Renata Biba, Petra Cvjetko, Mihaela Jakopčić
et al.
Plastic contamination has become one of the most pressing environmental issues due to rapidly increasing production of disposable plastic products, their fragmentation into smaller pieces, and long persistence in the environment, which affects all living organisms, including plants. In this study, <i>Allium cepa</i> roots were exposed to 0.01, 0.1, and 1 g L<sup>−1</sup> of commercial polystyrene (PS-MPs) and polymethyl methacrylate microparticles (PMMA-MPs) for 72 h. Dynamic light scattering (DLS) analyses showed high stability of both types of MPs in ultrapure water used for <i>A. cepa</i> treatment. Morphometric analysis revealed no significant change in root length compared to control. Pyrolysis hyphenated to gas chromatography and mass spectrometry (Py-GC-MS) has proven PS-MPs uptake by onion roots in all treatments, while PMMA-MPs were recorded only upon exposure to the highest concentration. Neither MPs induced any (cyto)toxic effect on root growth and PMMA-MPs even had a stimulating effect on root growth. ROS production as well as lipid and protein oxidation were somewhat higher in PS-MP treatments compared to the corresponding concentrations of PMMA-MP, while neither of the applied MPs induced significant damage to the DNA molecule assayed with a Comet test. Significantly elevated activity of H<sub>2</sub>O<sub>2</sub> scavenging enzymes, catalase, and peroxidases was measured after exposure to both types of MPs. Obtained results suggest that onion roots take up PS-MPs more readily in comparison to PMMA-MPs, while both types of MPs induce a successful activation of antioxidant machinery in root cells that prevented the occurrence of toxic effects.
Willem H.P. BOSHOFF, Botma VISSER, Cornel M. BENDER
et al.
Fig rust, caused by Cerotelium fici, was first recorded in South Africa in 1927. Recent observations have revealed high incidence of rust and untimely defoliation of fig trees (Ficus carica) in residential gardens and commercial orchards. Using phylogenetic analysis, the causal organism of a fig rust isolate (PREM63073) collected in 2020 was confirmed as Phakopsora nishidana. Inoculation and microscope studies showed that mulberry plants were immune to P. nishidana isolate PREM63073. Infection of fig leaves occurred through stomata on the abaxial leaf surfaces. Very long germ tubes were observed for P. nishidana, often with no clear contact with the leaf surfaces and an apparent lack of directional growth towards stomata. Inoculated plants from 15 fig cultivars varied in their severity of leaf infection, whereas fruit of the cultivar Kadota developed reddish-brown blemishes without sporulation. Currently, C. fici and P. nishidana are recognised as occurring on F. carica in South Africa. This suggests a need to resolve the worldwide distribution and identity of the rust species involved.
Ayako N. Sakamoto, Tomoaki Sakamoto, Yuichiro Yokota
et al.
Abstract The suppressor of gamma response 1 (SOG1), a NAM, ATAF1, 2, and CUC2 (NAC)‐type transcription factor found in seed plants, is a master regulator of DNA damage responses (DDRs). Upon DNA damage, SOG1 regulates the expression of downstream DDR genes. To know the origin of the DDR network in land plants, we searched for a homolog(s) of SOG1 in a moss Physcomitrium (Physcomitrella) patens and identified PpSOG1a and PpSOG1b. To assess if either or both of them function(s) in DDR, we knocked out the PpSOG1s using CRISPR/Cas9‐mediated gene editing and analyzed the responses to DNA‐damaging treatments. The double‐knockout (KO) sog1a sog1b plants showed resistance to γ‐rays, bleomycin, and ultraviolet B (UVB) treatments similarly seen in Arabidopsis sog1 plants. Next, we irradiated wild‐type (WT) and KO plants with γ‐rays and analyzed the whole transcriptome to examine the effect on the expression of DDR genes. The results revealed that many P. patens genes involved in the checkpoint, DNA repair, replication, and cell cycle‐related genes were upregulated after γ‐irradiation, which was not seen in sog1a sog1b plant. These results suggest that PpSOG1a and PpSOG1b work redundantly on DDR response in P. patens; in addition, plant‐specific DDR systems had been established before the emergence of vascular plants.
José Alfredo Santiz-Gómez, Miguel Abud-Archila, Víctor Manuel Ruíz-Valdiviezo
et al.
