Available online 29 March 2023
In Press, Journal Pre-proofWhat’s this?
Author links open overlay panel, , , , , ,
Water availability is a concern for agricultural production and sustainability, escalating the need for an efficient weed control. Weeds are in direct competition with crops for water and its unsuccessful control risks water management across the crop season. However, little is known regarding the impact of herbicide on weed water use behavior. Thus, the objective of this study was to unveil the effect of glyphosate doses on Merremia aegyptia (L.) Urb. water transpiration, water use efficiency (WUE), and intrinsic water use efficiency (iWUE). Two greenhouse studies were conducted using the troublesome weed hairy woodrose (M. aegyptia) in four glyphosate doses (1.4; 15; 111; and 740 g a.e. ha−1) plus an untreated control. Water transpiration was measured in a 3-day-interval until 21 days after treatment (DAT), determining WUE based on its dry biomass and water use. iWUE was determined at 21 DAT through IRGA analysis. Glyphosate label dose (740 g a.e. ha−1) effectively reduced water transpiration 3 DAT and ceased whole water transpiration by 12 DAT. Lower doses (111 and 15 g a.e. ha−1) reduced 39 and 20% of water transpiration, in comparison to the untreated control, and increased its iWUE. Therefore, label dose application of glyphosate successfully controlled hairy woodrose and ceased its water transpiration.
Weeds are the greatest biotic restraint for crop production (Chauhan, 2020), competing directly with crops for nutrients, water, space, and light (Patterson, 1995). Considering climate changes and water scarcity, water availability has become a great concern among growers to maintain high yields and quality production (Cai et al., 2015). Brazilian agriculture fields are widely spread throughout the country, which comprehends different environments and weather conditions. Among these environments, water availability as well as best practices in water management are a common concern, which also involves good practices in weed management, considered one of the key points for water sustainability (Ziska, 2020).
Most weed species have high photosynthetic activity due to a survival characteristic, consequently requiring great amount of water in a short period of time (Aguiar et al., 2016). Therefore, an efficient weed control is necessary to maintain yield quality and to avoid water losses due to weed competition. For instance, a plant from the genus Ipomoea, considered a troublesome weed throughout agriculture fields in Brazil, has shown the potential to use as much water as the crop itself during its development growth (Araldi et al., 2012). Hairy woodrose [Merremia aegyptia (L.) Urb] is an annual climbing herb, well adapted to Brazilian weather conditions, and is neutral photoblastic, showing a very adaptive growth within the no-tillage systems, being reported within maize, soybeans, and sugarcane crops (Araldi et al., 2012; Martins et al., 2010). This weed is more problematic after canopy closure, with potential to reduce sugarcane yield in 60% as well as interfere the mechanized harvesting process (Beluci et al., 2018).
Hairy woodrose is commonly managed by glyphosate spraying, especially considering that great part of maize and soybean used are glyphosate-resistant crops. Glyphosate inhibits the synthesis of aromatic amino acids and secondary compounds derived from these amino acids by acting at the enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) (Duke, 1988). Thereby, glyphosate will affect plant photosynthesis and can reduce plant transpiration by stomatal closure (Shaner, 1978). However, there is a lack of studies on the effect of glyphosate on weeds water use as well as regarding how it affects plant's water use efficiency over time of application.
Herbicides may drastically affect plant transpiration as it acts into the plant, ceasing its photosynthetic activity (Araldi et al., 2011). However, in the cases which herbicide does not control the weed, such as in herbicide resistance or insufficient amount of the active ingredient, the herbicide can still affect plant water use (Garlon et al., 2010). One of the ways to evaluate plants water use is by determining its water use efficiency (WUE): determining the ratio of plant yield or plant biomass to the amount of water used (i.e., plant transpiration) (Mega et al., 2019). Another way of assessing plant WUE is performed by determining the ratio of the fluxes of net photosynthesis, through CO2 assimilation, and conductance for water vapor, known as intrinsic water use efficiency (iWUE), usually performed with infrared gas analyzers (IRGA) (McAusland et al., 2013; Li et al., 2017).
A better understanding of the effect of herbicides on water use over the time of application is still required, exploring its impact on the whole agricultural system sustainability and supporting growers on key management decisions. The hypothesis is that glyphosate affects plant water transpiration soon after application and before any symptoms are shown as well as those lower doses, although it does not control the weed, it will affect water transpiration. Therefore, considering the importance of crop water use as well as to determine the effect of glyphosate on hairy woodrose water transpiration, the objective of this study was to determine the effect of glyphosate doses on M. aegyptia water transpiration, its water use efficiency and intrinsic water use efficiency.
