![\"\"](\"https:\/\/smastr16.blob.core.windows.net\/pgibt\/sites\/242\/2023\/01\/faixaposipa.jpg\")
<\/p>\n<\/p>\n
Em 28 de abril de 2022, por meio de videoconfer\u00eancia a aluna Regina Rodrigues Calixto do programa de P\u00f3s-Gradua\u00e7\u00e3o em Biodiversidade Vegetal e Meio Ambiente do Instituto de Pesquisas Ambientais (IPA), bolsista FAPESP (n\u00b0 2019\/19058-5) defendeu a disserta\u00e7\u00e3o de mestrado intitulada: \u201cEstrat\u00e9gias de uso de nitrog\u00eanio em excesso no solo por esp\u00e9cies da Floresta Atl\u00e2ntica sob a influ\u00eancia de alta temperatura\u201d.<\/p>\n
![\"\"](\"https:\/\/smastr16.blob.core.windows.net\/pgibt\/sites\/242\/2023\/08\/regina_rodrigues_calixto_ms-800x391.jpg\")
A banca examinadora foi presidida pela orientadora Dra Marisa Domingos (IPA) e contou com a participa\u00e7\u00e3o do Dra. Catarina Carvalho Nievola (IPA), Dr. Ricardo Keiichi Nakazato (Lobov Cient\u00edfica).<\/p>\n
Despite the anthropogenic deposition of soluble N compounds and the warming of the atmosphere have already been confirmed in the surroundings of urban remnants of Atlantic Forest in S\u00e3o Paulo, little is known about the effects of these environmental disturbances on biogeochemical processes in the soil and on the metabolism of N in the species present in these forest remnants. Therefore, the present study was proposed with the aims of verifying whether: 1) there is an increase in the bioavailability of NH4<\/sub>+ <\/sup>and NO3<\/sub>–<\/sup> in the soil and in the concentrations of soluble N in the roots and leaves of young plants of a pioneer tree species and a non-pioneer tree species, when grown in pots containing topsoil from an urban fragment of Atlantic Forest, after nitrogen addition; 2) the level of activity of nitrate reductase and glutamine sythetase, the concentrations of pigments in leaves and growth differ between those species; 3) the proportions between NH4<\/sub>+<\/sup> and NO3<\/sub>–<\/sup> in the soil and the strategies of use of these soluble forms of N by the three species are altered by the increase of the air temperature. Two independent experiments were carried out (one for each species) in a growth chamber, subdivided into two autonomous environments, called chamber 1 and chamber 2. In chamber 1, the plants were kept in a thermoperiod of 26\u00baC day\/19\u00baC night and in chamber 2, in a thermoperiod of 32\u00baC day\/20\u00baC night. Each experiment started with 96 plants per chamber, 48 plants grown in urban forest soil without N addition and 48 plants grown in the same soil with N addition, composing 4 completely randomized replicates per treatment, with 12 plants each. Three plants were removed per treatment replicate at 7, 14, 21 and 28 days of experiment. Roots and leaves of them were pooled to obtain 4 mixed samples from both organs per treatment every 7 days. The mixed root and leaf samples were analyzed for the activity of the enzymes nitrate reductase (NR) and glutamine sythetase (GS) and concentrations of NH4<\/sub> and NO3<\/sub>, chlorophylls a and b and carotenoids. Measurements of 14 height and number of leaves were measured, and dry biomass of leaves and roots was determined every 7 days. The soil used for the growth of the 3 seedlings per treatment replicate were removed at 7, 14, 21 and 28 days of experiment. It was also pooled to compose 4 mixed samples per treatment and per week for analysis of NH4<\/sub>+<\/sup> and NO3<\/sub>–<\/sup> concentrations. The data were submitted to analysis of variance with three factors (Factor 1: temperature; factor 2: soil treatment; factor 3: time). In a scenario of climate change and high disease deposition, there are indications that the species E. leiocarpa <\/i>is more susceptible to these effects, given that it showed a reduction in the number of leaves and an increase in pigments characteristic of oxidative stress. And the pioneer C. floribundus <\/i>demonstrated efficient strategies in the use of N and tolerance to climatic stress, which may be indicated for restoration work.<\/span><\/p>\n Key Words: High temperature, disease deposition, disease metabolism.