Dry Mass Production Research Articles

Morphometry, productivity and bromatological analisis of purple elephant grass according to nitrogen fertilization

The objective was to evaluate the morphometric, productive and chemical aspects of purple elephant grass as a function of nitrogen fertilization. The treatments consisted of applying 0, 20, 40, 60, and 80 kg ha-1 of N, using a randomized block design, with five treatments and four replications. The following were evaluated: plant height, number, length and leaf mass, stem diameter and mass, leaf/stem ratio, production of green and dry mass, support capacity for dairy cows, crude protein, neutral detergent fiber and mineral matter. The data were submitted to analysis of variance and Tukey's test at 5% probability. The increase in N doses did not affect (p < 0.05) the morphometry of the purple elephant grass, however it positively stimulated the productivity, the animal support capacity and the bromatological components of the harvested material. The lack of response to nitrogen fertilization may be related to the edaphocilimatic conditions during the experiment and efficiency in the use of N of the variety used. The results demonstrate the high demand of the cultivar for N, actively interfering in the forage yield.

Physiological, biochemical and nutritional changes in soybean in response to application of steel slag

Steel slag is a powdery industrial residue that has CaO, MgO and SiO2 in its composition, which enables its use in agriculture for soil acidity correction. Most studies involving this residue have focused on understanding its effects on the soil, not always considering its action on the plant metabolism. Thus, the present study aimed to evaluate physiological, biochemical and nutritional changes in soybean plants due to application of lime and steel slag on the soil surface or by incorporation. The experiment was carried out in the field, with six soil acidity corrective materials: stainless steel slag, steel slag, ladle slag, wollastonite rock, dolomitic lime and calcined dolomite, plus a negative control, which did not receive correctives. Two application methods were adopted: soil surface application or incorporation. Sixty days after application, the soybean crop was established. Soybean response changed with the application method, since incorporation of corrective materials provided greater production of fresh and dry leaf mass and stem fresh mass, increased chlorophyll b and leaf K levels, and contributed to a greater number of plants per hectare and pods per plant, compared to surface application. Besides such benefits, there was no difference between the effect of application methods on soybean yield, indicating that both incorporation and surface application are efficient in increasing soybean grain yield. The correctives steel slag, wollastonite and calcined dolomite provided significant increases in soybean yield

Silicon leaf spraying increases biofortification production, ascorbate content and decreases water loss post-harvest from land cress and chicory leaves

Silicon (Si) leaf spraying can benefit the production and post-harvest quality of leafy vegetables, however the effect of Si application in land cress and chicory is unknown. This study aimed to verify Si supplementation by foliar spraying when using different sources and concentrations in content of Si and ascorbate in leaves, fresh and dry mass production, and water loss of chicory and land cress during storage. The experimental design was randomized in a 2 x 4 factorial scheme, with potassium silicate and sodium and potassium silicate stabilized with sorbitol, and four concentrations: 0 (control), 0.84, 1.68, and 2.52 g L −1 of Si. Tree foliar applications were carried out in four replications. Si foliar sprayings were applied every ten days; with the first application at 28 days after transplanting. It was determined that applying Si as a foliar spray was practical to increase the Si accumulation, plant growth, and biofortification as well as decrease the post-harvest water loss of land cress and chicory leaves. The Si concentration of 2.52 g L−1 as potassium silicate was recommended for foliar application in land cress and chicory.

Performance and genetic diversity of pre-commercial sweet sorghum hybrids in Central-Western and Southern Brazil