Materials and methods
Two greenhouse studies were conducted to evaluate the effect of glyphosate doses on M. aegyptia water transpiration and its water use efficiency in September/2020 and January/2021, located at Sao Paulo State University, Botucatu-Sao Paulo (22o50′32″S, 48o25′29″W). The greenhouse was kept at 25 ± 3 °C under natural light conditions during the whole conduction of the studies.
The effects of glyphosate doses on hairy woodrose water transpiration and WUE was performed by adapting two
Glyphosate label dose (740 g a.e. ha−1) resulted in satisfactory M. aegyptia control at 21 DAT (Fig. 2), causing over 90% of plant injury. Moreover, at this evaluation date, glyphosate application at 111 g a.e. ha−1 and 15 g a.e. ha−1 resulted in 39% and 20% of injury, respectively (Fig. 3). Plants treated with 740 g a.e. ha−1 of glyphosate presented a reduction in water use 3 DAT, consuming 25% less water in comparison to the untreated control, whereas the treatment of 111 g a.e. ha−1 resulted
This study investigated the effect of glyphosate doses on hairy woodrose water use. Crop-weed competition will affect not only crop yield, but scarce primary resources, such as water. As the profitability of a farm is accounted for its net balance of costs and benefits, water-related costs are one of the main concerns in many agricultural scenarios (Singh et al., 2021). Plant water transpiration increases as plants develops and grows in size, making it necessary to rapidly control the weeds to
Glyphosate at label dose effectively reduced hairy woodrose water use 3 days after treatments and ceased its water use 12 days after treatment. These results highlight the importance of an efficient weed control in order to avoid losses and reducing costs with water management. The glyphosate doses tested did not affect WUE. In addition, glyphosate at 111g a.e. ha−1 increased plant's carbon assimilation (A) and increased iWUE. Further studies are needed to understand the effect of herbicides on
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001 and CNPQ (Project code: 140170/2020–0). We thank Bryan Dias, Gustavo Gamboa, and Gabriel Moretti for their assistant in the project.
- L.H.S. Zobiole et al.
Water use efficiency and photosynthesis of glyphosate-resistant soybean as affected by glyphosate
Pestic. Biochem. Physiol.
- J.C. Clifton-Brown et al.
Water use efficiency and biomass partitioning of three different Miscanthus genotypes with limited and unlimited water supply
- L.M. Aguiar et al.
Herbicide tolerance and water use efficiency in forest species used in degraded areas recovery programs
- L.H. Allen et al.
Carbon dioxide and temperature effects on evapotranspiration and water use efficiency of soybean
- R. Araldi et al.
Photosynthetic efficiency and water consumption of Ipomoea triloba after herbicide application
- R. Araldi et al.
Relationship between water consumption and herbicide absorption in weeds and sugarcane
- L.R. Beluci et al.
One-eye-set sugarcane susceptibility to weed interference
An Acad. Bras Ciências
- X. Cai et al.
Impacts of climate change on agricultural water management: a review
Wiley Interdiscip. Rev.: Water
- B.S. Chauhan
Grand challenges in weed management
- S.O. Duke
Alteration of plant physiology by glyphosate and its by-product aminomethylphosphonic acid: an overview
J. Exp. Bot.
Sacral Nerve Stimulation Alleviates Intestinal Inflammation Through Regulating the Autophagy of Macrophages and Activating the Inflammasome Mediated by a Cholinergic Antiinflammatory Pathway in Colitis Rats
Neuromodulation: Technology at the Neural Interface, 2023
Inflammatory bowel disease (IBD) is characterized by chronic progressive intestinal inflammation. Sacral nerve stimulation (SNS) ameliorates colon inflammation caused by IBD. The aim of this study was to investigate the antiinflammatory benefits of SNS in colitis rats and explore the roles of the cholinergic antiinflammatory pathway, macrophage autophagy, and nucleotide oligomerization domain-like receptor thermal protein domain associated protein 3 (NLRP3) inflammatory bodies.
Rats were divided into four groups: healthy control, dextran sulfate sodium (DSS), DSS+ sham-SNS, and DSS+ SNS groups. An electrode was surgically placed in the right sacral nerve (S3) for stimulation. The disease activity index (DAI) score was recorded each day, and the degree of inflammatory injury was evaluated using hematoxylin and eosin staining. The alpha7 nicotinic acetylcholine receptor (α7nAChR) and autophagy- and NLRP3-related factors were assessed using immunofluorescence staining and Western blotting.
