1,721,045 research outputs found
Ultrastruttura del citoplasma di granuli pollinici di due cultivars di Malus domestica Borkh
No full text
Cytological effects of different pH on Allium roots
No full textThe cytological effects of acid pH were studied using root meristems of Allum cepa. Increasing levels of acidity in the growth medium resulted in a corresponding reduction in root length, mitotic index and chromosome aberrations. There is an increase of both chromosomal and mitotic abnormalities, such as sticky bridges, along with the increase in acidity op to pH 3.5, when mitotic activity is inhibite
Origin and development of Ailanthus glandulosa Desf. root suckers
No full textAilanthus glandulosa Desf. is a well known infestant plant, because of the ability of its roots to produce an excessive number of suckers.Such ability has been studied through an anatomical research on Ailanthus roots, with the purpose of determining the origin of the buds and their subsequent development into suckers. Moreover the reaction of the root system to a drastic natural and anthropic disturbance was examined
Alterazioni biochimiche indotte dal deterioramento in semi a riserva oleaginosa
No full textIl principale obiettivo delle ricerche sull’invecchiamento dei semi è l’identificazione di markers che permettano di rilevare il deterioramento prima che questo si manifesti attraverso la perdita della vitalità e del vigore e consentano di stabilire per ogni specie la velocità con cui esso avviene. La ricerca in oggetto ha utilizzato semi a riserva oleaginosa come modello per valutare i cambiamenti indotti dal deterioramento sul rilascio totale di ROS, su alcuni sistemi antiossidanti non enzimatici (tocoferolo) ed enzimatici (perossidasi e catalasi) e sulla composizione in acidi grassi e fitosteroli. Il deterioramento dei semi è associato a un incremento dei ROS, ad un declino degli enzimi antiossidanti (POD e CAT) e degli acidi grassi e ad un aumento del contenuto in Toc. L’aumento del rilascio dei ROS e la diminuizione del contenuto in acidi grassi sono dei parametri utili per il monitoraggio della qualità del seme durante la conservazione
Harmomegathy in heteranteric species
No full textHarmomegathy was described in five heterantheric species. The harmomegatic mechanism was evidentiated "in vitro" using solutions at different sucrose concentration
Identification of shoot apical meristem cells committed to form vascular elements in Pisum sativum L. and Vicia faba L.
No full textA cytochemical study of naphthol AS-D esterases in vegetative shoot apices of Pisum sativum and Vicia faba L. has shown the presence of carboxyl esterases (E.C. 3.1.1.1.) in those meristem cells already committed to form vascular elements. These cells form a sequence linking the morphologically identifiable procambium to the cells of the tunica layers at a site either already identifiable as the next primordium or which will form the next primordium. The implications of this result are briefly discussed in relation to the control of primordia formation and procambial cell development
Branchlets abscission in Quercus cerris L. related to oak decline: anatomical studies
No full textThe basic anatomy of lateral twig insertion onto the main branch in both healthy and damaged Quercus cerris L. trees was studied. An abscission zone is always present: in healthy trees it is formed by a smaller number of cell layers than in damaged ones, where it is more evident with many layers of cells. Cells of the abscission zone are roundish, with many intercellular spaces between them; cell walls are thin, non-lignified and without secondary walls. No starch was found in cells of the abscission zone, where, instead, a few scattered calcium oxalate druses are seen. © 1995 Springer-Verlag
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