No abstract

AbStRACt. Information on anatomical structure is needed by breeders working on improvement for drought tolerance. For studying the effect of polyploidy on cassava anatomy and its significance to tolerance to drought, we induced a polyploidy type of a selected clone (UnB 530) by applying an aqueous solution of 0.2% colchicine on lateral buds for a period of 12 h. The stem identified as tetraploid was propagated to produce the whole plant. Free-hand cross-sections of the median portion between stem internodes were made. They were clarified using 50% sodium hypochlorite solution, stained with 1% safranin-alcian blue, passed through an ethanol series and butyl acetate and mounted in synthetic resin. The tetraploid type showed more prismatic and druse crystals in the cortical parenchyma, and its pericycle fibers had thicker walls. The secondary xylem of tetraploid types was wider than diploid ones, having thinner walls and less starch.

A composição química de amostras de âmbar provenientes da Bacia do Recôncavo (Salvador, Bahia), datadas do Cretáceo Inferior, foi determinada por meio de CG-EM para caracterização das suas possíveis fontes botânicas. Os principais compostos identificados foram diterpenoides, tais como abietano, deidroabietano, tetraidroreteno, deidroabietol, ácido deidroabiético, ferruginol e sugiol. Outras classes de diterpenoides ou triterpenos não foram detectados. A composição dos extratos e os dados quimiotaxonômicos permitiram relacionar as amostras com coníferas das famílias Podocarpaceae ou Cheirolepidiaceae devido à detecção do ferruginol, um biomarcador específico para estas famílias. Desta forma, os dados concernentes aos âmbares da Bacia do Recôncavo forneceram informações quanto à presença de uma flora resinífera na Formação Maracangalha, quando da deposição de seus sedimentos durante o Cretáceo Inferior.The chemical composition of Lower Cretaceous amber samples from Recôncavo Basin (Salvador, Bahia) was performed by GC-MS to characterize possible botanical sources. The compounds identified were hydrocarbonic and polar diterpenoids, such as abietane, dehydroabietane, tetrahydroretene, dehydroabietol, dehydroabietic acid, ferruginol and sugiol. Other diterpenoid classes were not detected as well as triterpenoids. The composition of the extracts and chemosystematic data allows relating the samples to conifers of Podocarpaceae or Cheirolepidiaceae families due to detection of ferruginol, a specific biomarker to these families. The data concerning Cretaceous amber in the Recôncavo Basin provided information concerning the presence of a resinous flora in the Maracangalha Formation sediments during the Lower Cretaceous.

The Bauru Group is a sequence at least 300 m in thickness, of Cretaceous age (Turonian-Maastrichtian), located in southeastern Brazil (Bauru Basin), and consists of three formations, namely Adamantina, Uberaba and Marília. Throughout the Upper Cretaceous, there was an alternation between severely hot dry and rainy seasons, and a diverse fauna and flora was established in the basin. The ichnofossils studied were found in the Adamantina Formation outcrops and were identified as Arenicolites isp., ?Macanopsis isp., Palaeophycus heberti and Taenidium barretti, which reveal the burrowing behavior of the endobenthic invertebrates. There are also other biogenic structures such as plant root traces, coprolites and vertebrate fossil egg nests. The Adamantina Formation (Turonian-Santonian) is a sequence of fine sandstones, mudstones, siltstones and muddy sandstones, whose sediments are interpreted as deposited in exposed channel-bars and floodplains associated areas of braided fluvial environments.