The DSS group showed a higher DAI score, colon shortening, upregulated proinflammatory action, and colon damage, and the DSS+ SNS group showed significantly improved symptoms. The number of α7nAChR+ cells and the expression level of autophagy decreased in the DSS group but increased in the DSS+ SNS group. Conversely, the DSS group showed increased activation of NLRP3 inflammatory bodies, whereas the DSS+ SNS group showed decreased activation of NLRP3 inflammatory bodies.
In this study, SNS ameliorated colon inflammation by enhancing macrophage autophagy and inhibiting the activation of NLRP3 inflammatory bodies, which may be related to the opening of the cholinergic antiinflammatory pathway.
Development of a new PCR assay and a recombinase-aided amplification based isothermal amplification coupled with lateral flow dipstick assay for potato late blight detection
Crop Protection, Volume 168, 2023, Article 106235
Late blight caused by Phytophthora infestans is the most devastating potato disease, yet leaf infections are not reliably detected by current assays during the incubation phase of the pathogen and asymptomatic plants. In this study, the genome of P. infestans was queried against the NCBI nucleic acid database and a 1050 bp species-specific DNA fragment was identified. Using this fragment, polymerase chain reaction (PCR) and recombinase-aided amplification-lateral flow dipstick (RAA-LFD) assays were developed for the detection of potato late blight pathogen. Both assays effectively distinguished P. infestans from related species (e.g., P. capsici). The detection limits of the three PCR primer pairs under optimized conditions (59.3°C, 35 PCR cycles) were 1.31×10−1fg, 1.18×10−2fg, and 1.24×10−1fg, corresponding to 27.31 copies, 2.49 copies, and 25.51 copies, respectively. While the detection limit of the RAA-LFD assay at 37°C for 25min was 5×10−4fg (0.10 copies), which was better than all reported molecular detection assays for potato late blight. Both PCR (59.3°C, 35 PCR cycles) and RAA-LFD (37°C for 10min) positively detected all symptomatic leaves. When extending the amplification time to 20min, the RAA-LFD assay detected most of the leaves with incubation phase of the disease. The molecular detection assays developed in this study were species-specific and are expected to be used in detecting potato late blight in the incubation phase in leaves and asymptomatic plants, which will aid in accurate monitoring and early warning of potato late blight.
Drivers of survival in a small mammal of conservation concern: An assessment using extensive genetic non-invasive sampling in fragmented farmland
Biological Conservation, Volume 230, 2019, pp. 131-140
Although important to guide conservation management, detailed demographic studies on rare or elusive species inhabiting fragmented, human-dominated landscapes are often hampered by the species' low densities, and the logistic and ethical constraints in obtaining reliable information covering large areas. Genetic non-invasive sampling (gNIS) provides cost-effective access to demographic information, though its application to small mammals is still scarce. We used gNIS to infer on the demography of an endemic small mammal, the Cabrera vole (Microtus cabrerae), occurring as a spatially-structured population in a 462-ha Mediterranean farmland landscape. We intensively sampled fresh vole feces in four seasons, extracted the DNA, and performed individual identification based on genotypes built using nine microsatellites. We then estimated population size and individual survival relative to environmental variables, controlling for heterogeneity in capture probabilities using capture-mark-recapture modelling. Population size increased during the wet season and decreased during the dry season, while survival remained constant across the study period. Individuals captured along road-verges and around water-bodies survived longer than those captured near agricultural fields. The use of gNIS on a heterogeneous landscape such as our study area allowed us to demonstrate that human land-use activities affect Cabrera vole demographic parameters in Mediterranean farmland, with implications for conservation planning towards its long-term persistence. Our approach can be widely applied to other elusive small mammals of conservation concern, but for which informative demographic data are still scarce.
Monitoring the effectiveness of photodynamic therapy with periodic renewal of the photosensitizer on intracanal Enterococcus faecalis biofilms
Photodiagnosis and Photodynamic Therapy, Volume 13, 2016, pp. 123-127
Photodynamic therapy (PDT) can eliminate microorganisms in a root canal. However, the parameters for disinfection remain undefined. This study assessed the effectiveness of a PDT protocol against intracanal Enterococcus faecalis biofilms.
