scholarly journals Deepening Rooting Depths Improve Plant Water and Carbon Status of a Xeric Tree during Summer Drought

Forests ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 592
Author(s):  
Xin-Jun Zheng ◽  
Gui-Qing Xu ◽  
Yan Li ◽  
Xue Wu
Keyword(s):  
Water Status ◽  
Photochemical Efficiency ◽  
Small Diameter ◽  
Stem Diameter ◽  
Physiological Traits ◽  
Rooting Depth ◽  
Summer Drought ◽  
Mortality Pattern ◽  
Adult Trees ◽  
Diameter Classes

Exploring the effects of drought on trees of different sizes is an important research topic because the size-dependent mortality pattern of the major dominant species significantly affects the structure and function of plant communities. Here we studied the physiological performance and non-structural carbohydrates (NSCs) dynamics of a small xeric tree species, Haloxylon ammodendron (C.A.Mey.) of different tree size with varying rooting depth, during summer drought. We measured predawn (Ψpd) and midday (Ψm) leaf water potential, osmotic potential at saturated turgor (π100), and turgor lost point (Ψtlp), stomatal conductance (gs) at noon, maximum photochemical efficiency of photosystem II (Fv/Fm) in the morning, and NSCs concentration, from June–September. Our results demonstrated that the summer drought reduces the overall performance of physiological traits of the small young trees more than the larger adult trees. Ψpd, gs and Fv/Fm dropped larger in the small-diameter groups than the larger diameter groups. Substantial osmotic adjustments were observed in small size individuals (with lower π100 and Ψtlp) to cope with summer drought. Furthermore, mean concentration of NSCs for the leaf and shoot were higher in September than in July in every basal stem diameter classes suggested the leaf and shoot acted as reserve for NSC. However the root NSCs concentrations within each basal stem diameter class exhibited less increase in September than in the July. At the same time, the small young tress had lower root NSCs concentrations than the larger adult tree in both July and September. The contrasting root NSC concentrations across the basal stem diameter classes indicated that the roots of smaller trees may be more vulnerable to carbon starvation under non-lethal summer drought. The significant positive relationship between rooting depth and physiological traits & root NSCs concentration emphasize the importance of rooting depth in determining the seasonal variation of water status, gas exchange and NSCs.

Coastal fog during summer drought improves the water status of sapling trees more than adult trees in a California pine forest

Oecologia ◽  
2016 ◽  
Vol 181 (1) ◽  
pp. 137-148 ◽  
Author(s):  
Sara A. Baguskas ◽  
Christopher J. Still ◽  
Douglas T. Fischer ◽  
Carla M. D’Antonio ◽  
Jennifer Y. King
Keyword(s):  
Water Status ◽  
Pine Forest ◽  
Summer Drought ◽  
Adult Trees ◽  
Coastal Fog

DROUGHT TOLERANCE IN CHICKPEA AS EVALUATED BY ROOT CHARACTERISTICS, PLANT WATER STATUS, MEMBRANE INTEGRITY AND CHLOROPHYLL FLUORESCENCE TECHNIQUES

2012 ◽  
Vol 48 (3) ◽  
pp. 378-387 ◽  
Author(s):  
NEERAJ KUMAR ◽  
A. S. NANDWAL ◽  
R. S. WALDIA ◽  
S. SINGH ◽  
S. DEVI ◽  
...  
Keyword(s):  
Drought Tolerance ◽  
Water Status ◽  
Photochemical Efficiency ◽  
Dry Weight ◽  
Rooting Depth ◽  
Plant Water ◽  
Root Characteristics ◽  
Shoot Ratio ◽  
Root Shoot Ratio ◽  
Total Dry Weight