The carrot is considered a model system in plant cell culture. Spray drying represents a widely used technology to preserve microorganisms, such as bacteria and yeasts. In germplasm conservation, the most used methods are freeze drying and cryopreservation. Therefore, the aim of this work was to evaluate the effect of spray drying on the viability and totipotency of somatic carrot cells. Leaf, root and stem explants were evaluated to induce callus with 2 mg/L of 2,4-dichlorophenoxyacetic acid (2,4-D). Calli obtained from the stem were cultivated in a liquid medium with 1 mg/L of 2,4-D. Cell suspensions were spray dried with maltodextrin-gum Arabic and maltodextrin-xanthan gum mixtures, two outlet air temperatures (50 and 60 °C) and 120 °C inlet air temperature. Results showed that carrot cells were viable after spray drying, and this viability remained for six months at 8 °C. The totipotency of the microencapsulated cells was proven. Cells that were not spray dried regenerated 24.6 plantlets, while the spray dried cells regenerated 19 plantlets for each gram of rehydrated powder. Thus, spray drying allowed researchers to obtain viable and totipotent cells. This work is the first manuscript that reported the spray drying of plant somatic cells.
Silicon (Si) is a ubiquitous element in soil with well-known beneficial effects under certain conditions, in several plant species, if supplied in available form for uptake. It may alleviate damage in various stress situations and may also promote growth when no obvious stressors are applied. Effects of Si are often linked to mitigation of oxidative stress, in particular to the induction of antioxidant defense mechanisms. In the work presented, the impact of silicon provision on pro-oxidant systems was investigated in cucumber. Plants of the F1 cultivar hybrid ‘Joker’ were grown under in vitro conditions in the absence of any applied external stressor. Silicon provision decreased H<sub>2</sub>O<sub>2</sub> content and lowered lipid peroxidation in the leaves of the treated plants. This was paralleled by declining polyamine oxidase (PAO) and diamine oxidase (DAO) activities. Several PAO as well as lipoxygenase (LOX) genes were coordinately downregulated in Si-treated plants. Unlike in similar systems studied earlier, the Si effect was not associated with an increased transcript level of gene coding for antioxidant enzymes. These results suggest an inhibitory effect of Si provision on pro-oxidant amine oxidases, which may decrease the level of reactive oxygen species by retarding their production. This extends the molecular mechanisms linked to silicon effects onto redox balance in plants.
Martina K. Ried, Rebekka Wild, Jinsheng Zhu
et al.
Plants regulate phosphate homeostasis via the interaction of PHR transcription factors with SPX receptors bound to inositol pyrophosphate signaling molecules. Here the authors show that inositol pyrophosphate-bound SPX interacts with the coiled-coil domain of PHR, which regulates the oligomerization and activity of the transcription factor.
Oenothera rosea L´Hér. ex Ait. es una planta silvestre de la familia Onagraceae. Esta planta se reconoce por sus propiedades terapéuticas; por lo que, surge interés por cultivarla. El objetivo de este estudio fue caracterizar las semillas de O. rosea y el desarrollo de las plantas, en invernadero, hasta el final de la etapa reproductiva. La hipótesis fue que independientemente del sitio de recolecta y la variabilidad en tamaño de las semillas, las plantas de O. rosea responden al cultivo en condiciones protegidas. Las semillas se recolectaron en cuatro sitios del estado de Veracruz. El diseño experimental fue en bloques al azar generalizado, con 10 repeticiones (15 semillas por unidad experimental) para germinación y emergencia, y cuatro plantas por muestreo, cada 10 días, durante 110 días, para evaluar el crecimiento y la biomasa de las estructuras. Las plantas se cultivaron, en recipientes de 500 mL de capacidad, con turba vegetal, en un invernadero, de julio a septiembre de 2018. La biomasa seminal promedio varió entre 0.0027 y 0.0091 g. Entre 10 y 70% de semillas no germinaron en dependencia del tamaño de semilla y del sitio de recolecta. La proporción de semillas que no germinó varió entre 10 y 80 % entre los sitios de recolecta. Ciento diez días después de la siembra, las plantas de semilla grande mostraron más altura del tallo (hasta 35%), número de yemas florales (60%), número de cápsulas maduras (el doble) y longitud de la raíz (27.2%) respecto a las de semillas pequeñas. En contraste, el diámetro del tallo (a la altura del sustrato) y el número de hojas, su anchura y longitud fueron independientes del tamaño de la semilla. Las plantas de O. rosea crecen y se desarrollan vigorosas en invernadero; en poco más de 100 días de cultivo se asegura la disponibilidad de todos sus tejidos.