Sweet sorghum is a promising source of ethanol production. In this sense, the investigation of genetic diversity aims to direct heterotic crosses and identify populations that display transgressive segregation in advanced generations. For this, two experiments consisting of 10 sweet sorghum genotypes were installed in 2015/16 at the municipalities of Sinop, in the state of Mato Grosso (MT), and Passo Fundo, in the state of Rio Grande do Sul (RS), Brazil. The variables evaluated in this assessment comprised fresh mass production, dry mass production, Ethanol liters per hectare, soluble solid contents, plant height and flowering. The sweet sorghum performance and genetic diversity was estimated. Five genetic groups were observed. Fresh mass, Ethanol, flowering and height were significant for both locations, demonstrating the influence of environment on hybrid behavior. Crosses between genotypes 4x8 at Passo Fundo, and 9x10 at Sinop are favorable, as these genotypes exhibit good agronomic characteristics, especially for the main variable employed in the sugar-alcohol industry. Flowering contributed the most to genotype separation in both locations. Crosses between genotypes 4x8 and 4x9 are promising to obtain superior segregating populations for both environments, as they exhibited the greatest diversity-interfering contributions considering the investigated variables.

Efficacy of Potential Control Agents Against Rosellinia necatrix and Their Physiological Impact on Avocado.

Rosellinia necatrix is the causal agent of white root rot (WRR), a fatal disease affecting many woody plants, including avocado (Persea americana). As with other root diseases, an integrated approach is required to control WRR. No fully effective control methods are available, and no chemical or biological agents against R. necatrix have been registered for use on avocado in South Africa. Fluazinam has shown promising results in the greenhouse and field in other countries, including Spain. The current study aimed to investigate the potential of a fumigant, chloropicrin, and biological control agents (B-Rus, Beta-Bak, Mity-Gro, and Trichoderma) against R. necatrix both invitro and invivo as compared with fluazinam. In a greenhouse trial, results showed that Trichoderma and B-Rus were as effective as fluazinam at inhibiting R. necatrix invitro and suppressed WRR symptoms when applied before inoculation with R. necatrix. In contrast, Mity-Gro and Beta-Bak failed to inhibit the pathogen invitro and in the greenhouse trial, despite application of the products to plants before R. necatrix infection. Fluazinam suppressed WRR symptoms in plants when applied at the early stages of infection, whereas chloropicrin rendered the pathogen nonviable when used as a preplant treatment. Plants treated with Trichoderma, B-Rus, and fluazinam sustained dry mass production and net CO2 assimilation by maintaining the green leaf tissues despite being infected with the pathogen. This study has important implications for the integrated management of WRR.

10Boron Is Mobile in Cowpea Plants.

Cowpea [Vigna unguiculata (L.) Walp] is cultivated in tropical and subtropical regions worldwide, but its production is usually limited by boron (B) deficiency, which can be mitigated by applying B via foliar spraying. In plants with nutrient mobility, the residual effect of foliar fertilization increases, which might improve its efficiency. An experiment was carried out to evaluate the concentration and mobility of the B isotopic tracer (10B) in different organs of cowpea plants, after the application of this micronutrient in the growing media and also to leaves. Treatments were designed based on B fertilization as follows: without B in the growth media, with 10B applied via foliar spraying (10B-L), with B in the growth media (substrate) and 10B via foliar spraying (10B-L + B-S), and with 10B in the growth media (substrate) without foliar spraying (10B-S), and a control without fertilization. A redistribution of 10B was observed in new leaves when the element was supplied via foliar spraying, resulting in greater leaf area, dry mass and dry matter production of aerial parts, and also the whole plant. 10Boron was redistributed when applied via foliar spraying in cowpea plants, regardless of the plant's nutritional status, which in turn might increase internal B cycling.

Chemical and physical attributes of five Oxisols as predictors of shoot dry mass of white oats

In no-tillage systems, oats are one of the species most used as a cover crop in the subtropical region of Brazil. This study aims is to determine a set of chemical and physical properties of five Oxisols after surface liming, and to determine whether these properties are related to the shoot dry mass production of white oat (Avena sativa L.) variety IPR Aphrodite, in order to establish a model to predict its yield.. For this purpose, a field experiment was conducted during 2015 and 2016 in Londrina County in the State of Paraná with samples of B horizon collected from five Oxisols with clay content ranging from 15-80 dag kg-1 arranged in microplots since 2004. Soil pH in CaCl2, calcium, magnesium, potassium, potential cation exchange capacity (CEC), base saturation, microporosity, total porosity, field capacity, permanent wilting point, clay and sand of the Oxisols were the parameters that most influenced the dry mass production of white oats. Oxisol extrinsic factors such as values pH and base saturation, as well as the calcium and magnesium contents, positively altered with surface liming, boosting the production of oat dry mass production.

