Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Superação de dormência em sementes de Pithecellobium dulce (Roxb.) Benth.

This research aimed to evaluate different methods for breaking dormancy in seeds of Pithecellobium dulce (Roxb.) Benth., arboreal species of multiple use in the semiarid region of Northeast Brazil. The treatments were: control – intact seeds (T1); immersion in water until it reaches 80 °C (T2), and 100 °C (T3), concentrated sulfuric acid for five minutes (T4), 10 minutes (T5 ), and 15 minutes (T6), mechanical scarification with sandpaper number 80 (T7), mechanical scarification with sandpaper number 80 + immersion in water for six hours (T8), and for 12 hours (T9), soaking in water for 24 hours (T10), and for 48 hours (T11). The characteristics evaluated were such: emergency, mean emergency time, shoot length, root length, number of leaves, leaf area and total dry matter. The best method for breaking dormancy of seeds of Pithecellobium dulce (Roxb.) Benth. is mechanical scarification with sandpaper number 80.Nesta pesquisa objetivou-se avaliar diferentes métodos de superação de dormência em sementes de Pithecellobium dulce (Roxb.) Benth., espécie arbórea de uso múltiplo na região semiárida do Nordeste do Brasil. Os tratamentos empregados foram: testemunha (T1) – sementes intactas; imersão em água até atingir temperatura de 80 °C (T2) e 100 °C (T3); imersão em ácido sulfúrico concentrado durante cinco minutos (T4), 10 minutos (T5) e 15 minutos (T6); escarificação mecânica com lixa número 80 (T7); escarificação mecânica com lixa número 80 + imersão em água por seis horas (T8) e 12 horas (T9); imersão em água por 24 horas (T10) e 48 horas (T11). As características avaliadas foram: emergência, tempo médio de emergência, comprimento da parte aérea, comprimento da raiz primária, número de folhas, área foliar e massa da matéria seca total. O melhor método para superar a dormência de sementes de Pithecellobium dulce (Roxb.) Benth. é a escarificação mecânica com lixa número 80

Conditioning in the promotion and uniformization of Umbu seed germination

Abstract Seed dormancy may decrease during storage and some environmental conditions may accelerate this process. The aim of this work was to determine efficient techniques to condition umbu seeds in order to promote and standardize their germination. Seeds were stored for 180 days in paper bags kept in five ambient conditions: laboratory (25 ºC and 55% RH); warm oven (40 °C and 53% RH); hot oven (50 °C and 49% RH); dry chamber (18 °C and 65% RH) and cold chamber (10 °C and 65% RH). Seed quality was evaluated every 60 days by means of the following tests and determinations: water content; germination test (25 °C and 55% RH, weekly evaluated up to 91 days after sowing); first count test (14 days); germination rate index; mean germination time and electrical conductivity. The conditioning of umbu seeds in laboratory, or in warm oven (40 ºC) used efficient techniques to promote and standardize germination; under these conditions, after six months of storage, germination increased from 31% to 84 and 74%, respectively

Qualidade fisiológica de sementes de pimenta em função da idade e do tempo de repouso pós-colheita dos frutos

Um aspecto importante da produção de sementes é a determinação da maturidade fisiológica e do momento adequado de colheita, visando obter sementes de alta qualidade, minimizando a sua deterioração no campo. Diante disso, esta pesquisa teve por objetivo estudar a influência do estado de maturação dos frutos e dos períodos de repouso pós-colheita na qualidade fisiológica de sementes de pimenta (Capsicum baccatum L.), variedade Dedo-de-Moça, para determinação do ponto adequado para colheita das sementes. Os frutos foram colhidos em quatro estádios de maturação, com base na sua coloração: verde intenso (15 DAA), verde amarelado (25 DAA), verde avermelhado (35 DAA) e vermelho intenso (45 DAA) e submetidos ao armazenamento por 0; 5 e 10 dias para então, proceder à extração das sementes. Foram determinados o peso dos frutos, comprimento, diâmetro e espessura da polpa. A qualidade das sementes foi avaliada pelos testes de germinação, primeira contagem de germinação, emergência de plântulas, grau de umidade, massa seca de 100 sementes, peso de mil sementes e condutividade elétrica. Diante dos resultados, conclui-se que a maturidade fisiológica das sementes de pimenta, variedade Dedo-de-Moça, é indicada pela coloração vermelho intenso dos frutos (45 DAA); o repouso pós-colheita dos frutos por dez dias melhora o potencial fisiológico das sementes

