Chloramphenicol effects on adventitious root production by radish hypocotyls

Abstract The excision of the root accelerates greatly the formation of adventitious roots in the hypocotyl of etiolated radish seedlings, but if the seedlings develop in CAP 1×10−4M, no adventitious root are induced after cutting. IAA either alone or associated with CAP, significantly increases the number of primordia in normal hypocotyls if given at the moment of cutting, while it has not stimulatory effect on the hypocotyls of seedlings grown in CAP. IAA has significant effect on both elongation and tickening of hypocotyl segments prepared from seedlings grown in CAP, and this could indicate a specific action of the inhibitor either on a particular process or on particular cells. The endo…

An Investigation of the Seasonal Pattern of Mannitol Content in Deciduous and Evergreen Species of the Oleaceae Growing in Northern Sicily

In several species of the Oleaceae, mannitol, already present at considerable levels, accumulates in response to stress. This family comprises both deciduous and evergreen species, and we investigated the role of mannitol in deciduous malacophyll and evergreen sclerophyll species growing under the same conditions in the field. The relationship between mannitol content and changes in rainfall or temperature was also studied. The mannitol content of leaves of Fraxinus ornus L., F. angustifolia Vahl., Olea europaea L. and Phillyrea media L. was determined by gas chromatography. Leaf samples were collected once a month for 1 year. In the two ash species, the seasonal pattern of mannitol content…

Seasonal pattern of mannitol and malate accumulation in leaves of two manna ash species (Fraxinus ornusL. andF. angustifoliaVahl) growing in Sicily

ABSTRACT The content of mannitol and malate was assayed enzimatically during spring, summer and autumn, in leaves of two species of ash, Fraxinus ornus L. and Fraxinus angustifolia Vahl, traditionally cultivated in Sicily for the extraction of manna. Both species contain high levels of mannitol and show, on a dry weight basis, a 65–80% increase in the summer content of this polyol. The malate content differs in the two species: in F. ornus it shows a summer increase, but it is relatively low (65–115 µmol g-1 DW), while in F. angustifolia it is higher (275–318 µmol g-1 DW), but remains more or less constant throughout the year. The results suggest that in these species, under the local field…

Casparian Strips in the Leaf Intrastelar Canals of Isoetes duriei Bory, a Mediterranean Terrestrial Species

Abstract Anatomical observations, using light and fluorescence microscopy, were made on leaves of Isoetes duriei to verify the presence of casparian bands around the intrastelar canals. This peculiar anatomical feature, previously reported for some Isoetes species, is confirmed. The possible role of this endodermis-like structure, in the transport of water due to root pressure or in the accumulation of certain metabolites, is discussed in relation to the ecological and anatomical features of the species.

Karyological observations on Isoetes duriei Bory (Lycophyta, Isoetaceae) in Sicily

Morphological observations on the co-occurring geophytes Isoetes duriei Bory (Lycophyta, Isoetaceae) and Romulea columnae Sebast. et Mauri (Anthophyta, Iridaceae)

Some preliminary observations on the morphoplogy and leaf anatomy of two geophytes, Isoetes duriei and Romulea columnae, co-occurring in a Mediterranean temporary pond, have been reported. The species examined possess characters favourable to the survival of both flooded and arid conditions. The adaptive traits to flooding appear plastic in R. columnae, while I. duriei is “structurally” an aquatic plant. Evolutionary and ecological aspects are briefly discussed.