Using seasonal physiological and biochemical responses to select forest components adapted to soybean and corn intercropping.

Given the increasing utilization of forest components in integration systems worldwide, coupled with the growing demand for food in regions facing water restrictions, this study aims to evaluate how physiological and biochemical parameters contribute to the diversification of adaptive mechanisms among native species and eucalyptus genotypes intercropped with soybean or corn. The native tree species Anadenanthera macrocarpa and Dipteryx alata, and the eucalyptus genotypes Urograndis I-144 and Urocam VM01, were grown in soybean and corn intercropping areas and evaluated in fall, winter, spring, and summer. The study evaluated morning water potential, chloroplast pigment concentration, gas exchange, cell damage, and antioxidant enzyme activity. Intercropped with soybean, development the of A. macrocarpa improved through instantaneous water use efficiency, energy use by the electron transport chain, chloroplast pigments, and catalase enzyme activity. On the other hand, A. macrocarpa when, intercropped with corn, despite increasing energy absorption by the reaction center, there is a need for non-photochemical dissipation and in the activity of the enzymes superoxide dismutase and ascorbate peroxidase in response to water and oxidative deficits. In D. alata, the physiological and biochemical responses were not influenced by intercropping but by seasons, with increased chloroplast pigments in fall and electron transport in summer. However, in corn intercropping, the dissipation of excess energy allowed leaf acclimatization. The I-144 and VM01 genotypes also showed no significant differences between intercrops. The results describe photosynthetic and biochemical challenges in the native species A. macrocarpa intercropped with corn, such as a greater need for enzymatic and non-enzymatic defense mechanisms in response to more negative water potential. In D. alata, the challenges are present in both intercrops due to improved mechanisms to protect the photosynthetic apparatus. The survival of the I-144 genotype may be inefficient in both intercrops under prolonged drought conditions, as it modifies the photosystem; in contrast, genotype VM01 was the most adapted to the system for using captured energy, reducing water loss and being resilient.

Raman spectroscopy - a visit to the literature on plant, food, and agricultural studies.

Raman spectroscopy, a fast, non-invasive, and label-free optical technique, has significantly advanced plant and food studies and precision agriculture by providing detailed molecular insights into biological tissues. Utilizing the Raman scattering effect generates unique spectral fingerprints that comprehensively analyze tissue composition, concentration, and molecular structure. These fingerprints are obtained without chemical additives or extensive sample preparation, making Raman spectroscopy particularly suitable for in-field applications. Technological enhancements such as surface-enhanced Raman scattering, Fourier-transform-Raman spectroscopy, and chemometrics have increased Raman spectroscopy sensitivity and precision. These and other advancements enable real-time monitoring of compound translocation within plants and improve the detection of chemical and biological contaminants, essential for food safety and crop optimization. Integrating Raman spectroscopy into agronomic practices is transformative and marks a shift toward more sustainable farming activities. It assesses crop quality - as well as the quality of the food that originated from crop production - early plant stress detection and supports targeted breeding programs. Advanced data processing techniques and machine learning integration efficiently handle complex spectral data, providing a dynamic and detailed view of food conditions and plant health under varying environmental and biological stresses. As global agriculture faces the dual challenges of increasing productivity and sustainability, Raman spectroscopy stands out as an indispensable tool, enhancing farming practices' precision, food safety, and environmental compatibility. This review is intended to select and briefly comment on outstanding literature to give researchers, students, and consultants a reference for works of literature in Raman spectroscopy mainly focused on plant, food, and agronomic sciences. © 2024 Society of Chemical Industry.

Relative Water Content, Chlorophyll Index, and Photosynthetic Pigments on Lotus corniculatus L. in Response to Water Deficit.

