Resumen Introducción. El girasol silvestre o polocote (Helianthus annuus L.) es la principal maleza anual en el cultivo de sorgo y maíz en el norte de Tamaulipas, México. Existe escasa información sobre esta especie para realizar bioensayos con herbicidas. Objetivo. Establecer una metodología para la obtención de plántulas de polocote para bioensayos con herbicidas, desde la semilla hasta la multiplicación en vivero. Materiales y métodos. La semilla de polocote se recolectó en enero del año 2023, en el Campo Experimental del Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (INIFAP), en Río Bravo, Tamaulipas. Después, se ejecutó la prueba de germinación inicial sobre papel filtro y viabilidad con tetrazolio. Se comprobó latencia por baja germinación (12 %) y alta viabilidad (86 %). Se usaron doce tratamientos para romper la latencia, mediante etanol (70 %) y agua (75, 25). Como control se utilizó solamente agua. Los tratamientos se aplicaron a temperaturas de 5 °C y 20 °C, sobre papel filtro, algodón y peat moss, en cajas Petri durante siete días. Posteriormente, se mantuvieron a una temperatura de ±25 °C. Con los resultados anteriores, se estableció la fase de vivero con cuatro esquemas con trasplante de semilla pregerminada y dos con siembra directa. Resultados. El mejor tratamiento para romper latencia fue inmersión en agua a 5 °C por siete días sobre algodón, con una germinación del 73 %. Los mejores métodos para obtener plantas fueron charolas con plántulas y trasplante en macetas negras con 75 % y 50 % de supervivencia, respectivamente. La sombra inhibió el crecimiento de las plantas. La siembra directa, con o sin prehidratación de la semilla, fue desfavorable para la germinación y emergencia. Conclusión. La obtención de plántulas de girasol silvestre fue superior cuando la semilla se sometió a pretratamiento hídrico y trasplante posterior a charolas o a bolsas.

Abstract Introduction. The wild sunflower or polocote (Helianthus annuus L.) is the main annual weed in the cultivation of sorghum and corn in northern Tamaulipas, Mexico. To date, there is little information about this species to carry out bioassays with herbicides. Objective. Establish a methodology for obtaining polocote seedlings for bioassays with herbicides, from seed to multiplication in the nursery. Materials and methods. The polocote seed was collected in January 2023, within the National Institute of Forestry, Agriculture and Livestock Research (INIFAP) Experimental Field, in Río Bravo, Tamaulipas. Afterwards, the initial germination test was carried out on filter paper and viability with tetrazolium. Latency was confirmed due to low germination (12 %) and high viability (86 %). Twelve treatments were used to break dormancy using ethanol (70 %) and water (75, 25). As a control only water were used. The treatments were applied at temperatures of 5 °C and 20 °C, on filter paper, cotton, and peat moss in Petri dishes for seven days. Subsequently, they were kept at a temperature of ±25 °C. With the previous results, the nursery phase was established with four schemes with pre-germinated seed transplantation and two with direct sowing. Results. The best treatment to break dormancy was immersion in water at 5 °C for seven days on cotton, with 73 % germination. The best methods to obtain plants were trays with seedlings and transplanting into black open-air pots, with 75 % and 50 % survival, respectively. Shade inhibited plant growth. Direct sowing, with or without seed prehydration, was unfavorable for germination and emergence. Conclusion. Obtaining wild sunflower seedlings was higher when the seed was subjected to water pre-treatment and subsequent transplanting into trays or open-air bags.

ABSTRACT Tausch’s goat grass (Aegilops tauschii Coss.) is a troublesome and widespread weed that poses a significant challenge in winter wheat fields. Understanding the germination biology of Tausch’s goat grass is crucial for predicting its potential distribution area. To better understand its germination and emergence ecology, this study evaluated the effects of various environmental factors on seed germination and seedling emergence in laboratory and greenhouse experiments. Seed germinations were settled across a range of constant temperatures (5, 10, 15, 20, 25, and 27 °C), and optimal germination rates were observed at 5, 15, 20, and 25 °C. The light and pH had no discernible effect on germination. Germination in this study was inhibited at osmotic potentials ranging from 0 to -0.7 MPa. The seedling emergence rate was highest (100%) when seeds were not buried (depth of 0 cm), emergence gradually declined while the depth of burial increased, no seedlings emerge at the depth of 6 cm. Those implied that deep plowing could effectively limit germination and emergence of this species. This study provides valuable insights into the germination conditions of Tausch’s goat grass and lays the groundwork for scientific prediction and control measures.

