Biphenyls and xanthones from the podostemaceae

Abstract Investigation of the fruiting parts of Mourera fluviatilis afforded 6-desoxyjacareubin, trapezifoliaxanthone and a series of eight new biphenyl derivatives; 3,5-dimethoxybiphenyl; 2,2-dimethyl-5-methoxy-7-phenylchromene; 2,2-dimethyl-7-methoxy-5-phenylchromene; 2-(3,3-dimethylallyl)-3-hydroxy-5-methoxybiphenyl; 2,3-dihydro-6-methoxy-4-phenyl-2,3,3-trimethylcoumarone; [(2,3-dihydro-3,3-dimethyl-6-methoxy-4-phenyl)-2-coumaronyl]methanol; 2,3-dihydro-3,3-dimethyl-6-methoxy-2-oxo-4-phenylcoumarone; and a dimeric biphenyl.

Developmental morphology of Apinagia multibranchiata (Podostemaceae) from the Venezuelan Guyanas

Abstract Apinagia ( c. 50 spp.) is the largest genus of American Podostemaceae. Apinagia multibranchiata (Matth.) Royen is a haptophyte endemic to the Venezuelan Guyanas. It fits well with the Podostemoideae bauplan known from other New World genera, such as Marathrum and Mourera . Shoots arise in pairs from filamentous creeping adhesive roots. During the rainy season submerged vegetative shoots grow up to more than a metre long. They are normally unbranched and provided with distichously arranged leaves which are laterally flattened into one plane. The lanceolate leaves may show a fimbriate tip. Tufts of threads are found on the upper leaf surface which faces the sky. When the water recede…

Untersuchungen über die Verankerung der Samen von Podostemaceen

Bioactive chromenes from Rhyncholacis penicillata.

Investigation of the aerial parts of Rhyncholacis penicillata afforded the new chromenes, 7-hydroxy-6-(3-methylbutyryl)-5-oxymethyl-chromene (rhynchonin A) and 7-hydroxy-6-(2-methylbutyryl)-6-oxymethylchromene (rhynchonin B). Structures were elucidated by spectroscopic methods and independent synthesis. Rhynchonin A showed broad insecticidal, acaricidal and nematicidal potency including strong biological activity against Heliothis zea.

The architecture ofMourera fluviatilis(Podostemaceae): developmental morphology of inflorescences, flowers, and seedlings

Mourera fluviatilis from northern South America is a spectacular member of the Podostemaceae (river-weeds). Its racemelike inflorescences are up to 64 cm long and have 40‐90 flowers arranged in two opposite rows. Inflorescence development starts with the initiation of a double-sheathed (dithecous) bract in a terminal position. All lateral bracts (again dithecous) are initiated in basipetal order along the two flanks of the inflorescence. Each gap between two neighboring bracts contains a single flower. The flowers are bisexual, each with a whorl of 16‐20 ligulate tepals and 14‐40 stamens, which are arranged in one or two whorls. Floral development starts with the formation of a girdling pri…

SEM-Untersuchungen an myxospermen Diasporen

The epidermal structure of mucilage producing seeds and fruits before and after contact with water is studied. Main emphasis is laid on the elucidation of structural peculiarities of the dessicated mucilaginous substances.

Untersuchungen über die Endospermschleime der Samen von Cercis siliquastrum L. und Ononis natrix L

Zusammenfassung Die Samen der Caesalpiniacee Cercis siliquastrum sowie die der Papilionacee Ononis natrix enthalten im unterschiedlich stark entwickelten Endosperm quellbare Zellwandschleime. Die Samen von Ononis natrix besitzen ein vergleichsweise gering entwickeltes Endosperm, jedoch sind die einzelnen Zellen bis zur volligen Reduktion des Lumens schleimerfullt. Bei Wasserzugabe quellen diese Zellwandschleime beider Arten unterschiedlich stark auf. Die Anfarbbarkeit der Endospermschleime wird anhand der Samen von Cercis siliquastrum fur verschiedene Farbstoffe beschrieben. Zur naheren Charakterisierung der Quellbarkeit der Endospermschleime werden Quellungsindex sowie Viskositatsveranderu…

Bestimmung des Schleimgehaltes myxospermer Diasporen verschiedener Angiospermenfamilien

The mucilage content of structurally differing myxospermatic diaspores from 49 species belonging to 19 families ofAngiospermae has been determined by applying various extraction procedures. The results demonstrate no obvious relationship between the size, mucilage quantity, and the swelling factor of the diaspores studied. Furthermore, mucilage producing structures and structural peculiarities of the mucilages themselves are elaborated.