Efecto de la contaminación ambiental sobre las superficies foliares de Pinus nigra de Els Ports (Castellón)

Possible alterations caused by air pollution in the wax structures of Pinus nigra needles, growing in 'els Ports' location (Castellón), have been examined by scanning electron microscopy. Our results show that the percentage of structurally functional epistomatic chambers decrease with needle age, being the adaxial surfaces preferently eroded. Structural alterations of epistomatic waxes in needles from trees growing in this area are greatly enhanced in comparison to controls.

Amylases from orange leaves. Characterization and relation to starch breakdown.

Starch content in adult orange (Citrus sinensis L. Osbeck) leaves was highest at the end of the winter rest period and decreased during flowering and fruit set. Young inflorescence leaves accumulated starch until the June drop period to decrease to a low value at the end of it. Both, α- and ß-amylase activities were found in the leaves and the enzymes separated through Sephadex G100 filtration. By electrophoresis in polyacrylamide gels with 0.25 % amylopectine, α-amylase was resolved in 5 bands, and ß-amylase in 7. Total amylolitic activity in the leaves was determined throughout the annual cycle in both adult and young leaves. Enzyme activities were not correlated with the rate of starch …

Actividad amilolítica y movilización del almidón en hojas de naranjo (Citrus sinensis L. Osbeck, cv. Washington Navel), en relación con la fructificación

Possible involvement of gibberellins on leaf expansion and carbohydrate accumulation in Citrus

During the spring flush of growth both vegetative shoots and inflorescences are formed in Citrus. Some of these inflorescences bear both flowers and leaves (GOLDSCHMIDT and MONSELISE 1972). The leaves from leafy inflorescences are smaller in size (GUARDIOLA et al. 1984) and differ in composition, both organic (SANZ et al. 1987b) and mineral (EMBLETON et al. 1973) as compared to leaves from vegetative sprouts. Some of these differences are related to the competition of nearby developing flowers and fruitlets, but a different type of regulation may also be involved. Early removal of developing reproductive organs had no effect on leaf growth (SANZ et al. 1987a). Further, inflorescence leaves …