ABSTRACT Spermidine (Spd), a naturally occurring molecule in plants, is being investigated for its potential to improve the bean’s tolerance to salinity stress. This study explores how common beans (Phaseolus vulgaris L.) can be helped to thrive in salty environments. This research involved a group receiving regular watering with half strength Hoagland’s solution (HS), and other group watered with a modified form of the same solution containing 75 mM NaCl to stimulate salt stress. Seedlings were treated with foliar applications of Spd (0, 0.5, 1 mM) at five intervals: 15, 20, 25, 30, and 35 d after sowing. Applying Spd significantly reduced damage caused by salt and protected essential pigments for photosynthesis (total chlorophyll by 33% and carotenoids by 57% over than the Spd-untreated plants under saline conditions). Additionally, 1 mM Spd enhanced the antioxidant enzyme activities, i.e., superoxide dismutase, catalase, and ascorbate peroxidase by 15%, 55% and 4.6% and promoted the buildup of beneficial compounds like proline, free amino acids and sugars. Remarkably, exogenous Spd application reduced Na+ accumulation while improving K+ content in common beans under salinity stress. Additionally, it enhanced the cell membrane stability index (CMSI) during stressful situations, the maximum CMSI (94.31%) was recorded with 1 mM Spd under non-stress conditions, whereas the minimum CMSI (72.97%) was registered under salinity without Spd. Under salinity condition, the real-time quantitative PCR (qRT-PCR) results demonstrated a significant increase in the expression of the vacuolar-localized Na+/H+ antiporter protein (NHX1), and the multifunctional osmotic protection protein (Osmotin) in comparison to the control. Furthermore, common bean treated with Spd showed significantly higher expression levels of SOS1, NHX1, and Osmotin, under normal and salinity conditions, with the highest gene expression observed under 1 mM spermidine treatment under saline conditions. Spermidine at 1 mM notably decreased malondialdehyde levels compared to 0.5 mM (10.68 vs. 12.11 nmol g-¹ FW). Overall, the findings propose that Spd may be an effective tool for cultivating common beans in saline areas, potentially paving the way for increased food production in challenging environments.

Abstract Expansion of avocado production areas in Colombia has led to an increased demand for plant propagation material. However, this expansion has exacerbated phytosanitary challenges, particularly root rot disease mainly associated with Phytophthora spp. Therefore, this study aimed to identify Phytophthora species associated with root rot in avocado seedlings within nurseries. Avocado plants exhibiting wilting symptoms were collected from nurseries in the departments of Quindío, Risaralda, and Valle del Cauca (Colombia). Segments of diseased roots were selected, cut, and surface-disinfected, before being planted on Potato Dextrose Agar (PDA) supplemented with antibiotics and fungicides. Microorganism identification was conducted using taxonomic keys and confirmed by molecular techniques employing the identification based on phylogenetic hypothesis, using ITS1-5.8s-ITS2 region encoding for rRNA. Isolates obtained from necrotic avocado roots were identified as P. cinnamomi and P. heveae. The pathogenicity of the isolates was confirmed in avocado seedlings through inoculation, resulting in symptom reproduction. Consequently, this study identified P. cinnamomi and P. heveae as causal agents of root rot in avocado during the nursery stage.

