Coordination between leaf, stem, and root hydraulics and gas exchange in three arid-zone angiosperms during severe drought and recovery

2018 ◽  
Vol 41 (12) ◽  
pp. 2869-2881 ◽  
Author(s):  
Danielle Creek ◽  
Chris J. Blackman ◽  
Timothy J. Brodribb ◽  
Brendan Choat ◽  
David T. Tissue
Keyword(s):  
Gas Exchange ◽  
Arid Zone ◽  
Severe Drought

scholarly journals Interaction of CO<sub>2</sub> concentrations and water stress in semiarid plants causes diverging response in instantaneous water use efficiency and carbon isotope composition

2017 ◽  
Vol 14 (14) ◽  
pp. 3431-3444 ◽  
Author(s):  
Na Zhao ◽  
Ping Meng ◽  
Yabing He ◽  
Xinxiao Yu
Keyword(s):  
Water Stress ◽  
Gas Exchange ◽  
Water Use Efficiency ◽  
Water Use ◽  
Environmental Changes ◽  
Isotope Composition ◽  
Water Soluble ◽  
Severe Drought ◽  
Semiarid Areas ◽  
Use Efficiency

Abstract. In the context of global warming attributable to the increasing levels of CO2, severe drought may be more frequent in areas that already experience chronic water shortages (semiarid areas). This necessitates research on the interactions between increased levels of CO2 and drought and their effect on plant photosynthesis. It is commonly reported that 13C fractionation occurs as CO2 gas diffuses from the atmosphere to the substomatal cavity. Few researchers have investigated 13C fractionation at the site of carboxylation to cytoplasm before sugars are exported outward from the leaf. This process typically progresses in response to variations in environmental conditions (i.e., CO2 concentrations and water stress), including in their interaction. Therefore, saplings of two typical plant species (Platycladus orientalis and Quercus variabilis) from semiarid areas of northern China were selected and cultivated in growth chambers with orthogonal treatments (four CO2 concentration ([CO2])  ×  five soil volumetric water content (SWC)). The δ13C of water-soluble compounds extracted from leaves of saplings was determined for an assessment of instantaneous water use efficiency (WUEcp) after cultivation. Instantaneous water use efficiency derived from gas-exchange measurements (WUEge) was integrated to estimate differences in δ13C signal variation before leaf-level translocation of primary assimilates. The WUEge values in P. orientalis and Q.  variabilis both decreased with increased soil moisture at 35–80 % of field capacity (FC) and increased with elevated [CO2] by increasing photosynthetic capacity and reducing transpiration. Instantaneous water use efficiency (iWUE) according to environmental changes differed between the two species. The WUEge in P. orientalis was significantly greater than that in Q. variabilis, while an opposite tendency was observed when comparing WUEcp between the two species. Total 13C fractionation at the site of carboxylation to cytoplasm before sugar export (total 13C fractionation) was species-specific, as demonstrated in the interaction of [CO2] and SWC. Rising [CO2] coupled with moistened soil generated increasing disparities in δ13C between water-soluble compounds (δ13CWSC) and estimates based on gas-exchange observations (δ13Cobs) in P. orientalis, ranging between 0.0328 and 0.0472 ‰. Differences between δ13CWSC and δ13Cobs in Q. variabilis increased as [CO2] and SWC increased (0.0384–0.0466 ‰). The 13C fractionation from mesophyll conductance (gm) and post-carboxylation both contributed to the total 13C fractionation that was determined by δ13C of water-soluble compounds and gas-exchange measurements. Total 13C fractionation was linearly dependent on stomatal conductance, indicating that post-carboxylation fractionation could be attributed to environmental variation. The magnitude and environmental dependence of apparent post-carboxylation fractionation is worth our attention when addressing photosynthetic fractionation.

scholarly journals INFLUÊNCIA DA IRRIGAÇÃO SUPLEMENTAR COM ÁGUAS RESIDUÁRIAS SOBRE AS TROCAS GASOSAS FOLIARES DO ALGODOEIRO

