scholarly journals Bark water vapour conductance is associated with drought performance in tropical trees

2020 ◽  
Vol 16 (8) ◽  
pp. 20200263
Author(s):  
Brett T. Wolfe
Keyword(s):  
Soil Water ◽  
Water Vapour ◽  
Water Deficit ◽  
Tree Species ◽  
Tropical Trees ◽  
Functional Trait ◽  
Evergreen Species ◽  
Drought Conditions ◽  
Stem Water ◽  
Highly Correlated

Bark water vapour conductance ( g bark ) is a rarely considered functional trait. However, for the few tree species measured to date, it appears high enough to create stem water deficits associated with mortality during droughts, when access to water is limited. I tested whether g bark correlates with stem water deficit during drought conditions in two datasets of tropical trees: one of saplings in forest understories during an annual dry season and one of potted saplings in a shadehouse during extreme drought conditions. Among all 14 populations of eight species measured, g bark varied more than 10-fold (0.86–12.98 mmol m −2 s −1 ). In the forest understories, g bark was highly correlated with stem water deficit among four deciduous species, but not among evergreen species that likely maintained access to soil water. In the shadehouse, g bark was positively correlated with stem water deficit and mortality among all six species. Overall, tree species with higher g bark suffer higher stem water deficit when soil water is unavailable. Incorporating g bark into soil–plant–atmosphere hydrodynamic models may improve projections of plant mortality under drought conditions.

THE EFFECT OF WATER DEFICIT ON N2(C2H2) FIXATION BY WHITE BEAN AND SOYBEAN

1988 ◽  
Vol 68 (4) ◽  
pp. 957-967 ◽  
Author(s):  
D. L. SMITH ◽  
M. DIJAK ◽  
D. J. HUME
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Water Deficit ◽  
Acetylene Reduction ◽  
Physiological Responses ◽  
Plant Water ◽  
Diffusive Resistance ◽  
Drought Conditions ◽  
Plant Water Potential ◽  
White Bean

White bean (Phaseolus vulgaris L.) is generally reported to fix less N than soybean (Glycine max Merrill [L.]). Recent work has shown that in soybean the onset of physiological responses that conserve plant and soil water occurs at greater water deficits than in some other legumes. Little is known about water use regulation in white bean. Research was conducted to compare the responses of these two species to water deficit, particularly its effects on N2 fixation, in both controlled environment and field conditions. In the growth room, plant water potential, leaf diffusive resistance, acetylene reduction and nodule mass per plant were measured for both species during progressive drought, and compared to watered controls. In the field, the leaf diffusive resistance of irrigated and unirrigated plants of both species was measured, as was the soil water potential in plots where these crops were grown. Under conditions of increasing water deficit white bean reacts to conserve plant and soil water sooner than soybean: closing its stomates earlier under drought conditions and maintaining higher plant water potentials. White bean acetylene reduction declined more rapidly over time and over plant water potential levels, but not over changes in leaf diffusive resistance, than that of soybean, as the droughting progressed. In the field, under drought conditions, white bean root nodules senesced, while soybean nodules did not, and white bean was observed to exhibit more parahelionasty than soybean. The onset of physiological responses that conserve plant and soil water occurred at lesser water deficits in white bean than soybean, and this was reflected in more extreme effects on N2 fixation by white bean.Key words: White bean, soybean, water deficit, acetylene reduction, nitrogen fixation, nodulation

scholarly journals Elevated atmospheric CO2 concentration improves water use efficiency and growth of a widespread Cerrado tree species even under soil water deficit

2019 ◽  
Vol 33 (3) ◽  
pp. 425-436 ◽  
Author(s):  
João Paulo Souza ◽  
Nayara Magry Jesus Melo ◽  
Alessandro Dias Halfeld ◽  
Kamilla I. C. Vieira ◽  
Bruno Luan Rosa
Keyword(s):  
Water Use Efficiency ◽  
Soil Water ◽  
Water Deficit ◽  
Water Use ◽  
Tree Species ◽  
Co2 Concentration ◽  
Atmospheric Co2 ◽  
Soil Water Deficit ◽  
Elevated Atmospheric Co2 ◽  
Use Efficiency

scholarly journals Irrigation and Crop Load Influence Fruit Size and Water Relations in Field-grown `Spadona' Pear