<\/span><\/p>\n Apesar da deposi\u00e7\u00e3o antr\u00f3pica de compostos sol\u00faveis de N e o aquecimento da atmosfera j\u00e1 terem sido comprovados no entorno de remanescentes urbanos de Floresta Atl\u00e2ntica em S\u00e3o Paulo, pouco se conhece sobre os efeitos desses dist\u00farbios ambientais sobre os processos biogeoqu\u00edmicos no solo e sobre o metabolismo de N nas esp\u00e9cies presentes nesses remanescentes florestais. Sendo assim, o presente estudo foi proposto com os objetivos de: 1) verificar se h\u00e1 aumento da biodisponibilidade de NH<\/span>4+ <\/span>e NO<\/span>3- <\/span>no solo e das concentra\u00e7\u00f5es de N sol\u00favel nas ra\u00edzes e folhas de plantas jovens de uma esp\u00e9cie arb\u00f3rea pioneira e uma esp\u00e9cie arb\u00f3rea n\u00e3o pioneira, quando cultivadas em vasos contendo solo superficial proveniente de um fragmento urbano de Floresta Atl\u00e2ntica, ap\u00f3s adi\u00e7\u00e3o de nitrog\u00eanio; 2) verificar se o n\u00edvel de atividade de nitrato redutase e glutamina sintetase, as concentra\u00e7\u00f5es de pigmentos em folhas e o crescimento diferem entre as referidas esp\u00e9cies; 3) verificar se as propor\u00e7\u00f5es entre NH<\/span>4+ <\/span>e NO<\/span>3- <\/span>no solo e se as estrat\u00e9gias de aproveitamento dessas formas sol\u00faveis de N pelas duas esp\u00e9cies s\u00e3o alteradas pela eleva\u00e7\u00e3o da temperatura do ar. Foram realizados dois experimentos independentes (um para cada esp\u00e9cie) em uma c\u00e2mara de crescimento, subdividida em dois ambientes aut\u00f4nomos, denominados c\u00e2mara 1 e c\u00e2mara 2. Na c\u00e2mara 1, as plantas foram mantidas em termoper\u00edodo de 26\u00baC dia\/19\u00baC noite e na c\u00e2mara 2, em termoper\u00edodo de 32\u00baC dia\/20\u00baC noite. Cada experimento foi iniciado com 96 plantas por c\u00e2mara, sendo 48 plantas cultivadas em solo de floresta urbana com tratamento de fertiliza\u00e7\u00e3o balanceada e 48 plantas cultivadas no mesmo solo com fertiliza\u00e7\u00e3o balanceada + N, compondo-se 4 r\u00e9plicas inteiramente casualizadas por tratamento, com 12 plantas cada. Foram retiradas 3 plantas por r\u00e9plica de tratamento aos 7, 14, 21 e 28 dias de experimento. Ra\u00edzes e folhas destas foram reunidas de modo a obter 4 amostras mistas de ambos os \u00f3rg\u00e3os por tratamento a cada 7 dias. As amostras mistas de ra\u00edzes e folhas foram analisadas quanto \u00e0 atividade das enzimas nitrato redutase (NR) e glutamina sintetase (GS) e concentra\u00e7\u00f5es de N-NH<\/span>4 <\/span>e N-NO<\/span>3<\/span>, clorofila as a e b e carotenoides. Foram realizadas medidas de altura e n\u00famero de folhas e determinada a biomassa seca de folhas e ra\u00edzes a cada 7 dias. O solo utilizado para crescimento das 3 plantas por r\u00e9plica de tratamento foi retirado aos 7, 14, 21 e 28 dias de experimento e tamb\u00e9m foi reunido para compor 4 amostras mistas por tratamento e por semana para an\u00e1lise das concentra\u00e7\u00f5es de NH<\/span>4+ <\/span>e NO<\/span>3-<\/span>. Os dados foram submetidos a an\u00e1lise de vari\u00e2ncia com tr\u00eas fatores (Fator 1: temperatura; fator 2: tratamento de solo; fator 3: tempo). Em um cen\u00e1rio de mudan\u00e7as clim\u00e1ticas e alta 12 <\/span>deposi\u00e7\u00e3o de nitrog\u00eanio, h\u00e1 ind\u00edcios de que a esp\u00e9cie E. leiocarpa <\/i>seja mais suscet\u00edvel a esses efeitos, visto que apresentou redu\u00e7\u00e3o no n\u00famero de folhas e aumento de pigmentos caracter\u00edsticos do estresse oxidativo. E a pioneira C. floribundus <\/i>demonstrou estrat\u00e9gias eficientes no uso do N e toler\u00e2ncia ao estresse clim\u00e1tico, podendo ser indicada para trabalhos de restaura\u00e7\u00e3o.<\/span><\/p>\n Palavras-chave<\/span>: <\/span>Alta temperatura, deposi\u00e7\u00e3o de nitrog\u00eanio, metabolismo de nitrog\u00eanio.<\/span><\/p>\nRESUMO<\/strong><\/h4>\n
\n![\"pdf_grande\"](\"https:\/\/smastr16.blob.core.windows.net\/pgibt\/2013\/09\/pdf_grande.gif\")
<\/a>Regina Rodrigues Calixto<\/strong><\/a>
\nEstrat\u00e9gias de uso de nitrog\u00eanio em excesso no solo por esp\u00e9cies da Floresta Atl\u00e2ntica sob a influ\u00eancia de alta temperatura<\/a><\/p>\n
\n