Avaliação dos sistemas de pastejo em propriedades rurais de leite em Confresa-MT

O manejo correto de uma pastagem é o fator determinante para uma boa produção e resposta por parte do animal. Assim o presente trabalho visou comparar o desenvolvimento dos sistemas rotacionado e extensivo de pastejo em propriedades rurais produtoras de leite do município de Confresa-MT. A metodologia do projeto buscou a aplicação de questionário, coleta de amostras de forragem, e acompanhamento da produção leiteira das doze propriedades escolhidas, as amostras de cada propriedade avaliada foram coletadas e encaminhadas para o laboratório de bromatologia do Instituto Federal de Mato Grosso – Campus Confresa, um total de 36 amostras de diferentes forrageiras avaliadas. Foram analisados três tratamentos, sistema rotacionado de pastejo com dois dias de ocupação, rotacionado com mais de dois dias de ocupação e sistema contínuo de pastejo. Segundo dados estatísticos ao teste de Tukey a 5% o sistema rotacionado com 2 dias de ocupação apresentou resultados superiores em teores de massa verde, massa seca e produtividade leiteira em relação aos demais sistemas. Verificou se que o período de descanso foi fator primordial para tal resultado.

Silicon mitigates nutritional stress in quinoa (Chenopodium quinoa Willd.)

Nutritional deficiency is common in several regions of quinoa cultivation. Silicon (Si) can attenuate the stress caused by nutritional deficiency, but studies on the effects of Si supply on quinoa plants are still scarce. Given this scenario, our objective was to evaluate the symptoms in terms of tissue, physiological and nutritional effects of quinoa plants submitted to nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) deficiencies under Si presence. The experiment consisted of a factorial scheme 6 × 2, using a complete solution (CS), -N, -P, -K, -Ca, -Mg combined with absence and presence of Si (1.5 mmol L−1). Symptomatic, physiological, nutritional and evaluation vegetative were performed in quinoa crop. The deficiencies of N, P, K, Ca and Mg in quinoa cultivation caused visual symptoms characteristic of the deficiency caused by respective nutrients, hence decreasing the plant dry mass. However, Si supply attenuated the deficiency effects by preserving the photosynthetic apparatus, increasing the chlorophyll production, increasing the membrane integrity, and decreasing the electrolyte leakage. Thus, the Si supply attenuated the visual effects provided by deficiency of all nutrients, but stood out for N and Ca, because it reflected in a higher dry mass production. This occurred because, the Si promoted higher synthesis and protection of chlorophylls, and lower electrolyte leakage under Ca restriction, as well as decreased electrolyte leakage under N restriction.

LEAF DIAGNOSIS AND PRODUCTIVITY OF FORAGE SORGHUM FERTIGATED WITH NITROGEN DOSES IN TWO HARVESTS

The aim of the present study was to evaluate the degrees of macronutrients in the diagnostic leaf and the productivity of forage sorghum IPA 467, submitted to fertigation with nitrogen doses, during two harvests (summer and winter), both without regrowth. From January 20 to May 18 and from June 17 and October 14, 2016, two experiments were conducted in Canindé de São Francisco, State of Sergipe, in the Brazilian semi-arid. The experimental design was randomized complete blocks, with four replications. The treatments consisted of four doses of N (0; 80; 160 and 240 kg ha-1). Joint analysis of variance was carried out, considering each different harvest as a new factor. The characteristics evaluated were the content of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) in the leaves, height of the plant, diameter of the stem,green mass productivity, dry mass productivity and percentage of dry mass. The macronutrient content in the leaves was incremented with increasing doses of N, except Ca which presented no influence. The winter crop promoted the highest content of K, while the summer crop presented an elevated absorption of Mg. The varying dosage of N or the harvests season did not influence dry mass productivity (average of 17,386 ton/ha-1). The content of N (23.16-26.68 g kg-1), P (3.16-4.11 g kg-1), K (10.98-33.36 g kg-1), Ca (3.61 g kg-1) and Mg (4.78-9.64 g kg-1) can be considered enough for the full development of the plant.