2001 ◽  
Vol 126 (2) ◽  
pp. 252-255 ◽  
Author(s):  
Amos Naor
Keyword(s):  
Stomatal Conductance ◽  
Water Potential ◽  
Soil Water ◽  
Fruit Size ◽  
Leaf Water ◽  
Stem Water Potential ◽  
Crop Load ◽  
Water Potentials ◽  
Stem Water ◽  
Highly Correlated

Interrelations between water potential and fruit size, crop load, and stomatal conductance were studied in drip-irrigated `Spadona' pear (Pyrus communis L) grafted on quince C (Cydonia oblonga L.) rootstock and growing in a semi-arid zone. Five irrigation rates were applied in the main fruit growth phase: rates of 0.25, 0.40, 0.60, 0.80, and 1.00 of “Class A” pan evaporation rate. The crop in each irrigation treatment was adjusted to four levels (200 to 1200 fruit per tree) by hand thinning at the beginning of June 1999. The crop was harvested on 1 Aug. 1999, and fruit size was determined by means of a commercial sorting machine. Soil, stem, and leaf water potentials and stomatal conductance were measured during the season. Crop yield was highly correlated with stem and soil water potentials. The highest midday stem water potential was lower than values commonly reported for nonstressed trees, and was accompanied by high soil water potential, indicating that the maximal water absorption rate of the root system under those particular soil conditions was limited. Stomatal conductance was highly correlated with leaf water potential (r2 = 0.54), but a much better correlation was found with stem water potential (r2 = 0.80). Stomatal conductance decreased at stem water potentials less than -2.1 MPa. Both stem water potential and stomatal conductance were unaffected by crop load under a wide range of irrigation rates.

scholarly journals Interspecific variation in growth and tree water status of conifers under water-limited conditions

2020 ◽  
Vol 68 (4) ◽  
pp. 368-381
Author(s):  
Adriana Leštianska ◽  
Peter Fleischer ◽  
Peter Fleischer ◽  
Katarína Merganičová ◽  
Katarína Střelcová
Keyword(s):  
Water Deficit ◽  
Tree Species ◽  
Water Status ◽  
Abies Alba ◽  
Interspecific Variation ◽  
Species Tolerance ◽  
Stem Water ◽  
Band Dendrometers ◽  
Species Specific ◽  
Climate Events

AbstractWe monitored seasonal dynamics of stem water status of four coniferous species (Abies alba, Larix decidua, Picea abies and Pinus sylvestris) planted at the Borová hora Arboretum (300 m a.s.l., Zvolen valley, Central Slovakia) beyond their ecological and production optima, in the region with warmer and drier climate compared to the sites of their origin. Species-specific stem water deficit and maximum daily shrinkage were extracted from diurnal band dendrometer records of stem circumference recorded by digital band dendrometers DRL26 installed on five trees per species, and correlations with environmental variables were analysed. The seasonal stem circumference increment of all tree species was higher in 2017 than in the drier and hotter year of 2018. The greatest seasonal stem circumference increment in the observed periods of 2017 and 2018 was observed for A. alba and P. sylvestris, respectively. The highest and lowest values of daily and seasonal stem water deficit were observed for L. decidua and A. alba, respectively. The analysis of trees' short-term response to extreme climate events seems to be the promising and suitable method for detecting tree species tolerance towards drought.

scholarly journals Molecular plasticity to soil water deficit differs between sessile oak (Quercus Petraea (Matt.) Liebl.) high and low water use efficiency genotypes

2021 ◽  
Author(s):  
Gregoire LE PROVOST ◽  
Theo Gerardin ◽  
Christophe Plomion ◽  
Oliver Brendel
Keyword(s):  
Water Use Efficiency ◽  
Soil Water ◽  
Water Deficit ◽  
Water Use ◽  
Transpiration Rate ◽  
Tree Species ◽  
Fine Tuning ◽  
Soil Water Deficit ◽  
Sessile Oak ◽  
Use Efficiency

