Water-Stress Influences on Three New Promising HLB-Tolerant Citrus Rootstocks

Drought and flooding conditions are increasingly common abiotic factors that affect citrus crops in both the Mediterranean Basin and Florida. Furthermore, emerging diseases, such as Huanglongbing (HLB), are a potential risk for these crops in those producing areas. This study aimed to evaluate the behavior under water-stress treatments of three new citrus rootstocks (UFR-6, B11R5T60, and 2247 x 6070-02-2) with reported tolerance of HLB, comparing them with a common commercial citrus rootstock (Carrizo citrange). Four water conditions were established: Control, Medium Water Stress (MWS), Drought, and Flooding. Chlorophyll index (SPAD), growth in height, relative growth rate, biomass (fresh and dry weight) and plant water status were evaluated. Citru rootstock response were different for each genotype; Carrizo citrange was negatively affected by all water treatments in the chlorophyll index (SPAD) and biomass production. By contrast, UFR-6 showed a positive response in SPAD and growth under MWS and Drought, B11R5T60 displayed similar behavior to Control under all water stresses, and the response of 2247 x 6070-02-2 under MWS treatment was adequate but was not under Drought or Flooding conditions. Our study describes the behavior of these promising new citrus rootstocks against water stress; B11R5T60 exhibiting the best performance. These results can be useful for the citrus industry to address water-stress problems in these crops.

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High Phosphorus Acquisition and Allocation Strategy Is Associated with Soybean Seed Yield under Water- and P-Limited Conditions

Agronomy ◽

10.3390/agronomy11030574 ◽

2021 ◽

Vol 11 (3) ◽

pp. 574

Author(s):

Yun-Yin Feng ◽

Jin He ◽

Yi Jin ◽

Feng-Min Li

Keyword(s):

Water Stress ◽

Water Supply ◽

Seed Yield ◽

Soybean Seed ◽

Dry Weight ◽

Water Regimes ◽

P Acquisition ◽

Application Rates ◽

Soybean Genotypes ◽

Water Treatments

Both water stress and P deficit limit soybean seed yield, but the effects of water regimes and P application rates, their interaction on P status, acquisition, and partitioning, and their roles in yield performance have not been well-studied. Two soybean genotypes (Huangsedadou (HD) and Zhonghuang 30 (ZH)) with contrasting seed yield and root dry weight (DW) were used to investigate the P status, P acquisition, P partitioning, and yield formation under two water regimes (well-watered (WW) and cyclic water stress (WS)) and three P rates (0 (P0), 60 (P60), and 120 (P120) mg P kg−1 dry soil). The results show that increased P and water supply increased the seed yield, shoot and root DW and P concentrations and accumulations in different organs. Cultivar ZH had a significantly higher seed yield than HD at P60 and P120 under WS and at P0 under WW, but a lower seed yield at P60 and P120 under WW. Cultivar ZH had a significantly higher P harvest index and P acquisition efficiency, but a significantly lower shoot and root DW than HD. The interaction between water treatments and P rates had significant effects on leaf and stem P concentration. Cultivar ZH had significantly lower P partitioning to leaves and stems but significantly higher P partitioning to seeds than HD. The seed yield was positively correlated with leaf and seed P accumulations and P acquisition efficiency under WS. We conclude that (1) adequate water supply improved the P mobilization from leaves and stems at maturity, which may have improved the seed yield; and (2) the high P acquisition efficiency is coordination to high P partition to seeds to produce a high seed yield under water- and P-limited conditions.

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Salinity Effect on Plant Physiological and Nutritional Parameters of New Huanglongbing Disease-Tolerant Citrus Rootstocks

Agronomy ◽

10.3390/agronomy11040653 ◽

2021 ◽

Vol 11 (4) ◽

pp. 653

Author(s):

Lidia Aparicio-Durán ◽

Aurea Hervalejo-García ◽

Rocío Calero-Velázquez ◽

Juan M. Arjona-López ◽

Francisco J. Arenas-Arenas

Keyword(s):

