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B. Schaffer
Tropical Research and Education Center, University of Florida, 18905 S.W. 280th Street, Homestead, FL 33031, USA

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Journal article
Published: 21 May 2021 in Scientia Horticulturae
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Laurel wilt, caused by the fungus Raffaelea lauricola, is a lethal vascular disease that affects many members of the Lauraceae family, including avocado (Persea americana Mill.) trees. Previous studies have shown differences in laurel wilt susceptibility among genotypes, with cultivars of the West Indian (WI) race generally more susceptible to laurel wilt than Guatemalan (G) or Mexican (M) race cultivars. We conducted four experiments to compare susceptibility and ecophysiological responses to laurel wilt among scion/rootstock combinations from the different botanical races. In the first two experiments, clonally propagated ‘Simmonds’ (WI) scion grafted on ‘Waldin’ (WI), ‘Reed’ (G) or ‘Duke 7’ (M) rootstock (Experiment 1), or grafted on ‘Waldin’, ‘Nabal’ (G) or ‘Zutano’ (M) rootstock (Experiment 2) were compared. In the other two experiments, ‘Waldin’, ‘Reed’ or ‘Duke 7’ scion grafted on ‘Duke 7’ rootstock (Experiment 3), or ‘Reed’ rootstock (Experiment 4) were compared. For each scion/rootstock combination, trees were divided into two treatments: inoculated with R. lauricola, or 2) inoculated with deionized water as a control. Disease severity in all trees was determined daily using a rating scale based on the percentage of visible symptoms. Net CO2 assimilation (A), stomatal conductance of water vapor (gs), the daily xylem sap flow rate, and the ratio of variable to maximum chlorophyll fluorescence (Fv/Fm) in leaves were determined three times per week until one or more scion/rootstock combination in the laurel wilt treatment showed severe symptoms. Trees from each treatment were then harvested and stem sections observed for browning of the sapwood (a characteristic laurel wilt symptom), and plated on a selective medium to recover the fungus if present. Raffaelea lauricola was recovered in all trees in the laurel wilt treatment and no trees in the control treatment. Laurel wilt susceptibility varied among the scion/rootstock combinations. Trees in the laurel wilt treatment with ‘Simmonds’ as the scion developed more symptoms and exhibited a greater reduction in physiological variables than the control trees, regardless of the genotype of the rootstock. ‘Duke 7’, either as the scion or rootstock, inoculated with the laurel wilt pathogen had less disease development and less of a reduction in physiological variables than the other genotypes. The results indicate that there are differences in laurel wilt susceptibility among grafted avocado cultivars of different genotypes. These difference may be related to the botanical race of the scion and/or the rootstock.

ACS Style

RaizA Castillo-Argaez; Joshua L. Konkol; Ana I. Vargas; Randy C. Ploetz; Bruce Schaffer. Disease severity and ecophysiology of rootstock/scion combinations of different avocado (Persea americana Mill.) genotypes in response to laurel wilt. Scientia Horticulturae 2021, 287, 110250 .

AMA Style

RaizA Castillo-Argaez, Joshua L. Konkol, Ana I. Vargas, Randy C. Ploetz, Bruce Schaffer. Disease severity and ecophysiology of rootstock/scion combinations of different avocado (Persea americana Mill.) genotypes in response to laurel wilt. Scientia Horticulturae. 2021; 287 ():110250.

Chicago/Turabian Style

RaizA Castillo-Argaez; Joshua L. Konkol; Ana I. Vargas; Randy C. Ploetz; Bruce Schaffer. 2021. "Disease severity and ecophysiology of rootstock/scion combinations of different avocado (Persea americana Mill.) genotypes in response to laurel wilt." Scientia Horticulturae 287, no. : 110250.

Journal article
Published: 20 February 2021 in Agronomy
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Salinity is one of the most common and critical environmental factors that limit plant growth and reduce crop yield. The aquifers, the primary sources of irrigation water, of south Florida are shallow and highly permeable, which makes agriculture vulnerable to projected sea level rise and saltwater intrusion. This study evaluated the growth responses of two ornamental nursery crops to the different salinity levels of irrigation water to help develop saltwater intrusion mitigation plans for the improved sustainability of the horticultural industry in south Florida. Two nursery crops, Hibiscus rosa-sinensis and Mandevilla splendens, were treated with irrigation water that had seven different salinity levels from 0.5 (control) to 10.0 dS/m in the experiment. Crop height was measured weekly, and growth was monitored daily using the normalized difference vegetation index (NDVI) values derived from multispectral images collected using affordable sensors. The results show that the growth of H. rosa-sinensis and M. splendens was significantly inhibited when the salinity concentrations of irrigation water increased to 7.0 and 4.0 dS/m, for each crop, respectively. No significant differences were found between the NDVI values and plant growth variables of both H. rosa-sinensis and M. splendens treated with the different irrigation water salinity levels less than 2.0 dS/m. This study identified the salinity levels that could reduce the growth of the two nursery crops and demonstrated that the current level of irrigation water salinity (0.5 dS/m) would not have significant adverse effects on the growth of these crops in south Florida.

ACS Style

Xinyang Yu; YoungGu Her; Anjin Chang; Jung-Hun Song; E. Campoverde; Bruce Schaffer. Assessing the Effects of Irrigation Water Salinity on Two Ornamental Crops by Remote Spectral Imaging. Agronomy 2021, 11, 375 .

AMA Style

Xinyang Yu, YoungGu Her, Anjin Chang, Jung-Hun Song, E. Campoverde, Bruce Schaffer. Assessing the Effects of Irrigation Water Salinity on Two Ornamental Crops by Remote Spectral Imaging. Agronomy. 2021; 11 (2):375.

Chicago/Turabian Style

Xinyang Yu; YoungGu Her; Anjin Chang; Jung-Hun Song; E. Campoverde; Bruce Schaffer. 2021. "Assessing the Effects of Irrigation Water Salinity on Two Ornamental Crops by Remote Spectral Imaging." Agronomy 11, no. 2: 375.