Background: Water use efficiency (WUE) is an important adaptive trait for soil water deficit. The molecular and physiological bases of WUE regulation in crops have been studied in detail in the context of plant breeding. Knowledge for most forest tree species lags behind, despite the need to identify populations or genotypes able to cope with the longer, more intense drought periods likely to result from climate warming. Results: We aimed to bridge this gap in knowledge for sessile oak (Quercus Petraeae Matt. L.), one of the most ecologically and economically important tree species in Europe, using a factorial design including two genotypes (low and high WUE) and two watering regimes (control and drought). By monitoring the ecophysiological response, we were able to identify groups of genotypes with high and low WUE. We then performed RNA-seq to quantify gene expression for the most extreme genotypes exposed to two watering regimes. By analyzing the interaction term, we were able to capture the molecular strategy of each group of plants for coping with drought. Regardless of water availability, the high WUE genotypes overexpressed genes associated with drought responses, and the control of stomatal density and distribution, and displayed a downregulation of genes associated with early stomatal closure and high transpiration rate. High-WUE genotypes, thus, coped with drought by fine-tuning the expression of genes with known functions in the regulation of stomatal size, density, movement or aperture and transpiration rate. Conclusion: Fine physiological screening of sessile oaks with contrasting WUE, and their molecular characterization i) highlighted subtle differences in transcription between low and high WUE genotypes, identifying key molecular players in the genetic control of this trait, and ii) revealed the genes underlying the molecular strategy that had evolved in each group to cope with water deficit, providing new insight into the value of WUE for adaptation to drought.

scholarly journals Effects of Soil Water Deficit on Three Tree Species of the Arid Environment: Variations in Growth, Physiology, and Antioxidant Enzyme Activities

2021 ◽  
Vol 13 (6) ◽  
pp. 3336 ◽  
Author(s):  
Fahad Rasheed ◽  
Adnan Gondal ◽  
Kamziah Abdul Kudus ◽  
Zikria Zafar ◽  
Muhammad Farrakh Nawaz ◽  
...  
Keyword(s):  
Soil Water ◽  
Water Deficit ◽  
Tree Species ◽  
Defense Mechanism ◽  
Dry Weight ◽  
Arid Environment ◽  
Root Production ◽  
Antioxidant Enzyme Activities ◽  
Abiotic Factor ◽  
Soil Water Deficit

Low water availability predicted under climate change is a major abiotic factor limiting plants growth and productivity. In this study a greenhouse experiment was conducted on three important tree species of arid environment: Conocarpus erectus (CE), Acacia modesta (AM), and Salix tetrasperma (ST). Young saplings were subjected to control (C), medium (MWD) and severe soil water deficit (SWD) treatments and response was evaluated. Results showed that in all the three species leaf, stem and root dry weight production remained similar to C under MWD treatment but decreased significantly under SWD. The highest decrease in total dry weight was noticed in ST and the lowest was evidenced in AM under SWD. Root:shoot ratio increased significantly in both CE and AM under MWD and SWD. Furthermore, chlorophyll content decreased while proline content increased significantly in both MWD and SWD treatments. The production of oxidants (hydrogen peroxide and superoxide anions) and antioxidants (superoxide dismutase, catalase, peroxidase and ascorbate peroxidase) increased significantly under both MWD and SWD treatments and were the highest in AM in both MWD and SWD treatments. Therefore, we may conclude that all the three species can tolerate medium water stress due to increased root production and an effective antioxidant defense mechanism.

scholarly journals Overexpression of MdATG8i improves water use efficiency in transgenic apple by modulating photosynthesis, osmotic balance, and autophagic activity under moderate water deficit

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Xin Jia ◽  
Ke Mao ◽  
Ping Wang ◽  
Yu Wang ◽  
Xumei Jia ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Deficit ◽  
Water Use ◽  
Photosynthetic Capacity ◽  
Critical Role ◽  
Drought Conditions ◽  
Moderate Drought ◽  
Use Efficiency ◽  
Autophagic Activity