Mediterranean Basin ◽

Plant Material ◽

Mineral Content ◽

Emerging Diseases ◽

Carrizo Citrange ◽

Salinity Response ◽

Chlorophyll Index ◽

Damage Symptoms ◽

Mediterranean Conditions ◽

The Mediterranean Basin

Salinity is a major agriculture problem for citrus in the Mediterranean basin, which is a major global producer region. Citrus crops are also threatened by emerging diseases such as Huanglongbing (HLB). The use of different rootstocks increases the variability of citrus plant material in orchards, thus preventing extensive damage caused by abiotic and/or biotic diseases. In this work, we have evaluated the salinity response of five citrus rootstocks (US942, US897, X639, Forner Alcaide No. 5 and Carrizo citrange) some of which have known tolerance to HLB, under Mediterranean conditions. Four treatments with different salt concentrations (0, 25, 50 and 75 mM of NaCl) were applied by watering the plants three times per week for eleven weeks. Chlorophyll index (SPAD), growth and plant symptom parameters were recorded on a biweekly basis. At the end of the trial, roots, stem and leaves biomass and plant mineral content were obtained. The increasing concentration of NaCl resulted in visible leave damage symptoms for all citrus rootstocks assayed, hindering plant growth in all citrus rootstocks assayed, except for X639. The highest concentration of toxic ions in leaves was detected in Carrizo citrange and US897 for Cl−, while the lowest concentration of Na+ was obtained in X639. These results provide growers with information about the sensitivity to salinity of different citrus rootstocks.

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Water status and yield of sunflowers (Helianthus annuus) subjected to water stress during four stages of development

The Journal of Agricultural Science ◽

10.1017/s0021859600061463 ◽

1977 ◽

Vol 89 (3) ◽

pp. 663-666 ◽

Cited By ~ 6

Author(s):

N. Sionit

Keyword(s):

Water Stress ◽

Seed Yield ◽

Sunflower Seed ◽

Oil Content ◽

Water Status ◽

Dry Weight ◽

Stages Of Development ◽

Stages Of Growth ◽

Head Formation ◽

Total Dry Weight

SummaryThe effects on seed yield of two levels of water stress at four stages of development were investigated in two varieties of sunflower, Krasnodarets and Record. The plants were grown from seed in large pots in an air-conditioned glasshouse at 26/20 °C and 70% relative humidity, with natural summer illumination. They were subjected to water stress before head formation, during head formation, during flowering, and during seed development.The leaf water potential of plants subjected to a water stress of – 16 bars returned to normal after rewatering, but plants subjected to – 23 bars did not return to their prestress level and some leaves died. A water stress of – 16 bars caused no significant reduction in dry weight of the vegetative structures, but stress at all stages of growth reduced seed yield. A water stress of – 23 bars reduced both total dry weight and seed yield at all stages of growth, seed yield being reduced more by a stress of – 23 bars than of – 16 bars. Oil content was slightly reduced by water stress.Water stress during anthesis reduced sunflower seed yield more than during later stages of development.

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CITRUS ROOTSTOCK SHOOTS ENHANCE SCION GROWTH AFTER BUD FORCING

HortScience ◽

10.21273/hortsci.25.9.1152d ◽

1990 ◽

Vol 25 (9) ◽

pp. 1152d-1152

Author(s):

Jeffrey G. Williamson ◽

Karen E. Koch ◽

William S. Castle

Keyword(s):

Citrus Sinensis ◽

Dry Weight ◽

Poncirus Trifoliata ◽

Carrizo Citrange ◽

Bud Emergence ◽

Citrus Rootstock ◽

Fibrous Roots

Carrizo citrange [Citrus sinensis (L.) Osb. × Poncirus trifoliata (L.) Raf.] seedlings were budded with `Hamlin' orange [Citrus sinensis (L.) Osb.] and subjected to 3 bud forcing treatments: (1) topping [T] by removing the seedling above the bud union; (2) lopping [L] by cutting half way through the seedling above the bud union and breaking the rootstock over; or, (3) bending [B] the seedling top over and tying it to the base of the plant. As scion buds emerged and grew, plants were sacrificed for dry weight measurements; also, the portion of the rootstock seedling above the bud union was exposed to 14CO2 at 3 stages of scion development. Plants with seedling tops attached (B,L) gained more dry weight and fibrous roots than T seedlings. Scion elongation was greater for B plants than for T plants. Plants usually flushed twice regardless of bud forcing treatment. No treatment differences were noted for time of flushing or scion bud emergence. Labeled photosynthate from attached rootstock leaves was translocated to scions during both flushes suggesting that recently fixed C enhanced scion growth for B and L plants.

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Evaluation of Three New Citrus Rootstocks under Boron Toxicity Conditions

Agronomy ◽

10.3390/agronomy11122490 ◽

2021 ◽

Vol 11 (12) ◽

pp. 2490

Author(s):

Lidia Aparicio-Durán ◽

Frederick G. Gmitter ◽

Juan M. Arjona-López ◽

Jude W. Grosser ◽

Rocío Calero-Velázquez ◽

...