This study aimed to evaluate different L. corniculatus L. ecotypes under water-deficit conditions to identify changes in relative water content and photosynthetic pigments as indicators of physiological responses during different years' seasons. The experiment was conducted in a randomized block design with three replicates. Ten treatments were performed as a factorial of 2 × 5, where the first variation factor was the soil water content-no water deficit (NDW) with 100% field capacity (FC), and water deficit (DW) corresponding to 85.4% of the FC-and the second variation factor comprised four ecotypes and one variety of L. corniculatus. A significant effect was identified on the concentration of photosynthetic pigments, mainly total chlorophyll, with chlorophyll a in the 255301 ecotype with records of 187.8, 167.5, and 194.6 mg g-1 FW in WD, corresponding to an increase of 86.0%, 172.6%, and 16.6%, respectively, in relation the lower values obtained in the ecotype 202700 under NWD. In carotenoids, higher concentrations were observed in the 255301 and 202700 ecotypes and the Estanzuela Ganador variety under WD in most seasonal periods, except summer; a similar response was found in the 202700 ecotype and the Estanzuela Ganador variety during the winter season, also in WD. The results showed that the first two principal components accounted for 71.8% of the total variation, with PC1 representing chlorophyll a, chlorophyll b, and total chlorophyll, and PC2 representing carotenoids, temperature, relative chlorophyll index, and relative water content. The observations were grouped based on soil moisture content, with the optimal moisture group exhibiting higher chlorophyll and carotenoid concentrations. The findings suggest that soil moisture content significantly affects the performance of L. corniculatus ecotypes, and the plant shows seasonal variations in response to water-deficit conditions. This research contributes to understanding the physiological responses of L. corniculatus and its potential as a water-efficient forage crop for promoting sustainable agriculture and enhancing food security.

Investigating the synergistic effects of biochar, trans-zeatin riboside, and Azospirillum brasilense on soil improvement and enzymatic activity in water-stressed wheat.

BACKGROUND: Water stress is a major danger to crop yield, hence new approaches to strengthen plant resilience must be developed. To lessen the negative effects of water stress on wheat plants, present study was arranged to investigate the role of synergistic effects of biochar, trans-zeatin riboside (t-ZR), and Azospirillum brasilense on soil improvement and enzymatic activity in water-stressed wheat. RESULTS: In a three-replication experiment comprising of four treatments (T0: Control, T1: Drought stress (DS), T2: DS + t-ZR with biochar, T3: DS + A. brasilense with biochar), we observed notable improvements in soil quality and enzymatic activities in water-stressed wheat plants with the application of t-ZR and A. brasilense with biochar. In drought stress, Treatment having the application of A. brasilense with biochar performs best as compared to the other and significant increased the enzymatic activities such as peroxidase (7.36%), catalase (8.53%), superoxide dismutase (6.01%), polyphenol oxidase (14.14%), and amylase (16.36%) in wheat plants. Different enzymatic activities showed different trends of results. Soil organic C, dissolved organic C, dissolved organic N also enhanced 29.46%, 8.59%, 22.70% respectively with the application of A. brasilense with biochar under drought stress condition. CONCLUSIONS: The synergistic action of A. brasilense and biochar creates an effective microbiological environment that supports essential plant physiological processes during drought stress. This enhancement is attributed to improved soil fertility and increased organic matter content, highlighting the potential of these novel strategies in mitigating water stress effects and enhancing crop resilience.

A library of electrophysiological responses in plants - a model of transversal education and open science.

Electrophysiology in plants is understudied, and, moreover, an ideal model for student inclusion at all levels of education. Here, we report on an investigation in open science, whereby scientists worked with high school students, faculty, and undergraduates from Chile, Germany, Serbia, South Korea, and the USA. The students recorded the electrophysiological signals of >15 plant species in response to a flame or tactile stimulus applied to the leaves. We observed that approximately 60% of the plants studied showed an electrophysiological response, with a delay of ~ 3-6 s after stimulus presentation. In preliminary conduction velocity experiments, we verified that observed signals are indeed biological in origin, with information transmission speeds of ~ 2-9 mm/s. Such easily replicable experiments can serve to include more investigators and students in contributing to our understanding of plant electrophysiology.

Response to carvacrol monoterpene in the emergence of Allium cepa L. seeds exposed to salt stress.

