scholarly journals Hypernodulating soybean mutant line nod4 lacking ‘Autoregulation of Nodulation’ (AON) has limited root-to-shoot water transport capacity

2019 ◽  
Vol 124 (6) ◽  
pp. 979-991 ◽  
Author(s):  
Emile Caroline Silva Lopes ◽  
Weverton Pereira Rodrigues ◽  
Katherine Ruas Fraga ◽  
José Altino Machado Filho ◽  
Jefferson Rangel da Silva ◽  
...  
Keyword(s):  
Plant Growth ◽  
Water Potential ◽  
Water Transport ◽  
Leaf Water Potential ◽  
Root Nodules ◽  
Leaf Water ◽  
Transport Capacity ◽  
N Content ◽  
Photosynthetic Rates ◽  
Root Conductance

AbstractBackground and AimsAlthough hypernodulating phenotype mutants of legumes, such as soybean, possess a high leaf N content, the large number of root nodules decreases carbohydrate availability for plant growth and seed yield. In addition, under conditions of high air vapour pressure deficit (VPD), hypernodulating plants show a limited capacity to replace water losses through transpiration, resulting in stomatal closure, and therefore decreased net photosynthetic rates. Here, we used hypernodulating (nod4) (282.33 ± 28.56 nodules per plant) and non-nodulating (nod139) (0 nodules per plant) soybean mutant lines to determine explicitly whether a large number of nodules reduces root hydraulic capacity, resulting in decreased stomatal conductance and net photosynthetic rates under high air VPD conditions.MethodsPlants were either inoculated or not inoculated with Bradyrhizobium diazoefficiens (strain BR 85, SEMIA 5080) to induce nitrogen-fixing root nodules (where possible). Absolute root conductance and root conductivity, plant growth, leaf water potential, gas exchange, chlorophyll a fluorescence, leaf ‘greenness’ [Soil Plant Analysis Development (SPAD) reading] and nitrogen content were measured 37 days after sowing.Key ResultsBesides the reduced growth of hypernodulating soybean mutant nod4, such plants showed decreased root capacity to supply leaf water demand as a consequence of their reduced root dry mass and root volume, which resulted in limited absolute root conductance and root conductivity normalized by leaf area. Thereby, reduced leaf water potential at 1300 h was observed, which contributed to depression of photosynthesis at midday associated with both stomatal and non-stomatal limitations.ConclusionsHypernodulated plants were more vulnerable to VPD increases due to their limited root-to-shoot water transport capacity. However, greater CO2 uptake caused by the high N content can be partly compensated by the stomatal limitation imposed by increased VPD conditions.

Carbon dioxide enrichment and water stress interaction on growth of two tomato cultivars

1984 ◽  
Vol 102 (3) ◽  
pp. 687-693 ◽  
Author(s):  
Alejandra Paez ◽  
H. Hellmers ◽  
B. R. Strain
Keyword(s):  
Carbon Dioxide ◽  
Water Stress ◽  
Plant Growth ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Osmotic Potential ◽  
Water Status ◽  
Carbon Dioxide Concentration ◽  
Leaf Water ◽  
Total Leaf

SummaryIf atmospheric carbon dioxide concentration continues to increase, plant growth and crop yield could be affected. New Yorker and Better Boy cultivars of tomato (Lycopersicon esculentum) were used to investigate possible intraspecific variation in the response of crop species to increased CO2. Because precipitation and temperature are predicted to change with the increasing atmospheric CO2 concentration, the response of the two cultivars to the interaction between CO2 and water stress was also examined. Seeds of the two cultivars were germinated and grown under controlled environmental conditions, in either 350 or 675 μ1 CO2/1.The plant water status of the two cultivars was inherently different but was little affected by the CO2 concentration when the plants were well watered. When water was withheld for 5 days the total leaf water potential and osmotic potential decreased in both CO2 treatments but less rapidly in high CO2 than in low. Under low CO2 total leaf water potential decreased to a lower value than osmotic potential. The differences were due, at least in part, to the reduced stomatal conductance and transpiration rate under high CO2.Increased CO2 ameliorated the detrimental effects of drought stress on plant growth. The results indicate that increased CO2 could differentially affect the relative drought resistance of species cultivars.