SUMMARYRoot traits, such as depth and root biomass, have been identified as the most promising plant traits in chickpea for terminal drought tolerance. With this objective, five contrasting genotypes of chickpea, viz. ICCV-4958, H-208, HC-5, RSG-931 and CSJ-379, having wide adaptability to drought prone areas at national level were assessed for various root characteristics under two environments, i.e. irrigated and rain-fed. The sampling was done at full bloom stage and there were significant differences in the rooting depth among the genotypes both under irrigated and rain-fed conditions. The chickpea roots penetrated to a minimum depth of 92 cm in CSJ-379 and maximum of 122 cm in ICCV-4958 under rain-fed conditions. The rooting depth remained higher under rain-fed than irrigated environment. Under irrigated conditions, the chickpea roots were able to grow to a maximum depth of 99 and 97 cm in HC-5 and ICCV-4958, respectively. Among the genotypes, biomass per plant of the root was higher in ICCV-4958 (6.7 g) and HC-5 (5.6 g) under rain-fed conditions. Similar observations were recorded for root/shoot ratio, dry weights of stem, leaf, nodules and total dry weight per plant. The moisture stress increased the biomass partitioning towards the roots. The water potential (ψw), osmotic potential (ψs) and relative water content (RWC %) of leaf were –0.98 MPa, –1.82 MPa and 60%, respectively, in the genotype HC-5, and –1.02 MPa, –1.72 MPa and 64%, respectively, in ICCV-4958 under rain-fed conditions. The rates of photosynthesis, and transpiration, values of the stomatal conductance and photochemical efficiency/quantum yield as indicated by Fv/Fm ratio were in the range of 6.7 to 10.6 (μmol m−2 s−1), 1.27 to 2.38 (mmol m−2 s−1), 0.23 to 0.48 (mol m−2 s−1) and 0.457 to 0.584, respectively, under rain-fed conditions. Genotypes HC-5 and ICCV-4958 also maintained higher photosynthetic and transpiration rates and Fv/Fm ratio than others. The maximum Fv/Fm values in these genotypes were correlated with the higher photosynthetic rate and dry matter yield per plant. Relative stress injury (RSI %) values in HC-5 and ICCV-4958 noticed were 25.3% and 23.7%, respectively. The results of this study indicate that under rain-fed conditions, genotypes ICCV-4958 and HC-5 had higher dry weight of stem, leaves, roots, nodules and total dry weight per plant, rooting depth, root/shoot ratio, photosynthetic and transpiration rates, photochemical efficiency and better plant water status but lower stomatal conductance than other genotypes. These traits are directly associated with maximum seed yield per plant, i.e. 15.6 g and 14.7 g per plant, respectively, in these genotypes. Therefore, both the genotypes in future can be used in crop improvement programme of chickpea breeding for drought tolerance.

scholarly journals Signal Intensity of Stem Diameter Variation for the Diagnosis of Drip Irrigation Water Deficit in Grapevine

Horticulturae ◽  
2021 ◽  
Vol 7 (6) ◽  
pp. 154
Author(s):  
Chen Ru ◽  
Xiaotao Hu ◽  
Wene Wang ◽  
Hui Ran ◽  
Tianyuan Song ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Signal Intensity ◽  
Signal To Noise Ratio ◽  
Water Status ◽  
Stem Diameter ◽  
Vegetative Stage ◽  
Signal To Noise ◽  
Diameter Variation ◽  
Expansion Stage ◽  
Noise Ratio

Precise irrigation management of grapevines in greenhouses requires a reliable method to easily quantify and monitor the grapevine water status to enable effective manipulation of the water stress of the plants. This study describes a study on stem diameter variations of grapevine planted in a greenhouse in the semi-arid area of Northwest China. In order to determine the applicability of signal intensity of stem diameter variation to evaluate the water status of grapevine and soil. The results showed that the relative variation curve of the grapevine stem diameter from the vegetative stage to the fruit expansion stage showed an overall increasing trend. The correlations of MDS (maximum daily shrinkage) and DI (daily increase) with meteorological factors were significant (p < 0.05), and the correlations with SWP, RWC and soil moisture were weak. Although MDS and DI can diagnose grapevine water status in time, SIMDS and SIDI have the advantages of sensitivity and signal intensity compared with other indicators. Compared with MDS and DI, the R2 values of the regression equations of SIMDS and SIDI with SWP and RWC were high, and the correlation reached a very significant level (p < 0.01). Thus, SIMDS and SIDI are more suitable for the diagnosis of grapevine water status. The SIMDS peaked at the fruit expansion stage, reaching 0.957–1.384. The signal-to-noise ratio of SIDI was higher than that of MDS across the three treatments at the vegetative stage. The value and signal-to-noise ratio of SIDI at the flowering stage were similar to those of SIMDS, while the correlation between SIDI and the soil moisture content was higher than that of SIMDS. It can be concluded that that SIDI is suitable as an indicator of water status of grapevine and soil during the vegetative and flowering stages. In addition, the signal-to-noise ratio of SIMDS during the fruit expansion and mature stages was significantly higher than that of SIDI. Therefore, SIMDS is suitable as an indicator of the moisture status of grapevine and soil during the fruit expansion and mature stages. In general, SIMDS and SIDI were very good predictors of the plant water status during the growth stage and their continuous recording offers the promising possibility of their use in automatic irrigation scheduling in grapevine.

