Effect of witch's broom disease on the phenology of Cupuassu

The cupuassu (Theobroma grandiflorum [Willd. ex Spreng.] Schum.) is expanding rapidly as a fruit crop in Brazilian Amazonia. The principal limiting factor is witch's broom disease, caused by Crinipellis perniciosa (Stahel) Singer, the only economic control for which is phytosanitary pruning. The phenology of 10 cupuassu plants grown in a fertilized monoculture on a nutrient poor Oxisol near Manaus, Amazonas, Brazil, was studied from May 1987 to December 1990. The number of flowers was reduced by the witch's broom and the pruning, but the duration and periodicity of flowering were not much affected. The mean number of fruits per tree fell from 36 in 1987 to 6 in 1989 as a result of the disease and its control, but recovered to 15 in 1990. Fruiting was slightly earlier and its duration was shorter than in a previous study, possibly due to the fertilization or the genotype studied. Fruit set fell from 1.4% in 1987 to 0.5% in 1989 and recovered to 1.8% in 1990, suggesting recovery of the plants. Leaf and shoot flushing and leaf fall increased markedly as a result of the disease in late 1987 and 1988 and were markedly reduced by pruning in 1989-90. Phenophases were not much affected by witch's broom disease and its control, although the number of flowers and fruits were.", 'enO cultivo do cupuaçuzeiro [Theobroma grandiflorum (Willd. ex Spreng.) Schum.] está em franca expansão na Amazônia brasileira. O principal fator limitante é a vassoura de bruxa, doença causada pela Crinipellis perniciosa (Stahel) Singer, cujo único controle econômico conhecido é a poda fitossanitária. A fenologia de dez cupuaçuzeiros em monocultivo, em solo Latossolo Amarelo distrófico adubado na região de Manaus, AM, foi avaliada de maio 1987 a dezembro 1990. O número de flores foi reduzido pela vassoura e pela poda, mas a duração e periodicidade da floração não foram muito afetadas. O número médio de frutos por planta caiu de 36 em 1987 para 6 em 1989, afetado pela vassoura e pela poda, tendo recuperado para 15 em 1990. A frutificação foi antecipada e sua duração reduzida em comparação ao estudo anterior, possivelmente devido à adubação e/ou ao genótipo estudado. O vingamento caiu de 1,4% em 1987 para 0,5% em 1989 e aumentou para 1,8% em 1990, sugerindo a recuperação das plantas. A brotação foliar e queda das folhas aumentaram marcadamente como resultado da influência da vassoura de bruxa em 1988 e foram reduzidas pela poda no período de 1989-90. Os fenofases não foram muito afetados pela vassoura de bruxa embora o número de flores e frutos tenham sido

Curso diário e sazonal do potencial hídrico foliar de mogno em sistema agroflorestal

This study aimed to evaluate the daily and seasonal course of the leaf water potential of Mahogany (Swietenia macrophylla King) (Meliaceae) in an agroforestry system (SAF). The experiment was carried out in Swietenia macrophylla trees planted in agroforestry system installed at the Experimental Field of Embrapa Western Amazon, Manaus-AM. We evaluated the leaf water potential (ψf) of the daily and seasonal course in 2004 and 2005 through the use of pressure bomb Scholander. The results showed that the values of ψf of Swietenia macrophylla, generally speaking, were higher in the early morning and late afternoon, with a marked reduction at noon and that, in regard to seasonal precipitation, the lowest rates were reported to the less rainy season, ranging from -26bar in 2004 to -31bar in 2005. It was found that the water potential of Swietenia macrophylla in agroforestry system was significantly reduced due to the low rainfall between June and October 2005. © 2015, Sociedade de Investigacoes Florestais. All rights reserved

