Tiago Zanatta Aumonde

Respostas na germinação e no crescimento inicial de rabanete sob ação de extrato aquoso de Piper mikanianum (Kunth) Steudel

This study evaluated the allelopathic effects of an extract from P. mikanianum leaves on the germination and early growth of radish (Raphanus sativus L.). Leaf extracts were prepared at concentrations of 2, 4 and 8%. The pH and osmotic potential of the extracts were determined. Germination bioassay consisted of five replicates of 25 radish seeds distributed in Petri dishes with germitest paper and 7 mL of extract or water, and were kept at 25oC in B.O.D. for five days. Germination percentage (PG), germination speed (VG), germination speed index (IVG) and index of allelopathic effect (RI) were determined. For bioassay initial growth, seeds were germinated until the protrusion of the radicle was 2 mm and transferred to Gerbox boxes containing germitest paper and 15 mL of extract or water, which were kept for seven days at 25oC in B.O.D. to evaluate the length of the radicle and hypocotyl, fresh and dry mass, water content and chlorophyll content (a, b ​​and total). Leaf extracts from P. mikanianum negatively affected all parameters examined for germination (PG, VG, IVG and RI). The extracts affected the initial growth, causing reduction of the radicle length and stimulating the growth of the hypocotyl. In addition, the extracts at 8% concentration reduced fresh weight and water content. Extracts at concentrations of 2 and 4% increased the content of chlorophyll b and total chlorophyll. Thus, Piper mikanianum exerted an allelopathic effect on radish.

Seed vigor, antioxidant metabolism and initial growth characteristics of red rice seedlings under different light intensities

This work aimed to evaluate the effect that different intensities of light have on the physiological attributes of red rice seeds and seedlings. Before and after emergence, seedlings were exposed to light levels of 35%; 65% and 100% in a greenhouse. We evaluated shoots and roots, in terms of length and dry mass, as well as leaf area and content of chlorophyll (a,b and total). In leaves and roots, we quantified the activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and guaiacol peroxidase (POX). We determined the leaf area ratio (FA), leaf mass ratio (FW), specific leaf area (SA), and shoot/root ratio (PW). At higher light intensities, shoot length decreased, whereas root length, dry mass and number of tillers increased. Leaf area was greatest in seedlings exposed to a 65% light level. The FA, FW, SA and PW were lowest at a light intensity of 100%. Differences in light intensity had qualitative and quantitative effects on chlorophyll contents. The activity of SOD and CAT was higher at lower light levels, whereas the inverse was true for APX and POX activity. Extremes of light availability alter the activity of antioxidant enzymes, negatively affecting the initial growth characteristics and photosynthetic pigments of red rice seedlings.

Seedling length in wheat determined by image processing using mathematical tools

Seed vigour is determined by a series of laboratory tests, many of these laborious and time-consuming. In view of this, the present study aimed to compare the determination of seedling length in wheat using image processing, with the traditional method, as well as the ability of the method to determine seed vigour. The experimental design was completely randomised, with five replications comprising a single-factor experimental scheme. The data were analysed for normality by the Shapiro-Wilk test and variance analysis using ANOVA at 5% probability. The response variables were correlated using Pearsons test, and the methodologies for determining the length of the shoots and roots, by measuring with a graduated rule and by image processing, were compared using the F-test at 5% probability. To compare mean values between cultivars, Tukeys test at 5% probability was used. The length of the shoots and roots of wheat seedlings, determined by image processing using the Matlab ® mathematical tool, is efficient in separating the cultivars

Methodologies based on seedling performance for vigor assessment of pumpkin seeds 1

Seed vigor tests provide additional information provided by the germination test, producing more consistent data in different field conditions. This study aimed to evaluate procedures and methodologies for vigor testing to indicate which tests are sensitive to identify vigor levels between lots of pumpkin and squash seeds. Two species pumpkin (Cucurbita maxima) and squash (Cucurbita pepo) were used, and each one was represented by four lots, whose initial quality was assessed using the following tests: germination and first count, earliness of rdicle emission, speed, coefficient of velocity and mean germination time, Timsons index, vigor rating, seedling emergence, and mean emergence rate. In the test of earliness of rdicle emission at two days, there was no difference between lots of Cucurbita maxima, and there was adequate separation of Cucurbita pepo lots, while the cool germination test rated lots similarly to the primary root emergence test. For the Pumpkin and Caserta seeds, the cool germination, primary root emergence at 3 and 4 days and seedling vigor rating tests showed separation efficiency of lots as for physiological potential.

Composição do substrato, vigor e parâmetros fisiológicos de mudas de timbaúva (Enterolobium contortisiliquum (vell.) morong)

Este trabalho objetivou avaliar a influencia da composicao de um substrato organoarenoso sobre a emergencia e parâmetros fisiologicos de crescimento de plântulas de timbauva. As sementes foram submetidas a germinacao nas seguintes composicoes do substrato: T1) 100% areia; T2) 75% areia + 25% Tecnomax®; T3) 50% areia + 50% Tecnomax®, T4) 25% areia + 75% Tecnomax®; e T5) 100% Tecnomax®. As avaliacoes foram efetuadas aos 45, 90, 135 e 180 dias apos a semeadura, aferindo a altura da parte area e o diâmetro do coleto. Aos 180 DAS, determinaram-se a massa da materia seca de parte aerea, a massa da materia seca de raizes, a massa da materia seca total e os teores de clorofila a, b e clorofila total. A emergencia e os parâmetros fisiologicos de crescimento foram afetados negativamente pela composicao exclusiva de Tecnomax®, assim como os valores de clorofila b. O substrato comercial associado ao material inerte (areia) proporcionou maior expressao do vigor das sementes, teores de clorofila b e maior crescimento de mudas de timbauva.