Impact of Hydrogels on Early Growth of Maize in Sandy Regosols: Progress towards Improving Growth Performance by Enhancing Water and Nutrients Retention Capacity of the Soil

Super Absorbent Polymers or hydrogels are known for enhancing the water-holding properties of soils. This experiment was conducted to evaluate the influence of four different locally-produced hydrogels and one commercially available hydrogel on the early growth of maize in sandy Regosols. Maize variety, Pacific 984 was tested with six treatments in Randomized Complete Block Design. T1 - Reference hydrogel (Sodium polyacrylate-based), T2 - Acrylic acid and acrylamide-based hydrogel where urea has incorporated chemically up to 11.08% (g/g), T3 - without urea incorporating to the hydrogel used in T2, T4 - similar to T2, but urea incorporated only up to 6.17% (g/g), T5- agriculture grade commercial hydrogel (Potassium polyacrylate-based) and T6 - control (without hydrogel) were used for the study. Soil properties and plant growth parameters were quantified. A significant difference was observed in soil pH, total N and available P among treatments after one month of application. Treatment 2 showed the highest total N (0.19%) while T4 showed the highest P (18.94 ppm). The highest growth performances were given by locally produced hydrogels over commercial hydrogel and control treatments. Treatment 2 recorded the highest leaf area (1153.3 cm2/plant), plant height (128.90 cm) and total dry mass production (49.36 g/plant) while T4 has recorded the highest stem girth (4.87 cm). It was observed that locally produced hydrogels including the hydrogel without incorporating urea, have given superior performance over commercial hydrogels. Therefore, it can be concluded that locally produced hydrogel-formulations can enhance the growth of maize effectively than imported commercial hydrogels.

Growth of Alfavaca-Cravo in Response to Different Levels of Shade and Tiririca Density

The species Ocimum gratissimum L. is widely utilized in food, cosmetics, and folk medicine, and is also an important source of essential oils. Understanding its behavior in response to environmental conditions is of paramount importance to improving crop management methods. In this context, the following study aimed to evaluate the effects of shade, and of competition with weeds (Cyperus rotundus L.), on the growth of Ocimum gratissimum L. The experimental design adopted was randomized blocks, in a 5 × 5 factorial scheme, with 5 levels of shading (48%, 75%, 77%, 83% and 90%) and 5 densities of Cyperus rotundus L. (0, 5, 10, 15 and 20 per pot), with 4 repetitions. The variables analyzed were main stem height (MSH), diameter of stem base (DSB), number of leaves on the principal branch (NL), number of ramifications (NR), chlorophyll index of leaves (CIL), foliar area (FA), dry mass of the aerial part of the medicinal species (DMAPm), dry mass of the aerial part of the weed species (DMAPw) and essential oil content (EOC). The results demonstrate that the Ocimum gratissimum L. plants presented compatible tolerance responses to up to 70% shading, and that competition with Cyperus rotundus L. was detrimental in a density above 13 plants per pot in interaction with shading. The highest dry mass production and, consequently, the highest oil yield, were obtained from the 48% shading treatment.

BLACK OAT AND RYEGRASS INOCULATED WITH Azospirillum brasilense IN CROP-LIVESTOCK SYSTEM

ABSTRACT The success of the integrated crop-livestock system depends on the correct pasture management, particularly regarding nitrogen fertilization and grazing intensity. The objective of this study was to evaluate the total production of forage and the proportion of the botanical and structural components of black oat and annual ryegrass mixture. The experimental design was randomized blocks with three replicates and the treatments were arranged in a three-factorial scheme: seed inoculation (with and without Azospirillum brasilense inoculation), grazing management (conventional grazing, where the animals were kept in pasture with no control of pasture height; 30, 20 and 10 cm at the end of grazing, and a control without grazing), and nitrogen fertilization (0, 50 and 100 kg nitrogen ha-1). In treatments with pasture heights where grazing ended at 30, 20 and 10 cm, the height was monitored and biomass was collected when the animals entered and exited the plots. Manual separation of the components was used to determine the dry mass of green leaves, stems, senescent material and inflorescence. Total dry mass production was obtained based on the initial forage mass plus the daily accumulation rates. The proportion of structural components varied according to the different grazing managements, nitrogen doses and inoculation with Azospirillum brasilense. Biomass production of black oat and ryegrass mixture was increased by nitrogen application and Azospirillum brasilense inoculation.