TROCAS GASOSAS DE PLANTAS JOVENS DE TAXI-BRANCO SUBMETIDAS À VARIAÇÃO DE TEMPERATURA FOLIAR E SUSPENSÃO DA IRRIGAÇÃO

The study aimed to investigate the influence of leaf temperature variation associated with irrigation suspension on gas exchange of seedlings of Sclerolobium paniculatum Vogel. The study was carried out in a greenhouse at experimental area of Embrapa, Amazônia Ocidental. Plants were grown in a greenhouse and, after four months were subjected to three treatments (irrigated maintained until the field capacity, irrigation suspended for eight and 14 days). We evaluated the physiological parameters of gas exchange, net assimilation rate of CO2 (A), leaf transpiration (E), stomatal conductance (gs) and water use efficiency (WUE) which were obtained through a photosynthesis portable meter (CI-340, CID, Inc). The results showed reduction of net assimilation rate of CO2 depending on the elevation of the leaf temperature and without irrigation. After eight days without irrigation, decreased rates of photosynthetic assimilation of CO2 in 62, 65, 75, 58, 50 and 64%, and after 14 days the reduction was 80, 85, 85, 84, 86 and 93% compared to plants irrigated maintained at temperatures of 25, 30, 35, 40, 45 and 50 °C, respectively. The leaf transpiration was inversely proportional to rates of net photosynthetic assimilation of CO2, which has increased with an increased leaf temperature. The physiological behavior of gas exchange of Sclerolobium paniculatum showed variations both as regards to the effect of leaf temperature as the suspension of irrigation.O objetivo deste trabalho foi investigar a influência da variação de temperatura foliar associada à suspensão de irrigação sobre as trocas gasosas de plantas jovens de taxi-branco (Sclerolobium paniculatum Vogel). O estudo foi realizado em casa de vegetação na área experimental da Embrapa Amazônia Ocidental. As plantas cresceram em casa de vegetação e depois de quatro meses de aclimatização foram submetidas a três regimes hídricos (mantidas irrigadas até a capacidade de campo do solo, irrigação suspensa por oito e 14 dias). Foram avaliados os parâmetros fisiológicos de trocas gasosas, taxa de assimilação líquida de CO2 (A), transpiração foliar (E), condutância estomática (gs) e eficiência no uso da água (EUA) os quais foram obtidos por meio do medidor portátil de fotossíntese (CI-340, CID, Inc.). Os resultados mostraram que houve redução das taxas de assimilação líquida de CO2 em função da elevação da temperatura foliar e da suspensão da irrigação. Após oito dias de suspensão da irrigação houve redução das taxas de assimilação líquida de CO2 fotossintéticas em 62, 65, 75, 58, 50 e 64% e aos 14 dias esta redução foi de 80, 85, 85, 84, 86 e 93% em comparação as plantas mantidas irrigadas, nas temperaturas de 25, 30, 35, 40, 45 e 50°C, respectivamente. O comportamento das taxas de transpiração foliar foi inversamente proporcional às taxas de fotossíntese líquida, mostrando incremento em função do aumento da temperatura foliar. O comportamento fisiológico de trocas gasosas de Sclerolobium paniculatum apresentou variações tanto em relação ao efeito da temperatura foliar, quanto da suspensão de irrigação