Impact of the colonization of Leifsonia xyli subsp. xyli in a susceptible sugarcane genotype on water status and physiological traits

2021 ◽  
Author(s):  
Fernando Henrique Silva Garcia ◽  
Timóteo Herculino da Silva Barros ◽  
Rubens Duarte Coelho ◽  
Marie Caroline Ferreira Laborde ◽  
Ricardo Antunes Azevedo ◽  
...  
Keyword(s):  
Water Status ◽  
Physiological Traits

scholarly journals Drought reduced monoterpene emissions from the evergreen Mediterranean oak <i>Quercus ilex</i>: results from a throughfall displacement experiment

2009 ◽  
Vol 6 (7) ◽  
pp. 1167-1180 ◽  
Author(s):  
A.-V. Lavoir ◽  
M. Staudt ◽  
J. P. Schnitzler ◽  
D. Landais ◽  
F. Massol ◽  
...  
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Quercus Ilex ◽  
Photochemical Efficiency ◽  
Leaf Water ◽  
Control Treatment ◽  
Summer Drought ◽  
Drought Period ◽  
Significant Difference ◽  
Monoterpene Emission

Abstract. The effects of water limitations on the emission of biogenic volatile organic compounds are not well understood. Experimental approaches studying drought effects in natural conditions are still missing. To address this question, a throughfall displacement experiment was set up in a natural forest of Quercus ilex, an evergreen Mediterranean oak emitting monoterpenes. Mature trees were exposed in 2005 and 2006 either to an additional drought, to irrigation or to natural drought (untreated control). In both years, absolute monoterpene emission rates as well as the respective standard factors of the trees exposed to normal and additional drought strongly declined during the drought periods. Monoterpene emissions were lower in year 2006 than in year 2005 (factor 2) due to a more pronounced summer drought period in this respective year. We observed a significant difference between the irrigation and additional drought or control treatment: irrigated trees emitted 82% more monoterpenes during the drought period 2006 than the trees of the other treatments. However, no significant effect on monoterpene emission was observed between normal and additional drought treatments, despite a significant effect on leaf water potential and photochemical efficiency. During the development of drought, monoterpene emissions responded exponentially rather than linearly to decreasing leaf water potential. Emissions rapidly declined when the water potential dropped below −2 MPa and photosynthesis was persistently inhibited. Monoterpene synthase activities measured in vitro showed no clear reduction during the same period. From our results we conclude that drought significantly reduces monoterpene fluxes of Mediterranean Holm oak forest into the atmosphere due to a lack of primary substrates coming from photosynthetic processes.

Rooting depth and plant water relations explain species distribution patterns within a sandplain landscape

2004 ◽  
Vol 31 (5) ◽  
pp. 423 ◽  
Author(s):  
Philip K. Groom
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Water Loss ◽  
Rooting Depth ◽  
Summer Drought ◽  
Tissue Water ◽  
Shrub Species ◽  
Water Deficits ◽  
Groundwater Levels ◽  
Water Potentials

