Estudos sobre a nutrição mineral do arroz: XIII. efeitos das deficiências de micronutrientes nas variedades IAC-25 e IAC-47

Rice plants were grown in nutrient solution lither in the presence or in the absence of B, Cu and Zn. The symptoms of deficiency were usually in agreement with those described in the literature. Growth of the variety IAC-47 (number of leaves, tillering and total dry matter) was relatively more affected; this variety, however did produce grains under the minus Cu treatment (one fourth of the yield observed in the "complete" treatment), which did not happen in the case of the other variety. At the beginning of the grain filling period the following leaf contents could be considered as indication of deficiency: B-13 to 25 ppm; Zn-20 ppm; no conclusion could be drawn with respect to Cu levels.Plantas de arroz, variedades IAC-25 e IAC-47 foram cultivadas em solução nutritiva e com deficiência de B, Cu e Zn. Foram obtidos sintomas de carência dos três micronutrientes. As deficiências induzidas provocaram diminuição na matéria seca total e no número de folhas das duas variedades. O mesmo ocorreu no numero de perfilhos da var. IAC-47. Foi feita a determinação dos teores dos micronutrientes nas plantas submetidas aos diferentes tratamentos o que forneceu dados que ajudam a avaliação do estado nutricional

Messinian vegetation and climate of the intermontane Florina–Ptolemais–Servia Basin, NW Greece inferred from palaeobotanical data: how well do plant fossils reflect past environments?

The late Miocene is marked by pronounced environmentalchanges and the appearance of strong temperature andprecipitation seasonality. Although environmental heterogeneityis to be expected during this time, it is challenging to reconstructpalaeoenvironments using plant fossils. We investigated leavesand dispersed spores/pollen from 6.4 to 6 Ma strata inthe intermontane Florina–Ptolemais–Servia Basin (FPS) ofnorthwestern Greece. To assess how well plant fossils reflectthe actual vegetation of the FPS, we assigned fossil taxa tobiomes providing a measure for environmental heterogeneity.Additionally, the palynological assemblage was compared withpollen spectra from modern lake sediments to assess biases inspore/pollen representation in the pollen record. We found aclose match of the Vegora assemblage with modern Fagus–Abiesforests of Turkey. Using taxonomic affinities of leaf fossils, wefurther established close similarities of the Vegora assemblage with modern laurophyllous oak forests of Afghanistan. Finally, using information from sedimentaryenvironment and taphonomy, we distinguished local and distantly growing vegetation types.We thensubjected the plant assemblage of Vegora to different methods of climate reconstruction and discussedtheir potentials and limitations. Leaf and spore/pollen records allow accurate reconstructions ofpalaeoenvironments in the FPS, whereas extra-regional vegetation from coastal lowlands isprobably not captured