Journal article
Published: 02 November 2020 in EDIS
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Laurel wilt (LW) is a vascular disease caused by a fungal pathogen transmitted to avocado trees by several ambrosia beetle species and through root grafts among adjacent avocado trees. A critical part of preventing and controlling plant diseases is determining the causal agent so that the appropriate management practices can be implemented to eradicate or contain the outbreak. Proper sampling is a critical step in disease diagnosis and in the determination of the causal agent of disease. This new 3-page publication of the UF/IFAS Horticultural Sciences Department was written by Jonathan Crane, Romina Gazis, Jeff Wasielewski, Daniel Carrillo, Bruce Schaffer, Fredy Ballen, and Edward Evans.https://edis.ifas.ufl.edu/hs1394

ACS Style

Jonathan Henry Crane; Romina Gazis; Jeff Wasielewski; Daniel Carrillo; Bruce Schaffer; Fredy Ballen; Edward A. Evans. Sampling Guidelines and Recommendations for Submitting Samples for Diagnosing Laurel Wilt in Avocado Trees (Persea americana L.). EDIS 2020, 2020, 1 .

AMA Style

Jonathan Henry Crane, Romina Gazis, Jeff Wasielewski, Daniel Carrillo, Bruce Schaffer, Fredy Ballen, Edward A. Evans. Sampling Guidelines and Recommendations for Submitting Samples for Diagnosing Laurel Wilt in Avocado Trees (Persea americana L.). EDIS. 2020; 2020 (6):1.

Chicago/Turabian Style

Jonathan Henry Crane; Romina Gazis; Jeff Wasielewski; Daniel Carrillo; Bruce Schaffer; Fredy Ballen; Edward A. Evans. 2020. "Sampling Guidelines and Recommendations for Submitting Samples for Diagnosing Laurel Wilt in Avocado Trees (Persea americana L.)." EDIS 2020, no. 6: 1.

Original article
Published: 27 October 2020 in Acta Physiologiae Plantarum
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The success of watershed riparian forest restoration programs can be affected by the selection of plant species tolerant to flooding and soil types that occur along water courses. We evaluated physiological and growth responses of Cytharexyllum myrianthum seedlings to flooding in three different soil types representative of the Almada River Watershed (ARW), southern Bahia, Brazil. The soils selected, based on the relative abundance and importance in the ARW, were: Luvisol, Argisol, and Spodosol. After 35 days of flooding, the Argisol had the lowest and the Spodosol had the highest reduction–oxidation (redox) potential (Eh). After 35 days of flooding, the Luvisol had higher pH and electrical conductivity (Ec) than the other soils. Stomatal conductance (gs) and net photosynthesis (A) significantly declined in all soil types after 7 days of flooding. After that period, morphological changes characteristic of flood-tolerant plants, such as lenticel hypertrophy and adventitious root formation, were observed in all flooded plants. Following the morphological changes, gs and A in flooded plants increased to values close to those of the non-flooded plants. The highest relative growth rates based on mass (RGRm) and net assimilation rates (NAR) for the non-flooded plants were observed in the Argisol. After 35 days of flooding, no significant differences in RGRm or NAR were observed between non-flooded and flooded plants in the Luvisol, but large significant decreases in RGRm and NAR were observed for the flooded plants in the Spodosol. Our results demonstrated that the ability of seedlings of the same species to acclimate to flooded soil conditions differs among soil types. Therefore, the characteristics of soils present in a watershed should be considered when selecting tree species for the reforestation of riparian forests.

ACS Style

Laize Queiroz-Alves; Karine Ferreira Pereira; Adrielle Leal; Ândrea Carla Dalmolin; Ronaldo Lima Gomes; Bruce Schaffer; Martielly Santana Dos Santos; Junior Pastor Pérez-Molina; Marcelo Schramm Mielke. Influence of soil characteristics on physiological and growth responses of Cytharexyllum myrianthum Cham. (Verbenaceae) to flooding. Acta Physiologiae Plantarum 2020, 42, 1 -11.

AMA Style

Laize Queiroz-Alves, Karine Ferreira Pereira, Adrielle Leal, Ândrea Carla Dalmolin, Ronaldo Lima Gomes, Bruce Schaffer, Martielly Santana Dos Santos, Junior Pastor Pérez-Molina, Marcelo Schramm Mielke. Influence of soil characteristics on physiological and growth responses of Cytharexyllum myrianthum Cham. (Verbenaceae) to flooding. Acta Physiologiae Plantarum. 2020; 42 (11):1-11.

Chicago/Turabian Style

Laize Queiroz-Alves; Karine Ferreira Pereira; Adrielle Leal; Ândrea Carla Dalmolin; Ronaldo Lima Gomes; Bruce Schaffer; Martielly Santana Dos Santos; Junior Pastor Pérez-Molina; Marcelo Schramm Mielke. 2020. "Influence of soil characteristics on physiological and growth responses of Cytharexyllum myrianthum Cham. (Verbenaceae) to flooding." Acta Physiologiae Plantarum 42, no. 11: 1-11.

Journal article
Published: 20 October 2020 in Tree Physiology
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Laurel wilt, a lethal vascular wilt disease caused by the fungus Raffaelea lauricola, affects several tree species in the Lauraceae, including three Persea species. The susceptibility to laurel wilt of two forest tree species native to the southern USA, Persea borbonia and Persea palustris, [(Raf.) Sarg.] and avocado, Persea americana (Mill.) cv Waldin, was examined and related to tree physiology and xylem anatomy. Net CO2 assimilation (A), stomatal conductance (gs), leaf chlorophyll index (LCI), leaf chlorophyll fluorescence (Fv/Fm), xylem sap flow, theoretical stem hydraulic conductivity (Kh) and xylem vessel anatomy were assessed in trees of each species that were inoculated with R. lauricola and in control trees. Laurel wilt caused a reduction in A, gs, LCI, Fv/Fm and blockage of xylem vessels by tyloses formation that negatively impacted Kh and sap flow in all Persea species. However, disease susceptibility as indicated by canopy wilting and sapwood discoloration was less pronounced in P. americana cv Waldin than in the two forest species. Xylem vessel diameter was significantly smaller in P. borbonia and P. palustris than in P. americana cv Waldin. Differences in laurel wilt susceptibility among species appear to be influenced by physiological and anatomical tree responses.

