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.

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.

scholarly journals Growth Enhancement of Phragmites australis, Eichhornia crassipes and Saccharum officinarum for Rhizoremediation of Crude Oil

2018 ◽  
Vol 7 (1) ◽  
pp. 60-84
Author(s):  
Monday Ubogu ◽  
Lucky O. Odokuma ◽  
Ejiro Akponah
Keyword(s):  
Crude Oil ◽  
Leaf Area ◽  
Root Length ◽  
Growth Parameters ◽  
Control Plant ◽  
Dry Weight ◽  
Saccharum Officinarum ◽  
Germination Percentage ◽  
Growth Enhancement ◽  
Plant Soil

P. australis, E. crassipes (in mangrove swamp) and S. officinarum (in rainforest) are capable of tolerating some levels of crude oil in soil. However, some important growth characteristics such speedy growths, extensive root system and increased biomass desirable for efficient rhizoremediation are depressed. To cushion this suppressive effects, plants were subjected to the following treatments: Plant + Soil (PS) (Control); Plant + Soil + Oil (PSO); Plant + Soil + Oil + Fertilizer (PSOF); Plant +Soil + Oil + Fertilizer + Microorganisms (PSOFM); and Plant + Soil + Fertilizer + Microorganisms + Solarization (PSOFMS). Treatments were monitored for 120 days to determine their effects on the following growth parameters: Germination, germination percentage, height, and root length, dry weight, and leaf area. Results indicated that treatments PSOF, PSOFM and PSOFMS enhanced all growth parameters over contaminated untreated soil (PSO) with the exception of germination in P. australis and S. officinarum; while root length, leaf area in E. crassipes were statistically the same for PS, PSO, PSOFM and PSOFMS (P ˂ 0.05). Overall, growth enhancement efficiencies of the applied treatments were in the order: PSOFM ˃ PSOF ˃ PSOFMS. Thus, growth of these plants can be enhanced in crude oil contaminated soil by the above treatments for efficient rhizoremediation.

scholarly journals Axial anatomy of the leaf midrib provides new insights into the hydraulic architecture and cavitation patterns of Acer pseudoplatanus leaves

2019 ◽  
Vol 70 (21) ◽  
pp. 6195-6201 ◽  
Author(s):  
Silvia Lechthaler ◽  
Pierluigi Colangeli ◽  
Moira Gazzabin ◽  
Tommaso Anfodillo
Keyword(s):  
Leaf Area ◽  
Good Predictor ◽  
Path Length ◽  
Vessel Diameter ◽  
Acer Pseudoplatanus ◽  
Hydraulic Architecture ◽  
Leaf Base ◽  
Embolism Resistance ◽  
Conduit Diameter ◽  
Hierarchical Scheme

Abstract The structure of leaf veins is typically described by a hierarchical scheme (e.g. midrib, 1st order, 2nd order), which is used to predict variation in conduit diameter from one order to another whilst overlooking possible variation within the same order. We examined whether xylem conduit diameter changes within the same vein order, with resulting consequences for resistance to embolism. We measured the hydraulic diameter (Dh), and number of vessels (VN) along the midrib and petioles of leaves of Acer pseudoplatanus, and estimated the leaf area supplied (Aleaf-sup) at different points of the midrib and how variation in anatomical traits affected embolism resistance. We found that Dh scales with distance from the midrib tip (path length, L) with a power of 0.42, and that VN scales with Aleaf-sup with a power of 0.66. Total conductive area scales isometrically with Aleaf-sup. Embolism events along the midrib occurred first in the basipetal part and then at the leaf tip where vessels are narrower. The distance from the midrib tip is a good predictor of the variation in vessel diameter along the 1st order veins in A. pseudoplatanus leaves and this anatomical pattern seems to have an effect on hydraulic integrity since wider vessels at the leaf base embolize first.

The hydraulic architecture of Eucalyptus trees growing across a gradient of depth-to-groundwater

2015 ◽  
Vol 42 (9) ◽  
pp. 888 ◽  
Author(s):  
Sepideh Zolfaghar ◽  
Randol Villalobos-Vega ◽  
Melanie Zeppel ◽  
Derek Eamus
Keyword(s):  
Hydraulic Conductivity ◽  
Leaf Area ◽  
Water Availability ◽  
Safety Margin ◽  
Hydraulic Architecture ◽  
Sapwood Area ◽  
Huber Value ◽  
Xylem Vulnerability ◽  
Safety Margins ◽  
Hydraulic Safety

Heterogeneity in water availability acts as an important driver of variation in plant structure and function. Changes in hydraulic architecture represent a key mechanism by which adaptation to changes in water availability can be expressed in plants. The aim of this study was to investigate whether differences in depth-to-groundwater influence the hydraulic architecture of Eucalyptus trees in remnant woodlands within mesic environments. Hydraulic architecture of trees was examined in winter and summer by measuring the following traits: Huber value (HV: the ratio between sapwood area and leaf area), branch hydraulic conductivity (leaf and sapwood area specific), sapwood density, xylem vulnerability (P50 and Pe) and hydraulic safety margins across four sites where depth-to-groundwater ranged from 2.4 to 37.5 m. Huber value increased significantly as depth-to-groundwater increased. Neither sapwood density nor branch hydraulic conductivity (sapwood and leaf area specific) varied significantly across sites. Xylem vulnerability to embolism (represented by P50 and Pe) in both seasons was significantly and negatively correlated with depth-to-groundwater. Hydraulic safety margins increased with increasing depth-to-groundwater and therefore trees growing at sites with deeper water tables were less sensitive to drought induced embolism. These results showed plasticity in some, but not all, hydraulic traits (as reflected in HV, P50, Pe and hydraulic safety margin) in response to increase in depth-to-groundwater in a mesic environment.

scholarly journals Intraspecific variability of some functional traits of Trigonocaryum involucratum (Steven) Medw., a caucasus endemic plant

2020 ◽  
Vol 44 (2) ◽  
pp. 129-136
Author(s):  
Ramazan Murtazaliev ◽  
Dzhalaludin Anatov ◽  
Jana Ekhvaia ◽  
Ziyarat Guseinova ◽  
Ketevan Batsatsashvili
Keyword(s):  
Leaf Area ◽  
Plant Traits ◽  
Linear Regression Analysis ◽  
Elevation Gradient ◽  
Seed Mass ◽  
Intraspecific Variability ◽  
Population Variation ◽  
Endemic Plant ◽  
High Solar Radiation ◽  
Shoot Number

Plant traits have been used to predict species and community responses to environmental gradients. We studied variation of leaf area (LA), specific leaf area (SLA), flowering shoot number and seed mass along an elevation gradient in the case of Trigonocaryum involucratum, a scree-growing plant endemic to the Caucasus ecoregion. The study had two major aims: (1) to compare the role of intra-population and inter-population variation of functional trait values; and (2) to ascertain dependence between elevation and trait values and their variation. We collected trait data in several populations in Dagestan (Russian Federation), where the species has about a 1000-m amplitude of elevational distribution. The intraspecific variability of trait values was assessed via standard statistical tools (one-way ANOVA and linear regression analysis). The trait values mostly have high inter-population variation (more than 90% for each of the trait values compared to intra-population variation of each trait), indicating adaptation of populations to site conditions. Much higher intra- vs. inter-population variation in SLA at subnival elevations indicates local micro-site diversity and may serve as a buffer against future stress related to climate change. All the trait values negatively but significantly correlate (weakly or moderately) with elevation. Negative correlation presumably shows a certain increase in the limiting effect of the elevation gradient associated with changes in temperature, soil nutrient availability and soil water content, as well as with high solar radiation. More evidence from a broader study of the species throughout its distribution range is needed for firmer conclusions about the intraspecific variability of T. involucratum.

scholarly journals Comparison of Cabbage Seedling Growth in Four Transplant Production Systems

1999 ◽  
Vol 9 (1) ◽  
pp. 133a
Author(s):  
Jonathan M. Frantz ◽  
Gregory E. Welbaum ◽  
Zhengxing Shen ◽  
Ron Morse
Keyword(s):  
Plant Growth ◽  
Leaf Area ◽  
Water Availability ◽  
Production Systems ◽  
Root Zone ◽  
Control Plant ◽  
Seedling Mortality ◽  
Hydroponic System ◽  
Black Plastic ◽  
And Control

“Float-bed” (FB) is a simple hydroponic system used by the tobacco industry for transplant production. “Ebb-and-flood” (EF) is a modified FB system with periodic draining of the bed to limit water availability and control plant growth. Field-bed cabbage (Brassica oleracea L. gp. Capitata) transplant production was compared with FB, EF, and overhead-irrigated plug-tray greenhouse systems. Plants were produced in May and June and transplanted in a field near Blacksburg, Va., in June and July of 1994 and 1995, respectively. Beds for FB and EF production consisted of galvanized metal troughs (3.3 × 0.8 × 0.3 m) lined with a double layer of 0.075-mm-thick black plastic film. In 1994, both EF and FB seedlings were not hardened before transplanting, were severely stressed after transplanting, and had higher seedling mortality compared with plants from other systems. Plug-tray transplants showed the greatest increase in leaf area following transplanting and matured earlier than seedlings produced in other systems. In 1995, EF- and FB-grown cabbage plants were hardened by withholding water before transplanting, and seedlings had greater fresh mass and leaf area than plug-tray or field-bed seedlings 3.5 weeks after transplanting. Less succulent cabbage transplants were grown in EF and FB systems containing 66 mg·L-1 N (40% by nitrate) and 83 mg·L-1 K. Compared with the FB system, the EF system allowed control of water availability, which slowed plant growth, and increased oxygen concentration in the root zone. Both EF and FB systems are suitable for cabbage transplant production.

scholarly journals Conifer and broadleaved trees differ in branch allometry but maintain similar functional balances

2020 ◽  
Vol 40 (4) ◽  
pp. 511-519
Author(s):  
Lan Zhang ◽  
Yajun Chen ◽  
Guangyou Hao ◽  
Keping Ma ◽  
Frans Bongers ◽  
...  
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Specific Conductivity ◽  
Sugar Transport ◽  
Common Species ◽  
Ray Parenchyma ◽  
Broadleaved Tree Species ◽  
Xylem Growth ◽  
Broadleaved Tree ◽  
The Cost

Abstract Conifers and broadleaved trees coexist in temperate forests and are expected to differ in partitioning strategies between leaf and stem. We compare functional balances between water loss and water supply, and between sugar production and sugar transport/storage, and associate these with xylem growth to better understand how they contribute to these life form strategies. We sampled canopy branches from 14 common species in a temperate forest in northeast China and measured xylem area, phloem area, ray area, ray percentage, dry wood density, xylem conductivity and mean xylem growth rate for branch stems, and the leaf area and specific leaf area for leaves, and calculated the leaf-specific conductivity. Conifers and broadleaved trees did not differ significantly in tissue areas, xylem growth rate and the relation between phloem area and leaf area. Conifers had higher xylem area but lower ray area relative to leaf area. For the same xylem conductivity, phloem area and ray parenchyma area did not differ between conifers and broadleaved trees. Xylem growth rate was similar relative to leaf area and phloem area. Our results indicate that conifers tend to develop more xylem area per leaf area and more tracheid area at the cost of ray parenchyma area, probably to compensate for the low water transport ability of tracheid-based xylem. The divergent strategies between conifers and broadleaved tree species in leaf area and xylem area partitioning probably lead to the convergence of partitioning between leaf area and phloem area. Consequently, conifers tend to consume rather than store carbon to achieve a similar xylem expansion per year as coexisting broadleaved trees.

The influence of low soil temperature on the growth of vesicular–arbuscular mycorrhizal Fraxinuspennsylvanica

1987 ◽  
Vol 17 (8) ◽  
pp. 951-956 ◽  
Author(s):  
C. P. Andersen ◽  
E. I. Sucoff ◽  
R. K. Dixon
Keyword(s):  
Leaf Area ◽  
Growth Rates ◽  
Root Zone ◽  
Arbuscular Mycorrhizal ◽  
Green Ash ◽  
P Content ◽  
Vesicular Arbuscular ◽  
Area Growth ◽  
Leaf Area Growth ◽  
Leaf P

Green ash (Fraxinuspennsylvanica Marsh.) seedlings were either inoculated with Glomusetunicatum or not inoculated and grown for approximately 5 weeks under glasshouse conditions to permit root colonization with vesicular–arbuscular (V–A) mycorrhizae. Two experiments were conducted to characterize V–A mycorrhizae influence on seedling growth at low root temperature. In experiment 1, seedlings were subjected to four root zone temperatures ranging from 7.5 to 20 °C for 24 days to measure leaf area and plant height on intact seedlings. In experiment 2, seedlings were exposed to root temperatures of 12.0, 16.0, and 20.0 °C for 30 days and seedlings were destructively harvested at 6-day intervals to measure growth variables and biomass distribution. Results of experiments 1 and 2 were similar. In experiment 1, leaf area growth of mycorrhizal seedlings was significantly greater than nonmycorrhizal controls at all temperatures. Relative leaf area growth rate was greater in mycorrhizal than nonmycorrhizal seedlings at 7.5 and 11.5 °C, similar between treatments at 15.5 °C, and greater in nonmycorrhizal seedlings at 20.0 °C, differences possibly resulting from the larger size of mycorrhizal seedlings at the start of the temperature treatments. In experiment 2, temperature treatments were imposed on seedlings of the same size. Mycorrhizal seedlings had greater leaf area growth rates and relative leaf area growth rates than nonmycorrhizal seedlings at all temperatures. Phosphorus concentrations and total P content in roots and leaves did not differ significantly between mycorrhizal treatments at any temperature; however, mycorrhizal seedlings had consistently greater leaf P content than nonmycorrhizal controls. Glomusetunicatum actively stimulates green ash growth at moderately low root temperatures.

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