Abiotic stresses including sodium chloride (NaCl) are known to negatively affect plant physiology and seed germination by inducing a delay in establishing seedling emergence. The monoterpene carvacrol is the major component of several aromatic plants and seems to interfere with germination and seedling growth. In this study, we investigated whether treatment with carvacrol attenuates the effects of NaCl on the germination and development of Allium cepa, where biochemical parameters were also analyzed. The results showed that the Emergency Speed Index (ESI) was near to 2.0 in the control group. The groups NaCl, carvacrol alone, and in co-treatment with NaCl exhibited an ESI below 0.8, being significantly smaller when compared to the control. NaCl + carvacrol significantly inhibited seed emergence in relation to the NaCl group. Only the content of malondialdehyde was significantly altered by NaCl.

Modelos de regresión para predecir la cosecha con variables asociadas a la calidad del fruto, el tiempo de defoliación y la altitud del durazno Jarillo / Regression models to predict the harvest with variables associated with the quality of the fruit, the time of defoliation and the altitude of the Jarillo peach

RESUMEN El cultivo de durazno (Prunus persica (L.) Batsch.) es de gran importancia en la provincia de Pamplona, dada su adaptación a la zona, como un frutal caducifolio. Los modelos matemáticos son relevantes en la agricultura para evitar muestreos destructivos, lo que supone la pérdida de material de investigación y la compra de costosos equipos de medición. Para estimar variables de respuesta de características del fruto del cultivar Jarillo a diferentes altitudes, se llevó a cabo un estudio en el paisaje de montaña de Norte de Santander, Colombia, evaluando 660 frutos desde el inicio de la formación hasta su maduración, a una altitud de 1.670, 1.870 y 2.170 m s.n.m. El rendimiento y el número de frutos totales fue mayor en la menor altitud evaluada. A 1.870 m s.n.m. el contenido de solidos solubles totales fue menor; la relación de madurez tendió a incrementarse en las tres altitudes, pero en menor proporción, para 1.870 m s.n.m. El análisis de regresión lineal múltiple indicó diversos modelos de regresión lineal simple adecuados, según, sea el caso, para estimar sólidos solubles totales, cosecha total y peso fresco del durazno por altitud.

ABSTRACT The peach crop (Prunus persica (L.) Batsch.) is of great importance in the province of Pamplona, due to its adaptation to the area as a deciduous fruit tree. Mathematical models are relevant in agriculture to avoid destructive sampling, which involves the loss of research material and the purchase of expensive measuring equipment. To estimate response variables of fruit characteristics of the Jarillo cultivar at different altitudes, a study was carried out in the mountain landscape of Norte de Santander, Colombia, evaluating 660 fruits from the beginning of fruit formation to fruit ripening at an altitude of 1,670, 1,870, and 2,170 m a.s.l. Yield and number of total fruits were higher at lower altitudes and decreased at higher altitudes. At 1,870 m a.s.l., total soluble solids content was lower. The maturity relation tended to increase at all three altitudes, but to a lesser extent at 1,870 m a.s.l. Multiple linear regression analyses indicated several simple linear regression models suitable for estimating total soluble solids, total yield, and fresh weight of peaches by altitude.

POMONA: a multiplatform software for modeling seed physiology.

Seed physiology is related to functional and metabolic traits of the seed-seedling transition. In this sense, modeling the kinetics, uniformity and capacity of a seed sample plays a central role in designing strategies for trade, food, and environmental security. Thus, POMONA is presented as an easy-to-use multiplatform software designed to bring several logistic and linearized models into a single package, allowing for convenient and fast assessment of seed germination and or longevity, even if the data has a non-Normal distribution. POMONA is implemented in JavaScript using the Quasar framework and can run in the Microsoft Windows operating system, GNU/Linux, and Android-powered mobile hardware or on a web server as a service. The capabilities of POMONA are showcased through a series of examples with diaspores of corn and soybean, evidencing its robustness, accuracy, and performance. POMONA can be the first step for the creation of an automatic multiplatform that will benefit laboratory users, including those focused on image analysis.