In the present study, an essential oil was distilled from the leaves of <i>Piper coruscans</i> Kunth, a native Amazonian species belonging to the family Piperaceae and quite common in Ecuador. The chemical analysis was performed by GC-MS (qualitative) and GC-FID (quantitative), on polar and non-polar columns, detecting a total of 58 compounds of which 52 were identified. All the identified compounds were quantified. The essential oil was mainly constituted of sesquiterpenes (54.1–55.0%) and oxygenated sesquiterpenoids (32.5–33.6%), the major constituents being: (<i>E</i>)-β-caryophyllene (24.1–25.0%), α-humulene (11.6–12.0%), caryophyllene oxide (9.3–10.9%), linalool (4.5–5.2%), humulene epoxide II (3.6–4.1%), (<i>E</i>)-nerolidol (3.7–4.0%), α-copaene (3.7–3.9%), α-muurolol (3.4–3.7%), α-selinene (3.4–3.5%), β-selinene (3.1–3.3%), and one undetermined oxygenated sesquiterpenoid (3.1–3.3%). The aqueous phase (hydrolate) of the distillation process was also submitted to chemical analysis, showing linalool as the main organic compound in solution, with a concentration of 12.3–15.7 mg/100 mL. The essential oil was than analyzed for the enantiomeric distribution of its monoterpene constituents, affording the following enantiomeric excesses in two β-cyclodextrin-based enantioselective columns: (1<i>S</i>,5<i>S</i>)-(-)-α-pinene (60.0–69.6%), (1<i>S</i>,5<i>S</i>)-(-)-β-pinene (5.2–7.2%), (<i>R</i>)-(-)-α-phellandrene (72.5–78.2%), (<i>R</i>)-(+)-limonene (28.6%) and (<i>R</i>)-(-)-linalool (1.8–3.1%).
Guillermo Baena, Ana B. Feria, Luis Hernández-Huertas
et al.
Phospho<i>enol</i>pyruvate carboxylase (PEPC) is an enzyme with key roles in carbon and nitrogen metabolisms. The mechanisms that control enzyme stability and turnover are not well known. This paper investigates the degradation of PEPC via selective autophagy, including the role of the monoubiquitination of the enzyme in this process. In Arabidopsis, the genetic inhibition of autophagy increases the amount of monoubiquitinated PEPC in the <i>atg2</i>, <i>atg5</i>, and <i>atg18a</i> lines. The same is observed in <i>nbr1</i>, which is deficient in a protein that recruits monoubiquitinated substrates for selective autophagy. In cultured tobacco cells, the chemical inhibition of the degradation of autophagic substrates increases the quantity of PEPC proteins. When the formation of the autophagosome is blocked with 3-methyladenine (3-MA), monoubiquitinated PEPC accumulates as a result. Finally, pull-down experiments with a truncated version of NBR1 demonstrate the recovery of intact and/or fragmented PEPC in Arabidopsis leaves and roots, as well as cultured tobacco cells. Taken together, the results show that a fraction of PEPC is cleaved via selective autophagy and that the monoubiquitination of the enzyme has a role in its recruitment towards this pathway. Although autophagy seems to be a minor pathway, the results presented here increase the knowledge about the role of monoubiquitination and the regulation of PEPC degradation.
Black-grass (Alopecurus myosuroides) is one of the most important grass weeds in Bavaria. Chemical weed control with high efficacy is very important in crops like winter cereals, oilseed rape and maize. Crop rotations with more winter cereals, reduced soil cultivation and e.g. contract harvesting enhanced distribution of blackgrass in arable farming regions. Effects of herbicide resistance were observed since the last 20 years. The blackgrass herbicide resistance is well observed by the official plant protection service of Bavaria. A wide experience of resistance tests shows the development of resistant black-grass and provides an opportunity for future prospects in resistance dynamics.
