BACKGROUND AND AIMS Previous studies have shown that silica in grass leaves defends them against small herbivores, which avoid high-silica grasses and digest them less efficiently. This study tested the idea that silica can reduce digestibility by preventing the mechanical breakdown of chlorenchyma cells. METHODS Both the percentage of total chlorophyll liberated from high- and low-silica gra...

using plant growth regulators at the stresses environment can improve plant growth and crop production. hence, in this research response of photosynthesis rate, chlorophyll, soluble sugar and flower dry weight of chamomile to methyl jasmonate under different salinity levels was studied. values of 0 (control), 75, 150, 225 and 300μm methyl jasmonate (meja) with salinity levels of 2, 6, 10 and 14...

Elevated atmospheric CO2 increases plant C fixation, and much of the soluble C content of deciduous leaf litter entering streams is leached as dissolved organic C (DOC). The effects of DOC from trembling aspen (Populus tremuloides Michaux) leaf litter grown under elevated (ELEV 1⁄4 720 ppm) and ambient (AMB1⁄4 360 ppm) CO2 on stream periphyton were measured during a 35-d experiment in outdoor a...

the effect of four citrus rootstocks {sour orange (citrus aurantium), bakraeii (c. reticulata × c. limetta, mexican lime (c. aurantifolia) and volkamerlemon (c. volkameriana)} were evaluated on sweet lime leaf chlorophyll content and mineral concentrations (n, p, k, ca, na, mg, fe, zn, mn, cl, cu, and b) in a completely randomized design of four replications. budded sweet lime on the above root...

to comparison the photosynthetic parameters and leaf chlorophyll content and fluorescence of safflower (carthamus tinctorios l.) cultivars under salinity stress, a pot experiment was carried out as factorial based on completely randomized design with three replications in summer 2011 in university of yasouj. first factor included four salinity levels (zero, 75, 150 and 225 mm (formed as 20 to 1...

Some proteolytic enzymes occurring in the leaves of field-grown corn (Zea mays) (B73) were identified and partially characterized. Changes in activities of several proteolytic enzymes and in concentrations of protein and chlorophyll as a function of intraleaf segments (tip to base), leaf position, and leaf senescence during grain development and maturation were followed in crude leaf extracts.T...

T h e PROSPECT leaf optical properties and SAIL canopy reflectance models were coupled and inverted using a set of 96 AVIRIS (Airborne Visible~Infrared Imaging Spectrometer) equivalent spectra gathered in afield experiment on sugar beet plots expressing a large range in leaf area index, chlorophyll concentration, and soil color. In a first attempt, the model accurately reproduced the spectral r...

Several methods for extracting the chlorophyll sensitive red-edge position (REP) from hyperspectral data are reported in literature. This study is a continuation of a recent paper published as ‘A new technique for extracting the red edge position from hyperspectral data: the linear extrapolation method’. The method was validated experimentally for estimation of foliar nitrogen concentrations of...

In recent decades petroleum pollution in the tropical rainforest has caused significant environmental damage in vast areas of the Amazon region. At present the extent of this damage is not entirely clear. Little is known about the specific impacts of petroleum pollution on tropical vegetation. In a field expedition to the Ecuadorian Amazon over 1100 leaf samples were collected from tropical tre...