Contribution of Arbuscular Mycorrhizal and Endophytic Fungi to Drought Tolerance in Araucaria araucana Seedlings.

In its natural distribution, Araucaria araucana is a plant species usually exposed to extreme environmental constraints such as wind, volcanism, fires, and low rainfall. This plant is subjected to long periods of drought, accentuated by the current climate emergency, causing plant death, especially in its early growth stages. Understanding the benefits that both arbuscular mycorrhizal fungi (AMF) and endophytic fungi (EF) could provide plants under different water regimes would generate inputs to address the above-mentioned issues. Here, the effect of AMF and EF inoculation (individually and combined) on the morphophysiological variables of A. araucana seedlings subjected to different water regimes was evaluated. Both the AMF and EF inocula were obtained from A. araucana roots growing in natural conditions. The inoculated seedlings were kept for 5 months under standard greenhouse conditions and subsequently subjected to three different irrigation levels for 2 months: 100, 75, and 25% of field capacity (FC). Morphophysiological variables were evaluated over time. Applying AMF and EF + AMF yielded a noticeable survival rate in the most extreme drought conditions (25% FC). Moreover, both the AMF and the EF + AMF treatments promoted an increase in height growth between 6.1 and 16.1%, in the production of aerial biomass between 54.3 and 62.6%, and in root biomass between 42.5 and 65.4%. These treatments also kept the maximum quantum efficiency of PSII (Fv/Fm 0.71 for AMF and 0.64 for EF + AMF) stable, as well as high foliar water content (>60%) and stable CO2 assimilation under drought stress. In addition, the EF + AMF treatment at 25% FC increased the total chlorophyll content. In conclusion, using indigenous strains of AMF, alone or in combination with EF, is a beneficial strategy to produce A. araucana seedlings with an enhanced ability to tolerate prolonged drought periods, which could be of great relevance for the survival of these native species under the current climate change.

Effect of applications of 1-MCP and ethylene on the ripening and degreening process of banana fruits cv. Barranquillo

The banana cv. Barranquillo (Musa acuminata, AAA, 'Gros Michel') is a highly desired fruit because of its productive potential and organoleptic quality but various aspects of the ripening process are unknown. The objective of this research was to evaluate the effect of applications of 1-MCP and ethylene on the ripening and degreening process. Two experiments were carried out at room temperature with fruits harvested at commercial maturity. The first four treatments evaluated maturation: control, ethylene, 1-MCP, and 1-MCP + ethylene. In the second experiment, different concentrations of ethylene based on ethephon (0, 100, 500 and 1000 µL L-1) were evaluated. The fruits treated with 1-MCP decreased the ripening process, and 1-MCP was a good alternative for conserving the fruits; the ethylene had opposite results. The color index of the skin, weight loss, firmness, total soluble solids, and maturity ratio had changes associated with the presence of ethylene. In the second experiment, the ethylene applications between 100 and 500 µL L-1 sufficiently stimulated degreening but accelerated the ripening process.

El banano cv. Barranquillo (Musa acuminata, AAA, 'Gros Michel') es un fruto muy apetecido por su potencial productivo y calidad organoléptica, pero se desconocen varios aspectos del proceso de maduración. El objetivo de esta investigación fue evaluar el efecto de la aplicación de 1-MCP y etileno en la maduración y en el proceso de desverdizado. Se realizaron dos experimentos a temperatura ambiente y con frutos cosechados en madurez comercial; en el primero, se evaluaron cuatro tratamientos, para entender la regulación de la maduración, estos fueron: testigo, etileno, 1-MCP y 1-MCP+etileno. En el segundo experimento, se evaluaron diferentes concentraciones de etileno, a base de etefon (0, 100, 500 y 1000 µL L-1). Los frutos tratados con 1- MCP presentaron una disminución en el proceso de maduración, por tanto, el 1-MCP, se convierte en una buena alternativa de conservación, mientras que con etileno, el proceso fue opuesto. Se evidenció que el índice de color de la epidermis, la pérdida de peso, la firmeza, los sólidos solubles totales y la relación de madurez se consideran cambios asociados a la presencia de etileno. En el segundo experimento se encontró que, aplicaciones de etileno entre 100 y 500µL L-1, se consideran suficientes para estimular el desverdizado, pero aceleran el proceso de maduración.