ACS Style

RaizA Castillo-Argaez; Aime Vazquez; Joshua L Konkol; Ana I Vargas; Randy C Ploetz; Edgardo Etxeberria; Bruce Schaffer. Sap flow, xylem anatomy and photosynthetic variables of three Persea species in response to laurel wilt. Tree Physiology 2020, 41, 1004 -1018.

AMA Style

RaizA Castillo-Argaez, Aime Vazquez, Joshua L Konkol, Ana I Vargas, Randy C Ploetz, Edgardo Etxeberria, Bruce Schaffer. Sap flow, xylem anatomy and photosynthetic variables of three Persea species in response to laurel wilt. Tree Physiology. 2020; 41 (6):1004-1018.

Chicago/Turabian Style

RaizA Castillo-Argaez; Aime Vazquez; Joshua L Konkol; Ana I Vargas; Randy C Ploetz; Edgardo Etxeberria; Bruce Schaffer. 2020. "Sap flow, xylem anatomy and photosynthetic variables of three Persea species in response to laurel wilt." Tree Physiology 41, no. 6: 1004-1018.

Journal article
Published: 13 October 2020 in Agronomy
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Root hairs play an important role in phosphorus (P) nutrition of plants. To better understand the relationship between root hairs and P acquisition efficiency (PAE) in barley, experiments were conducted with the wild-type barley (cv. ’Pallas’) and its root-hairless mutant (brb). A hydroponic split-root system was used to supply P as Ca3(PO4)2 (tri-calcium phosphate, TCP) to one-half and other nutrients to the other half of the root system. Using TCP as a sole P source can simulate a soil solution with buffered low P concentration in hydroponics to induce prolific root hair growth. Root morphology, plant growth, and P uptake efficiency were measured with 50 mg L−1 TCP supplied to the roots in the split-root system and 0, 35, or 1000 μM NaH2PO4 in a non-split-root hydroponic system. The wild-type plants developed root hairs, but they did not contribute to the significant genotypic differences in the P uptake rate when a soluble P source was supplied in the non-split root system, indicating that root hair formation does not contribute to P uptake in a non-split root solution. On the other hand, when grown in a split-root system with one-half of the roots supplied with TCP, the wild-type showed 1.25-fold greater P uptake than the root hairless mutant. This study provides evidence that root hairs play an essential role in plant P uptake when P bioavailability is limited in the root zone.

ACS Style

Yucong Xie; Bala Rathinasabapathi; Bruce Schaffer; Rao Mylavarapu; Guodong Liu. Phosphorus Uptake and Growth of Wild-Type Barley and Its Root-Hairless Mutant Cultured in Buffered-and Non-Buffered-P Solutions. Agronomy 2020, 10, 1556 .

AMA Style

Yucong Xie, Bala Rathinasabapathi, Bruce Schaffer, Rao Mylavarapu, Guodong Liu. Phosphorus Uptake and Growth of Wild-Type Barley and Its Root-Hairless Mutant Cultured in Buffered-and Non-Buffered-P Solutions. Agronomy. 2020; 10 (10):1556.

Chicago/Turabian Style

Yucong Xie; Bala Rathinasabapathi; Bruce Schaffer; Rao Mylavarapu; Guodong Liu. 2020. "Phosphorus Uptake and Growth of Wild-Type Barley and Its Root-Hairless Mutant Cultured in Buffered-and Non-Buffered-P Solutions." Agronomy 10, no. 10: 1556.

Journal article
Published: 02 September 2020 in EDIS
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This is the Spanish translation of Recommendations for Control and Mitigation of Laurel Wilt and Ambrosia Beetle Vectors in Commercial Avocado Groves in Florida (HS1360). Laurel wilt and the ambrosia beetle vectors that transmit this lethal disease have and will continue to affect avocado production in Florida. At least 50% of the commercial producers are Hispanic Americans and some are more comfortable with publications in Spanish. The translator and reviewer are both previous employees of UF/IFAS. English Version: Crane, Jonathan, Daniel Carrillo, Edward Evans, Romina Gazis, Bruce Schaffer, Fredy Ballen Orozco, and Jeff Wasielewski. 2020. “Recommendations for Control and Mitigation of Laurel Wilt and Ambrosia Beetle Vectors in Commercial Avocado Groves in Florida”. EDIS 2020 (2). https://doi.org/10.32473/edis-hs1360-2020.

ACS Style

Jonathan H. Crane; Daniel Carillo; Edward A. Evans; Romina Gazis; Bruce Schaffer; Fredy Ballen; Jeff Wasielewski; Rubén Regalado. Recomendaciones para el Control y Mitigación de la Marchitez del Laurel y sus Vectores, los Escarabajos Ambrosia, en Arboledas Comerciales de Aguacate en Florida. EDIS 2020, 2020, 1 .

AMA Style

Jonathan H. Crane, Daniel Carillo, Edward A. Evans, Romina Gazis, Bruce Schaffer, Fredy Ballen, Jeff Wasielewski, Rubén Regalado. Recomendaciones para el Control y Mitigación de la Marchitez del Laurel y sus Vectores, los Escarabajos Ambrosia, en Arboledas Comerciales de Aguacate en Florida. EDIS. 2020; 2020 (5):1.

Chicago/Turabian Style

Jonathan H. Crane; Daniel Carillo; Edward A. Evans; Romina Gazis; Bruce Schaffer; Fredy Ballen; Jeff Wasielewski; Rubén Regalado. 2020. "Recomendaciones para el Control y Mitigación de la Marchitez del Laurel y sus Vectores, los Escarabajos Ambrosia, en Arboledas Comerciales de Aguacate en Florida." EDIS 2020, no. 5: 1.