RESUMO A utilização de mudas de alta qualidade pode ser uma estratégia eficaz na restauração de áreas degradadas. Este estudo teve como objetivo avaliar a produção de mudas de Cariniana estrellensis e Gallesia integrifolia utilizando níveis de sombreamento, e o crescimento dessas mudas em área de reflorestamento. De novembro/21 a março/22, a altura e o diâmetro do coleto das mudas foram avaliados, e após 103 dias, a área foliar, a biomassa, o índice de qualidade de Dickson e a produtividade da água foram determinados. Cada espécie constituiu um experimento distinto, disposto em delineamento em blocos casualizados com quatro tratamentos (níveis de sombreamento de 0; 37,6; 49,4 e 75,8%) e quatro repetições, com dez mudas por repetição. As mudas foram produzidas em tubetes de 280 mL preenchidos com biossólido e irrigadas por gotejamento com sistema automático de acionamento. Considerando a água proveniente da chuva e a irrigação suplementar, as mudas de C. estrellensis receberam, em média, 3,94; 3,60; 3,37 e 2,97 L por planta, enquanto as de G. integrifolia receberam 3,83; 3,63; 3,99 e 3,31 L por planta, respectivamente, durante o ciclo. As maiores produtividades da água foram encontradas nas mudas que receberam maior volume de água. As mudas de C. estrellensis produzidas com sombreamento de 49,4 e 75,8% apresentaram maior crescimento, e um ano após o transplantio alcançaram, em média, alturas de 76,0 e 72,3 cm, respectivamente. As mudas de G. integrifolia produzidas sob sombreamento de 49,4% apresentaram maior desempenho durante a fase de viveiro e melhor adaptação após transplantio.

ABSTRACT The utilization of high-quality seedlings can be an effective strategy for restoring degraded areas. This study aimed to evaluate the production of Cariniana estrellensis and Gallesia integrifolia seedlings using shading levels and the growth of these seedlings in reforestation areas. From November/21 to March/22, the seedlings’ height and stem diameter were evaluated, and after 103 days, the leaf area, biomass, Dickson quality index and water yield were determined. Each species constituted a distinct experiment, arranged in a randomized block design with four treatments (shading levels of 0, 37.6, 49.4, and 75.8%) and four repetitions, with ten seedlings per repetition. The seedlings were produced in 280 mL tubes filled with biosolids and irrigated by drip with an automatic activation system. Considering water from rain and supplementary irrigation, C. estrellensis seedlings received, on average, 3.94, 3.60, 3.37, and 2.97 L per plant, while G. integrifolia seedlings received 3.83, 3.63, 3.99, and 3.31 L per plant, respectively, during the cycle. The highest water yields were found in seedlings that received the largest volume of water. C. estrellensis seedlings produced under 49.4 and 75.8% shading showed greater growth, and one year after transplanting reached, on average, heights of 76.0 and 72.3 cm, respectively. G. integrifolia seedlings produced under 49.4% shading showed greater performance during the nursery phase and better adaptation after transplanting.

ABSTRACT Jambu is important nationally and internationally for its dietary and medicinal use, notably for espilanthol. Despite its versatility, breeding work is scarce. This study aimed to evaluate aerial traits and estimate genetic parameters in jambu accesses to support a breeding program. The experiment was conducted in a greenhouse at the Universidade Federal da Amazônia, Capitão Poço campus. The treatments included 172 genotype clones from seven municipalities in the Northeast mesoregion, obtained from a farmer’s market. Seedlings were cloned and transplanted after three weeks. The design was completely randomized with three replications and 20 cm × 20 cm spacing. At harvest, genotypes were manually removed and taken to the Campus Agricultural Engineering Laboratory to measure 17 aerial part traits. Variance components, genotypic values, and genetic parameters were estimated using REML/BLUP methodology. Genetic and phenotypic correlation matrices and selection gains of 75, 50, and 25% of the genotypes were calculated. Significant genetic variance and high heritability were observed for traits such as plant fresh mass, leaf fresh mass, and stem fresh mass, which are favorable for selection. Indirect selection can enhance leaf and capitula mass without significantly increasing stem diameter. Selecting 50% of the population yields good selection gains without compromising genetic variability.

ABSTRACT Phosphorus (P) is a limiting nutrient for coffee seedlings. To meet this requirement, coffee growers usually apply di-ammonium phosphate (DAP), which is highly sensitive to local price fluctuations. The use of arbuscular mycorrhizal fungi (AMF) and phosphate-solubilizing fungi (PSF) has been recommended, but the results derived from their application are inconsistent and uncertain, depending on soil fertility status. The response of AMF and PSF application in the plant growth of coffee seedlings during the nursery stage was evaluated in four non-sterile soils, which represent the most abundant type of soils in the coffee regions of Colombia: Eutropept, Dystropept, Fulvudand, and Ultisol. The treatments included a commercial AMF inoculum, PSF-Phlebia subserialis-CH4, and a consortium of AMF+PSF, at four P levels (0, 0.5, 1, and 2 g.plant-1 P2O5) using DAP fertilizer. Shoot dry weight (SDW) was affected by P applications in Fulvudand. In the other soils, a P-response occurred with 0.5 g.plant-1 , whereas 1 and 2 g.plant-1 of P2O5 caused a significant reduction in SDW. AMF increased SDW by 40% in Eutropept. The negative effect of higher P amounts was mitigated (> 70%) through PSF and AMF+PSF in Ultisol and Eutropept, respectively. In plants in which microorganisms increased SDW, the P concentration was 0.17 to 0.22%. The plant growth promotion of coffee seedlings during the nursery stage with AMF and/or PSF applications varied according to soil type and P amounts applied.

