Caracterizacion de plantas de chicozapote (Manilkara zapota (L.) P. van Royen) de la coleccion del CATIE, mediante el uso del analisis multivariado.

Efetuou-se a caracterização de plantas de sapotilha da coleção do CATIE com base em características qualitativas e quantitativas. Foram consideradas, no presente estudo, 49 variaveis, sendo 31 quantitativas e 18 qualitativas. Para análise estatistica dos dados, utilizou-se da análise de conglomerados, análise discriminante, discriminante canonicas, provas F para caracteristicas quantitativas e X2 para as qualitativas. As 13 plantas avaliadas formaram tres grupos, com quatro, seis e três plantas, respectivamente. Para estes agrupamentos, a prova F indicou somente seis características significativas entre os grupos das 31 avaliadas: diametro do fruto, diametro da polpa, rendimento do fruto, largura da folha, acidez e glicose. X2 apontou apenas a forma do fruto como diferente entre os três grupos das 18 avaliadas.

Climate seasonality limits leaf carbon assimilation and wood productivity in tropical forests.

The seasonal climate drivers of the carbon cy- cle in tropical forests remain poorly known, although these forests account for more carbon assimilation and storage than any other terrestrial ecosystem. Based on a unique combina- tion of seasonal pan-tropical data sets from 89 experimental sites (68 include aboveground wood productivity measure- ments and 35 litter productivity measurements), their asso- ciated canopy photosynthetic capacity (enhanced vegetation index, EVI) and climate, we ask how carbon assimilation and aboveground allocation are related to climate seasonal- ity in tropical forests and how they interact in the seasonal carbon cycle. We found that canopy photosynthetic capacity seasonality responds positively to precipitation when rain- fall is < 2000 mm yr-1 (water-limited forests) and to radia- tion otherwise (light-limited forests). On the other hand, in- dependent of climate limitations, wood productivity and lit- terfall are driven by seasonal variation in precipitation and evapotranspiration, respectively. Consequently, light-limited forests present an asynchronism between canopy photosyn- thetic capacity and wood productivity. First-order control by precipitation likely indicates a decrease in tropical forest pro- ductivity in a drier climate in water-limited forest, and in cur- rent light-limited forest with future rainfall < 2000 mm yr-1.