Atlantis Star (mesosulfuron-methyl; iodosulfuron-methyl-sodium; thiencarbazone-methyl; mefenpyr-diethyl) is a new cereal herbicide to control blackgrass (Alopecurus myosuroides; sensitive and high infestation), brome grass (Bromus spec.), ryegrass (Lolium spec.), wild oat (Avena fatua), loose silky-bentgrass (Apera spica-venti L.), annual meadow-grass (Poa annua L.) and dicot weeds. Atlantis Star can be used in winter wheat, winter triticale, winter rye, winter durum wheat and spelt.
The publication is based on efficacy trials from two years of spring application with Atlantis Star.
The purpose of this study is exploring the role of some chemicals, namely magnetic iron (Fe3O4) and sodium selenate (Na2SeO4) on avoiding or minimizing soil salt hazards on growth and quality of Jacaranda acutifolia Humb. & Bonpl. seedlings. Thus, a pot experiment was conducted under the full sun at the nursery of Hort. Res. Inst., ARC, Giza, Egypt during 2011 and 2012 seasons, where one-year-old seedlings of Jacaranda were planted in 30 cm diameter plastic pots filled with about 7 kg of sand and clay mixture (1:1, v:v) salinized with an equal mixture of NaCl and CaCl2 pure salts (1:1, w:w) at the concentrations of 0, 1000, 2000 and 4000 ppm. Magnetic iron was applied three times as soil drench at the rate of 4 g/pot, while sodium selenate was added 3 times as foliar spray at 2 ppm. The effect of a combination between Fe3O4 at 4 g/pot and Na2SeO4 at 2 ppm was also studied. The obtained results revealed that means of vegetative and root growth characters were progressively decreased with increasing soil salinity level with significant differences relative to control means in the two seasons, but they were significantly increased as a result of applying magnetic iron, selenate or both in the combined treatment. The best vegetative and root growth, however was attained by planting in unsalinized soil mixture with the addition of both Fe3O4 (4 g/pot) and Na2SeO4 (2 ppm), as this interaction treatment gave the tallest plants, the longest root, the highest number of leaves and the heaviest fresh and dry weights of aerial parts and roots compared to all other interactions in both seasons. It was also noticed that leaf content of chlorophyll a and b and percentage of nitrogen, phosphorus and potassium were gradually decreased as the soil salinity level was increased, while they were significantly increased by drenching the soil with magnetic iron or spraying the foliage with the sodium selenate solution, or by adding these two chemicals in together. The opposite was the right regarding leaf content of carotenoids, sodium %, chloride % and free proline, as these constituents were progressively increased with rising salinity level, but were decreased by the two used chemicals when applied either individually or in combination. In general, applying magnetic iron alone or combining with Naselenate gave better results than the sole application of Na-selenate, whereas the mastery in all previous measurements was for the interaction of planting in unsalinized soil plus application of Fe3O4 (4 g/pot) + Na2SeO4 (2 ppm) that recorded the utmost high means in both seasons. From these results, it is recommended to drench the soil mixture with 4 g/pot of magnetic iron, alone or plus spraying of Na-selenate 2 ppm on the foliage to get the best growth and quality of Jacaranda acutifolia seedlings planted in either salinized or unsalinized soil.
Rice paddies are a major anthropogenic source of the atmospheric methane.
However, because of the high spatial heterogeneity, making accurate estimations of the
methane emission from rice paddies is still a big challenge, even with
complicated models. Data scarcity is one of the substantial causes of the
uncertainties in estimating the methane emissions on regional scales. In the
present study, we discussed how data scarcity affected the uncertainties in
model estimations of rice paddy methane emissions, from county/provincial
scale up to national scale. The uncertainties in methane emissions from the rice
paddies of China was calculated with a local-scale model and the Monte Carlo
simulation. The data scarcities in five of the most sensitive model
variables, field irrigation, organic matter application, soil properties,
rice variety and production were included in the analysis. The result showed
that in each individual county, the within-cell standard deviation of
methane flux, as calculated via Monte Carlo methods, was 13.5–89.3%
of the statistical mean. After spatial aggregation, the national total
methane emissions were estimated at 6.44–7.32 Tg, depending on the base scale
of the modeling and the reliability of the input data. And with the given
data availability, the overall aggregated standard deviation was 16.3% of
the total emissions, ranging from 18.3–28.0% for early, late and
middle rice ecosystems. The 95% confidence interval of the estimation was
4.5–8.7 Tg by assuming a gamma distribution. Improving the data
availability of the model input variables is expected to reduce the
uncertainties significantly, especially of those factors with high model
sensitivities.