Plant growth, leaf water potential, nitrogenase activity and nodule anatomy in

Trees ◽  
1997 ◽  
Vol 12 (1) ◽  
pp. 42 ◽  
Author(s):  
A. F. Mrema ◽  
U. Granhall ◽  
L. Sennerby-Forsse
Keyword(s):  
Plant Growth ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Nitrogenase Activity ◽  
Leaf Water

scholarly journals ARABICA COFFEE CULTIVARS IN DIFFERENT WATER REGIMES IN THE CENTRAL CERRADO REGION

2019 ◽  
Vol 14 (3) ◽  
pp. 349
Author(s):  
Adriano Delly Veiga ◽  
Gustavo Costa Rodrigues ◽  
Omar Cruz Rocha ◽  
Gabriel Ferreira Bartholo ◽  
Antônio Fernando Guerra ◽  
...  
Keyword(s):  
Water Stress ◽  
Plant Growth ◽  
Grain Yield ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Leaf Water ◽  
High Yield ◽  
Phenotypic Characterization ◽  
Arabica Coffee ◽  
Water Regimes

Phenotypic characterization of coffee cultivars under an irrigation system, as well as adaptability to controlled water stress, aiming at flowering uniformity, high yield and grain quality, plays an important role in coffee production in the cerrado areas. A field trial was carried out aiming to evaluate the agronomic performance of arabica coffee cultivars under different water regimes, using center pivot irrigation: irrigation throughout the year (WR1); suspended at the end of June for 40 days until leaf water potential reached -1.5 MPa (WR2); suspended at the end of June for 70 days until leaf water potential reached -2.3 MPa (WR3); suspended at the end of June for 100 days until leaf water potential reached -3.4 MPa (WR4); and a non-irrigated regime (WR5). The following traits were analyzed: plant height, stem diameter, canopy projection, number of plagiotropic branches, coffee grain yield, percentage of fruit in the cherry stage, and sieve retention percentages. Higher yield, plant growth, and percentage of fruit in the cherry stage are observed in the water regime with seventy days of controlled water stress (WR3). The Obatã IAC 1669-20 cultivar exhibits high yield and plant growth values in an irrigated system, and Catuaí Amarelo IAC 86 stands out in the non-irrigated system. For these genotypes, the coffee grain yield is most highly correlated with number of reproductive branches.

scholarly journals Substrate Type and Salinity Affect Growth Allocation, Tissue Ion Concentrations, and Physiological Responses of Carrizo Citrange Seedlings

HortScience ◽  
2009 ◽  
Vol 44 (5) ◽  
pp. 1432-1437 ◽  
Author(s):  
Francisco García-Sánchez ◽  
James P. Syvertsen
Keyword(s):  
Salt Tolerance ◽  
Gas Exchange ◽  
Plant Growth ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Leaf Growth ◽  
Physiological Responses ◽  
Leaf Water ◽  
Substrate Type ◽  
Carrizo Citrange

To gain insight into salinity tolerance of citrus, we studied growth, leaf, and root Cl– concentrations and physiological responses of 5-month-old seedlings of the citrus rootstock Carrizo citrange [Citrus sinensis (L.) Osb. × Poncirus trifoliate L.] grown in a greenhouse in three different substrates: Candler sand soil, Floridana sandy clay soil, or a commercial soilless peat/perlite/vermiculite potting media. Plants were kept well-watered with a complete nutrient solution plus either no salt (control) or 50 mM NaCl for 9 weeks. Without salinity, substrate type did not affect total plant growth although there were differences in shoot/root dry weight ratio and mineral nutrient relationships attributable to substrate. Predawn leaf water potential, midday CO2 assimilation, and leaf water use efficiency were highest in seedlings grown in the soilless peat. The salt treatment decreased leaf and root growth, reduced leaf Ca2+, and increased leaf K+ concentration in all the three substrates. Overall, plant growth was negatively related to leaf Cl–. Leaf growth reductions were least in Candler-grown seedlings and greatest in Floridana soil as Cl– concentrations were lowest in Candler sand and highest in Floridana soil. Leaf Na+ was also highest in Floridana seedlings. In contrast to salt ions in leaves, roots of salinized seedlings in Candler sand had the highest Na+ and Cl– concentration. Salinity reduced net gas exchange of leaves similarly in all three substrates. Salinity reduced both leaf water potential and osmotic potential such that leaf turgor was increased. Thus, salinity-induced reductions in growth and net gas exchange were not the result of loss of turgor but more likely resulting from toxic ion accumulation in leaves. Based on the relative rankings of leaf growth and leaf Cl– concentrations, Carrizo seedlings from Candler sand had the highest salt tolerance and those grown in Floridana soil had the lowest salt tolerance. Substrate type should be considered when characterizing plant growth and physiological responses to salinity.

scholarly journals Growth and Physiological Responses of Rangpur Lime Seedlings Irrigated by a Prototype Subirrigation Tray

HortScience ◽  
2015 ◽  
Vol 50 (1) ◽  
pp. 123-129 ◽  
Author(s):  
Carlos Vinicius Garcia Barreto ◽  
Rhuanito Soranz Ferrarezi ◽  
Flávio Bussmeyer Arruda ◽  
Roberto Testezlaf
Keyword(s):  
Plant Growth ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Physiological Responses ◽  
Stomatal Closure ◽  
Leaf Water ◽  
Higher Plant ◽  
Irrigation Systems ◽  
Rangpur Lime ◽  
Overhead Irrigation