Irriga ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 677-682
Author(s):  
Adriana Cruz de Oliveira ◽  
Antonio Flavio Batista de Araujo ◽  
Claudivan Feitosa de Lacerda ◽  
Juvenaldo Florentino Canjá ◽  
Luciana Luzia Pinho ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Gossypium Hirsutum ◽  
Leaf Gas Exchange ◽  
Leaf Temperature ◽  
Treated Wastewater ◽  
Cotton Leaf ◽  
Severe Drought ◽  
Gossypium Hirsutum L ◽  
Supplementary Irrigation ◽  
E Mail

INFLUÊNCIA DA IRRIGAÇÃO SUPLEMENTAR COM ÁGUAS RESIDUÁRIAS SOBRE AS TROCAS GASOSAS FOLIARES DO ALGODOEIRO   ADRIANA CRUZ DE OLIVEIRA1; ANTONIO FLAVIO BATISTA DE ARAUJO2; CLAUDIVAN FEITOSA DE LACERDA3; JUVENALDO FLORENTINO CANJÁ4; LUCIANA LUZIA PINHO5 E NAARA IORRANA GOMES SOUSA6     1 Mestranda no Programa de Pós-Graduação em Engenharia Agrícola, Departamento de Engenharia Agrícola, Universidade Federal do Ceará-UFC, Av. Mister Hull, s/n -Pici, Centro de Ciências Agrárias, Bloco 804, CEP: 60455-760, Fortaleza-CE, Brasil. E-mail: [email protected] 2 Doutorando no Programa de Pós-Graduação em Engenharia Agrícola, Departamento de Engenharia Agrícola, Universidade Federal do Ceará-UFC, Av. Mister Hull, s/n -Pici, Centro de Ciências Agrárias, Bloco 804, CEP: 60455-760, Fortaleza-CE, Brasil. E-mail: [email protected] 3 Professor Titular do Departamento de Engenharia Agrícola, Universidade Federal do Ceará-UFC, Av. Mister Hull, s/n -Pici, Centro de Ciências Agrárias, Bloco 804, CEP: 60455-760, Fortaleza-CE, Brasil. E-mail: [email protected] 4Mestrando no Programa de Pós-Graduação em Engenharia Agrícola, Departamento de Engenharia Agrícola, Universidade Federal do Ceará-UFC, Av. Mister Hull, s/n -Pici, Centro de Ciências Agrárias, Bloco 804, CEP: 60455-760, Fortaleza-CE, Brasil. E-mail: [email protected] 5 Mestranda no Programa de Pós-Graduação em Engenharia Agrícola, Departamento de Engenharia Agrícola, Universidade Federal do Ceará-UFC, Av. Mister Hull, s/n -Pici, Centro de Ciências Agrárias, Bloco 804, CEP: 60455-760, Fortaleza-CE, Brasil. E-mail: [email protected] 6 Mestranda no Programa de Pós-Graduação em Engenharia Agrícola, Departamento de Engenharia Agrícola, Universidade Federal do Ceará-UFC, Av. Mister Hull, s/n -Pici, Centro de Ciências Agrárias, Bloco 804, CEP: 60455-760, Fortaleza-CE, Brasil. E-mail: [email protected]     1 RESUMO   O uso de águas residuárias na irrigação tem crescido como suplementação para driblar a escassez hídrica. Contudo, pouco se sabe sobre as respostas das culturas sobre sua aplicação. Assim, objetivou-se avaliar os impactos da irrigação suplementar com águas residuárias tratadas sobre as trocas gasosas do algodoeiro (Gossypium hirsutum L), simulando-se cenários hídricos considerados normais, seca e seca severa, na presença e ausência de NPK. O experimento foi conduzido no município de Russas – CE, em área vizinha à lagoa de estabilização da CAGECE – Companhia de Água e Esgoto do Estado do Ceará, em DBC, no esquema de parcelas subsubdivididas, com quatro blocos. As parcelas foram cenários hídricos (normal, seca e seca severa); a subparcela foi a suplementação ou não com água residuária tratada nos veranicos simulados; a subsubparcela foi a aplicação ou não de NPK. A cultivar utilizada foi BR 433. Aos 25 dias após a semeadura foram analisadas fotossíntese, transpiração, concentração interna de CO2 e temperatura foliar. Os cenários de seca e seca severa apresentaram pequeno impacto sobre as trocas gasosas foliares do algodoeiro. Entretanto, a irrigação suplementar reduziu a temperatura foliar e atenuou os efeitos do cenário de seca sobre a fotossíntese, independente da aplicação ou não de NPK.   Palavras-chave: Gossypium hirsutum L, Reúso de água, Seca.         OLIVEIRA, A. C. de; ARAUJO, A. F. B. de; LACERDA, C. F. de; CANJÁ, J. F.; PINHO, L. L.; SOUSA, N. I. G. INFLUENCE OF SUPPLEMENTAL IRRIGATION WITH WASTEWATER ON COTTON LEAF GAS EXCHANGE     2 ABSTRACT   The use of wastewater in irrigation has grown as a supplement to circumvent water scarcity. However, little is known about the responses of cultures to its application. Thus, the objective was to evaluate the impacts of supplementary irrigation with treated wastewater on gas exchange of cotton (Gossypium hirsutum L), simulating water scenarios considered normal, drought and severe drought, in the presence and absence of NPK. The experiment was conducted in the municipality of Russas - CE, in an area next to the stabilization pond of CAGECE - Companhia de Agua e Esgoto do Estado do Ceará, in DBC, in the subdivided plot scheme, with four blocks. The plots were water scenarios (normal, drought and severe drought); the subplot was supplemented or not with wastewater treated in the simulated summer days; the sub-installment was the application or not of NPK. The cultivar used was BR 433. At 25 days after sowing, photosynthesis, transpiration, internal CO2 concentration and leaf temperature were analyzed. The drought and severe drought scenarios had little impact on the cotton leaf gas exchange. However, supplementary irrigation reduced leaf temperature and attenuated the effects of drought scenario on photosynthesis, whether or not NPK was applied.   Keywords: Gossypium hirsutum L, Water reuse, Drought.