O objetivo deste trabalho foi avaliar a atividade residual de herbicidas utilizados em pós-emergência da cultura da soja sobre o milheto cultivado em sucessão. O experimento foi realizado em Latossolo Vermelho distroférrico de textura argilosa em região de cerrado. Os herbicidas chlorimuron-ethyl (0,015 kg ha-1), imazethapyr (0,060 kg ha-1), imazethapyr (0,100 kg ha-1) e fomesafen (0,250 kg ha-1) foram utilizados em pós-emergência do cultivar de soja Msoy-6101. Utilizou-se o delineamento de blocos casualizados, com quatro repetições, em esquema de parcelas subdivididas (5 x 4). Nas subparcelas, realizou-se a semeadura do milheto (híbrido ADR-7010) em quatro períodos, correspondendo a 0, 40, 80 e 120 dias após a aplicação dos herbicidas (DAA). Durante a condução do ensaio, avaliou-se a intoxicação da cultura aos 7 e 28 dias após a emergência, o estande, a altura e a matéria seca da parte aérea das plantas de milheto. Ao final do ciclo da cultura, determinou-se o rendimento de grãos. O imazethapyr (0,060 kg ha-1) e chlorimuron-ethyl (0,015 kg ha-1) não alteraram significativamente o rendimento da cultura do milheto em semeaduras posteriores a 80 DAA. Para fomesafen, o intervalo mínimo de segurança entre a aplicação e a semeadura do milheto foi de 100 dias. Por outro lado, maior persistência foi observada para imazethapyr na dose 0,100 kg ha-1, chegando a 120 dias de bioatividade sobre o milheto, que teve seu rendimento de grãos alterando mesmo quando semeado durante esse período.<br>The objective of this study was to evaluate the residual activity of herbicides used in post-emergence soybean on Pearl Millet grown in succession. The experiment was conducted in clay soil in cerrado region. The herbicides chlorimuron-ethyl (0.015 kg ha-1), imazethapyr (0.060 kg ha-1), imazethapyr (0.100 kg ha-1) and fomesafen (0.250 kg ha-1) were used in post-emergence soybean cultivar Msoy-6101, in plots of 80 m² that were subdivided into sub-plots of 20 m² (5 x 4 m). A randomized block design with four replications was used in a split plot scheme 5 x 4. Pearl millet hybrid ADR-7010 was sown in the sub-plots in four periods after herbicide application, corresponding to 0, 40, 80 and 120 days after herbicide application (DAA). Pearl Millet injuries were evaluated at 7 and 28 days after emergence, together with stand, height and dry biomass of plant, as well as crop grain yield. Imazethapyr (0.060 kg ha-1) and chlorimuron-ethyl (0.015 kg ha-1) did not significantly affect crop yield in sowing after 80 DAA. As for the herbicide fomesafen, the minimum period between application and sowing of the crop was 100 days. Greater persistence was observed for imazethapyr (0.100 kg ha-1), reaching 120 days of bioactivity on Pearl Millet, which had its performance affected even when sown during this period.
Se evaluó la tasa de recambio fl orístico en bosques de alta montaña (por encima delos 1500 m.s.n.m.) al nivel taxonómico de géneros en dos áreas geográfi cas y surelación con factores espaciales, climáticos y históricos. Las áreas defi nidas fueron:1) Colombia, la cual se defi ne para los sitios en este país localizados alrededor delEcuador geográfi co; y 2) Neotrópico: sitios externos a Colombia más distantesdel Ecuador geográfi co. Las preguntas a responder fueron: ¿Qué tan comparablesson las tasas de recambio fl orístico de géneros en las diferentes áreas geográfi cas?y ¿Qué tan similares son los factores que controlan la distribución de géneros?La diversidad beta fue diferente según el área geográfi ca. La variación climática,representada por la precipitación, fue más relevante a escala del neotrópico, mientrasque la variación altitudinal lo fue a escala de Colombia. Los patrones de distribuciónal nivel de género, fueron poco congruentes con los reportados a nivel de especiesen bosques montanos del neotrópico, especialmente cuando se consideraron datoscercanos alrededor del Ecuador geográfi co en Colombia.