Citrus rootstock production in Brazil commonly uses manual overhead irrigation systems to water plants. Manual irrigation systems present low efficiency, apply more water than needed, and result in release of nutrients and pesticides into the soil with a potential to contaminate groundwater. Closed irrigation systems that avoid the disposal of nutrient solutions like subirrigation can be used to increase production efficiency and reduce the environmental contamination. Our objective was to evaluate the effect of subirrigation applied by a prototype tray on plant growth and morphological and physiological responses of Rangpur lime (Citrus limonia Osbeck ‘Limeira’) seedlings subjected to different water levels in conic containers filled with pine bark substrate. We tested three treatments: T1) subirrigation with water reaching two-thirds of the container height (8 cm); T2) subirrigation with water reaching one-third of the container height (4 cm); and T3) control with manual overhead irrigation. Subirrigation resulted in higher plant growth of Rangpur lime seedlings. At 90 days after sowing (DAS), we observed significant effects of T1 over the other treatments on plant growth, as indicated by higher total dry mass (P = 0.0057), shoot/root ratio (P = 0.0089), shoot height (P = 0.0004), leaf area (P = 0.0005), and root length (P = 0.0333). The number of bifurcations was 400% higher in T3 than at the subirrigated treatments, which can lead to an increase in the labor costs for pruning. Seedlings grown under T1 presented leaf water potential 13% higher compared with T3 at predawn, which was the time of highest stomatal efficiency, presenting the lowest water loss, maximum stomatal closure, and higher transpiration at lower stomatal resistance. T2 plants displayed intermediate water status with a water potential 5% higher than T3. T3 plants showed a higher transpiration rate under maximum stomatal closure, reducing leaf water potential. The subirrigated treatment with water level of two-thirds of container height (8 cm) induced higher plant growth and shortened the crop cycle, anticipating the transplanting to the next phase (grafting) with the possibility of reducing production costs in the nursery.

scholarly journals Azospirillum baldaniorum Sp245 Induces Physiological Responses to Alleviate the Adverse Effects of Drought Stress in Purple Basil

Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1141
Author(s):  
Lorenzo Mariotti ◽  
Andrea Scartazza ◽  
Maurizio Curadi ◽  
Piero Picciarelli ◽  
Annita Toffanin
Keyword(s):  
Gas Exchange ◽  
Plant Growth ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Water Status ◽  
Xylem Sap ◽  
Leaf Water ◽  
Growth And Yield ◽  
Gas Exchange Parameters ◽  
Leaf Water Status

Azospirillum spp. are plant growth-promoting rhizobacteria (PGPR) that exert beneficial effects on plant growth and yield of agronomically important plant species. The aim of this study was to investigate the effects of a root treatment with Azospirillum baldaniorum Sp245 on hormones in xylem sap and physiological performance in purple basil (Ocimum basilicum L. cv. Red Rubin) plants grown under well-watered conditions and after removing water. Treatments with A. baldaniorum Sp245 included inoculation with viable cells (1ˑ107 CFU mL–1) and addition of two doses of filtered culture supernatants (non-diluted 1ˑ108 CFU mL–1, and diluted 1:1). Photosynthetic activity, endogenous level of hormones in xylem sap (salicylic acid, jasmonic acid, and abscisic acid), leaf pigments, leaf water potential, water-use efficiency (WUE), and drought tolerance were determined. Fluorescence and gas exchange parameters, as well as leaf water potential, showed that the highest dose of filtered culture supernatant improved both photosynthetic performance and leaf water status during water removal, associated with an increase in total pigments. Moreover, gas exchange analysis and carbon isotope discrimination found this bacterial treatment to be the most effective in inducing an increase of intrinsic and instantaneous WUE during water stress. We hypothesize that the benefits of bacterial treatments based on A. baldaniorum Sp245 are strongly correlated with the synthesis of phytohormones and the induction of plant-stress tolerance in purple basil.

Analysis of Photosynthesis Depression under Low Leaf Water Potential by Comparison of CO2 Exchange and O2 Evolution Rates.

1996 ◽  
Vol 65 (4) ◽  
pp. 590-598 ◽  
Author(s):  
Katsuhiro WAKABAYASHI ◽  
Tadashi HIRASAWA ◽  
Kuni ISHIHARA
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Co2 Exchange ◽  
Leaf Water ◽  
O2 Evolution

Use of a Hydraulic Press for Estimation of Leaf Water Potential in Grain Sorghum 1

1986 ◽  
Vol 78 (4) ◽  
pp. 749-751 ◽  
Author(s):  
S. K. Hicks ◽  
R. J. Lascano ◽  
C. W. Wendt ◽  
A. B. Onken
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Grain Sorghum ◽  
Hydraulic Press ◽  
Leaf Water
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