21 kDa; and 3) two bands <14 kDa. Major depletion of storage proteins coincided with the completion of germination. Water potentials that inhibited germination also inhibited degradation of storage proteins. During germination under optimum conditions, the soluble protein fraction increased, coinciding with a decrease in the insoluble fraction.

A Comparison of Indirect Watering Devices for Benefiting Newly Transplanted Urban Trees

2019 ◽  
Vol 45 (4) ◽  
Author(s):  
Shaik Hossain ◽  
H. Christoph Stuhlinger ◽  
Matthew Olson ◽  
Benjamin Babst
Keyword(s):  
Water Stress ◽  
Surface Runoff ◽  
Root Zone ◽  
Urban Trees ◽  
Substantial Variation ◽  
Water Release ◽  
Purchase Cost ◽  
Time Required ◽  
Reduced Water ◽  
Tree Stem

Three types of indirect watering devices were compared to evaluate their performance and to determine their benefits to newly transplanted river birch (Betula nigra) trees grown in containers with well drained compost in a controlled greenhouse experiment. Two examples of each device type were used to water trees in this study: upright bags, ring bags, and open tubs. Watering device characteristics, including purchase cost, weight, capacity, and drainage times, were measured prior to installing the devices around the trees. Tree stem heights and calipers, along with leaf coverage and leaf water potential, were measured to determine any growth or water stress differences associated with watering treatments. There was substantial variation in costs and drainage times among watering devices, with ring bags being the least expensive and draining water completely during the drainage test. However, there was no evidence that watering devices benefited tree growth, leaf rating, or water stress in comparison with direct watering, with the possible exception of Treegator ring bags, which may have reduced water stress marginally. Although water release from some of the indirect watering devices was much slower than direct watering, water release from all of the devices was completed within ten hours, which is too rapid to reduce the frequency of watering in our experiment. The major benefits of these devices are slower release of water to the soil, with reduced operator time required, and more infiltration into the soil and root zone, which avoids the surface runoff caused by quick hose (direct) watering.

scholarly journals In vitro screening of rice genotypes using polyethylene glycol under drought stress

2016 ◽  
Vol 27 (2) ◽  
pp. 128-135 ◽  
Author(s):  
J Akte ◽  
S Yasmin ◽  
MJH Bhuiyan ◽  
F Khatun ◽  
J Roy ◽  
...  
Keyword(s):  
Water Stress ◽  
Drought Stress ◽  
Water Content ◽  
Relative Water Content ◽  
Dry Weight ◽  
Proline Accumulation ◽  
Shoot Length ◽  
Fresh Weight ◽  
Relative Water

Five rice varieties viz. Binadhan-4, Binadhan-5, Binadhan-6, Binadhan-10 and Iratom-24 were evaluated in vitro under different water stress conditions. Several parameters such as germination percentage, shoot length, root length, shoot-root ratio, fresh weight, dry weight, turgid weight, relative water content and proline accumulation were studied. Drought condition was created by MS medium supplemented with five treatments of PEG, with a control such as 0%, 1%, 2%, 3% and 4% of PEG. The highest germination (100%) was found in the variety Binadhan-10 under low water stress conditions induced by 1% PEG. Similarly, the highest percentage of germination was found in all varieties under control condition (0% PEG). The lowest percentage of germination was obtained in the variety Iratom-24. But under severe stress (4% PEG), the highest percentage of germination was found only in the variety Binadhan-10. Moreover, the variety Binadhan-10 was found to be the best at 4% PEG for shoot length, root length, shoot-root ratio, relative water content and also the best at 1% PEG for fresh weight, dry weight, turgid weight. Water stress decreased relative water content and increased proline accumulation in rice. The highest relative water content was recorded in the variety Binadhan-10 and the lowest value recorded in the variety Binadhan-5. The highest proline content was obtained from the binadhan-6 at the highest treatment (4% PEG). Binadhan-10 showed the best performance almost in all the parameters under drought stress because of its own nature of tolerancy.Progressive Agriculture 27 (2): 128-135, 2016

Fruit Growth and Dry Matter Accumulation in Grapefruit During Periods of Water Withholding and After Reirrigation

1988 ◽  
Vol 15 (5) ◽  
pp. 633 ◽  
Author(s):  
A Cohen ◽  
A Goell
Keyword(s):  
Water Stress ◽  
Dry Matter ◽  
Volume Growth ◽  
Fruit Growth ◽  
Dry Matter Accumulation ◽  
Fresh Weight