Metabolism of guarana (Paullinia cupana Kunth var. sorbilis) plants and fruit production subjected to glyphosate doses.

Guarana (Paullinia cupana Kunth var. sorbilis) is a typically Amazonian plant of high economic value due to the compounds found in its seed. For guarana to reach the maximum productive potential, management practices such as weed control are necessary. The use of herbicides is a viable alternative, however, its drift may lead to adverse effects on the primary and secondary plant metabolisms and cause losses in crop production. This study evaluated the differential drift effects of glyphosate doses on the physiology of guarana plants and the production of compounds of economic interest in their seeds. Glyphosate doses (57.6, 115.2, 230.4, 460.8 g ae ha-1) were applied to adult guarana plants after the flowering period. The photosynthetic functions and metabolism effects were evaluated. Herbicide treatments led to oxidative stress due to increased lipid peroxidation and increased carbohydrate and amino acid in their leaflets. Despite this, glyphosate showed no effect on fruit production or the content of secondary metabolites of commercial interest in seeds.

ZnO nanoparticles as potential fertilizer and biostimulant for lettuce.

Zn is an indispensable nutrient for crops that usually presents low bioavailability. Different techniques have been proposed to improve the bioavailability of Zn, including the use of nanofertilizers. The objective of the study was to evaluate the applications of drench (D) and foliar (F) ZnO nanoparticles (NZnO) compared to those of ionic Zn2+ (ZnSO4) in lettuce. The plants cv. Great Lakes 407 was produced in pots of 4 L with perlite-peat moss (1:1) under greenhouse conditions. The treatments consisted of NZnO applications that replaced the total Zn provided with a Steiner solution, as follows: Zn2+ (100%D) (control); Zn2+ (50%D+50%F); NZnO (100%D); NZnO (50%D+50%F); NZnO (75%D); NZnO (50%D); NZnO (75%F) and NZnO (50%F). Four applications of Zn were made with a frequency of 15 days. 75 days after transplant (DAP), the fresh and dry biomass, chlorophyll a, b, and ß-carotene, phenolics, flavonoids, antioxidant capacity, vitamin C, glutathione, H2O2, total protein, and enzymatic activity of PAL, CAT, APX, and GPX were evaluated. The mineral concentrations (N, P, K, Ca, Mg, S, Cu, Fe, Mn, Mo, Zn, Ni, and Si) in the leaves and roots of plants were also determined. The results showed that, compared to Zn2+, NZnO promoted increases in biomass (14-52%), chlorophylls (32-69%), and antioxidant compounds such as phenolics, flavonoids, and vitamin C. The activity of enzymes like CAT and APX, as well as the foliar concentration of Ca, Mg, S, Fe, Mn, Zn, and Si increased with NZnO. A better response was found in the plants for most variables with foliar applications of NZnO equivalent to 50-75% of the total Zn2+ applied conventionally. These results demonstrate that total replacement of Zn2+ with NZnO is possible, promoting fertilizer efficiency and the nutraceutical quality of lettuce.

Global Trends of Acidity in Rainfall and Its Impact on Plants and Soil.

Due to its deleterious and large-scale effects on the ecosystem and long-range transboundary nature, acid rain has attracted the attention of scientists and policymakers. Acid rain (AR) is a prominent environmental issue that has emerged in the last hundred years. AR refers to any form of precipitation leading to a reduction in pH to less than 5.6. The prime reasons for AR formation encompass the occurrence of sulfur dioxide (SO2), nitrogen oxides (NOx), ozone (O3), and organic acids in air produced by natural as well as anthropogenic activities. India, the top SO2 emitter, also shows a continuous increase in NO2 level responsible for AR formation. The plants being immobile unavoidably get exposed to AR which impacts the natural surrounding negatively. Plants get affected directly by AR due to reductions in growth, productivity, and yield by damaging photosynthetic mechanisms and reproductive organs or indirectly by affecting underground components such as soil and root system. Genes that play important role in plant defense under abiotic stress gets also modulated in response to acid rain. AR induces soil acidification, and disturbs the balance of carbon and nitrogen metabolism, litter properties, and microbial and enzymatic activities. This article overviews the factors contributing to AR, and outlines the past and present trends of rainwater pH across the world, and its effects on plants and soil systems.

Salicylic acid does not relieve salt stress on gas exchange, chlorophyll fluorescence, and hydroponic melon growth / O ácido salicílico não alivia o estresse salino nas trocas gasosas, fluorescência da clorofila e crescimento hidropônico do meloeiro

Abstract The objective of this study was to evaluate the salicylic acid applications in attenuating the harmful effects of saline nutrient solution on the physiology and growth of 'Gaúcho' melon cultivated in the NFT hydroponic system. The experiment was conducted in a greenhouse, in Pombal-PB, Brazil. The cultivation system used was the Nutrient Film Technique - NFT hydroponics. A completely randomized split-plot design was used, with the plot referring to four levels of salinity in the nutrient solution - ECns (2.1 control, 3.2, 4.3, and 5.4 dS m-1) and the sub-plot four concentrations of salicylic acid (SA) (0, 1.5, 3.0, and 4.5 mM), applied via foliar spray, with six replications. Nutrient solution of 4.3 and 5.4 dS m-1 electrical conductivity promotes higher maximum and variable fluorescence, respectively. The stomatal conductance, transpiration, stem diameter, main branch length, leaf dry mass, and stem dry mass of 'Gaúcho' melon plants decrease with the increase in salinity of the nutrient solution. Salicylic acid increases the initial fluorescence and the main branch length of 'Gaúcho' melon plants in hydroponic cultivation. Salicylic acid at a concentration of 1.5 to 4.5 mM did not attenuate the effects of salt stress on the internal CO2 concentration, CO2 assimilation rate, and root dry mass of 'Gaúcho' melon plants.

Resumo O objetivo deste trabalho foi avaliar as aplicações do ácido salicílico como atenuador dos efeitos deletérios da solução nutritiva salina sobre a fisiologia e o crescimento do melão 'Gaúcho' cultivado em sistema hidropônico NFT. O experimento foi conduzido em casa de vegetação, em Pombal - PB, Brasil. O sistema de cultivo utilizado foi a técnica do fluxo laminar de nutrientes - NFT. Foi utilizado um delineamento inteiramente casualizado em parcelas subdivididas, sendo a parcela referente a quatro níveis de salinidade de solução nutritiva - CEsn (2,1 controle, 3,2, 4,3 e 5,4 dS m-1) e a subparcelas quatro concentrações de ácido salicílico - AS (0, 1,5, 3,0 e 4,5 mM), aplicado via pulverização foliar, com seis repetições. A solução nutritiva de 4,3 e 5,4 dS m-1 condutividade elétrica promove maior fluorescência máxima e variável, respectivamente. A condutância estomática, a transpiração, o diâmetro do caule, o comprimento do ramo principal, a massa seca da folha e a massa seca do caule do meloeiro 'Gaúcho' diminuiu com o aumento da salinidade da solução nutritiva. O ácido salicílico aumenta a fluorescência inicial e o comprimento do ramo principal do meloeiro 'Gaúcho' em cultivo hidropônico. O ácido salicílico na concentração de 1,5 a 4,5 mM não atenuou os efeitos do estresse salino sobre a concentração interna de CO2, taxa de assimilação de CO2 e massa seca da raiz do meloeiro 'Gaúcho'.

Morpho-physiological and anatomical characteristics of Urochloa brizantha cv. Marandu in silvopastoral and monoculture systems

To gain insights into the forage morphological and anatomical characteristics in a silvopastoral system (SPS) with Bolsa de Pastor (Zeyheria tuberculosa) and palisadegrass 'Marandu' (Urochloa brizantha) monoculture (MONO). The SPS was established through natural regeneration of the tree species. Treatments were a SPS and MONO distributed in a completely randomized design with six replicates and repeated measures were the harvest periods. Response variables were morpho-physiological and anatomical characteristicss: green: dead material ratio, leaf blade: stem+sheath ratio, leaf area index, chlorophyll and carotenoid concentrations, proportions of non-lignified and achlorophyllous areas, lignified areas in stems, proportions of non-lignified and achlorophyllous areas, lignified and chlorophyllous areas in leaves, as well as cell length in longitudinal section of stem. Morpho-physiological patterns were altered (p < 0.05) under natural shading conditions due to higher photosynthetic efficiency in the SPS. There was no effect (p > 0.05) of the systems on anatomical patterns, proportions of non-lignified and achlorophyllous, lignified and chlorophyllous tissues, these proportions were influenced only by the periods of the year, both for stems and leaves. Cells of the internodes of the grasses of the studied systems had the same length. The SPS alters morpho-physiological characteristics of palisadegrass and increases the concentration of chlorophyll a and b.(AU)

Soil-Plant Relationships in Soybean Cultivated under Crop Rotation after 17 Years of No-Tillage and Occasional Chiseling.

No-tillage cover crops contribute to better soil quality, being able to replace mechanized tillage management. This observation can only be made after several years of adopting conservationist practices and through research on soil-plant relationships. The objective of the research was to verify the relationship between the production components, physiological, root development, and physical-hydric properties of the soil in the yield of soybean grown in succession to different cover crops or with soil chiseling. The experiment was carried out in a randomized block design with four replications, comparing the cultivation of sunn hemp (Crotalaria juncea) and millet (Penninsetum glaucum L.) as cover crops and a treatment with soil chiseling. The evaluations were carried out during soybean (Glycine max L.) cultivation in the 2019/20 summer crop, that is, after 17 years of experimenting started in 2003. Rotation with sunn hemp increased soybean yield by 6% and 10%, compared with millet rotation and soil chiseling. The species used in crop rotation in a long-term no-tillage system interfere with the physical and water characteristics of the soil, affecting the physiological responses and soybean yield. The rotation with sunn hemp offers greater water stability to the plants and provides greater soybean yield in succession. Future research that better addresses year-to-year variation, architecture, and continuity of pores provided by crop rotation, and evaluations of gas exchange, fluorescence, and activities of stress enzymes in soybean plants may contribute to a better understanding of soil-plant relationships in long-term no-till.

Arbuscular Mycorrhizal Fungi Promote Physiological and Biochemical Advantages in Handroanthus serratifolius Seedlings Submitted to Different Water Deficits.

Climate change causes increasingly longer periods of drought, often causing the death of plants, especially when they are in the early stages of development. Studying the benefits provided by arbuscular mycorrhizal (AM) fungi to plants in different water regimes is an efficient and sustainable strategy to face climate change. Thus, this study investigated the influence of AM fungi on Handroanthus serratifolius seedlings under different water regimes, based on biochemical, and nutritional growth parameters. The experiment was carried out in H. serratifolius seedlings cultivated with mycorrhizas (+AMF) and without mycorrhizas (-AMF) in three water regimes; a severe water deficit (SD), a moderate water deficit (MD), and a well-watered (WW) condition. AM fungi provided greater osmoregulation under water deficit conditions through the accumulation of soluble sugars, total free amino acids, and proline, as well as by reducing sugar. The increase in the absorption of phosphorus and nitrate was observed only in the presence of fungi in the well-watered regimen. A higher percentage of colonization was found in plants submitted to the well-watered regimen. Ultimately, AM fungi promoted biochemical, nutritional, and growth benefits for H. serratifolius seedlings under the water deficit and well-hydrated conditions, proving that AMF can be used to increase the tolerance of H. serratifolius plants, and help them to survive climate change.

