Abstract Contamination of water sources due to herbicide is of great concern. Clomazone is a pesticide with a high contamination potential which could possibility lixiviate to water streams. Changes caused by residual herbicide include flora modifications which are generally detrimental for some species. The lack of morphological studies performed in aquatic plants exposed to herbicide-contaminated environments has encouraged the development of our research. For the first time, we present a study that aimed to evaluate leaf injuries visible to the naked eye as well as microscopical effects which may be caused by clomazone on Pistia stratiotes. Pistia stratiotes was subjected to five concentrations of clomazone. Our analysis showed leaf injuries, especially after 15 days of clomazone application. Hormesis was observed when the water lettuce was subjected to the lower concentrations. Total leaf area showed increase following by reduction while injured until reaching the highest concentration. Although the concentrations of clomazone tested in our study are not lethal to water lettuce, such herbicide have still caused morphoanatomical damages on leaves which advocates for the use of P. stratiotes as a bioindicator of the presence of herbicides such as clomazone in water.

Resumo: O objetivo deste trabalho foi avaliar os efeitos de diferentes arranjos de plantas de eucalipto sobre as características morfoanatômicas de lâminas foliares de plantas de capim 'Marandu' [(Urochloa brizantha (Syn. Brachiaria brizantha)] cultivadas em sistemas agrossilvipastoris. O experimento foi estabelecido em condições de campo, em um delineamento de blocos ao acaso, com quatro repetições, em que as parcelas foram representadas pelos espaçamentos de plantio de eucalipto (12x2 e 12x4 m), e as subparcelas, pela distância entre o capim 'Marandu' e as fileiras de eucalipto (6, 4 e 2 m). Adicionou-se um controle apenas com capim 'Marandu', cultivado a sol pleno. As variáveis de anatomia foliar do capim 'Marandu' foram avaliadas quanto à interferência do sombreamento pelas árvores. A distância entre as plantas de capim 'Marandu' e as linhas de eucalipto interferiram na anatomia da lâmina foliar da forragem, e as maiores modificações ocorreram nas medidas lineares e proporções teciduais nos arranjos com maior densidade de eucalipto. A interferência do sombreamento pelo eucalipto nas características anatômicas das folhas de capim 'Marandu' depende do arranjo adotado. Isto ocorre em razão da adaptação do capim à baixa incidência de luz, com a consequente redução de sua atividade fisiológica e crescimento.

Abstract: The objective of this work was to evaluate the effects of different arrangements of eucalyptus plants on the morphoanatomical characteristics of leaf blades of 'Marandu' grass [(Urochloa brizantha (Syn. Brachiaria brizantha)] plants cultivated in agrosilvopastoral systems. The experiment was set in field conditions in a randomized complete block design with four replicates, in which the plots were represented by planting spacings of eucalyptus (12x2 and 12x4 m), and the subplots, by the distance between 'Marandu' grass and eucalyptus rows (6, 4, and 2 m). A control was added, composed by 'Marandu' grass cultivated in full sun. Variables of the leaf anatomy of 'Marandu' grass were evaluated for shading interference by trees. The distance of 'Marandu' grass plants from the eucalyptus lines interfered with the leaf blade anatomy of the forage, and the highest modifications occurred in linear measures and tissue proportions in the arrangements with the highest eucalyptus density. The shading interference of eucalyptus on the anatomical characteristics of leaf blades of 'Marandu' grass depends on the adopted arrangement. This occurs due to the grass adaptation to the low-light incidence, with a consequent reduction in its physiological activity and growth.

RESUMO Complexos rupestres apresentam uma grande diversidade de padrões fenológicos como resposta à alta biodiversidade deste ecossistema e sua variação ambiental. Espécies dioicas apresentam distinção entre os sexos quanto às exigências nutricionais para crescimento e reprodução, compreendendo fatores determinantes na variação da fenologia reprodutiva e vegetativa, principalmente em ambientes restritivos. O estudo objetivou compreender a fenologia reprodutiva e vegetativa da espécie dioica Baccharis platypoda, associando as estratégias fenológicas ao sistema sexual e às variações sazonais do ambiente. O estudo foi realizado em três áreas de campo rupestre, onde foi observada a fenologia de trinta plantas, entre setembro/2010 e setembro/2011. Foram aplicados o método de intensidade de Fournier, correlação de Spearman e análise circular. As fenofases reprodutivas tiveram início no mês de fevereiro com encerramento entre setembro e outubro, enquanto que as fenofases vegetativas apresentaram variações de intensidade ao longo desse período. As fenofases vegetativas de ambos os sexos apresentaram baixo padrão sazonal, enquanto que as fenofases reprodutivas apresentaram forte sazonalidade. A espécie B. platypoda apresentou pequenas variações nas estratégias fenológicas de indivíduos masculinos e femininos, principalmente na duração das fenofases reprodutivas e no crescimento vegetativo para alocação de recursos. A fenologia reprodutiva da espécie esteve associada a algumas variáveis ambientais, principalmente para as fenofases de frutificação, enquanto que a fenologia vegetativa, de modo geral, esteve mais associada à fenologia reprodutiva das espécies.

