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| MÁRQUEZ,EDJULY J.; FARIÑAS,MARIO R.; BRICEÑO,BENITO; RADA,FERMÍN J.. |
| In Venezuelan paramos grasses, after Asteraceae, are the second family in numerical importance. We studied their distribution in an altitudinal gradient located in Venezuela, Sierra de La Culata, between 2,500 and 4,200 m of altitude. Twenty one 32 m parallel line transects every 50 m were placed along the gradient, perpendicular to the main slope. Each line was divided into contiguous 50 x 50 cm sampling units. Grass species occurrence inside each sample unit was considered to determine their frequency in each line or altitude. The peak and altitudinal amplitude was determined through the weighted averaging method. A total of 47 grass species were found along the gradient. Agrostis was the best-represented genus in the gradient. Considering the... |
| Tipo: Journal article |
Palavras-chave: Altitudinal patterns; Phytogeography; Poaceae; South American Andes; Tropical high mountain. |
| Ano: 2004 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2004000400008 |
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| RADA,FERMÍN; BRICEÑO,BENITO; AZÓCAR,AURA. |
| Temperature determines plant formations and species distribution along altitudinal gradients. Plants in the tropical high Andes, through different physiological and morphological characteristics, respond to freezing night temperatures and high daytime energy inputs which occur anytime of the year. The main objective of this study was to characterize day and night temperature related responses of two Lupinus species with different altitudinal ranges (L. meridanus, 1,800-3,600 and L. eromonomos, 3,700-4,300 m of altitude). Are there differences in night low temperature resistance mechanisms between the species along the gradient? How do these species respond, in terms of optimum temperature for photosynthesis, to increasing altitude? Lupinus meridanus shows... |
| Tipo: Journal article |
Palavras-chave: Lupinus meridanus; Lupinus eromonomos; Frost avoidance; Freezing tolerance; Optimum temperature for photosynthesis. |
| Ano: 2008 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2008000300003 |
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