ABSTRACT: In the state of Amazonas, the ‘Pêra’ orange scion is traditionally cultivated on ‘Rangpur’ lime tree. The restricted use of a single scion-rootstock combination has left local orchards vulnerable to adverse conditions and incidence of pests and diseases, which may negatively interfere with both productivity and fruit quality and the citrus activity sustainability in the state. The expansion of the number of scion-rootstock combinations becomes a viable alternative to overcome such problems. To meet this demand from citrus growers, 30 combinations with 10 scions and 3 rootstocks were evaluated in the sixth and seventh year after planting seedlings in the field in the municipality of Rio Preto da Eva, AM. In this experiment, productivity, juice yield, soluble solids, pH, titratable acidity, ratio and technological index were evaluated. ‘Pineapple’ scion with ‘Sunki Tropical’ and ‘BRS Bravo’ rootstocks can be productive alternatives in relation to traditional ‘Pêra’ orange scion under ‘Rangpur’ lime combination in the state of Amazonas. ‘Lima’ orange with ‘Sunki Tropical’ mandarin, ‘Rangpur lime SC’ and ‘BRS Bravo’ lime rootstocks can be alternatives for the fresh market in the state. Combinations that showed good fruit quality are ‘Pêra’, ‘Salustiana’, ‘Valência Tuxpan’ and ‘Westin’ scions with ‘BRS Bravo’ rootstock, and ‘Pêra D6’ scion with ‘Rangpur lime SC’ lemon rootstock. These combinations are alternatives for the diversification of orchards in the state of Amazonas. ABSTRACT Amazonas Pêra Rangpur tree scionrootstock rootstock diseases problems growers 1 Eva AM experiment yield solids pH acidity ‘Pineapple Pineapple Sunki Tropical BRS Bravo ‘Lima Lima mandarin SC ‘Pêra, , ‘Salustiana, Salustiana ‘Salustiana ‘Salustiana’ Valência Tuxpan ‘Westin Westin D6 D

RESUMO: No estado do Amazonas cultiva-se, tradicionalmente, a laranjeira ‘Pêra’ sobre o limoeiro ‘Cravo’. O uso restrito de uma única combinação de copa-porta-enxerto tem deixado os pomares locais vulneráveis à condições adversas e a incidência de pragas e doenças, podendo interferir negativamente tanto na produtividade como na qualidade dos frutos e sustentabilidade citrícola do Estado. A ampliação do número de combinações-copas-porta-enxertos torna-se uma alternativa viável para superar tais problemas. Para atender a esta demanda dos produtores de citros foram avaliadas 30 combinações com 10 copas e três porta-enxertos no sexto e sétimo ano após o plantio das mudas no campo, no município de Rio Preto da Eva, AM. Nesse experimento foram avaliadas: a produtividade, o rendimento de suco, os sólidos solúveis, o pH, a acidez titulável, o ratio e o índice tecnológico. A copa ‘Pineapple’ com os porta-enxertos tangerineira ‘Sunki Tropical’ e ‘BRS Bravo’ podem ser alternativas produtivas em relação a tradicional combinação laranja ‘Pêra’ sob limoeiro ‘Cravo’ no Amazonas. A copa laranja ‘Lima’ com os porta-enxertos tangerineira ‘Sunki Tropical’, limoeiro ‘Cravo Santa Cruz’ e ‘BRS Bravo’ podem ser alternativas para o mercado in natura no estado. As combinações que apresentaram boa qualidade do fruto são as copas ‘Pêra’, ‘Salustiana’, ‘Valência Tuxpan’ e ‘Westin’ com o porta-enxerto ‘BRS Bravo’, e a copa ‘Pêra D6’ com o porta-enxerto limoeiro ‘Cravo Santa Cruz’. Estas combinações são alternativas para a diversificação dos pomares do estado do Amazonas. RESUMO cultivase, cultivase cultiva se, se cultiva-se tradicionalmente Pêra ‘Cravo. Cravo . copaportaenxerto porta enxerto doenças Estado combinaçõescopasportaenxertos enxertos tornase torna problemas 3 1 portaenxertos campo Eva AM suco solúveis pH titulável tecnológico ‘Pineapple Pineapple Sunki Tropical BRS Bravo ‘Lima Lima Tropical, , Cruz ‘Pêra, ‘Salustiana, Salustiana ‘Salustiana ‘Salustiana’ Valência Tuxpan ‘Westin Westin portaenxerto Bravo, D6 D Cruz.