Phenological and physicochemical changes during fruit development in two peach cultivars in the high tropics / Cambios fenológicos y fisicoquímicos durante el desarrollo del fruto en dos cultivares de duraznero en trópico alto

ABSTRACT Several aspects of the development of the peach fruit under tropical conditions are unknown, this information allows agronomic practices to be carried out with technical criteria. Therefore, the objective was to determine the different changes and phenological changes of peach fruit depending on the Growing Degree Days (GDD) in the varieties 'Dorado' and 'Rubidoux', grown in the Colombian high tropics. This study randomly selected 51 trees and 100 flowers per plant that were in full flowering for sampling every 15 days until harvest to determine physical variables such as firmness, color index of the epidermis and pulp, and chemical properties such as soluble solids, titratable acidity, and respiratory rate. From full bloom to harvest, the Dorado and Rubidoux varieties took 1081.8 GDD (153 days) and 1667.1 GDD (205 days) respectively. The firmness increased in the two cultivars during phase 1 of development, then decreased until harvest. The color index of the epidermis and pulp increased during ripening, indicating yellow tones in the two varieties. The soluble solids increased continuously, with final values of 15.9 ± 0.9 and 15.5 ± 0.3 °Brix. The acidity increased during phase 2 and then decreased during ripening. The respiratory rate decreased between phase 1 and 3, with an increase in phase 2, which is related to the lignification of the endocarp in the two cultivars. These results contribute to the understanding of the development of the two peach cultivars under tropical conditions.

RESUMEN Se desconocen varios aspectos del desarrollo del fruto de duraznero en condiciones tropicales, información que permite realizar labores agronómicas con criterio técnico, por tanto, el objetivo fue determinar los diferentes cambios fisicoquímicos y fenológicos del fruto de durazno, en función del tiempo térmico, de las variedades 'Dorado' y 'Rubidoux', cultivados en zonas de trópico alto colombiano. Se seleccionaron al azar 51 árboles y 100 flores/planta, en estado de plena floración. Cada 15 días y hasta la cosecha, se hicieron mediciones de la firmeza, el índice de color de epidermis y pulpa, los sólidos solubles, la acidez titulable y la tasa respiratoria. De plena floración a cosecha, las variedades Dorado y Rubidoux tardaron 1081,8 GDC (153 días) y 1667,1 GDC (205 días), respectivamente. La firmeza presentó un incremento en los dos cultivares durante la fase 1 de desarrollo, luego disminuyó hasta la cosecha. El índice de color de epidermis y pulpa aumentó durante la maduración, con tonalidades amarillas, en las dos variedades. Los sólidos solubles incrementaron de forma continua y en los dos cultivares, con valores finales de 15,9 ± 0,9 y 15,5 ± 0,3 °Brix. La acidez mostró un incremento durante la fase 2 y luego disminuyó durante la maduración. La tasa respiratoria decreció entre la fase 1 y 3, con un incremento en la fase 2, relacionado con la lignificación del endocarpio, en los dos cultivares. Estos resultados contribuyen al entendimiento del desarrollo de los dos cultivares de durazno, bajo condiciones tropicales.

Transporter networks can serve plant cells as nutrient sensors and mimic transceptor-like behavior.

Sensing of external mineral nutrient concentrations is essential for plants to colonize environments with a large spectrum of nutrient availability. Here, we analyzed transporter networks in computational cell biology simulations to understand better the initial steps of this sensing process. The networks analyzed were capable of translating the information of changing external nutrient concentrations into cytosolic H+ and Ca2+ signals, two of the most ubiquitous cellular second messengers. The concept emerging from the computational simulations was confirmed in wet-lab experiments. We document in guard cells that alterations in the external KCl concentration were translated into cytosolic H+ and Ca2+ transients as predicted. We show that transporter networks do not only serve their primary task of transport, but can also take on the role of a receptor without requiring conformational changes of a transporter protein. Such transceptor-like phenomena may be quite common in plants.