scholarly journals Moringa leaf extract improves biochemical attributes, yield and grain quality of rice (Oryza sativa L.) under drought stress

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254452
Author(s):  
Shahbaz Khan ◽  
Abdul Basit ◽  
Muhammad Bilal Hafeez ◽  
Sohail Irshad ◽  
Saqib Bashir ◽  
...  
Keyword(s):  
Oryza Sativa ◽  
Drought Stress ◽  
Gas Exchange ◽  
Photosynthetic Pigments ◽  
Leaf Extract ◽  
Grain Quality ◽  
Growth Stages ◽  
Severe Drought ◽  
Moringa Leaf Extract

Changing climate, food shortage, water scarcity and rapidly increasing population are some of the emerging challenges globally. Drought stress is the most devastating threat for agricultural productivity. Natural plant growth substances are intensively used to improve the productivity of crop plants grown under stressed and benign environments. The current study evaluated whether leaf extract of different moringa (Moringa oleifera L.) could play a role in improving drought-tolerance of rice (Oryza sativa L.). Rice plants were grown under three drought conditions, i.e., no, moderate and severe drought (100, 75 and 50% field capacity, respectively). Moringa leaf extract (MLE) obtained from four landraces (Multan, Faisalabad, D. G. Khan and exotic landrace from India) was applied during critical crop growth stages, i.e., tillering, panicle initiation and grain filling. Drought stress adversely affected the gas exchange attributes, photosynthetic pigments, antioxidant enzymes’ activities, yield and quality parameters of rice. Application of MLE from all landraces significantly improved physiological, biochemical and yield parameters under stressed and normal environmental conditions. The highest improvement in gas exchange traits (photosynthetic rate, stomatal conductance and respiration rate), photosynthetic pigments (chlorophyll a, b and carotenoids) and enzymatic activities (superoxide dismutase, catalase) and oxidative marker (H2O2) was recorded with MLE obtained from Faisalabad landrace. The application of MLE of Faisalabad landrace also improved yield and grain quality of rice grown under drought stress as well as drought-free environment. Thus, MLE of Faisalabad can be successfully used to improve growth, productivity and grain quality of rice under drought stress.