Changes in volume, fresh weight and dry matter (DM) contents were followed in fruits from girdled and non-girdled branches borne on regularly irrigated (RI) as well as water-stressed (S) trees. Water stress was imposed by withholding irrigation for various periods. The results indicate that, even during prolonged periods of drought, DM accumulation in fruits on S trees was only slightly impaired, even when fruit volume growth was reduced to zero or even to shrinkage. After irrigation was resumed, fruits from S trees grew faster than those from RI trees, indicating that some of the DM which had accumulated was available for volume growth. The possibility of using the rate of DM accumulation in the fruit as an indicator for the timing of irrigation is discussed.

scholarly journals 683 PB 236 WATER STRESS REDUCES ASPARAGUS GROWTH

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 531d-531
Author(s):  
Dan Drost
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Root Zone ◽  
Near Field ◽  
Field Capacity ◽  
Fresh Weight ◽  
Irrigation Rate ◽  
Growing Period ◽  
Long Term Study ◽  
Irrigation Treatments

In 1992, a long term study was initiated to determine water use of asparagus and to assess water stress effects on asparagus growth. Asparagus (Syn 4-56) crowns were planted and maintained at soil moisture levels near field capacity during the first year. In 1993, irrigation treatments based on 60, 40, and 0 percent of evapotranspiration (ET) were applied to asparagus during the fern growing period (mid-June to October). Soil moisture, shoot and root growth, and fern water potentials were measured throughout the year. Prior to the irrigation treatments, asparagus had 39 buds per plant with a shoot and root fresh weight of 573 and 270 grams, respectively. Soil moisture in the root zone (0 to 60 cm) approached the permanent wilting point in the 40%. and 0% of ET treatments by mid-August. A decrease in irrigation rate from 80 to 0% of ET had no effect on fern fresh weight at the end of the growing season. However, as irrigation rate decreased from 80 to 0% of ET, root fresh weight (586, 533, 415 grams) and bud number (78, 59, 53) decreased linearly. These results suggest yield and growth may be reduced in 1994.

scholarly journals Irrigation Scheduling to Increase Muskmelon Fruit Biomass and Soluble Solids Concentration

HortScience ◽  
2006 ◽  
Vol 41 (2) ◽  
pp. 367-369 ◽  
Author(s):  
Robert L. Long ◽  
Kerry B. Walsh ◽  
David J. Midmore ◽  
Gordon Rogers
Keyword(s):  
Water Stress ◽  
Fruit Development ◽  
Cucumis Melo ◽  
Irrigation Management ◽  
Irrigation Scheduling ◽  
Soluble Solids ◽  
Sugar Accumulation ◽  
Fresh Weight ◽  
Solids Concentration ◽  
Soluble Solids Concentration

A common practice for the irrigation management of muskmelon (Cucumis melo L. reticulatus group) is to restrict water supply to the plants from late fruit development and through the harvest period. However, this late fruit development period is critical for sugar accumulation and water stress at this stage is likely to limit the final fruit soluble solids concentration (SSC). Two field irrigation experiments were conducted to test the idea that maintaining muskmelon plants free of water stress through to the end of harvest will maximise sugar accumulation in the fruit. In both trials, water stress before or during harvest detrimentally affected fruit SSC and fresh weight (e.g., no stress fruit 11.2% SSC, weight 1180 g; stress fruit 8.8% SSC, weight 990 g). Maintaining plants free of water stress from flowering through to the end of harvest is recommended to maximise yield and fruit quality.

scholarly journals Changes in biometric, density, and microscopic features of Parrotia persica trees in longitudinal and radial directions of the stem

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 3563-3574
Author(s):  
Ali Hassanpoor Tichi ◽  
Hadi Gholamiyan ◽  
Mojtaba Rezanezhad Divkolae
Keyword(s):  
Transverse Direction ◽  
Growth Ring ◽  
Basic Density ◽  
Tree Height ◽  
Anatomical Study ◽  
Dry Density ◽  
Breast Height ◽  
Microscopic Features ◽  
Tree Stem ◽  
Diffuse Porous

The biometric, density, and microscopic features of Parrotia persica species were investigated in this work. Three completely healthy P. persica trees were randomly felled. Three discs of 5 cm thickness were cut at three height levels (at breast height, 3 m, and 4.5 m) of each stem. The test specimens were sequentially taken from pith to bark. The biometric characteristics of the fiber and their density were analyzed. The microscopic features were studied according to the IAWA List of Hardwoods. It was found that all biometric factors of P. persica were decreased with increasing tree height from base to top. In contrast, these factors were also increased with the increase of distance from the pith toward the bark. Oven-dry density and basic density were decreased with an increase in the height along the tree stem. However, in the transverse direction, oven-dry density and basic density were increased from pith to bark. The anatomical study indicated that P. persica is a diffuse-porous hardwood that has distinct growth ring boundaries, heterogeneous rays, scalariform perforation, and alternative intervessel pits.

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