Keyword(s):

Stomatal Conductance ◽

Mediterranean Basin ◽

Negative Impact ◽

Boron Toxicity ◽

Limiting Factor ◽

Carrizo Citrange ◽

Visual Damage ◽

Citrus Rootstock ◽

Relative Water ◽

Chlorophyll Index

Boron (B) toxicity is a common limiting factor both in arid and semiarid regions, such as the Mediterranean Basin. Citrus trees are sensitive to B-toxicity, which generates a negative impact in citrus orchards. In this work, two promising citrus rootstocks (UFR-6 and 2247 x 6070-02-2) have been assessed against B-toxicity and compared with Carrizo citrange, a common commercial citrus rootstock in Mediterranean Basin. Three B concentration treatments (Control, 1 and 2.5 mM H3BO3) were established, irrigating the plants three times per week for 21 days under greenhouse conditions. During the assay, above-ground symptoms, and chlorophyll index (SPAD) were recorded. At the end of the experiment, stomatal conductance, relative water content, and B concentration in leaves and roots were determined. The increasing B concentration in plants generates visual damage in leaves for all citrus rootstocks assayed. Carrizo citrange displayed the greatest visual symptoms, decreased its chlorophyll index (SPAD), and stomatal conductance throughout the B-treatment. However, UFR-6 and 2247 x 6070-02-2 displayed less symptoms than Carrizo citrange and only reduced its parameters under the 2.5 mM H3BO3 treatment. These results can aid citrus grower rootstock planting decisions with under B-toxicity conditions.

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REMOTE SENSING ALLOWS TO ESTIMATE WATER STRESS AND YIELD LOSSES OF BEAN CULTIVARS

Irriga ◽

10.15809/irriga.2021v26n1p1-12 ◽

2021 ◽

Vol 26 (1) ◽

pp. 1-12

Author(s):

Daniel Soares Alves ◽

Pablo Ricardo Nitsche ◽

Vania Moda Cirino ◽

Maria Brigida dos Santos Scholz ◽

José dos Santos Neto ◽

...

Keyword(s):

Remote Sensing ◽

Water Stress ◽

Phaseolus Vulgaris ◽

Water Status ◽

Spectral Response ◽

Yield Losses ◽

Physiological Quality ◽

Remote Sensing Techniques ◽

Water Treatments

REMOTE SENSING ALLOWS TO ESTIMATE WATER STRESS AND YIELD LOSSES OF BEAN CULTIVARS DANIEL SOARES ALVES1; PABLO RICARDO NITSCHE1; VANIA MODA CIRINO2; MARIA BRIGIDA DOS SANTOS SCHOLZ1; JOSÉ DOS SANTOS NETO2 E PAULO HENRIQUE CARAMORI1 1 Área de Agrometeorologia, Ecofisiologia e Tecnologia de Alimentos, Instituto de Desenvolvimento Rural do Paraná IAPAR – EMATER, Rod. Celso Garcia Cid, 375, Conjunto Ernani Moura Lima II, 86.047 – 902, Londrina, Paraná, Brasil. [email protected]; [email protected]; [email protected]; [email protected] 2 Área de Melhoramento e Propagação Vegetal, Instituto de Desenvolvimento Rural do Paraná IAPAR – EMATER, Rod. Celso Garcia Cid, 375, Conjunto Ernani Moura Lima II, 86.047 – 902, Londrina, Paraná, Brasil. [email protected] ; [email protected] 1 ABSTRACT Reflectance measurements can indicate the physiological quality of plants and contribute to the correct differentiation of cultivars. Here, we studied the spectral responses at wavelengths of 410–810 nm of four common bean (Phaseolus vulgaris) cultivars subjected to water stress in the flowering stage at the Rural Development Institute of Paraná in Londrina, in the state of Paraná, Brazil. The reflectance values presented differences among the water regimes treatments at the wavelengths studied. For plants without water stress, it was possible to distinguish between IPR Andorinha and IPR Colibri cultivars using wavelengths of 460 and 760 nm, respectively. With a wavelength of 810 nm, there was a differentiation among IPR Andorinha (reflectance of 25.13%), IAC Imperador (23.51%), and IPR Colibri (21.92%) cultivars; however, the latter was not significantly different from the IPR Curió (22.26%) cultivar. The highest correlations with yield (R2 > 0.90) occurred at wavelengths of 460, 510, 560, 610, and 710 nm. The water treatments increased the protein content only for IPR Andorinha cultivars. It is concluded that the spectral response correlates with productivity and makes it possible to identify the water status of bean cultivars. This demonstrates that remote sensing techniques can be used to identify water stress in this crop. Keywords: irrigation, Phaseolus vulgaris, reflectance, drought. ALVES, D. S.; NITSCHE, P. R.; CIRINO, V. M; SCHOLZ, M. B. S; NETO, J. D. S; CARAMORI, P. H. SENSORIAMENTO REMOTO PERMITE ESTIMAR O DÉFICIT HÍDRICO E PERDAS DE RENDIMENTO EM CULTIVARES DE FEIJÃO 2 RESUMO Medidas de reflectância podem indicar a qualidade fisiológica das plantas e contribuir para a correta diferenciação de cultivares. Estudou-se a resposta espectral, nos comprimentos de onda (λ) de 410 a 810 nm, em quatro cultivares de feijão (Phaseolus vulgaris) submetidas ao déficit hídrico no florescimento, no Instituto de Desenvolvimento Rural do Paraná, em Londrina – PR. A reflectância foi distinta entre os regimes hídricos em todos os comprimentos de onda (λ). Nos tratamentos sem déficit hídrico foi possível diferenciar as cultivares IPR Andorinha e IPR Colibri com λ de 460 nm e 760 nm, respectivamente. Com λ de 810 nm, houve diferenciação entre as cultivares IPR Andorinha (reflectância de 25,13%), IAC Imperador (23,51%) e IPR Colibri (21,92%), esta última sem diferença significativa com a cultivar IPR Curió (22,26%). As maiores correlações com a produtividade (R2 > 0,90) ocorreram com λ de 460, 510, 560, 610 e 710nm. Os tratamentos hídricos promoveram aumento no teor de proteína apenas para a cultivar IPR Andorinha. Conclui-se que a resposta espectral se correlaciona com a produtividade e possibilita identificar o status hídrico de cultivares de feijão. Isto permite o uso das técnicas de sensoriamento remoto como ferramenta auxiliar na identificação de estresse hídrico na cultura. Palavras-chave: irrigação, Phaseolus vulgaris, reflectância, seca.