Tree and shrub species of the Banksia woodlands on the sandplains of northern Swan Coastal Plain, Western Australia possess a range of strategies to avoid or tolerate soil water deficits during the annual summer drought. Shallow-rooted shrub species (< 1 m rooting depth) inhabit a range of locations in the landscape, from top of dune crests to wetland embankments. These are the most drought-tolerant of all sandplain species, surviving extremely low summer soil water potentials (< –7 MPa) and tissue water deficits by significantly reducing their transpirational water loss (< 0.2 mmol m–2 s–1). This is in contrast to the few shallow-rooted species restricted to low-lying or seasonally waterlogged areas which are reliant on subsurface soil moisture or groundwater to maintain their relatively high summer water use. Recent studies of water source usage of selected Banksia tree species have shown that these deep-rooted species access groundwater up to a maximum depth of 9 m depth during the summer months, or soil moisture at depth when groundwater was greater than maximum rooting depths, depending on the species. Medium- and deep-rooted (1–2 m and > 2 m, respectively) shrub species cope with the summer soil drying phase and related decrease in groundwater levels by conserving leaf water loss and incurring predawn water potentials between –1 and –4 MPa, enabling them to occur over a range of topographic positions within the sandplain landscape.

scholarly journals Assessing Scarcity of the North Central Veneer Log Resource

1999 ◽  
Vol 16 (3) ◽  
pp. 160-166 ◽  
Author(s):  
Mike McGuire ◽  
James Stevens ◽  
Karen Potter-Witter
Keyword(s):  
Small Diameter ◽  
White Oak ◽  
Resource Base ◽  
Usda Forest Service ◽  
The North ◽  
World Demand ◽  
International Demand ◽  
Preferred Species ◽  
Industry Professionals ◽  
Diameter Classes

Abstract Forest industry professionals have expressed concern about physical scarcity and diminishing quality in veneer logs of the preferred species, contradicting USDA Forest Service inventory results that report an expanding resource base. This study examined factors, influencing economic supply of select white oak, select red oak, hard maple, ash, black cherry, and black walnut veneer logs in the Lake States, Illinois, and Indiana. Increased competition due to international demand is placing additional pressure on available inventory. Changing demographics are acting to reduce supply as nontimber land uses increase in importance. Industry professionals were queried to quantify their perception of scarcity and determine which factors they consider most important. The dominant perception is that quality is decreasing. Profitable architectural and panel grade veneer logs are perceived to be diminishing while furniture grade veneer logs are not. Quantity is perceived to be decreasing in the large and medium diameter classes but increasing in the small diameter classes. Expectation is for future real prices 10 yr hence to increase between 20-30%. Factors for the perceived scarcity ranking highest in importance were increased international demand, previous high grading, landowner mistrust of loggers, and increased environmental regulations. Respondents agreed that the world demand for eastern hardwoods is strong and will continue to grow. North.J. Appl. For. 16(3):160-166.

Estimating shrub biomass from basal stem diameters

1976 ◽  
Vol 6 (2) ◽  
pp. 153-158 ◽  
Author(s):  
James K. Brown
Keyword(s):  
Unit Area ◽  
Rocky Mountain ◽  
Growth Characteristics ◽  
Stem Diameter ◽  
Shrub Species ◽  
Stem Wood ◽  
Coefficients Of Variation ◽  
Shrub Biomass ◽  
Linear Regressions ◽  
Diameter Classes

For 25 northern Rocky Mountain shrub species, linear regressions are presented for total aboveground weight on basal stem diameter (average r2 of 0.91) and for leaf weight on basal stem diameter (average r2 of 0.74). The percentage of stem-wood weight in diameter classes of 0 to 0.5 cm, 0.5 to 2 cm, and 2 to 5 cm varies with basal stem diameter and species growth characteristics (as shown in figures). For these classes, diameters of stem wood averaged 0.21 cm, 0.76 cm, and 2.37 cm, respectively; however, some species differed significantly from these averages. Coefficients of variation ranged from 60 to 340 for shrub weight per unit area sampled in 12 stands. Some distributions were positively skewed. Implications for sampling are discussed.

