Dentre as formações florestais do sul e sudeste do Brasil, a Floresta Ombrófila Mista é considerada uma das mais sensíveis às variações climáticas. Vários estudos paleoambientais buscam identificar em que época esse tipo de floresta se estabeleceu no sul do Brasil. Este artigo tem como objetivo apresentar o registro da Floresta Ombrófila Mista na região sudoeste e sul do Estado do Paraná, a partir de dados palinológicos e geocronológicos. Este estudo foi desenvolvido na Unidade de Conservação Estadual Área de Relevante Interesse Ecológico do Buriti, município de Pato Branco, PR, Brasil. Na análise palinológica foi registrado a presença de 37 táxons, sendo que, o registro de Araucaria é de pelo menos 13.400 anos AP 14C (est.), portanto, um dos registros mais antigos já encontrados no Estado do Paraná. A expansão de Araucaria e Podocarpus em torno de 4.210 anos A.P. indica que o clima era mais frio e mais úmido, com chuvas bem distribuídas.

The whitefly, Bemisia tabaci Biotype B (Hemiptera: Aleyrodidae), is considered one of the world’s major agricultural pest groups, attacking a wide range of crop hosts and causing considerable crop loss. Understanding the interactions between whiteflies and host plants promotes the development of novel strategies for controlling whiteflies. This study aimed to evaluate the biochemical alterations caused by induced resistance in soybean plants, challenged by B. tabaci. The experiment was performed at the Federal University of Technology, Parana. Soybean seeds (cv. BRS 284) were sown in polyethylene pots in the greenhouse. The elicitors sprayed on the soybean leaves were: acibenzolar-S-Methyl (ASM-0.005%); Salicylic Acid (SA-2Mm); foliar phosphite (ULTRA K®-0.004%); Chitosan (CH-1%); and silicon (SI-0.25%); whilst the control group was sprayed with distilled water. Plants were infested with 50 adult whiteflies in the cages that were released after applying the treatments. At 0, 24, 48 and 96 hours after the beginning of the experiment, biochemical analyses of total proteins and the activity of the phenylalanine ammonia-lyase (PAL), peroxidases (PO), phenolic compounds, chitinase, and β-1,3-glucanase were made. The results showed that the application of elicitors increased the route of the phenylpropanoids with the activation of PAL and formation of phenolic compounds. It was also verified the activation of pathogenicity-related enzymes such as peroxidases and chitinase.

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This work aimed to evaluate the physiological and biochemical performance of lettuce (Lactuca sativa L.) seeds treated with essential oils (EOs) of citronella (Cymbopogon sp.), guaçatonga (Casearia sylvestris Sw.), melaleuca (Melaleuca sp. L.), patchouli (Pogostemon sp. Benth), and pitangueira (Eugenia uniflora L.). The experimental design was completely randomized in double factorials (5 oils × 4 doses) at different doses (10, 20, 30, and 40 μL), with an additional treatment that served as growth control (without EOs, 0 μL). In other words, the experimental design entails 5 oils × 4 doses + 1 control, with 4 replicates of 100 Grand Rapid lettuce seeds without industrial chemical treatment. The response variables were: first germination count (FGC, %), last germination count (LGC, %), germination rate (GR), normal seedlings (NS, %), abnormal seedlings (AS, %), aerial part length (APL, cm), fresh mass (mf, g), total soluble proteins content (mg•g-1), and enzyme activities of β-1,3-glucanase (UA•mg-1) and phenylalanine ammonia-lyase (PAL, UA•mg-1). The lettuce plant proved to be a good reference plant for evaluations related to physiological and biochemical performance when treated with EOs. However, although treatment of lettuce seeds with EOs did not cause undesirable damages, it positively altered the physiological parameters APL and mf. All EOs affected the total proteins content and enzyme activities of PAL and β-1,3-glucanase. Therefore, EOs demonstrated the potential to activate the plant's defense mechanism to control phytopathogens. More specifically, 10 μL of citronella EO activated two plant defense mechanisms: PAL and β-1,3-glucanase activities. In addition, EOs of melaleuca (10 and 40 μL) and patchouli (20 and 30 μL) also activated PAL enzyme activity.