RESUMO No clima semiárido, o crescimento de mudas frutíferas é desafiado pelo estresse hídrico característico da região, o que pode restringir seu desenvolvimento e, consequentemente, afetar a produção. Nesse contexto, o objetivo foi avaliar o efeito do extrato pirolenhoso nas características de troca gasosa, pigmentos fotossintéticos, crescimento e biomassa de pitangueira sob diferentes intensidades de déficit hídrico. O experimento foi conduzido em casa de vegetação utilizando um delineamento em blocos casualizados em um esquema fatorial 3 × 2, com quatro repetições, correspondendo a períodos de déficit hídrico foram de 7 e 14 dias, além do controle (irrigação diária), no substrato sem e com extrato pirolenhoso. As plantas foram avaliadas quanto às características de trocas gasosas foliares, índices de clorofila, crescimento e biomassa seca. A aplicação de extrato pirolenhoso aos 7 dias de déficit hídrico elevou a taxa fotossintética, a eficiência de carboxilação e o índice de qualidade de Dickson das mudas de pitanga em 40,04, 42,85 e 41,51%, respectivamente, em comparação aos 14 dias de déficit hídrico. O extrato pirolenhoso foi efetivo como um atenuante do estresse hídrico nas mudas de pitanga, especialmente durante os primeiros sete dias de exposição ao estresse. Assim, sua aplicação é recomendada como uma medida preventiva e de curto prazo para mitigar tais efeitos nas mudas de pitanga. semiárido região consequentemente produção contexto gasosa fotossintéticos 2 repetições 1 irrigação diária, diária , diária) foliares clorofila seca fotossintética 4004 40 04 40,04 4285 42 85 42,8 4151 41 51 41,51% respectivamente Assim 400 4 0 40,0 428 8 42, 415 5 41,51 40, 41,5 41,

ABSTRACT In the semi-arid climate, the growth of fruit seedlings is challenged by the water stress characteristic of the region, which can restrict their development and, consequently, affect production. In this context, the aim was to assess the effect of pyroligneous extract on gas exchange characteristics, photosynthetic pigments, growth, and biomass of pitanga under different intensities of water deficit. The experiment was conducted using a randomized block design in a 3 × 2 factorial scheme, with four replicates, corresponding to water deficit periods (7 and 14 days) and control (daily irrigation), in substrates with and without pyroligneous extract. The plants were evaluated for gas exchange characteristics, chlorophyll indices, growth, and dry biomass. Application of pyroligneous extract after 7 days of water deficit increased the photosynthetic rate, carboxylation efficiency and Dickson quality index of pitanga seedlings by 40.04, 42.85 and 41.51%, respectively, compared to 14 days of water deficit. Pyroligneous extract was effective as a water stress attenuator in pitanga seedlings, especially during the first seven days of exposure to stress. Therefore, its application is recommended as a preventive and short-term measure to mitigate such effects on pitanga seedlings. semiarid semi arid climate region consequently production context characteristics pigments scheme replicates ( 1 daily irrigation, irrigation , irrigation) indices rate 4004 40 04 40.04 4285 42 85 42.8 4151 41 51 41.51% respectively Therefore shortterm short term 400 4 0 40.0 428 8 42. 415 5 41.51 40. 41.5 41.