Journal article
Published: 23 July 2020 in Physiologia Plantarum
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Water uptake from the soil via a vapor pathway was tested. Viburnum suspensum L. seedlings were divided into: (1) irrigated, (2) drought with vapor, and (3) drought without vapor treatments. Each plant was placed into a larger bucket containing deuterium labelled water as a vapor source (vapor treatment) or no water (drought and irrigation treatments). We also tested whether uptake via a vapor pathway could mitigate drought effects. Net CO2 assimilation (A ), transpiration (E ) and stomatal conductance (gs ) were measured daily until the first visible signs of stress. Soil water content, stem water potential (Ψ), and the stable hydrogen isotope ratio (δ2H) of soil and plant xylem water were then measured in all treatments. We show that water is taken up by plants through the vapor phase in dry soils. The δ2H values of the soil water in the vapor treatment were highly enriched compared to the background isotope ratios of the non‐vapor exposed irrigated and drought treatments. Stem water δ2H values for the vapor treatment were significantly greater than those for irrigation and drought treatments not exposed to isotopically‐enriched vapor. In this experiment, movement of water to the plant via the vapor phase did not mitigate drought effects. Net CO2 assimilation, E , plant Ψ and gs significantly decreased in the drought and vapor treatments relative to the controls, with no significant differences between vapor and drought treatments. This article is protected by copyright. All rights reserved.

ACS Style

Ana I. Vargas; Bruce Schaffer; Leonel Da Silva Lobo Sternberg. Plant water uptake from soil through a vapor pathway. Physiologia Plantarum 2020, 170, 433 -439.

AMA Style

Ana I. Vargas, Bruce Schaffer, Leonel Da Silva Lobo Sternberg. Plant water uptake from soil through a vapor pathway. Physiologia Plantarum. 2020; 170 (3):433-439.

Chicago/Turabian Style

Ana I. Vargas; Bruce Schaffer; Leonel Da Silva Lobo Sternberg. 2020. "Plant water uptake from soil through a vapor pathway." Physiologia Plantarum 170, no. 3: 433-439.

Journal article
Published: 03 December 2019 in Agronomy
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A two-year study was conducted to determine how soil texture affects calcium (Ca) absorption and partitioning in potted ‘Hass’ avocado trees. Trees were planted in 200 L pots in one of four soil types: clay (C), clay loam (CL), sandy loam (SL) or sand (S). Prior to planting, Ca content in each soil was in the normal range of availability, although the Ca concentration was highest in C soil. After two years of tree development, dry weights of shoots and roots were significantly higher in the SL and S soils than in C soil. Trees in the C soil had higher wood dry weight than trees in SL or S soils. The Ca contents (absolute quantities, not concentrations) in the roots, shoots and whole tree were significantly lower in the C soil than in the SL or S soils. The K/Ca ratio of trees in the C soil (K/Ca = 1.5) was significantly higher than that in the other soil types. Stem water potential was significantly lower for trees in the C soil compared to the other soils. These results indicate that Ca absorption and partitioning in young avocado trees varies with soil texture, probably associated with soil effects on root growth and/or plant water status.

ACS Style

Claudia Bonomelli; Pilar M. Gil; Bruce Schaffer. Effect of Soil Type on Calcium Absorption and Partitioning in Young Avocado (Persea americana Mill.) Trees. Agronomy 2019, 9, 837 .

AMA Style

Claudia Bonomelli, Pilar M. Gil, Bruce Schaffer. Effect of Soil Type on Calcium Absorption and Partitioning in Young Avocado (Persea americana Mill.) Trees. Agronomy. 2019; 9 (12):837.

Chicago/Turabian Style

Claudia Bonomelli; Pilar M. Gil; Bruce Schaffer. 2019. "Effect of Soil Type on Calcium Absorption and Partitioning in Young Avocado (Persea americana Mill.) Trees." Agronomy 9, no. 12: 837.

Journal article
Published: 11 November 2019 in Environmental and Experimental Botany
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Symptoms of laurel wilt, a vascular plant disease caused by the fungus Raffaelea lauricola, are similar to those of drought stress. We compared physiological responses of redbay and avocado trees infected with laurel wilt to responses of trees with drought stress. Trees were either inoculated with R. lauricola, subjected to drought stress, or irrigated daily and not inoculated (non-stressed, control). Disease symptoms, net CO2 assimilation (A), stomatal conductance of water vapor (gs), substomatal CO2 concentration (Ci), intrinsic water use efficiency (WUEi), leaf chlorophyll index (LCI), the ratio variable to maximum leaf chlorophyll fluorescence (Fv/Fm), leaf nitrogen (N) concentration, and the ratio of 13C to 12C (δ13C) in leaves were determined prior to inoculation and the imposition of drought stress and when plants showed moderate to severe stress symptoms. Laurel wilt-infected and drought-stressed trees of each species had lower A and gs and higher Ci, Fv/Fm, and LCI than non-stressed trees. Redbay trees with laurel wilt had significantly higher (less negative) leaf δ13C values than non-stressed trees, whereas no significant differences were found in leaf δ13C values among avocado treatments. In avocado trees with laurel wilt, there was a negative linear correlation between δ13C values and Ci but no significant correlation between δ13C values and leaf N in the inoculated trees. Inhibition of photosynthesis in avocado and redbay infected with laurel wilt was determined to be a result of the both stomatal and biochemical factors.

ACS Style

RaizA Castillo-Argaez; Bruce Schaffer; Aime Vazquez; Leonel D.S.L. Sternberg. Leaf gas exchange and stable carbon isotope composition of redbay and avocado trees in response to laurel wilt or drought stress. Environmental and Experimental Botany 2019, 171, 103948 .

AMA Style

RaizA Castillo-Argaez, Bruce Schaffer, Aime Vazquez, Leonel D.S.L. Sternberg. Leaf gas exchange and stable carbon isotope composition of redbay and avocado trees in response to laurel wilt or drought stress. Environmental and Experimental Botany. 2019; 171 ():103948.

Chicago/Turabian Style

RaizA Castillo-Argaez; Bruce Schaffer; Aime Vazquez; Leonel D.S.L. Sternberg. 2019. "Leaf gas exchange and stable carbon isotope composition of redbay and avocado trees in response to laurel wilt or drought stress." Environmental and Experimental Botany 171, no. : 103948.

Review
Published: 29 August 2019 in Plant Science
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Optimizing plant physiological function is essential to maintaining crop yields under water scarcity and in developing more water-efficient production practices. However, the most common strategies in addressing water conservation in agricultural production have focused on water-efficient technologies aimed at managing water application or on improving crop water-use efficiency through breeding. Few management strategies explicitly consider the management or manipulation of plant physiological processes, but one which does is termed primed acclimation (PA). The PA strategy uses the physiological processes involved in priming to pre-acclimate plants to water deficits while reducing irrigation. It has been shown to evoke multi-mechanistic responses across numerous crop species. A combination of existing literature and emerging studies find that mechanisms for pre-acclimating plants to water deficit stress include changes in root:shoot partitioning, root architecture, water use, photosynthetic characteristics, osmotic adjustment and anti-oxidant production. In many cases, PA reduces agricultural water use by improving plant access to existing soil water. Implementing PA in seasonally water-limited environments can mitigate yield losses to drought. Genotypic variation in PA responses offers the potential to screen for crop varieties with the greatest potential for beneficial priming responses and to identify specific priming and acclimation mechanisms. In this review we: 1) summarize the concept of priming within the context of plant stress physiology; 2) review the development of a PA management system that utilizes priming for water conservation in agroecosystems; and 3) address the future of PA, how it should be evaluated across crop species, and its utility in managing crop stress tolerance.

ACS Style

Christopher Vincent; Diane Rowland; Bruce Schaffer; Elias Bassil; Kelly Racette; Brendan Zurweller. Primed acclimation: A physiological process offers a strategy for more resilient and irrigation-efficient crop production. Plant Science 2019, 295, 110240 .

AMA Style

Christopher Vincent, Diane Rowland, Bruce Schaffer, Elias Bassil, Kelly Racette, Brendan Zurweller. Primed acclimation: A physiological process offers a strategy for more resilient and irrigation-efficient crop production. Plant Science. 2019; 295 ():110240.

Chicago/Turabian Style

Christopher Vincent; Diane Rowland; Bruce Schaffer; Elias Bassil; Kelly Racette; Brendan Zurweller. 2019. "Primed acclimation: A physiological process offers a strategy for more resilient and irrigation-efficient crop production." Plant Science 295, no. : 110240.

Journal article
Published: 13 August 2019 in Crop Protection
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Melon thrips, Thrips palmi Karny (Thysanoptera: Thripidae), is a significant pest of vegetable crops and ornamental plants due to feeding and oviposition injury to vegetative and reproductive tissues. As an integrated approach, we evaluated the efficacy of a phytoseiid mite, Amblyseius swirskii Athias-Henriot, and different colored and UV-reflective plastic mulches for managing T. palmi in snap bean (Phaseolus vulgaris L.), cucumber (Cucumis sativus L.), yellow squash (Cucurbita pepo L.), eggplant (Solanum melongena L.), Jalapeño pepper (Capsicum annuum L.), and tomato (Solanum lycopersicum L.). The five mulch treatments evaluated were: “Shine N′ Ripe” (Metalized top and black bottom), “Can-Shine” (Metalized top and white bottom), “Black” plastic black-on-black (Can-Grow-XSB), black-on-white (Can-Grow XSB), “White” plastic; white-on-black (Can-Grow XSB), and bare soil with no mulch. The number of T. palmi adults and larvae in leaf samples collected from the middle third (stratum) of plants in each treatment was determined. In 2015 at 49 days after planting (DAP), curative release of 40–50 A. swirskii per plant did not suppress T. palmi effectively when the thrips population was high. There were no significant interactions between A. swirskii and crop or A. swirskii and mulch type on the number of T. palmi. However, in 2016 at 15 DAP, preventive release of A. swirskii, reduced the number of T. palmi in each of the mulch and crop treatments. Metalized mulch reduced the number of T. palmi early in the season when plants’ canopy did not shade the mulched area. These results suggest that use of metalized reflective mulch and A. swirskii, each have the potential to manage T. palmi at low population densities.

ACS Style

Mohammad A. Razzak; Dakshina R. Seal; Philip A. Stansly; Bruce Schaffer; Oscar E. Liburd. A predatory mite, Amblyseius swirskii, and plastic mulch for managing melon thrips, Thrips palmi, in vegetable crops. Crop Protection 2019, 126, 104916 .

AMA Style

Mohammad A. Razzak, Dakshina R. Seal, Philip A. Stansly, Bruce Schaffer, Oscar E. Liburd. A predatory mite, Amblyseius swirskii, and plastic mulch for managing melon thrips, Thrips palmi, in vegetable crops. Crop Protection. 2019; 126 ():104916.

Chicago/Turabian Style

Mohammad A. Razzak; Dakshina R. Seal; Philip A. Stansly; Bruce Schaffer; Oscar E. Liburd. 2019. "A predatory mite, Amblyseius swirskii, and plastic mulch for managing melon thrips, Thrips palmi, in vegetable crops." Crop Protection 126, no. : 104916.

Journal article
Published: 11 June 2019 in Forest Science
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Carpotroche brasiliensis is a native tree of the Brazilian Atlantic Forest with potential economic value for cultivation in agroforestry systems. We conducted an experiment to determine the photosynthetic and survival responses of young C. brasiliensis plants to electrochemical changes in flooded soils as an indication of their flood tolerance and potential for cultivation in flood-prone areas. Soil flooding decreases the reduction–oxidation potential (redox) potential (Eh), pH, and electrical conductivity (Ec) of the soil, with subsequent recovery of the pH and Ec. Decreases in Eh negatively affect net photosynthesis (A). In flooded soil, decreased A was associated with decreased stomatal conductance (gs) and after 21 days was also associated with decreases in the instantaneous carboxylation efficiency (A/Ci) and potential quantum yield of photosystem II (Fv/Fm). Although flooded C. brasiliensis seedlings developed morphological structures known to increase flood tolerance, this was not enough to prevent severe signs of flooding stress. After 21 days of flooding, flooded plants were unflooded, and 17 days after plants were removed from flood, 90 percent of the unflooded plants died. Our results demonstrate that young plants of C. brasiliensis are suitable for planting in agroforestry systems only in areas with well-drained soils.