Distribution and increment of biomass in adjacent young Douglas-fir stands with different early growth rates

1987 ◽  
Vol 17 (7) ◽  
pp. 722-730 ◽  
Author(s):  
Miguel A. Espinosa Bancalari ◽  
David A. Perry
Keyword(s):  
Growth Rates ◽  
Aboveground Biomass ◽  
Early Growth ◽  
Douglas Fir ◽  
Rooting Depth ◽  
Summer Drought ◽  
Total Biomass ◽  
Area Index ◽  
Biomass Increment ◽  
Anaerobic Soils

Total biomass increments were determined for three adjacent 22-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) plantations in the Oregon Coast Range that had widely different early growth rates. Estimated total aboveground biomass of the stands, designated slow, intermediate, and fast, was 98.7, 148.7, and 203.7 Mg•ha−1, respectively; estimated mean biomass increment in the 5 years previous to sampling was 8.9, 12.6, and 12.3 Mg•ha−1•year−1. The slow stand had a greater proportion of aboveground biomass in branches and a smaller proportion in stem wood than the intermediate and fast stands. Differences in biomass increment were primarily due to stem rather than crown growth. Total below ground biomass was highest in the fast stand, the difference being due to roots >5 mm in diameter; weight of roots <5 mm was greater in the slow and intermediate stands. Roots >5 mm comprised about 77% of the total root system in those stands and 90% in the fast stand. Increment of roots >5 mm was 2.2, 2.5, and 3.0 Mg•ha−1•year−1 in the slow, intermediate, and fast stands. The ratio of productivity to total leaf nitrogen suggests that nitrogen is a principal limiting resource in the intermediate stand. The fast stand, with a leaf area index 50% greater than the others, is probably limited by light. The slow stand has anaerobic soils during at least part of the year, which may restrict rooting depth and thereby induce water stress during summer drought.

Summer dormancy in Festuca arundinacea Schreb.; the influence of season of sowing and a simulated mid-summer storm on two contrasting cultivars

2006 ◽  
Vol 57 (12) ◽  
pp. 1267 ◽  
Author(s):  
M. R. Norton ◽  
F. Volaire ◽  
F. Lelièvre
Keyword(s):  
Festuca Arundinacea ◽  
Water Status ◽  
Severe Drought ◽  
Summer Drought ◽  
Full Irrigation ◽  
Leaf Elongation ◽  
Aerial Growth ◽  
Summer Dormancy ◽  
Summer Storm ◽  
Moisture Conditions

Due to the shortage of information on summer dormancy in tall fescue (Festuca arundinacea, syn. Lolium arundinaceum), we tested the response of 2 cultivars of differing dormancy expression and growth stage to a range of summer moisture conditions, including full irrigation, drought, and a simulated mid-summer storm and analysed whether traits associated with summer dormancy conferred better survival under severe field drought. Autumn-sown reproductive and younger, spring-sown plants of 2 cultivars, claimed to exhibit contrasting summer dormancy, were established and then tested in summer 2002 under either long drought, drought + simulated mid-summer storm, or full irrigation. The autumn-sown reproductive plants of cv. Flecha exhibited traits that can be associated with partial summer dormancy since under summer irrigation they reduced aerial growth significantly and exhibited earlier herbage senescence. Moreover, cv. Flecha used 35% less soil water over the first summer. However, the water status of leaf bases of young vegetative tillers of both cultivars was similar under irrigation and also throughout most of the drought (leaf potential and water content maintained over –4 MPa and at approx. 1 g H2O/g DM, respectively). The summer-active cv. Demeter did not stop leaf elongation even in drought and produced twice as much biomass as Flecha under irrigation. Cultivar Demeter responded to the simulated storm with a decline in dehydrin expression in leaf bases, whereas no decline occurred in Flecha, presumably because it remained partially dormant. The younger, spring-sown swards of both cultivars had similar biomass production under summer irrigation but whereas Demeter regrew in response to the simulated storm, cv. Flecha did not, indicating that dormancy, although only partially expressed, was reinforced by summer drought. In all trials, cv. Flecha out-yielded Demeter in autumn regrowth. In particular, the severe drought in 2003 caused a 25% loss of the basal cover in cv. Demeter, whereas Flecha fully maintained its sward allowing it to produce a higher post-drought autumn yield. This work links summer dormancy with higher persistence over long, dry summers.

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