to study the effects of foliar application of common and nano-sized iron sulphate on five sunflower cultivars (alster, olsion, hysun36, yourflour and hysun33) under two levels of salinity (0 and 100 mm nacl), a pot experiment in factorial based using a randomized complete block design with three replications was conducted. plant height, leaf area, shoot weight, chlorophyll content and the conce...

Vegetation phenology, as used and studied the related studies, refers to the relationship between climate and periodic development of photosynthetic biomass. selected 15 Hornbeam plots (Carpinus betulus) from study area in a mountainous region from 520m to 1310m above sea level. Ground observations of hornbeam tree growth process from January to December 2004 in 15 day intervals were performed ...

The resource availability hypothesis predicts an increase in the allocation to secondary metabolites when carbon gain is improved relative to nutrient availability, which normally occurs during periods of low irradiance. The present work was carried out to confirm this hypothesis by investigating the effects of decreasing irradiance on the production of plant secondary metabolites (flavonoids a...

Fresh-cut leafy vegetables have been gaining importance in the human diet both for their nutraceutical proprieties and low calories content. The preparation procedures for fresh-cut production and the storage system may lead to severe leaf damages that may affect leaf colour and induce shortened shelf life. The aim of this work was to study the leaf pigment changes in cut and whole Swiss chard ...

Leaf color mutants are common in higher plants that can be used as markers in crop breeding or as an important tool in understanding regulatory mechanisms in chlorophyll biosynthesis and chloroplast development. In virescent leaf mutants, young leaves are yellow in color, which gradually return to normal green when the seedlings grow large. In the present study, we conducted phenotypic characte...

Seasonal patterns of dry mass invested in chlorophyll and epidermal phenolic compounds (EPhen) were investigated in vivo using optical methods, in leaves of 2-year-old oaks (Quercus petraea Matt. (Liebl.)) grown under semi-controlled conditions. The plasticity of the seasonal pattern was investigated by applying stem girdling treatment. In control young expanding leaves, leaf dry mass per area,...

Methods for chlorosis detection and physiological condition monitoring in Vitis vinifera L. through accurate chlorophyll a and b content (Cab) estimation at leaf and canopy levels are presented in this manuscript. A total of 24 vineyards were identified for field and airborne data collection with the Compact Airborne Spectrographic Imager (CASI), the Reflective Optics System Imaging Spectromete...

Crop gross primary productivity (GPP) is an important characteristic for evaluating crop nitrogen content and yield, as well as the carbon exchange. Based on the close relationship observed between GPP and total chlorophyll content in crops, we applied a model that relies on a product of chlorophyll-related vegetation index and incoming photosynthetically active radiation for remote estimation ...

The regulatory role of ethylene in leaf senescence was studied with excised tobacco leaf discs which were allowed to senesce in darkness. Exogenous ethylene, applied during the first 24 hours of senescence, enhanced chlorophyll loss without accelerating the climacteric-like pattern of rise in both ethylene and CO(2), which occurred in the advanced stage of leaf senescence. Rates of both ethylen...

Recent studies have demonstrated the usefulness of optical indices from hyperspectral remote sensing in the assessment of vegetation biophysical variables both in forestry and agriculture. Those indices are, however, the combined response to variations of several vegetation and environmental properties, such as Leaf Area Index (LAI), leaf chlorophyll content, canopy shadows, and background soil...