The ecdysteroid 20-hydroxyecdysone (20E) is a steroid hormone found in insects and few plants. To analyze its temporal and spatial distribution in Pfaffia glomerata (Amaranthaceae), we selected among 71 accessions, the accession 13 which showed the highest root 20E total quantity (1.48 g/plant root). The 20E was constantly detected in flowers, leaves, stems, and roots, but its percentage was variable throughout its development. The highest 20E percentage was found in flowers (0.82%), roots (0.66%), leaves (0.60%), and stems (0.24%). While stems showed the least variable 20E percentage (0.13% - 0.24%), followed by roots (0.42% - 0.66%), and flowers (0.47% - 0.82%). Leaves showed the greatest 20E percentage variation (0.21% - 0.60%). The stem and leaves 20E total amount remained constant, showing a little variation while root 20E total amount increased over time, suggesting that 20E may be accumulated in roots. These findings suggest that 20E has tissue specific functions in plant and may have ecological significance since uncoordinated pulses of 20E are often lethal to insects.

Na caracterização de oito acessos de Polygonum punctatum Ell., utilizou-se a técnica de eletroforese horizontal em gel de amido a 12%. Determinaram-se os fenótipos isoenzimáticos da malato desidrogenase (MDH), fosfatase ácida (ACP), peroxidase (PO), glutamato desidrogenase (GDH), leucina aminopeptidase (LAP), esterase (EST), álcool desidrogenase (ADH), glutamato oxaloacetato transaminase (GOT), isocitrato desidrogenase (IDH) e chiquimato desidrogenase (SKDH), utilizando extratos de folhas jovens de cada acesso. A eletroforese foi conduzida em géis de amido de milho e amido hidrolisado. O amido de milho mostrou resolução satisfatória na separação das bandas isoenzimáticas da IDH, ADH e MDH. No entanto, para os demais sistemas, o amido hidrolisado apresentou resolução superior à do amido de milho. Todos os sistemas enzimáticos estudados, com exceção do sistema LAP, apresentaram elevado polimorfismo, permitindo estabelecer padrões individuais em todos os acessos. Isso demonstrou o potencial das isoenzimas como marcadores genéticos no gênero Polygonum.

The technique of horizontal electrophoresis of 12% starch gel was used to characterize eight accesses of Polygonum punctatum Ell. The isozymatic phenotypes of the malate dehydrogenase (MDH), acid phosphatase (ACP), peroxidase (PO), glutamate dehydrogenase (GDH), leucine aminopeptidase (LAP), esterase (EST), alcohol dehydrogenase (ADH), glutamate oxalacetate transaminase (GOT), isocitrate dehydrogenase (IDH) and shikimate dehydrogenase (SKDH) were determined using young leaves extracts of each accession. The electrophoresis was performed in corn starch and hydrolysed starch gels. The corn starch showed a satisfactory resolution, for separation of the isozymics bands of IDH, ADH and MDH. However, for the other systems, the hydrolysed starch presented better resolution. All enzyme systems studied, except for LAP, presented high polymorphism, allowing to establish individual patterns in all accesses, demonstrating the potential of the isozymes as genetic markers for the Polygonum.

The [3+4] cycloaddition between furan and the oxyallyl cation generated from 1-bromo-1-phenylpropan-2-one (4), resulted in the formation of 2-phenyl-8-oxabicyclo[3.2.1]oct-6-en-3-one (5) in 30% yield. This compound was further converted into 2-phenyl-6,7-exo-isopropylidenedioxi-8-oxabicyclo[3.2.1]oct-2-ene (13) in 35.4% yield. The selective effect of compound (13) and its isomer 3-phenyl-6,7-exo-isopropylidenedioxi-8-oxabicyclo[3.2.1]oct -2-ene (1a) on the radicle growth of Sorghum bicolor L. (sorghum) and Cucumis sativus L. (cucumber) were evaluated. For both plants, compound 13 showed to be more potent than its isomer 1a.

A síntese de vários análogos do 8-oxabiciclo[3.2.1]oct-6-en-3-ona é relatada. O efeito desses compostos e do ácido 4-oxoexanóico sobre a germinação e crescimento radicular do Sorghum bicolor foi avaliado. Na concentração de 100 ppm os compostos 3-(metoxicarbonilmetil)-8-oxabiciclo[5.3.0]dec-4-eno-2,9-diona (13) e ácido 4-oxoexanóico (17) apresentaram efeito estimulador do crescimento radicular de 33-35% e a 1000 ppm um efeito inibitório foi observado em ambos os casos (29% (13) e 80,2% (17). Todos os outros compostos inibiram o crescimento radicular a 100 e 1000 ppm. Nenhum efeito significativo foi observado sobre a taxa de germinação

The synthesis of several analogues of 8-oxabicyclo[3.2.1]oct-6-en-3-one is reported. The effect of these compounds and 4-oxohexanoic acid on the germination and radicle growth of Sorghum bicolor was evaluated. At 100 ppm compounds 3-(methoxycarbonylmethyl)-8-oxabicyclo[5.3.0]dec-4-ene-2,9-dione (13) and 4-oxohexanoic acid (17) showed 33-35% stimulatory radicle growth, and at 1000 ppm a 29% (13) and 80.2% (17) inhibition was observed. All the other compounds showed an inhibitory effect on the radicle growth at 100 and 1000 ppm. None of the compound had a clear effect on the germination rate.