ABSTRACT Several species of harmful grass weeds were voluntarily brought in by man, mainly with the specific purpose of produce forage. These species compete with crops for physical area and environmental resources, can host pests and diseases, and interfere on harvesting. This work aimed to evaluate in field conditions, the effects of different specific seed weight and sowing depths on the emergence of the species Urochloa brizantha cv. marandú. It was adopted a randomized blocks design with four replications and the treatments arranged in a 6 x 3 factorial scheme, with six sowing depths (1.0, 2.0, 4.0, 8.0, 12.0 and 16.0 cm) and three specific seed weight (low, medium, and high). The treatment effects were evaluated by seedling emergence in field. The marandu-grass seedlings emerged until 12 cm depth, regardless of specific seed weight and year. Sowing depths between 1.0 and 4.0 cm depth have promoted the greater percentage of emergence, and the lowest average time and speed index for emergence of seedlings on field, regardless of the specific seed weight. High-specific weight seeds resulted in greater percentage of emergence on field, speed and synchronicity index of emergence of marandú-grass seedlings. Sowing depths higher than 1.0 cm induces a delay on marandú-grass propagation. man forage resources diseases harvesting conditions cv marandú scheme 1.0, 10 1 0 (1.0 20 2 2.0 40 4 80 8 8.0 120 12. 160 16 16. low, low (low medium high. high . high) marandugrass marandu year 1. 4. Highspecific High marandúgrass propagation (1. 2. 8. (1 (

ABSTRACT A bibliometric study was undertaken to analyze the spatiotemporal distribution of works related to managing boron (B) in Eucalyptus spp. from 1970 to 2022. This analysis was based on the Web of Science and Scopus databases, and 121 documents were retrieved. The eight main aspects analyzed were (1) annual scientific production, (2) most relevant research sources, (3) world scientific production, (4) association between countries, (5) most relevant affiliations, (6) indexed terms, (7) most relevant authors, and (8) most cited documents. The results indicated that publications of studies about B in eucalyptus have increased significantly over the last decade (2010-2020). Brazil has produced the most studies relating to the nutritional management of B in eucalyptus, as is mainly reflected in the numbers of researchers, research institutions, and journals that have published on the subject. Our study found that most works have been developed regionally, with little international collaboration between countries although researchers from the United States are the most frequent partners in international collaborations. The majority of the articles analyzed focused on studying the influence of B doses on the growth and rooting of eucalyptus seedlings. Finally, one significant gap in the literature is the need for studies on sources of B via soil and leaves, and new studies on this subject should be commissioned. Thus, the bibliometric review was an efficient approach for observing the main advances in managing B in eucalyptus in recent decades and identifying the leading research groups and future opportunities for scientific advances in this area. (B spp 197 2022 databases 12 retrieved 1 (1 production 2 (2 3 (3 4 (4 5 (5 affiliations 6 (6 terms 7 (7 authors 8 (8 20102020. 20102020 2010 2020 . (2010-2020) institutions regionally collaborations seedlings Finally leaves commissioned Thus area 19 202 ( 2010202 201 (2010-2020 20 201020 (2010-202 20102 (2010-20 (2010-2 (2010- (2010 (201 (20

ABSTRACT During the germination process, seeds are susceptible to abiotic and biotic stresses, such as attacks by pests and pathogens. In this context, chemical treatment of seeds can promote physiological and morphological changes in seeds and seedlings, in addition to protecting seeds. Two experiments were conducted with the following objectives: (I) assess the effect of soybean seed water content on seedling emergence under different water availability conditions; (II) assess the effect of chemical treatment of soybean seeds on seedling emergence under water stress conditions. In the first experiment, seeds of four cultivars had their water content adjusted to 8, 11, and 14% and were sown in soil under four water potential levels (-0.01; -0.02; -0.10 and -0.40 MPa). In the second experiment, seeds of the same cultivars were treated using metalaxyl, fludioxonil and thiamethoxam, and untreated seeds were used as controls. Sowing was carried out in soil under four water potentials, and seed quality parameters were evaluated in both experiments. The data subjected to analysis of variance, and the means were compared using the Tukey test at 5% probability level. There is no restriction on sowing soybean seeds with water content between 8 and 14% when the soil is under full water availability. Under conditions of soil water restriction, it is recommended to use seeds with water content between 11 and 14%. Under water deficit conditions, treated soybean seeds show better membrane maintenance and superior performance in seedling emergence. process stresses pathogens context seedlings objectives I (I II (II experiment 14 0.01 001 0 01 (-0.01 0.02 002 02 -0.02 0.10 010 10 -0.1 0.40 040 40 -0.4 MPa. MPa . MPa) metalaxyl thiamethoxam controls potentials variance 5 level 1 0.0 00 (-0.0 -0.0 0.1 -0. 0.4 04 4 0. (-0. -0 (-0 - (- (

