A desinfestação prévia de sementes de arroz irrigado em condições laboratoriais favorece a expressão do potencial fisiológico

The purpose of this study was to analyze prior seed disinfestation of irrigated rice seeds with sodium hypochlorite and its effect on physiological quality. The experiment was conducted in the seed analysis laboratory of Santa Catarina State University (UDESC). Twenty-four (four per cultivar) seed lots of the cultivars SCSBRS Tio Taka, Epagri 109, SCS116 Satoru, SCS118 Marquês, SCS121 CL, and SCS122 Miura, produced in the Upper Itajaí Valley in the 2016/2017 season, were used in a completely randomized experimental design with four replications. Germination and vigor tests were performed with and without disinfestation seeds. For the germination test with disinfected seeds, there was a higher percentage of normal seedlings and a smaller number of abnormal seedlings and dead seeds. There was significant decrease in vigor without prior seed disinfestation. The fungi that infested the seeds caused an increase in the percentage of abnormal seedlings and dead seeds. Seed disinfestation prior to physiological test positively affects the results regarding the physiological quality of irrigated rice seeds.O objetivo deste estudo foi avaliar o efeito da desinfestação prévia de sementes de arroz irrigado com hipoclorito de sódio na qualidade fisiológica. O estudo foi realizado no laboratório de análise de sementes da Universidade do Estado de Santa Catarina (UDESC). Foram utilizados 24 lotes (quatro por cultivar) de sementes dos cultivares SCSBRS Tio Taka, Epagri 109, SCS116 Satoru, SCS118 Marquês, SCS121 CL e SCS122 Miura, produzidas na região do Alto Vale do Itajaí na safra 2016/17. O delineamento experimental utilizado foi o inteiramente casualizado com quatro repetições. Testes fisiológicos de germinação e vigor foram realizados em sementes com e sem desinfestação. Para o teste de germinação com sementes desinfestadas, houve maior porcentagem de mudas normais e menor número de plântulas anormais e sementes mortas. O vigor teve uma redução significativa quando não efetuado a desinfestação prévia das sementes. Os fungos que infestaram as sementes causaram um aumento na porcentagem de plântulas anormais e sementes mortas. O uso da técnica de desinfestação de sementes antes da submissão a testes fisiológicos, afeta positivamente o resultado da qualidade fisiológica das sementes de arroz

O ácido giberélico promove a superação da dormência de sementes de arroz e a formação de plântulas anormais

O arroz é uma das espécies que apresenta dormência após a colheita, podendo esta ser prolongada durante o armazenamento das sementes. Este trabalho teve por objetivo determinar se o ácido giberélico (GA3) é um promotor eficiente da superação de dormência em sementes de arroz e avaliar mudanças nas estruturas biológicas via histoquímica. A cultivar utilizada foi a SCS122 Miura submetida a 0 mg L-1, 500 mg L-1 e 1000 mg L-1 de GA3. Foram realizadas análises de germinação, viabilidade, comprimento de raiz, parte aérea e plântula, microscopia óptica do amido e quantificação dos açúcares solúveis totais. A utilização de 500 mg L-1 e 1000 mg L-1 de GA3 foi eficiente para a superação da dormência de sementes de arroz, reduzindo o percentual de sementes dormentes para 4% e 1% respectivamente. Apesar de reduzir o percentual dormência, a presença de GA3 provoca aumento do percentual de plântulas anormais, e por isso, nas concentrações utilizadas, não pode ser recomendado como método de superação em sementes de arroz. A microscopia óptica é eficiente para verificar que com a superação de dormência, ocorre a degradação dos grânulos de amido, aumentando a disponibilidade de açúcares solúveis totais para o crescimento e desenvolvimento de plântulas.Rice is one species that present dormancy after harvest and can be prolonged during seed storage. This work aimed to determine whether gibberellic acid (GA3) is an efficient promoter of dormancy-breaking in rice seeds and evaluate changes in biological structures via histochemistry. The cultivar used was SCS122 Miura submitted to 0 mg L-1, 500 mg L-1, and 1000 mg L-1 of GA3. Germination, viability, root, shoot and seedling length, starch optical microscopy, and quantification of total soluble sugars were performed. The use of 500 mg L-1 and 1000 mg L-1 of GA3 was efficient in dormancy-breaking rice seeds, reducing the percentage of dormant seeds to 4% and 1%, respectively. Despite lowering the dormancy percentage, the presence of GA3 causes an increase in the percentage of abnormal seedlings. Therefore, it cannot be recommended as a method of dormancy-breaking rice seeds at the concentrations used. Optical microscopy is efficient to verify that with the dormancy-breaking, the degradation of starch granules occurs, increasing the availability of total soluble sugars for the growth and development of seedlings