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Light and water treatment during the early grain filling stage regulates yield and aroma formation in aromatic rice

Scientific Reports ◽

10.1038/s41598-020-71944-5 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Yuzhan Li ◽

Luxin Liang ◽

Xiaomeng Fu ◽

Zifeng Gao ◽

Hecheng Liu ◽

...

Keyword(s):

Water Stress ◽

Dry Weight ◽

Grain Filling ◽

Antioxidant Response ◽

Natural Light ◽

Aromatic Rice ◽

Low Light ◽

Light Water ◽

Total Dry Weight ◽

Water Treatments

Abstract The effect of light and water on aromatic rice remain largely unclear. A pot experiment was conducted to investigate the influences of light-water treatments (CK: natural light and well-watered conditions, WS: natural light and water-stressed conditions, LL: low light and well-watered conditions, LL-WS: low light and water-stressed treatment) on yield and 2-acetyl-1-pyrroline (2AP) formation in aromatic rice. Compared with CK, the light-water treatments decreased grain yield (10.32–39.19%) due to reductions in the filled grain percentage and total dry weight, in the regulation of biomass distribution, and in the attributes of gas exchange and antioxidant response parameters. The 2AP content in grains increased in the LL treatment (5.08–16.32%) but decreased in the WS treatment compared with that in CK. The changes in 2AP were associated with changes in 2AP formation-related traits and element content. Low light and water stress led to yield declines in aromatic rice, but low light alleviated the decrease in 2AP content caused by water stress.

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823 PB 272 CAN A POROUS CERAMIC SOIL AMENDMENT LIMIT WATER STRESS OF CONTAINER-GROWN IMPATIENS `ACCENT RED'?

HortScience ◽

10.21273/hortsci.29.5.551c ◽

1994 ◽

Vol 29 (5) ◽

pp. 551c-551

Author(s):

Michael B. Triff ◽

Timothy J. Smalley ◽

Mark Rieger ◽

David Radcliffe

Keyword(s):

Water Stress ◽

Soil Amendment ◽

Growth Parameters ◽

Tap Water ◽

Water Status ◽

Porous Ceramic ◽

Irrigation Treatment ◽

Visual Quality ◽

Dry Weight ◽

Xylem Pressure Potential

Isolite is a ceramic-like, porous soil amendment purported to sustain plant growth under reduced irrigation and increase plant survival during drought. The purpose of this greenhouse experiment was to determine the effect of an Isotite-amended soilless container medium on: (1) growth under reduced irrigation frequency and (2) water stress during drought of Impatiens × hybrids `Accent Red'. On 2 June 1993, seedlings were transplanted into 13.2 liter black plastic pots containing a 4:1 composted pine bark:coarse sand (vol.) medium amended with Isolite CG-1 granules at rates of 0%, 10%, 15%, and 20% (vol.). Study I. Seedlings were. irrigated with 500 ml tap water every two days for two weeks followed by a 4 week schedule of 500 ml tap water every 1, 2, 3, 4, or 5 days. In general, growth parameters were explained by irrigation treatment effects and did not differ with Isolite rate. Growth indices ranged from +54% to + 143%, while final visual quality grades ranged from 2.4 to 5.0 (5-point scale), shoot dry weight from 8.7 to 30.7 g, root dry weight from 2.0 to 7.9 g, and leaf area from 0.14 to 0.48 m2. Study II. Seedlings were irrigated with 500 ml tap water every 2 days for rive weeks followed by a two week drought. Plant water status parameters were similar at all rates of Isolite. Leaf expansion rates ranged from + 89% to +98%, white a final mid-day xylem pressure potential of -0.4 MPa and a final visual quality grade of 2.0 were uniform across all treatments. Under these conditions, Isolite did not limit water stress of container-grown Impatiens `Accent Red'.

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Germination and vigour in genotypes of forage sorghum at different levels of water and salt stress

Semina Ciências Agrárias ◽

10.5433/1679-0359.2020v41n5supl1p1975 ◽

2020 ◽

pp. 1975-1986

Author(s):

Luma Rayane de Lima Nunes ◽

Miller Clementino Cruz ◽

Charles Lobo Pinheiro ◽

Geocleber Gomes de Sousa ◽

Alek Sandro Dutra

Keyword(s):

Salt Stress ◽

Water Stress ◽

Arid Regions ◽

Abiotic Factors ◽

Dry Weight ◽

Germination Percentage ◽

Saline Stress ◽

Strong Impact ◽

Forage Sorghum ◽

Different Levels

Salinity and water deficiency are abiotic factors which have a strong impact on agricultural activities, especially in arid and semi-arid regions. The aim of this research was to analyse the tolerance of two genotypes of forage sorghum, EA 116 and BRS Ponta Negra, to different levels of water and salt stress during germination. The conditions of water and salt stress were simulated by moistening the substrate with a solution of mannitol and of sodium chloride (NaCl) respectively, with the water potential adjusted to 0 (distilled water), -0.1, -0.2, -0.3, -0.4, -0.5 and -0.6 MPa. The variables under analysis were germination percentage, first count, germination speed index, shoot and root length, seedling dry weight, electrolyte leakage and leaf Na+/K+ ratio. The experiment was conducted in a completely randomised design, and distributed in a 2 (genotypes) × 2 (stress condition) × 7 (osmotic potential) factorial scheme, with four replications. The EA 116 and BRS Ponta Negra genotypes show greater tolerance to water stress. The EA 116 cultivar maintained germination under water stress from 0 to -0.6 MPa and saline stress from 0 to -0.4 MPa.

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Monitoring Crop Water Status and Irrigation Needs Using Multispectral Airborne Sensors

HortScience ◽

10.21273/hortsci.30.4.905d ◽

1995 ◽

Vol 30 (4) ◽

pp. 905D-905

Author(s):

Thomas R. Clarke ◽

M. Susan Moran

Keyword(s):

Water Stress ◽

Near Infrared ◽

Water Status ◽

Canopy Cover ◽

Stress Index ◽

Crop Water ◽

Vegetative Cover ◽

Crop Water Stress Index ◽

Water Stress Index ◽

Subsurface Drip

Water application efficiency can be improved by directly monitoring plant water status rather than depending on soil moisture measurements or modeled ET estimates. Plants receiving sufficient water through their roots have cooler leaves than those that are water-stressed, leading to the development of the Crop Water Stress Index based on hand-held infrared thermometry. Substantial error can occur in partial canopies, however, as exposed hot soil contributes to deceptively warm temperature readings. Mathematically comparing red and near-infrared reflectances provides a measure of vegetative cover, and this information was combined with thermal radiance to give a two-dimensional index capable of detecting water stress even with a low percentage of canopy cover. Thermal, red, and near-infrared images acquired over subsurface drip-irrigated cantaloupe fields demonstrated the method's ability to detect areas with clogged emitters, insufficient irrigation rate, and system water leaks.

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