GAS EXCHANGE OF SEEDLINGS OF TAXI-BRANCO SUBMITTED TO LEAF TEMPERATURE VARIATION AND IRRIGATION SUSPENSION

O objetivo deste trabalho foi investigar a influ\ueancia da varia\ue7\ue3o de temperatura foliar associada \ue0 suspens\ue3o de irriga\ue7\ue3o sobre as trocas gasosas de plantas jovens de taxi-branco ( Sclerolobium paniculatum Vogel). O estudo foi realizado em casa de vegeta\ue7\ue3o na \ue1rea experimental da Embrapa Amaz\uf4nia Ocidental. As plantas cresceram em casa de vegeta\ue7\ue3o e depois de quatro meses de aclimatiza\ue7\ue3o foram submetidas a tr\ueas regimes h\ueddricos (mantidas irrigadas at\ue9 a capacidade de campo do solo, irriga\ue7\ue3o suspensa por oito e 14 dias). Foram avaliados os par\ue2metros fisiol\uf3gicos de trocas gasosas, taxa de assimila\ue7\ue3o l\uedquida de CO2 (A), transpira\ue7\ue3o foliar (E), condut\ue2ncia estom\ue1tica (gs) e efici\ueancia no uso da \ue1gua (EUA) os quais foram obtidos por meio do medidor port\ue1til de fotoss\uedntese (CI-340, CID, Inc.). Os resultados mostraram que houve redu\ue7\ue3o das taxas de assimila\ue7\ue3o l\uedquida de CO2 em fun\ue7\ue3o da eleva\ue7\ue3o da temperatura foliar e da suspens\ue3o da irriga\ue7\ue3o. Ap\uf3s oito dias de suspens\ue3o da irriga\ue7\ue3o houve redu\ue7\ue3o das taxas de assimila\ue7\ue3o l\uedquida de CO2 fotossint\ue9ticas em 62, 65, 75, 58, 50 e 64% e aos 14 dias esta redu\ue7\ue3o foi de 80, 85, 85, 84, 86 e 93% em compara\ue7\ue3o as plantas mantidas irrigadas, nas temperaturas de 25, 30, 35, 40, 45 e 50\ub0C, respectivamente. O comportamento das taxas de transpira\ue7\ue3o foliar foi inversamente proporcional \ue0s taxas de fotoss\uedntese l\uedquida, mostrando incremento em fun\ue7\ue3o do aumento da temperatura foliar. O comportamento fisiol\uf3gico de trocas gasosas de Sclerolobium paniculatum apresentou varia\ue7\uf5es tanto em rela\ue7\ue3o ao efeito da temperatura foliar, quanto da suspens\ue3o de irriga\ue7\ue3o.The study aimed to investigate the influence of leaf temperature variation associated with irrigation suspension on gas exchange of seedlings of Sclerolobium paniculatum Vogel. The study was carried out in a greenhouse at experimental area of Embrapa, Amaz\uf4nia Ocidental. Plants were grown in a greenhouse and, after four months were subjected to three treatments (irrigated maintained until the field capacity, irrigation suspended for eight and 14 days). We evaluated the physiological parameters of gas exchange, net assimilation rate of CO2 (A), leaf transpiration (E), stomatal conductance (gs) and water use efficiency (WUE) which were obtained through a photosynthesis portable meter (CI-340, CID, Inc). The results showed reduction of net assimilation rate of CO2 depending on the elevation of the leaf temperature and without irrigation. After eight days without irrigation, decreased rates of photosynthetic assimilation of CO2 in 62, 65, 75, 58, 50 and 64%, and after 14 days the reduction was 80, 85, 85, 84, 86 and 93% compared to plants irrigated maintained at temperatures of 25, 30, 35, 40, 45 and 50 \ub0C, respectively. The leaf transpiration was inversely proportional to rates of net photosynthetic assimilation of CO2, which has increased with an increased leaf temperature. The physiological behavior of gas exchange of Sclerolobium paniculatum showed variations both as regards to the effect of leaf temperature as the suspension of irrigation

GAS EXCHANGE OF OIL PALMS TRESS SUBMITTED TO LEAFTEMPERATURE MODIFIED GROWN IN DIFFERENT PLANTATION SYSTEMS

Studies on the influence of leaf temperature rise on gas exchange in tropical tree species grown in plantations are rare. With regard to the predicted increase in air temperature in the future in the Central Amazon, we investigated the influence of increasing leave temperature on the gas exchange of oil palms cultivated in monocultures as well as in mixed plantations with cassava or banana. This study was carried out at the Embrapa Experimental Station in Presidente Figueiredo – AM – Brazil, 60 km north of Manaus. The net photosynthesis (Pn), transpiration (E), stomatal conductance (gs) and the water use efficiency (WUE) of the plants were quantified by a portable photosynthesis meter (CI-340). In all plantations increasing leaf temperatures caused a significant decrease of the net photosynthesis (Pn), stomatal conductance (gs), and the water use efficiency (WUE) of the oil palms. Maximum transpiration rates (E) were observed at leaf temperatures between 38 and 46°C. In addition to the influence of leaf temperature rise, the planting system also had a significant influence on the gas exchange of palm plants

CURSO DIÁRIO E SAZONAL DO POTENCIAL HÍDRICO FOLIAR DE MOGNO EM SISTEMAAGROFLORESTAL1

Este trabalho objetivou avaliar o curso diário e sazonal do potencial hídrico foliar de mogno (Swietenia macrophylla King) (Meliaceae) em sistema agroflorestal (SAF). O experimento foi realizado em árvores de S. macrophylla plantadas num sistema agroflorestal instalado no Campo Experimental da Embrapa Amazônia Ocidental, Manaus, AM. Avaliou-se o potencial hídrico foliar (Ψf) dos cursos diário e sazonal nos anos 2004 e 2005, por meio da utilização de bomba de pressão tipo Scholander. Os resultados indicaram que os valores do Ψf de S. macrophylla, de modo geral, foram superiores no início da manhã e no final da tarde, com redução acentuada ao meio-dia, e que, em relação à sazonalidade de precipitação, as menores taxas foram reportadas para a época menos chuvosa, variando de -26 bar em 2004 para -31bar em 2005. Verificou-se que o potencial hídrico de Swietenia macrophylla em sistema agroflorestal sofreu reduções significativas em razão dos baixos índices pluviométricos entre junho e outubro de 2005

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