Tropical rainforests under severe drought stress: distinct water use strategies among and within species

2021 ◽  
Author(s):  
Angelika Kübert ◽  
Kathrin Kühnhammer ◽  
Ines Bamberger ◽  
Erik Daber ◽  
Jason De Leeuw ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Soil Water ◽  
Water Use ◽  
Leaf Gas Exchange ◽  
Physiological Responses ◽  
Leaf Water ◽  
Severe Drought ◽  
Subsequent Recovery ◽  
Species Specific

&lt;p&gt;Increasing drought in the tropics is a major threat to rainforests and can strongly harm plant communities. Understanding species-specific water use strategies to drought and the subsequent recovery is therefore important for estimating the risk to tropical rainforest ecosystems of drought. Conducting a large-scale long-term drought experiment in a model rainforest ecosystem (Biosphere 2 WALD project), we evaluated the role of plant physiological responses, above and below ground, in response to drought and subsequent recovery in five species (3 canopy species, 2 understory species). The model rainforest was exposed to a 9.5-week lasting drought. Severe drought was ended with a deep water pulse strongly enriched in &lt;sup&gt;2&lt;/sup&gt;H, which allowed us to distinguish between deep and shallow rooting plants, and subsequent rain (natural abundance range of &lt;sup&gt;2&lt;/sup&gt;H). We assessed plant physiological responses by leaf water potential, sap flow and high resolution monitoring of leaf gas exchange (concentrations and stable isotopes of H&lt;sub&gt;2&lt;/sub&gt;O and CO&lt;sub&gt;2&lt;/sub&gt;). Thereby, we could derive plant water uptake and leaf water use efficiency (WUE&lt;sub&gt;leaf&lt;/sub&gt;) in high temporal resolution, revealing short-term and long-term responses of plant individuals to drought and rewetting. The observed water use strategies of species and plants differed widely. No uniform response in assimilation (A) and transpiration (T) to drought was found for species, resulting in decreasing, relatively constant, or increasing WUE&lt;sub&gt;leaf&lt;/sub&gt; across plant individuals. While WUE&lt;sub&gt;leaf&lt;/sub&gt; of some plant individuals strongly decreased due to a breakdown in A, others maintained relatively high T and A and thus constant WUE&lt;sub&gt;leaf, &lt;/sub&gt;or increased WUE&lt;sub&gt;leaf&lt;/sub&gt; by decreasing T while keeping A relatively high. We expect that the observed plant-specific responses in A, T and WUE&lt;sub&gt;leaf&lt;/sub&gt; were strongly related to the plant individuals' access to soil water. We assume that plant individuals with constant WUE&lt;sub&gt;leaf&lt;/sub&gt; could maintain their leaf gas exchange due to access to water of deeper soil layers, while plants with increasing/decreasing WUE&lt;sub&gt;leaf&lt;/sub&gt; mainly depended on shallow soil water and only had limited or no access to deep soil water. We conclude that the observed physiological responses to drought were not only determined by species-specific water use strategies but also by the diverse strategies within species, mainly depending on the plant individuals' size and place of location. Our results highlight the plasticity of water use strategies beyond species-specific strategies and emphasize its importance for species&amp;#8217; survival in face of climate change and increasing drought.&lt;/p&gt;

Host Specificity, Dispersion and Persistence Through Drought of Two Arid Zone Mistletoes

1988 ◽  
Vol 36 (3) ◽  
pp. 299 ◽  
Author(s):  
N Reid ◽  
RT Lange
Keyword(s):  
Host Specificity ◽  
Arid Zone ◽  
Age Distribution ◽  
South Australia ◽  
Severe Drought ◽  
Branch Diameter ◽  
Popu Lation ◽  
Canopy Volume ◽  
Canopy Size

In the Whyalla region of South Australia, the loranthaceous mistletoe Amyema quandang (Lindl.) Tiegh. is virtually host-specific to Acacia papyrocarpa Benth., whereas Lysiana exocarpi (Behr.) Tiegh. (Loranthaceae) frequently parasitises 12 species in seven families, and less commonly infects seven other species. Amyema quandang is contagiously distributed with respect to Acacia papyrocarpa, larger trees supporting higher numbers of mistletoes. Host branch diameter (HBD) is assumed to index the age of individual mistletoes of Amyema quandang since seedlings only establish on thin host branches. The age distribution of A. quandang is skewed towards young plants since almost half the population para- sitises host branches Ͱ4 15 mm in diameter, within the range infected by seedlings. HBD is correlated with canopy size and the number of haustorial branches. The proportion of reproductive mistletoes increases with HBD and hyperparasitic L. exocarpi are confined to older plants of A. quandang with HBD Ͱ5 31 mm. As a result of the severe drought in 1982, 25% of large plants of A. quandang lost one or two main haustorial branches and suffered reductions in canopy volume, but only 4% died; by contrast, 31% of large L. exocarpi died and a further 19% lost most of their foliage. In the A. quandang population as a whole, recruitment balanced mortality (19%) over a 40 month period, but in the L. exocarpi popu- lation recruitment compensated for only half the mortality. None of the xerophytic shrub and tree hosts of either mistletoe died.

scholarly journals Recent increase in aerosol loading over the Australian arid zone

2010 ◽  
Vol 10 (4) ◽  
pp. 1689-1699 ◽  
Author(s):  
R. M. Mitchell ◽  
S. K. Campbell ◽  
Y. Qin
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Arid Zone ◽  
Severe Drought ◽  
Near Surface ◽  
Aerosol Loading ◽  
Ephemeral Lakes ◽  
Fine Mode ◽  
Fine Mode Aerosol ◽  
Ephemeral Vegetation

Abstract. Collocated sun photometer and nephelometer measurements at Tinga Tingana in the Australian Outback over the decade 1997–2007 show a significant increase in aerosol loading following the onset of severe drought conditions in 2002. This increase is confined to the season of dust activity, particularly September to March. In contrast, background aerosol levels during May, June and July remained stable. The enhanced aerosol loadings during the latter 5 years of the study period can be understood as a combination of dune destabilisation through loss of ephemeral vegetation and surface crust, and the changing supply of fluvial sediments to ephemeral lakes and floodplains within the Lake Eyre Basin. Major dust outbreaks are generally highly localised, although significant dust activity was observed at Tinga Tingana on 50% of days when a major event occurred elsewhere in the Lake Eyre Basin, suggesting frequent basin-wide dust mobilisation. Combined analysis of aerosol optical depth and scattering coefficient shows weak correlation between the surface and column aerosol (R2=0.24). The aerosol scale height is broadly distributed with a mode typically between 2–3 km, with clearly defined seasonal variation. Climatological analysis reveals bimodal structure in the annual cycle of aerosol optical depth, with a summer peak related to maximal dust activity, and a spring peak related to lofted fine-mode aerosol. There is evidence for an increase in near-surface aerosol during the period 2003–2007 relative to 1997–2002, consistent with an increase in dust activity. This accords with an independent finding of increasing aerosol loading over the Australian region as a whole, suggesting that rising dust activity over the Lake Eyre Basin may be a significant contributor to changes in the aerosol budget of the continent.

scholarly journals IS ABSCISIC ACID INVOLVED IN THE DROUGHT RESPONSES OF BRAZILIAN GREEN DWARF COCONUT?

2009 ◽  
Vol 45 (2) ◽  
pp. 189-198 ◽  
Author(s):  
F. P. GOMES ◽  
M. A. OLIVA ◽  
M. S. MIELKE ◽  
A-A. F. DE ALMEIDA ◽  
H. G. LEITE ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Water Stress ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Water Potential ◽  
Water Use ◽  
Severe Drought ◽  
Use Efficiency ◽  
Recovery Cycles ◽  
Mild Drought

SUMMARYAbscisic acid (ABA) accumulation in leaves of drought-stressed coconut palms and its involvement with stomatal regulation of gas exchange during and after stress were investigated. Two Brazilian Green Dwarf coconut ecotypes from hot/humid and hot/dry environments were submitted to three consecutive drying/recovery cycles under greenhouse conditions. ABA accumulated in leaflets before significant changes in pre-dawn leaflet water potential (ΨPD) and did not recover completely in the two ecotypes after 8 days of rewatering. Stomatal conductance was influenced by ABA under mild drought and by ΨPD under severe drought. There were no significant differences between the ecotypes for most variables measured. However, the ecotype from a hot/dry environment showed higher water use efficiency after repeated cycles of water stress.

scholarly journals The resistance and resilience of European beech seedlings to drought stress during the period of leaf development

2020 ◽  
Vol 40 (9) ◽  
pp. 1147-1164
Author(s):  
Roman Gebauer ◽  
Roman Plichta ◽  
Josef Urban ◽  
Daniel Volařík ◽  
Martina Hájíčková
Keyword(s):  
Drought Stress ◽  
Hydraulic Conductivity ◽  
Gas Exchange ◽  
Tree Ring ◽  
Leaf Development ◽  
Leaf Gas Exchange ◽  
Recovery Period ◽  
European Beech ◽  
Leaf Biomass ◽  
Severe Drought

Abstract Spring drought is becoming a frequently occurring stress factor in temperate forests. However, the understanding of tree resistance and resilience to the spring drought remains insufficient. In this study, European beech (Fagus sylvatica L.) seedlings at the early stage of leaf development were moderately and severely drought stressed for 1 month and then subjected to a 2-week recovery period after rewatering. The study aimed to disentangle the complex relationships between leaf gas exchange, vascular anatomy, tree morphology and patterns of biomass allocation. Stomatal conductance decreased by 80 and 85% upon moderate and severe drought stress, respectively, which brought about a decline in net photosynthesis. However, drought did not affect the indices of slow chlorophyll fluorescence, indicating no permanent damage to the light part of the photosynthetic apparatus. Stem hydraulic conductivity decreased by more than 92% at both drought levels. Consequently, the cambial activity of stressed seedlings declined, which led to lower stem biomass, reduced tree ring width and a lower number of vessels in the current tree ring, these latter also with smaller dimensions. In contrast, the petiole structure was not affected, but at the cost of reduced leaf biomass. Root biomass was reduced only by severe drought. After rewatering, the recovery of gas exchange and regrowth of the current tree ring were observed, all delayed by several days and by lower magnitudes in severely stressed seedlings. The reduced stem hydraulic conductivity inhibited the recovery of gas exchange, but xylem function started to recover by regrowth and refilling of embolized vessels. Despite the damage to conductive xylem, no mortality occurred. These results suggest the low resistance but high resilience of European beech to spring drought. Nevertheless, beech resilience could be weakened if the period between drought events is short, as the recovery of severely stressed seedlings took longer than 14 days.

Life histories of two arid-zone shrubs change with differences in habitat, grazing and climate

2014 ◽  
Vol 36 (3) ◽  
pp. 249 ◽  
Author(s):  
P. Norman ◽  
R. Denham ◽  
M. J. Calvert
Keyword(s):  
Life Histories ◽  
Arid Zone ◽  
Survival Rates ◽  
Climatic Conditions ◽  
Severe Drought ◽  
High Survival ◽  
Ecosystem Structure ◽  
Background Rate ◽  
Average Maximum ◽  
Eastern Australia

Shrubs are an important component of vegetation throughout the world. They are particularly significant in semiarid environments where they can dominate, driving ecosystem structure and functioning, and shaping land use. Life-history information was derived for Eremophila sturtii R.Br. and Dodonaea viscosa subsp. angustissima J.G.West, two widespread and common shrubs of semiarid eastern Australia. Plants growing under background climatic conditions took between 2 and 4 years to become established, attained the capacity to reproduce sexually at between 10 and 12 years, were in a sexually reproductive stage for between 17 and 28 years and lived an average maximum of 33–40 years. Under background climatic conditions between 70 and 80% of plants that entered the juvenile stage survived to sexual maturity while under severe drought this proportion fell to between 40 and 60%. Juvenile plants, particularly of E. sturtii, experienced the highest mortality under background conditions while, when exposed to severe drought, older plants, particularly D. viscosa subsp. angustissima in the intermediate stage, experienced the greatest increase in mortality, dying at more than twice the background rate. The high survival rates of E. sturtii and D. viscosa subsp. angustissima shown here, even under extreme drought conditions and in grazed- and ungrazed areas, help to explain why these shrub species have been observed to dominate vegetation in large areas of eastern Australia.

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