Vigor of hybrid corn seeds is determinant for the establishment of seedlings in the field

The objective of this work was to determine the importance of vigor during the initial establishment of the maize crop. The work was carried out using 8 lots of hybrid corn seed, in which four lots were characterized as high vigor and four lots characterized as low vigor. After obtaining the seeds, they were sown in the field to determine the association between vigor and seedling performance at 21 days after sowing. The experiment was carried out in a randomized block design with four replications. Seedling emergence was measured daily up to 21 days, and at the end of the period, the shoot length, root system length, total seedling length and their respective masses, root system volume and stem diameter were determined. Seed vigor was positively associated with all measured variables, except for root system length. All parameters evaluated were superior in the group of seeds characterized as having high vigor. It is concluded that the vigor of hybrid corn seeds is crucial for the higher speed and uniformity of emergence in the field, being essential to form seedlings with superior performance in field conditions

Revisión sistemática sobre los problemas de aprendizaje de los infantes en Latinoamérica 2010 - 2020

Mi presente investigación de revisión sistemática tuvo como objetivo Sistematizar las evidencias sobre problemas de aprendizaje en los infantes en Latinoamérica 2010 – 2020, con un enfoque cualitativo y de diseño No experimental descriptivo; para la investigación seleccionaron 30 artículos obtenidos en las bases de datos Scopus y Ebsco, las cuales se pudieron evidenciar que tienen relación al desarrollo del tema sobre los problemas de aprendizaje en los infantes y se basó de un instrumento de metodología Prisma, donde se obtuvieron 2, 860,3109 artículos de los cuales se fueron incluyeron los que tenían acceso 299,403, los que tenían un periodo de tiempo entre los años 2010 a 2020 encontramos 160,814, por materia 4,624, luego seleccionamos a partir del lugar, la lectura del título y resumen 75 al final solo se trabajó con 30 artículos con referente al tema a investigar. En conclusión se evidencio que los estudios encontrados en Latinoamérica en los años 2010 – 2020 tienen relación a los problemas de aprendizaje en los infantes, donde se puede concluir que los problemas de aprendizaje proviene del desarrollo cognitivo de los niños donde es el proceso mediante el cual el ser humano adquiere conocimientos desde la infancia a través del aprendizaje y la experiencia

Sowing density adjustment by rice seed vigor

ABSTRACT The use of high-vigor seeds combined with seeding density adjustment at sowing is speculated to ensure high yields. However, certain doubts regarding the effect of this combined approach on rice cultivation remain owing to the tillering capacity. In this context, the present study aimed to determine the effects of seeding density adjustment according to vigor on the initial establishment of seedlings in the field. A physiological characterization was conducted using the germination test, vigor by accelerated aging, electrical conductivity, first count, shoot length, root length, total seedling length, and dry mass in the 2019/2020 and 2020/2021 growing seasons. The evaluations were conducted using a completely randomized design with four replications. Subsequently, the seed lots were selected, from which a fraction of seeds were submitted to artificial vigor reduction. Afterward, these seeds were sown in the main producing regions of the state of Santa Catarina, under a randomized block design with four replications. Three treatment groups were formed: one without density adjustment, one with adjustment by germination, and one with adjustment by vigor in accelerated aging. Twenty-one days after sowing, the number of emerged seedlings per unit area was determined. An interaction between the factors of adjustment for density and seed quality was observed. This was evidenced in the fact that even with the adjustment of density by vigor, the seed lot with lower quality presented the emergence of a lower number of seedlings, and the performance of these seeds was not equivalent to that observed in the lot with superior quality. Accordingly, it was concluded that the seeding density adjustment by vigor combined with the use of seeds with high-vigor is a suitable strategy for achieving a significant increase in plant emergence during the initial establishment in the field

Brazilian Flora 2020: Leveraging the power of a collaborative scientific network

International audienceThe shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora