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Takahashi,Cassia A.; Ceccantini,Gregório C.T.; Mercier,Helenice. |
The leaf is the main organ of the vegetative body of tank epiphytic bromeliads, which may be subdivided into apical and basal parts. Little is known about the existence of morphological, anatomical or physiological differences between these two leaf portions. The objective of this study was to verify the existence of a differential capacity to assimilate nitrogen from urea between basal and apical leaf portions of Vriesea gigantea, a tank epiphytic bromeliad. Plants were cultivated in vitro in the presence of 5 mM urea for 15 days. During this period, the activities of the enzymes glutamine synthetase (GS, EC 6.3.1.2) and NADH-dependent glutamate dehydrogenase (NADH-GDH, EC 1.4.1.2) were quantified, as well as the densities of trichomes and stomata found... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Bromeliaceae; Glutamate dehydrogenase; Glutamine synthetase; Stomata; Trichome; Urea. |
Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202007000200004 |
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Mercier,Helenice; Souza,Beatriz Maia; Kraus,Jane Elizabeth; Hamasaki,Regina Mayumi; Sotta,Bruno. |
The in vitro culture of pineapple leaves on a shoot induction medium (SIM) results in the formation of protuberances and further development in shoots, and plantlets. The contents of endogenous indoleacetic acid (IAA) and five cytokinins (Cks), N6(2-isopentenyl)adenine (iP), N6(2-isopentenyl)adenosine (iPR), zeatin (Z), zeatin riboside (ZR) and N6-benzyladenine (BA), present in the basal portion of those leaves, were correlated to the organogenic response that occurs over 15 days of culture. The endogenous auxin/cytokinins ratio was lowest on the 3rd day, mainly due to a strong increase in the iP level. It seems that endogenous iP concentration triggered the induction signal for an organogenic response in pineapple leaf bases. The rise in iP content... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Ananas comosus; Auxin; Bromeliaceae; Cytokinin; Hormone signalling; Plant regeneration. |
Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202003000200006 |
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Oliveira,Maria Neudes Sousa de; Oliva,Marco Antonio; Martínez,Carlos Alberto; Mercier,Helenice; Silva,Marco Aurélio Pedron e. |
A hipótese de que a sensibilidade estomática ao ácido abscísico (ABA) possa ser influenciada pelas características da seiva xilemática, como pH e concentração de Ca2+, NO3- e PO4(3-), foi testada em plantas de Lycopersicon esculentum L. var. Santa Clara submetidas a estresse hídrico induzido pela adição de PEG 6000 à solução nutritiva. Estimou-se a sensibilidade estomática ao ABA pela relação transpiração/ABA xilemático. Plantas intactas foram submetidas a estresse hídrico rápido e lento e determinaram-se as variações de pH e as concentrações de Ca2+, NO3- e PO4(3-) na seiva do xilema Também se estudaram os efeitos de diversas concentrações de Ca2+, NO3- e PO4(3-) sobre a transpiração em folhas destacadas imersas em seiva artificial contendo ABA exógeno.... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Lycopersicon esculentum L.; Estresse hídrico; Seiva xilemática; Transpiração. |
Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202002000200006 |
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