Artificial Neural Network and Multivariate Models Applied to Morphological Traits and Seeds of Common Beans Genotypes

The aimed to characterize common beans genotypes utilizing multivariate models and artificial neural network thru the agronomic attributes and seeds dimensions. The experiment was conducted in the 2017/2018 crop season at the city of Tenente Portela - RS. The experimental design was expanded blocs, were 53 segregating F2 populations and ten cultivars considered checks, disposed in four repetitions. The accurate characterization of bean genotypes can be based in the reproductive period, cycle and seeds length. Genotypes with longer cycle increase the potential of ramifications, legume and seeds magnitude per plant and increase the seeds yield independent of the commercial group. The use of biometric approach allows revealing patterns to the genotype grouping, being the patterns magnitude dependent of the intrinsic premises to the Standardized Average Euclidian Distance, Tocher optimized grouping and Artificial Neural Network with non-supervised learning. It is defined that the Artificial Neural Network are determinant to define associative patterns, being these inferences indispensable to the common beans genotype selection that answer the agronomic attributes and seeds production.

Effects of Macronutrients in the Physiological Quality of Soybean Seeds

The aim of this work was to correlate macronutrient content of soybean seeds to physiological quality of different cultivars. The work was developed in the Federal University of Pelotas, in the facilities of the Seed Science and Technology Graduate Program. The experimental design was randomized blocks in arranged in four replicates. The following soybean cultivars were used: BMX Apolo RR (12 lots), BMX Ativa RR (13 lots), BMX Energia RR (26 lots), BMX Forca RR (24 lots), BMX Impacto RR (35 lots), BMX Magna RR (16 lots), BMX Turbo RR (44 lots), BMX Potencia RR (82 lots) and NA 5909 RR (28 lots), with seeds produced in northwest Rio Grande do Sul. The determination of nutritional contents found in plant tissues of soybean seeds, were measured: Nitrogen (N), Phosphorus (P), Potassium (K), Magnesium (Mg), Calcium (Ca), Sulfur (S). The macronutrient contents of the seeds vary according to genetic characteristics of the cultivars, with higher oscillations of nitrogen, phosphorus, magnesium and sulfur contents present in soybean seeds. Potassium and calcium are defined as the most stable nutrients for the cultivars and seed lots analyzed. High concentrations of nitrogen, phosphorus and calcium are determinants for the physiological quality of soybean seeds.

Adaptabilidade e estabilidade de genótipos de trigo de acordo com índice fenotípico de vigor de sementes

The objective of this work was to evaluate the adaptability and multi-trait stability of wheat (Triticum aestivum) genotypes according to the phenotypic index of seed vigor (PIV). Thirty wheat genotypes were grown in seven environments in the state of Rio Grande do Sul, Brazil, during one crop season. In each environment, a randomized complete block design with three replicates was used. The PIV was elaborated from the following traits: first germination count, germination percentage, accelerated aging, and electrical conductivity. The evaluated phenotypic index makes it possible to define macroenvironments for the production of wheat seeds with high physiological potential and to understand the implications of the genotype x environment interaction. The phenotypic index of seed vigor is effective to rank genotypes considering multi-trait selection related to the vigor of wheat seeds produced in Southern Brazil.

Ecology of Upland Rice Plants and Seeds Subjected to Growth Regulator

The objective of this work is to verify the influence of the plant regulator trinexapac-ethyl on plant growth and physiological quality of upland rice seeds. We used an upland rice genotype, and the growth regulator was the trinexapac-ethyl. The experiment was completely randomized in a 4 × 8 factorial design related to four concentrations of the plant regulator trinexapac-ethyl [0 (without growth regulator), 0.25, 0.50, and 0.75 L c.p. ha-1] and 7 plant collection times [14, 28, 42, 56, 70, 84, 98 days after emergence (DAE)], with four replicates. To determine growth attributes, we evaluated total dry matter, dry matter production rate, relative growth rate, leaf area ratio, leaf matter, leaf area index, solar energy conversion efficiency and partition of assimilates. The physiological quality of the seeds was evaluated based on germination, first germination count, field emergence, emergence speed index and seedling dry matter. Plant growth was affected by the growth regulator. Total dry matter, dry matter production rate and solar energy conversion efficiency decreased, while leaf area index, leaf area ratio and leaf matter increased due to the effects of the growth regulator. The dry matter partition of plants changed in plants subjected to the growth regulator, with a delay in the targeting of assimilates to reproductive organs and a greater allocation to roots at the end of the cycle in plants subjected to the doses 0.50 and 0.75 L·ha-1 of growth regulator. Seed vigor was adversely affected by the growth regulator.

Ação do extrato de Lolium multiflorum Lam. sobre atributos fisiológicos de sementes e plântulas de alface

O objetivo deste estudo foi avaliar a influencia da concentracao do extrato de L. multiflorum Lam.sobre o desempenho fisiologico de sementes e sobre o metabolismo antioxidante de plântulas de alface. Os tratamentos foram as concentracoes de 0; 2; 4; 6 e 8 % do extrato aquoso de folhas. Foram avaliados a germinacao, primeira contagem de germinacao, indice de velocidade de germinacao, condutividade eletrica, emergencia de plântulas, massa seca total de plântulas, conteudo de peroxido de hidrogenio, peroxidacao de lipideos, atividade das enzimas, superoxido dismutase, catalase e ascorbato peroxidase. O extrato de L. multiflorum afeta negativamente o desempenho fisiologico de sementes e plântulas de alface. O aumento da concentracao do extrato ocasiona elevacao na atividade das enzimas antioxidantes, as quais nao foram eficazes para reverter o efeito toxico do extrato, o que pode ser evidenciado pelo aumento da peroxidacao lipidica e conteudo de peroxido de hidrogenio.