TESTS FOR THE SELECTION OF FORAGE TURNIP PROGENY TO ORDER THE VIGOR AND LONGEVITY OF SEEDS

Forage turnip (Raphanus sativus L. var. oleiferus Metzg.) progeny with seeds of higher physiological quality are of importance for farmers and seed producing companies. The objective of this work was to identify tests to be used in laboratories for the selection of turnip progeny having seeds of higher germination, vigor, seedling emergence in the field, and storage potential. Seeds of 100 turnip progeny of paternal half-sibs were evaluated as to water content, 1,000-seed mass, first count of the standard germination test, accelerated aging, and seedling emergence in the field. The seeds were subjected to storage for 12 months in unifoliate paper bags kept under room conditions and then evaluated by means of the standard germination test, first count of the standard germination test, and water content. The data were examined as to variance and genetic and phenotypic correlations, heritability, coefficients of genetic variation, and selection gain. The standard germination test, first count of germination, and the accelerated aging test can be used to select forage turnip progeny for seed physiological quality and storage potential. None of the tests used were efficient at selecting progeny with high field emergence

Effects of processing phases on the quality of massai grass seeds

ABSTRACT Massai grass is an important tropical forage grass. The harvested seeds upon being received by the company, are found to be contaminated with impurities which are removable by processing machines. This procedure is necessary to produce seeds of a quality level within standards established for commercialization and sowing purposes. The objective of this project was to evaluate the effects of processing phases on the physical and physiological quality of massai grass (Panicum maximum x P. infestum, cv. Massai) seeds for commercialization purposes. Seeds were sampled before processing and after leaving the air and screen machine (upper and intermediary screens and bottom); first gravity table (drift, upper and intermediate spouts); treating machine; and second gravity table (upper, intermediate, and lower spouts). Seeds were evaluated as to water content, physical (purity and 1,000 seeds weight) and physiological quality (germination, first count of germination, seedling vigor classification, accelerated aging, seedling emergence in the field, speed of emergence index, and primary root length, shoot length). Massai grass seeds had their physical and physiological qualities improved when they were processed by an air and screen machine and a gravity table. Seeds from the intermediate discharge spout of the first gravity table, after going through the air and screen machine, are those of with highest physiological potential. The seeds of this species do not need to be processed to fit the germination and purity standards when the national market is the goal

Diferenciação de lotes de sementes de quiabo pelo teste de envelhecimento acelerado

Os testes de germinação e de vigor são componentes essenciais do processo de controle de qualidade das empresas produtoras de sementes, e o teste de envelhecimento acelerado é um dos mais utilizados para avaliação do vigor de sementes. Nesse sentido, a pesquisa teve como objetivo estudar a metodologia do teste de envelhecimento acelerado, visando à identificação de diferentes níveis de vigor de lotes de sementes de quiabo (Abelmoschus esculentus (L.) Moench). Para isso, quatro lotes de sementes da cultivar 'Colhe Bem' e cinco lotes da cultivar 'Santa Cruz 47' foram submetidos às seguintes avaliações: germinação, emergência de plântulas, envelhecimento acelerado tradicional e em solução saturada com NaCl (38 e 41ºC durante 24, 48, 72 e 96 horas) e grau de umidade no início dos testes e após a incubação para o teste de envelhecimento acelerado. Os testes de envelhecimento acelerado tradicional e em solução saturada com cloreto de sódio, a 41ºC durante 96 horas, constituem em opções promissoras para detectar diferenças de vigor entre lotes de sementes de quiabo