ACS Style

Laize Queiroz-Alves; Adrielle Leal; Ândrea Carla Dalmolin; Bruce Schaffer; Marcelo Schramm Mielke. Photosynthesis and Survival of Young Carpotroche brasiliensis Endl. (Achariaceae) Plants Subjected to Flooding. Forest Science 2019, 65, 670 -674.

AMA Style

Laize Queiroz-Alves, Adrielle Leal, Ândrea Carla Dalmolin, Bruce Schaffer, Marcelo Schramm Mielke. Photosynthesis and Survival of Young Carpotroche brasiliensis Endl. (Achariaceae) Plants Subjected to Flooding. Forest Science. 2019; 65 (6):670-674.

Chicago/Turabian Style

Laize Queiroz-Alves; Adrielle Leal; Ândrea Carla Dalmolin; Bruce Schaffer; Marcelo Schramm Mielke. 2019. "Photosynthesis and Survival of Young Carpotroche brasiliensis Endl. (Achariaceae) Plants Subjected to Flooding." Forest Science 65, no. 6: 670-674.

Journal article
Published: 25 April 2019 in Agricultural Water Management
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Shallow aquifers significantly impact crop growth as saturated soil conditions may occur. Canals are widely constructed in such areas to mitigate groundwater saturation or flooding. We applied a simulation model to estimate the occurrence of root zone saturation [root zone saturation index (RZSI)] for agricultural crops and to identify factors that influence root zone saturation in a shallow coastal aquifer and canal system. Results indicated that groundwater modeling combined with multiple linear regression can relate the influencing factors and root zone saturation durations in low lying farmland adjacent to canal systems. In our study, most areas had a low RZSI, but areas towards the northwest and southeast where the land surface elevation is generally low were predicted to have a greater RZSI. In general, positive correlations were found between the root zone saturation durations and rainfall amount, antecedent groundwater table elevation and average canal stages in areas where the higher RZSIs were predicted. Rainfall amount played a more important role than antecedent groundwater table elevation and canal stage in determining the root zone saturation during the wet season, while antecedent groundwater table elevation and canal stage played a more important role than rainfall amount during dry season. Correlations between the predicted root zone saturation duration and land surface elevation were negative and stronger during the wet season than the dry season, and the correlations were stronger in the deep (0–61 cm) root zone than with the shallow (0–18 cm) root zone. In area where the land surface elevation is relatively high, the root zone saturation duration was not influenced by rainfall amount, antecedent groundwater table elevation or canal stage, at least under the current management practices and climate conditions.

ACS Style

Meijing Zhang; Kati W. Migliaccio; Young Gu Her; Bruce Schaffer. A simulation model for estimating root zone saturation indices of agricultural crops in a shallow aquifer and canal system. Agricultural Water Management 2019, 220, 36 -49.

AMA Style

Meijing Zhang, Kati W. Migliaccio, Young Gu Her, Bruce Schaffer. A simulation model for estimating root zone saturation indices of agricultural crops in a shallow aquifer and canal system. Agricultural Water Management. 2019; 220 ():36-49.

Chicago/Turabian Style

Meijing Zhang; Kati W. Migliaccio; Young Gu Her; Bruce Schaffer. 2019. "A simulation model for estimating root zone saturation indices of agricultural crops in a shallow aquifer and canal system." Agricultural Water Management 220, no. : 36-49.

Journal article
Published: 20 March 2019 in Australian Journal of Crop Science
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Papaya (Carica papaya L.) is one of the main horticultural crops of many tropical and subtropical regions. The fruit is sold either as a fresh product or processed into drinks, jams, candies, dried and crystallized fruit, while the enzyme papain is used for medicinal purposes. Papaya fruits have high vitamins A and C contents, as well as are good sources of calcium. Brazil is one of the most important producers and exporters of papaya in the world; in 2016 c.a., 1,424,650 tons of papaya was produced in 30,372 hectares of the territory. Optimum light absorption and utilization by the canopy are important factors for maximizing papaya crop growth and productivity. Thus, knowing how papaya responds to light is important to develop management strategies to optimize fruit yield and quality. This short review aims to present the current research knowledge related to the effects of light intensity on the photosynthetic processes and growth of papaya. We demonstrate that photosynthetically active radiation (PAR) greatly affects the physiology of papaya. Understanding the interaction between light and physiological processes is extremely important for a sustainable profitable production under either greenhouse or field conditions. By using improved light science-based management, growers may optimize photosynthetic carbon assimilation and increase papaya yield and fruit quality

ACS Style

Jefferson R. Silva; Weverton Rodrigues; Katherine Fraga Ruas; Jessica Sousa Paixão; Roberta Samara Nunes De Lima; José Altino Machado Filho; Juan Alberto Cabrera Garcia; Bruce Schaffer; Julian Cuevas Gonzalez; Eliemar Campostrini. Light, photosynthetic capacity and growth of papaya (Carica papaya L.): a short review. Australian Journal of Crop Science 2019, 13, 480 -485.

AMA Style

Jefferson R. Silva, Weverton Rodrigues, Katherine Fraga Ruas, Jessica Sousa Paixão, Roberta Samara Nunes De Lima, José Altino Machado Filho, Juan Alberto Cabrera Garcia, Bruce Schaffer, Julian Cuevas Gonzalez, Eliemar Campostrini. Light, photosynthetic capacity and growth of papaya (Carica papaya L.): a short review. Australian Journal of Crop Science. 2019; 13 ((03) 2019):480-485.