ABSTRACT The mobilization of reserves determines the formation of seedlings during germination, being influenced by seed vigor and adverse stress conditions. Seeds with higher vigor have greater potential for mobilization of reserves, and it can favor performance under conditions of salt stress. The objective of this study was to identify how the mobilization of reserves stored in common bean seeds contributes to the overcoming of salt stress, seeking to identify the difference in hydrolysis and mobilization of reserves among seeds with superior vigor. Seeds from two genotypes contrasting in vigor (BAF44 and BAF55) were used. Salt stress was simulated using sodium chloride, and evaluations were performed at one, three, five and seven days of germination. The variables analyzed in seedling was length, dry mass, and metabolic expenditure, while biochemical analyses of total starch, total protein, total soluble sugars, total soluble proteins, and alpha-amylase activity were evaluated in the embryonic axis and/or cotyledons. The salt stress condition negatively affected the performance of the seedlings, resulting in a decrease in length, mass accumulation, and reduced use of seed reserves, associated with a lower hydrolysis of starch and proteins. Seeds with higher vigor showed higher dry mass and seedling length even when subjected to salt stress conditions, because of greater hydrolysis capacity and use of soluble proteins and soluble sugars, which result in seedlings with better performance under control and salt stress conditions. germination BAF44 BAF (BAF4 BAF55 used chloride one three expenditure protein sugars alphaamylase alpha amylase andor or cotyledons accumulation BAF4 (BAF BAF5

Resumen Introducción: Passiflora tripartita var. mollissima (banana passionfruit - curuba) es una de las frutas tropicales exóticas de la diversidad de la familia Passifloraceae en Sudamérica, promisoria por sus propiedades organolépticas y actividad antioxidante. Objetivo: Evaluar las respuestas fisiológicas y anatómicas de la curuba bajo déficit hídrico con el fin de comprender mejor los mecanismos que mitigan este estrés y afectan la producción de sus cultivos, que están sujetos al cambio climático y al calentamiento global. Métodos: Plántulas de 3 meses de edad se sometieron a un déficit hídrico mediante una reducción del riego al 70 % durante 49 días en condiciones de invernadero. Se realizaron mediciones morfológicas (área foliar, altura y número de hojas) y fisiológicas (conductancia estomática, Fv/Fm, contenido de clorofilas) a lo largo del tiempo, y transcurridos los tratamientos de irrigación se midieron parámetros de biomasa, además de rasgos anatómicos foliares. Resultados: Las plantas experimentaron una disminución en la altura, área foliar, número de hojas, índice de área foliar y contenido relativo de agua, respuestas comunes en plantas sometidas a una irrigación reducida. Adicionalmente, las plantas exhibieron ciertos mecanismos que pueden atribuirse a la tolerancia al déficit hídrico tales como una mayor relación raíz:vástago, cierre de estomas, un aumento en la densidad estomática, una reducción en el grosor del tejido del mesófilo y una disminución en el número de vasos del xilema y su diámetro; pues le permiten a la curuba disminuir la pérdida de agua y reducir la probabilidad de cavitación en los vasos del xilema. Conclusiones: Las plantas de la curuba tienen la capacidad de implementar estrategias de mitigación frente al déficit hídrico, lo que les permite sobrevivir y soportar condiciones ambientales desafiantes.