AbstractWater deficit is one of the major limiting factors for apple (Malus domestica) production on the Loess Plateau, a major apple cultivation area in China. The identification of genes related to the regulation of water use efficiency (WUE) is a crucial aspect of crop breeding programs. As a conserved degradation and recycling mechanism in eukaryotes, autophagy has been reported to participate in various stress responses. However, the relationship between autophagy and WUE regulation has not been explored. We have shown that a crucial autophagy protein in apple, MdATG8i, plays a role in improving salt tolerance. Here, we explored its biological function in response to long-term moderate drought stress. The results showed that MdATG8i-overexpressing (MdATG8i-OE) apple plants exhibited higher WUE than wild-type (WT) plants under long-term moderate drought conditions. Plant WUE can be increased by improving photosynthetic efficiency. Osmoregulation plays a critical role in plant stress resistance and adaptation. Under long-term drought conditions, the photosynthetic capacity and accumulation of sugar and amino acids were higher in MdATG8i-OE plants than in WT plants. The increased photosynthetic capacity in the OE plants could be attributed to their ability to maintain optimal stomatal aperture, organized chloroplasts, and strong antioxidant activity. MdATG8i overexpression also promoted autophagic activity, which was likely related to the changes described above. In summary, our results demonstrate that MdATG8i-OE apple lines exhibited higher WUE than WT under long-term moderate drought conditions because they maintained robust photosynthesis, effective osmotic adjustment processes, and strong autophagic activity.

Relation of Soil Water Deficit, Involved by Precipitation and Corn Yield on Vinkovci Area (Eastern Croatia)

1998 ◽  
Vol 26 (3) ◽  
pp. 289-296
Author(s):  
M. Jurišić ◽  
Ž. Vidaček ◽  
Ž. Bukvić ◽  
D. Brkić ◽  
R. Emert
Keyword(s):  
Soil Water ◽  
Water Deficit ◽  
Corn Yield ◽  
Soil Water Deficit

scholarly journals The Effect of Irrigation Rate on the Water Relations of Young Citrus Trees in High-Density Planting

2021 ◽  
Vol 13 (4) ◽  
pp. 1759
Author(s):  
Said A. Hamido ◽  
Kelly T. Morgan
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Soil Salinity ◽  
Planting Density ◽  
Stem Water Potential ◽  
Irrigation Rate ◽  
Biological Stress ◽  
Stem Water ◽  
Water Contents ◽  
Soil Water Contents

The availability and proper irrigation scheduling of water are some of the most significant limitations on citrus production in Florida. The proper volume of citrus water demand is vital in evaluating sustainable irrigation approaches. The current study aims to determine the amount of irrigation required to grow citrus trees at higher planting densities without detrimental impacts on trees’ water relation parameters. The study was conducted between November 2017 and September 2020 on young sweet orange (Citrus sinensis) trees budded on the ‘US-897’ (Cleopatra mandarin x Flying Dragon trifoliate orange) citrus rootstock transplanted in sandy soil at the Southwest Florida Research and Education Center (SWFREC) demonstration grove, near Immokalee, Florida. The experiment contained six planting densities, including 447, 598, and 745 trees per ha replicated four times, and 512, 717, and 897 trees per ha replicated six times. Each density treatment was irrigated at 62% or 100% during the first 15 months between 2017 and 2019 or one of the four irrigation rates (26.5, 40.5, 53, or 81%) based on the calculated crop water supplied (ETc) during the last 17 months of 2019–2020. Tree water relations, including soil moisture, stem water potential, and water supplied, were collected periodically. In addition, soil salinity was determined. During the first year (2018), a higher irrigation rate (100% ETc) represented higher soil water contents; however, the soil water content for the lower irrigation rate (62% ETc) did not represent biological stress. One emitter per tree regardless of planting density supported stem water potential (Ψstem) values between −0.80 and −0.79 MPa for lower and full irrigation rates, respectively. However, when treatments were adjusted from April 2019 through September 2020, the results substantially changed. The higher irrigation rate (81% ETc) represented higher soil water contents during the remainder of the study, the lower irrigation rate (26.5% ETc) represents biological stress as a result of stem water potential (Ψstem) values between −1.05 and −0.91 MPa for lower and higher irrigation rates, respectively. Besides this, increasing the irrigation rate from 26.5% to 81%ETc decreased the soil salinity by 33%. Although increasing the planting density from 717 to 897 trees per hectare reduced the water supplied on average by 37% when one irrigation emitter was used to irrigate two trees instead of one, applying an 81% ETc irrigation rate in citrus is more efficient and could be managed in commercial groves.

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