Chicago/Turabian Style

Jefferson R. Silva; Weverton Rodrigues; Katherine Fraga Ruas; Jessica Sousa Paixão; Roberta Samara Nunes De Lima; José Altino Machado Filho; Juan Alberto Cabrera Garcia; Bruce Schaffer; Julian Cuevas Gonzalez; Eliemar Campostrini. 2019. "Light, photosynthetic capacity and growth of papaya (Carica papaya L.): a short review." Australian Journal of Crop Science 13, no. (03) 2019: 480-485.

Evaluation study
Published: 09 March 2019 in Environmental Entomology
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Melon thrips, Thrips palmi Karny (Thysanoptera: Thripidae), is a serious pest of vegetable, ornamental, and fruit crops. As a potential component of an integrated pest management (IPM) program, different plastic mulches including white-on-black, black-on-white, black-on-black, two metalized ultraviolet (UV)-reflective mulches, and a no mulch control were evaluated for managing T. palmi on six field-grown vegetable crops (eggplant, cucumber, squash, snap bean, Jalapeno pepper, and tomato) during the Fall of 2015 and 2016. Metalized reflective mulch significantly reduced the number of T. palmi in all vegetable crops compared with the other treatments. The highest numbers of T. palmi were observed on the white-on-black mulch and control treatments. The numbers of adults and larvae were highest on eggplant followed by cucumber, snap bean, squash, and Jalapeno pepper. The lowest numbers of T. palmi were observed on tomato plants. This study indicated that growing vegetable crops on metalized mulch is an effective method of reducing T. palmi populations in vegetable crops and should be considered in IPM programs for this insect species.

ACS Style

Mohammad A Razzak; Dakshina R Seal; Philip A Stansly; Oscar E Liburd; Bruce Schaffer. Host Preference and Plastic Mulches for Managing Melon Thrips (Thysanoptera: Thripidae) on Field-Grown Vegetable Crops. Environmental Entomology 2019, 48, 434 -443.

AMA Style

Mohammad A Razzak, Dakshina R Seal, Philip A Stansly, Oscar E Liburd, Bruce Schaffer. Host Preference and Plastic Mulches for Managing Melon Thrips (Thysanoptera: Thripidae) on Field-Grown Vegetable Crops. Environmental Entomology. 2019; 48 (2):434-443.

Chicago/Turabian Style

Mohammad A Razzak; Dakshina R Seal; Philip A Stansly; Oscar E Liburd; Bruce Schaffer. 2019. "Host Preference and Plastic Mulches for Managing Melon Thrips (Thysanoptera: Thripidae) on Field-Grown Vegetable Crops." Environmental Entomology 48, no. 2: 434-443.

Articles
Published: 12 October 2018 in Communications in Soil Science and Plant Analysis
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The effects of plant age at the time of mowing on sunn hemp (Crotalaria juncea L.) tissue decomposition, nitrogen (N) release, and fiber content in Krome very gravelly loam were assessed. Combined leaf and stem tissue from 42-, 77- or 112-day-old sunn hemp plants was placed in mesh bags and buried below the soil surface in the field. Bags were removed bi-weekly and dry weights, N concentration, acid detergent fiber (ADF) and neutral detergent fiber (NDF) concentrations in buried sunn hemp tissues were determined. There was a rapid decrease plant tissue dry weight during the first 14 days after tissue was buried, followed by a slow gradual decrease. The amount N per hectare was much lower for 42-day-old than 112-day-old sunn hemp. Tissue of the youngest plants decomposed the quickest. Forty two-day-old tissue had a higher N concentration, N mineralization rate, and lower NDF and ADF than 77- or 112-day-old tissue. Mowing and soil incorporation of a 42-day-old instead of a 77- to 112-day-old sunn hemp cover crop prior to planting a cash crop can be beneficial for a fast-growing cash crop planted soon after soil incorporation of the cover crop.

ACS Style

A. Baitsaid; Bruce Schaffer; A.I. Vargas; Y. Li; G. Liu. Effect of plant age on in-soil decomposition and nitrogen content of sunn hemp tissue. Communications in Soil Science and Plant Analysis 2018, 49, 2680 -2688.

AMA Style

A. Baitsaid, Bruce Schaffer, A.I. Vargas, Y. Li, G. Liu. Effect of plant age on in-soil decomposition and nitrogen content of sunn hemp tissue. Communications in Soil Science and Plant Analysis. 2018; 49 (21):2680-2688.

Chicago/Turabian Style

A. Baitsaid; Bruce Schaffer; A.I. Vargas; Y. Li; G. Liu. 2018. "Effect of plant age on in-soil decomposition and nitrogen content of sunn hemp tissue." Communications in Soil Science and Plant Analysis 49, no. 21: 2680-2688.

Journal article
Published: 31 August 2018 in Environmental and Experimental Botany
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The mechanisms for tolerance of various abiotic stresses in plants are often considered to be similar, but there are also specific traits responsible for acclimation that differ according to the type and extent of stress. Water-deficit priming is the imposition of a period of moderate drought stress to induce tolerance to a subsequent stress. We hypothesized that priming improves papaya (Carica papaya L.) response to high light intensity. We tested the effects of water-deficit priming on photoinhibition upon shade removal. We assessed morphological and physiological variables associated with priming responses. Priming reduced the intensity and duration of photoinhibition upon shade removal and increased mean leaf area compared to non-primed plants. Photochemical responses to priming included reduced absorption and increased efficiencies of electron transfer from plastoquinone through photosystem I. Photosynthetic responses included upregulation of Rubisco and Ribulose 1,5-bisphosphate regeneration. Morphological responses included increased stomatal density and size. Anti-oxidant capacity was not affected by priming or prior shade treatment. We conclude that water-deficit priming improves papaya response to high light by different physiological mechanisms than shade-to-light acclimation itself. Rather than anti-oxidant upregulation, priming reduces energetic bottlenecks, thereby reducing oxidative stress during shade-to-high-light transitions.