Abstract Introduction: Passiflora tripartita var. mollissima (banana passionfruit) is one of the most promising exotic tropical fruits from the diversity of the Passifloraceae family in South America, because of its organoleptic properties and antioxidant activity. Objective: To evaluate the physiological and anatomical responses of banana passionfruit plants under water deficit to better understand the mechanisms that mitigate this stress and affect the production of crops subject to climate change and global warming. Methods: Three-month-old seedlings of banana passionfruit were subjected to a soil water deficit through an irrigation reduction at 70 % for 49 days under greenhouse conditions. Morphology (leaf area, height, and number of leaves) and physiological (stomatal conductance, Fv/Fm, total chlorophyll content) measurements were made through time, and after the irrigation treatments were measured biomass parameters and anatomical foliar traits. Results: The plants experienced a decrease in height, leaf area, number of leaves, leaf area index, and relative water content, that are common responses in plants subjected to reduced irrigation. Additionally, the plants exhibited certain mechanisms that can be attributed to water deficit tolerance such as higher root:shoot ratio, stomatal closing, an increase in stomatal density, a reduction in mesophyll tissue thickness, and a decrease in the number of vessels and its diameter as they enable the banana passionfruit to reduce water loss and decrease the probability of cavitation in xylem vessels. Conclusions: banana passionfruit plants could implement strategies against water scarcity, allowing them to survive and endure challenging environmental conditions.

Resumen Introducción. Las condiciones edafoclimáticas del Ecuador son ideales para el cultivo del arroz, los rendimientos son mayores al promedio mundial, pero su manejo agronómico conlleva a un aumento de cadmio en el suelo, que puede llegar al grano por translocación, lo cual afectan su inocuidad. Objetivo. Evaluar la absorción de cadmio mediante la técnica de omisión de macronutrientes en seis suelos del Ecuador y su efecto sobre el desarrollo vegetativo del cultivo de arroz. Materiales y métodos. El ensayo se realizó en la Estación Experimental Tropical Pichilingue del Instituto Nacional de Investigaciones Agropecuarias, Ecuador, durante el año 2018. Se estudiaron nueve tratamientos 1) Sin fertilización y sin Cd (testigo 1), 2) sin fertilización y con Cd (Testigo 2), 3) Fertilización completa y seis tratamientos de omisión de un nutriente a la vez, se usó un diseño de experimentos de bloques completamente al azar, parcelas divididas y tres repeticiones. Las variables evaluadas fueron las relacionadas a la producción de materia seca en raíz y parte aérea. Para la comparación entre medias, se utilizó la prueba de Tukey (p<0,05). Resultados. Las omisiones de los nutrientes (N y P) llevaron a la reducción de la absorción del Cd, que disminuyó la producción de materia seca, en particular en los suelos muy ácidos o alcalinos como en Sucumbíos (pH 4) y Guayas (pH 7,9), respectivamente. Conclusiones. La absorción de cadmio en plantas de arroz se redujo en mayor medida con la omisión de los macronutrientes N y P, principalmente en los suelos de Sucumbíos, Los Ríos, El Oro y Manabí, afectando también la omisión de nutrientes a la producción de materia seca y los rendimientos, observándose además que un pH por debajo de 5 o superior a 7,9 afecta la absorción de cadmio en los suelos estudiados

Abstract Introduction. The soil and climatic conditions of Ecuador are ideal for rice cultivation, yields are higher than the world average, but agronomic management leads to an increase of cadmium in the soil, which can reach the grain by translocation, which affects its safety. Objetive. To evaluate the absorption of cadmium through the omission of macronutrients technique in six soils of Ecuador and its effect on the vegetative development of rice crops. Materials and methods. The trial was carried out at the Pichilingue Tropical Experimental Station of the National Institute of Agricultural Research, Ecuador, during 2018. Nine treatments were studied: 1) Without fertilization and without Cd (control 1), 2) without fertilization and with Cd (Control 2), 3) Complete fertilization and six omission treatments of one nutrient at a time, a completely randomized block design of experiments, divided plots and three repetitions was used. The variables evaluated were those related to the production of dry matter in the root and aerial part. For the comparison between means, the Tukey test was used (p<0.05). Results. Nutrients omissions (N and P) led to reduced Cd absorption, which decreased dry matter production, particularly in very acidic or alkaline soils such as in Sucumbíos (pH 4) and Guayas (pH 7, 9), respectively. Conclusions. The absorption of cadmium in rice plants was reduced to a greater extent with the omission of the macronutrients N and P, mainly in the soils of Sucumbíos, Los Ríos, El Oro and Manabí, the nutrient omission technique also affecting the production of dry matter and yields, also observing that a pH below 5 or higher than 7.9 affects the absorption of cadmium in the soils studied.