ABSTRACT Rupestrian grasslands present great diversity of phenological patterns in response to the high biodiversity of this ecosystem and its environmental variation. Dioecious species show distinction between the genders in relation to the nutritional requirements for growth and reproduction, comprehending determining factors, especially in restrictive environments. The purpose of the study was to comprehend the reproductive and vegetative phenology of the dioecious species Baccharis playtypoda, joining the phenological strategies with the sexual system and the environment seasonal variations. The study was performed in three areas of rupestrian grassland, where the phenology of thirty plants from September/2010 through September/2011 was observed. The Fournier intensity method, Spearman’s correlation and circular analysis were used. The reproductive phenophases began in February and ended between September and October, while the vegetative phenophases presented intensity variation during that period. The vegetative phenophases of both genders has shown low seasonal standard, while the reproductive phenophases has presented strong seasonality. The species B. platypoda has presented little variations in the phenological strategies of male and female individuals, mainly during the reproductive phenophases and in the vegetative growth for the allocation of resources. The species’ reproductive phenology had been associated to some environmental variables, mainly for the fructification phenophases, while the vegetative phenology, in general, had been most associated to the reproductive phenology of the species.

RESUMO A contaminação de ecossistemas por resíduos de defensivos agrícolas, especial atenção deve ser dada para os herbicidas passíveis de lixiviação. O objetivo foi selecionar espécies arbóreas para a rizodegradação de ambientes contaminados por resíduos de 2,4-D e atrazine, e para recomposição de mata ciliar aos campos agrícolas e, consequentemente, diminuir riscos de contaminação de cursos hídricos. Foram avaliados 36 tratamentos compostos pela combinação de 12 espécies florestais: [inga- Inga marginata Willd, guapuruvu - Schizolobium parahyba (Vell), ipê amarelo- Handroanthus serratifolius (A.H.Gentry) S.Grose, carobinha - Jacaranda puberula Chan, cedro- Cedrela fissilis Vell, landin -Calophyllum brasiliense Camb, goiabinha- Psidium myrsinoides Berg, quaresmeira-Tibouchina granulosa Cogn, pau-ferro - Caesalpinia ferrea Mart, sibipiruna - Caesalpinia pluviosa DC, capitão -Terminalia argentea Mart & Zucc e braúna- Schinopsis brasiliensis Enge S.F.Blacke] e três soluções simulando o composto lixiviado (atrazine, 2,4-D e água - controle), com quatro repetições cada. Foram mensuradas a altura da planta, o diâmetro do caule, o número de folhas, a área foliar e o acúmulo de biomassa seca e a nutrição foliar. A maioria das espécies apresentou increaseo em macronutrientes mesmo submetidas à aplicação dos herbicidas, sendo que o inga apresentou maior tolerância em relação as análise de crescimento. Assim, recomenda-se a utilização das espécies mais tolerantes aos herbicidas Atrazine e 2,4-D em experimentos de campo para confirmar os resultados preliminares desta simulação.

ABSTRACT Ecosystems contamination by residues of pesticides requires special attention to the herbicides subject to leaching. The objective was to select tree species to rhizodegradation contaminated by residues of 2,4-D and atrazine and to recompose riparian areas to agricultural fields, then reducing the risk of contamination of water courses. A total of 36 treatments consisted of the combinations of forest species were evaluated [Inga marginata (Inga), Schizolobium parahyba (guapuruvu), Handroanthus serratifolius (ipê amarelo), Jacaranda puberula (carobinha), Cedrela fissilis (cedro), Calophyllum brasiliensis (landin), Psidium mirsinoides (goiabinha), Tibouchina glandulosa (quaresmeira), Caesalpinia férrea (pau-ferro), Caesalpinia pluviosa (sibipiruna), Terminalia argêntea (capitão) and Schinopsis brasiliensis (braúna)] and three solutions simulating leachate compound (atrazine, 2,4-D and water - control), with four replicates each. The characteristics measured were plant height, stem diameter, number of leaves, leaf area and dry biomass, and foliar nutrition. Forest species survived the herbicide application, and most showed an increase in macronutrients even under an herbicide application, and the Inga had the highest tolerance regarding growth analysis. It is recommended to use species that are more tolerant to Atrazine and 2,4-D in field experiments to confirm previous results of this simulation.