Association of Root and Leaf Silicon Application Decreases the C/Si Ratio, Increasing Carbon Gain and Dry Mass Production in Peanut Plants

ABSTRACT Silicon (Si), depending on the application method, can benefit the growth of peanuts by stoichiometric modification of carbon (C); however, this is not yet well known in this culture. Therefore, the objective was to evaluate whether different application forms of Si increases the growth of peanut plants due to stoichiometric changes C/Si and consequently stomatal conductance and photosynthesis. The experiment was carried out in a greenhouse in pots with nutrient solution using peanut plants cultivating granoleic. The treatments were: control, without Si application (-Si); Si via root (Si R) (2.0 mmol L−1) Si via leaf (Si F) (4.0 mmol L−1) and Si via root associated with leaf (Si R + F), arranged in randomized blocks with five repetitions. The variables analyzed were: Si content and accumulation, carbon percentage, C/Si ratio, efficiency of C use, photosynthesis, stomatal conductance, transpiration, dry matter and productivity. The application of root Si plus leaf spray is efficient to increase the accumulation of the element in the aerial part of the peanut. The benefit of Si in the growth of peanut plants is due to its effect of modifying the stoichiometric C/Si ratio in the plant, which resulted in an increase in the photosynthetic rate and, consequently, in the efficiency of the use of C and the production of dry matter and productivity of the plant.

Anatomical and physiological characteristics of leaves from Eugenia dysenterica DC. can predict nutritional deficiency symptoms

Plants receiving insufficient concentrations of the different essential nutrients may respond symptomatically to this stress. However, when the first visible symptoms of nutritional deficiency appear, plants already exhibit significant changes in their structure. As seedlings of E. dysenterica are important for the recovery of degraded areas and as the fruits of this species are widely exploited commercially, we decided to evaluate whether the omission of nutrients may affect the leaf anatomical ultrastructure, dry matter production and the synthesis of photosynthetic pigments in this plant, in an attempt to use data of this nature to predict symptoms of nutritional deficiency in seedlings of this species. For this purpose, we grow seedlings in a hydroponic system, offering all nutrients and also omitting each nutrient individually. Thus, we evaluated the effect of the omission of each nutrient on the anatomical leaf structure, dry mass production and the synthesis of photosynthetic pigments. Seedlings that grew in the absence of Ca and Mn exhibited compromised spongy parenchyma and mesophyll development, while the omission of K and Mg increased the number of epidermal cells and stomata. Low dry mass production in E. dysenterica was related to the omission of S and Mn, while P, N and Fe deficiencies directly affected the synthesis of pigments. Thus, leaf anatomical and physiological data can predict nutritional deficiency conditions, enabling the user to diagnose the deficiency before the onset of symptoms in E. dysenterica seedlings. Our results may help investigators to understand the effects of nutritional omissions on other native Cerrado plants

Acúmulo de matéria seca e nutrientes pelo milho cultivado sob doses de formulados npk mineral e organomineral

O conhecimento da extração e acúmulo de nutrientes pelas plantas durante seu desenvolvimento auxilia na determinação das suas necessidades nutricionais e é relevante para aprimorar a recomendação de fertilizantes minerais e organominerais. Objetivou-se avaliar o efeito de doses de fontes de formulado NPK mineral e organomineral na produtividade de massa seca da parte aérea e no acúmulo de macronutrientes e micronutrientes pelo milho. O experimento foi realizado em vasos plásticos, dispostos a céu aberto, preenchidos com 25 L de solo, coletado de um Latossolo Vermelho distrófico, fase cerrado, na Fazenda Experimental do Instituto Federal Goiano, Campus Rio Verde - GO. O delineamento experimental utilizado foi de blocos ao acaso, em esquema fatorial 5x2, com quatro repetições. Os tratamentos foram cinco doses de formulado NPK 04-14-08 (0, 150, 300, 450, 600 kg ha-1do produto, equivalente para vaso) e duas fontes de fertilizantes: mineral e organomineral da formulação, 04-14-08. A colheita das plantas de milho foi realizada aos 75 dias após a semeadura, com corte do colmo rente ao solo. Nas plantas, foram realizadas avaliações de produtividade de massa seca da parte aérea e acúmulo de macronutrientes (N, P, K, Ca, Mg e S) e micronutrientes (Cu, Fe, Mn e Zn). A fonte organomineral proporcionou maior produtividade de matéria seca ao milho. O acúmulo de nutrientes seguiu a ordem decrescente N > K > Mg > Ca > S > P > Fe > Mn > Zn > Cu. A fonte organomineral, nas mesmas doses do formulado mineral, apresenta potencial de substituir as fontes minerais.

The Major Chemical Constituents of Teosinte Grown as Mono and Mixed Cropping with Legumes in different Sowing Date

Teosinte (Euchlaena mexicana) is one of the most popular summer growing cereal fodder, yet with comparatively low level of chemical constituents. The quality of this fodder can be improved through better by cultivation management including sowing dates and mixed cropping with legume. The main objective of this study was to determine the forage quality as reflected by major chemical constituents of pure stands of teosinte and binary mixtures of teosinte with commonly available legumes under different dates of sowing. Four fodder combinations; teosinte mono crop, teosinte+ cowpea, tesosinte+ rice bean, and teosinte+ lablab bean was arranged to cultivate in three different date of sowing in the field in a Split Plot Design with 5 replications. Main plot treatments were different sowing dates and sub-plot treatments were combinations of fodder species. Dry herbage mass production, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL) and Ash were determined. The results showed that the significantly the highest Dry herbage and CP were obtained from fodder combination teosinte+ cowpea if sown at 18th April, whereas the significantly highest mean values of ADF and NDF were obtained for teosinte mono fodder crop. However, the lowest average value of ADF and NDF was obtained for fodder combination teosinte with cowpea. The average value of Ash and ADL of both harvest for fodder combination and date of sowing was statistically similar (p>0.05). The effect of treatments interaction/combination on cumulative dry herbage was statistically high (p<0.05) when teosinte+ cowpea was sown at 18th April. However, effect of treatments interaction/combination on average value of CP, NDF, ADF, ADL and Ash of both harvests (g/kg DM) was statistically similar (p>0.05). The results showed that mixture of teosinte with cowpea sown at 18th April could be the best combination in terms of quantity as well as for major chemical constituents that could reflect better quality of fodder harvest.

Macronutrient deficiency in cucumber plants: impacts in nutrition, growth and symptoms

This study aimed to assess the growth, nutrition and visual deficiency symptoms of cucumber plants as a function of macronutrient omission. The experiment was conducted in a completely randomized design, with seven treatments and four replicates, corresponding to nutrient solution without nutrient omission (CS) of Hoagland and Arnon, nitrogen (−N), phosphorus (−P), potassium (−K), calcium (−Ca), magnesium (−Mg) and sulfur (−S) omission. Omissions decreased the accumulation of macronutrients with detrimental effects in physiological variables and in the efficiency of absorption, transport and use of macronutrients, causing losses in growth and on dry mass production. Since the losses in dry mass in the shoot were up to 85%, 85%, 83%, 47%, 40% and 40% to the omission of Ca, Mg, N, P, K and S, respectively. The accumulation of macronutrients in the aerial part of cucumber plants that received the complete solution (CS) in relation to each omission (−) was 1058/75, 157/20, 958/152, 578/9, 147/5 and 142/12 for CSN/−NN, SCP/−PP, SCK/−KK, SCCa/−CaCa, SCMg/−MgMg and SCS/−SS, respectively. Therefore, the lowest macronutrients accumulation, the green color index, plant growth and dry matter production were reduced in cucumber plants. The order of limitation of macronutrients in the shoot dry matter production in cucumber plants was N = Ca = Mg > P > K = S.