Root canals were contaminated with E. faecalis for 21 days. The instrumentation was associated to irrigation with 0.85% saline or an alternate irrigation (AI) with 5.25% NaOCl and 17% EDTA. Complementary treatments included saline/PDT and AI/PDT. Four PDT cycles were performed using a diode laser (660nm, 40mW) delivered through a tapered optical fiber. In each cycle, the root canal was filled with 1.56μM/mL methylene blue and irradiated for 150s. Microbiological samples were collected before (S1) and after (S2) instrumentation; after PDT (S3); and daily over the course of 14 days (S4–S17). Colony-forming units (CFUs) were counted, positive cultures verified, and data subjected to parametric and proportion's tests.
The highest bacterial load reduction was observed in S2. In regard to S3, Saline/PDT reduced 1.3 log10 CFU counts (p=0.000 for S2) and no CFUs were recovered after AI/PDT treatment. All canals were CFU-free on the 14th day for saline/PDT, AI and AI/PDT. Positive cultures were observed in 60% of saline-irrigated canals on the 14th day, whereas the saline/PDT, AI and AI/PDT treatments resulted in germ-free canals after 10, 5 and 2 days, respectively.
Our findings suggest immediate and delayed antibacterial effects using the PDT protocol tested.
Spray coverage profiles from pecan air-blast sprayers, with a radial air-flow and a volute-generated focused air-flow, as affected by forward speed and application volume
Crop Protection, Volume 168, 2023, Article 106234
Pecan (Carya illinoinensis) is an important specialty crop in the U.S.A., but yield is limited by several diseases and pests. In mature-tree pecan orchards, large air-blast sprayers are commonly used to apply the pesticides to control these diseases and pests. The spray coverage, deposition and profiles are poorly defined under the range of application scenarios, limiting the recommendations that can be provided to growers to maximize control while minimizing input costs. To explore effects of sprayer setting parameters such as travel speed and spray volume rate on spray coverage on tall targets we set up a system (a simple vertical patternator) using a 19-m-tall pole with cards attached at eight height levels from 5 to 19m above ground, allowing to determine the vertical distribution pattern of two air-blast sprayers with different air discharge systems. Spray was applied with a standard radial-flow air-blast sprayer during six treatments being combinations of two travel speeds: 2.4 and 3.2km/h, and three spray volume rates: 470, 940 and 1970 L/ha, as well as with a focused air-flow system (a volute) sprayer during four treatments being combinations of two travel speeds: 2.4 and 3.2km/h, and two spray volume rates: 470 and 940L/ha. Results show that using a standard radial air-flow sprayer, application volume affected coverage at heights ≤17m (higher volumes resulting in more coverage). Higher speed using a standard radial air-flow sprayer resulted in greater spray coverage, but was inconsistent with the focused air-flow system. Using a focused air-flow system more spray coverage occurred at >17m compared to a standard radial air-flow sprayer. Spray coverage profiles affirmed the rapid decline in coverage with height using a standard radial air-flow sprayer. The results may help guide decisions on volute use, spray volume, and spray partitioning to different parts of the canopy to improve spray profile characteristics for applying more uniform spray coverage to mature pecan tree canopies.
Oosorption and migratory strategy of the milkweed bug, Oncopeltus fasciatus
Animal Behaviour, Volume 86, Issue 3, 2013, pp. 651-657
Migration evolves as a response to seasonally unfavourable environments but plasticity in reproductive physiology is another avenue by which insects can respond to resource-poor conditions. We investigated the relationship between individual variation in migratory propensity and the level of response to poor conditions modulated by the female reproductive physiology. We tested the hypothesis that, compared to migrants, residential behaviour is associated with a higher degree of phenotypic plasticity in oosorption, an adaptive physiological mechanism that allows females to recoup resources from undeveloped oocytes. Reallocation from reproduction to survival would allow females to skip migration and to cope with unfavourable environments. If this plasticity is evolved, we further predicted it would vary between as well as within populations. We examined variation associated with migratory behaviour in females from four populations of the milkweed bug, Oncopeltus fasciatus, using a behavioural assay to categorize females as either migrant or resident and observing the differences in oosorption between these groups. As expected, food availability, source population and wing length influenced the propensity for migratory flight, and food availability influenced levels of oosorption. We also found support for our key prediction that resident females are characterized by higher levels of ovarian oosorption than migrant females. Our study provides support for a physiological difference between migrant and resident females and suggests the presence of both physiological and behavioural tactics that interact with the potential for migration to provide adaptation to seasonally challenging environments.
© 2023 Elsevier Ltd. All rights reserved.