ACS Style

Christopher Vincent; Bruce Schaffer; Diane Rowland. Water-deficit priming of papaya reduces high-light stress through oxidation avoidance rather than anti-oxidant activity. Environmental and Experimental Botany 2018, 156, 106 -119.

AMA Style

Christopher Vincent, Bruce Schaffer, Diane Rowland. Water-deficit priming of papaya reduces high-light stress through oxidation avoidance rather than anti-oxidant activity. Environmental and Experimental Botany. 2018; 156 ():106-119.

Chicago/Turabian Style

Christopher Vincent; Bruce Schaffer; Diane Rowland. 2018. "Water-deficit priming of papaya reduces high-light stress through oxidation avoidance rather than anti-oxidant activity." Environmental and Experimental Botany 156, no. : 106-119.

Short communication
Published: 22 June 2018 in Scientia Horticulturae
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The effects of irrigation water savings by partial root zone drying (PRD) irrigation, shading or mulching on physiology, growth, yield, and wine quality of ‘Syrah’ grapevine (Vitis vinifera L.) was investigated. The study was conducted in a vineyard at two different sites, each with a different soil type and vegetation index. Plants were subjected to the following four treatments: T0) control, with conventional irrigation regimes used by local growers; T1) shade cloth covering the vine canopy resulting in a 50% reduction in irrigation volume compared to the control; T2) double color plastic mulch (white color facing up and black on the inside facing the soil) resulting in a 50% reduction in irrigation volume compared to the control; and T3) PRD irrigation resulting in a 50% reduction in irrigation volume compared to the control. In general, the use of PRD irrigation, shade cloth or plastic mulch did not significantly affect the physiological, growth or yield variables measured, except for fruit cluster weight, which was lower in T3 than in the other treatments, and wine alcohol and polyphenol content, which were higher in T3 than in the other treatments. Shade cloth and plastic mulch treatments resulted in a 50% reduction in water use with no detrimental effects on plant physiology, yield, or wine quality. In addition to a 50% reduction in the amount of irrigation water applied, PRD irrigation also improved wine quality by increasing alcohol and polyphenol contents.

ACS Style

P.M. Gil; P. Lobos; K. Durán; J. Olguín; D. Cea; Bruce Schaffer. Partial root-zone drying irrigation, shading, or mulching effects on water savings, productivity and quality of ‘Syrah’ grapevines. Scientia Horticulturae 2018, 240, 478 -483.

AMA Style

P.M. Gil, P. Lobos, K. Durán, J. Olguín, D. Cea, Bruce Schaffer. Partial root-zone drying irrigation, shading, or mulching effects on water savings, productivity and quality of ‘Syrah’ grapevines. Scientia Horticulturae. 2018; 240 ():478-483.

Chicago/Turabian Style

P.M. Gil; P. Lobos; K. Durán; J. Olguín; D. Cea; Bruce Schaffer. 2018. "Partial root-zone drying irrigation, shading, or mulching effects on water savings, productivity and quality of ‘Syrah’ grapevines." Scientia Horticulturae 240, no. : 478-483.

Book chapter
Published: 01 January 2018 in Water Scarcity and Sustainable Agriculture in Semiarid Environment
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Crop growth and yield, as well as crop quality, are expected to be affected by global climate change. Therefore, a high degree of uncertainty remains regarding food production and security under future climate scenarios, which, in addition to global warming, will include altered pest and disease incidences, as well as changes in the magnitude and (seasonal and yearly) distribution of rainfall, leading to increased flooding and drought incidences worldwide. Water scarcity has a tremendous potential to be harmful for papaya producers given the high water requirements of this crop. Depending on its duration and intensity, water scarcity might lead to situations of water deficit, which in turn affects key physiological processes such as stomatal conductance and photosynthesis. Knowing how papaya (Carica papaya L.) responds to environmental factors (water, light, and temperature) is important for developing management strategies to optimize fruit yield and quality. The objective of this chapter is to present current research knowledge related to the effects of water, light, and temperature and their interactions with the photosynthetic process and whole-plant physiology of papaya. We demonstrate that environmental factors studied profoundly affect the productivity and physiology of papaya. In the papaya, damage to photosynthetic carbon assimilation due to environmental stress, including water deficits, can reduce biomass production, and net carbon assimilation, which can influence growth, fruit yield, and fruit quality. Therefore, as drought conditions are expected to become more frequent worldwide due to climate change, understanding the effects of water deficits on papaya physiology, especially the photosynthetic processes, will be critical to maintaining productivity of this crop under water-limiting conditions. With improved, science-based management, growers will optimize photosynthetic carbon assimilation and increase papaya fruit productivity and quality.

ACS Style

Eliemar Campostrini; Bruce Schaffer; José D.C. Ramalho; Julián C. González; Weverton Rodrigues; Jefferson Rangel da Silva; Roberta S.N. Lima. Environmental Factors Controlling Carbon Assimilation, Growth, and Yield of Papaya ( Carica papaya L.) Under Water-Scarcity Scenarios. Water Scarcity and Sustainable Agriculture in Semiarid Environment 2018, 481 -505.

AMA Style

Eliemar Campostrini, Bruce Schaffer, José D.C. Ramalho, Julián C. González, Weverton Rodrigues, Jefferson Rangel da Silva, Roberta S.N. Lima. Environmental Factors Controlling Carbon Assimilation, Growth, and Yield of Papaya ( Carica papaya L.) Under Water-Scarcity Scenarios. Water Scarcity and Sustainable Agriculture in Semiarid Environment. 2018; ():481-505.

Chicago/Turabian Style

Eliemar Campostrini; Bruce Schaffer; José D.C. Ramalho; Julián C. González; Weverton Rodrigues; Jefferson Rangel da Silva; Roberta S.N. Lima. 2018. "Environmental Factors Controlling Carbon Assimilation, Growth, and Yield of Papaya ( Carica papaya L.) Under Water-Scarcity Scenarios." Water Scarcity and Sustainable Agriculture in Semiarid Environment , no. : 481-505.