Silicon fertigation and salicylic acid foliar spraying mitigate ammonium deficiency and toxicity in Eucalyptus spp. clonal seedlings.

Nitrogen deficiency and toxicity, primarily in its ammonium form (NH4+), can suppress plant growth and development. The use of silicon (Si) or salicylic acid (SA) may be an alternative to minimize the harmful effects of nutrient imbalances caused by NH4+, thereby improving the photosynthetic efficiency of plants. The aim of the present study was to assess the action of fertigation-applied Si and SA foliar spraying in mitigating NH4+ toxicity and deficiency in eucalyptus clonal seedlings. Two experiments were performed with eucalyptus clonal seedlings (Eucalyptus urophylla x Eucalyptus grandis), in a greenhouse. Both were carried out using a 4x2 factorial design and four concentrations of NH4+ (5, 15, 30 and 60 mmol L-1), in the absence and presence of Si (2 mmol L-1), in experiment I; or with and without SA foliar application (10-2 mmol L-1), in experiment II, with six repetitions. Nitrogen content rose as a result of increasing N-NH4+ concentration in the nutrient solution, and Si supplied via the nutrient solution was efficient in increasing the Si content in eucalyptus seedlings. The rise in N-NH4+ concentration favored the maintenance of the photosynthetic apparatus, but high N-NH4+ concentration increased energy loss through fluorescence and decreased the efficiency of photosystem II. The addition of Si to the nutrient solution proved to be beneficial to the photosynthetic apparatus by decreasing F0 at 15 and 30 mmol L-1 of NH4+; and Fm at all NH4+ concentrations studied. In addition, the beneficial element also increases Fv/Fm at all NH4+ concentrations studied. SA foliar application was also efficient in reducing photosynthetic energy losses by decreasing F0 and Fm at all NH4+ concentrations studied. However, SA only increased the Fv/Fm at the high concentrations studied (30 and 60 mmol L-1 of NH4+). Nitrogen disorder by deficiency or N-NH4+ toxicity reduced shoot dry mass production. The addition of Si to the nutrient solution and SA foliar application increased shoot dry mass production at all N-NH4+ concentrations studied, and benefitted the photosynthetic apparatus by decreasing fluorescence and improving the quantum efficiency of photosystem II as well as dry mass production.

Multiscale Assay of Unlabeled Neurite Dynamics Using Phase Imaging with Computational Specificity.

Primary neuronal cultures have been widely used to study neuronal morphology, neurophysiology, neurodegenerative processes, and molecular mechanism of synaptic plasticity underlying learning and memory. However, the unique behavioral properties of neurons make them challenging to study, with phenotypic differences expressed as subtle changes in neuronal arborization rather than easy-to-assay features such as cell count. The need to analyze morphology, growth, and intracellular transport has motivated the development of increasingly sophisticated microscopes and image analysis techniques. Due to its high-contrast, high-specificity output, many assays rely on confocal fluorescence microscopy, genetic methods, or antibody staining techniques. These approaches often limit the ability to measure quantitatively dynamic activity such as intracellular transport and growth. In this work, we describe a method for label-free live-cell cell imaging with antibody staining specificity by estimating the associated fluorescence signals via quantitative phase imaging and deep convolutional neural networks. This computationally inferred fluorescence image is then used to generate a semantic segmentation map, annotating subcellular compartments of live unlabeled neural cultures. These synthetic fluorescence maps were further applied to study the time-lapse development of hippocampal neurons, highlighting the relationships between the cellular dry mass production and the dynamic transport activity within the nucleus and neurites. Our implementation provides a high-throughput strategy to analyze neural network arborization dynamically, with high specificity and without the typical phototoxicity and photobleaching limitations associated with fluorescent markers.