Shade and sun leaves of Valencia orange [Citrus sinensis (L.) Osbeck] were collected to evaluate comparative effects of their leaf chlorophyll concentration, water content, thickness, and mesophyll volume of air on visible light reflectance, specifically the 0.45-, 0.55-, and 0.65-#m wavelength (WLs). The reflectance at the 0.45-, 0.55-, and 0.65-/~m WLs of sun leaves but not shade leaves was n...

Farmers must balance the competing goals of supplying contributions of background reflectance, while spectral vegetation indices that combined reflectances of near-infrared adequate N for their crops while minimizing N losses to the environment. To characterize the spatial variability of N and other visible bands (MCARI and NIR/Green) were responsive to both leaf chlorophyll concentrations and ...

increasing energy demands associated with economic growth and industrialization have resulted in dramatic increases in air pollution emissions. air pollution damages the plant mainly by disrupting cell homeostatic conditions.in the present study, diverse plant criteria indicating air pollution from different levels including cell biochemistry, leaf and tree crown in the plane-tree were determin...

* Corresponding author. E-mail addresses: [email protected] (M. Fang). 1537-5110/$ – see front matter a 2009 IAgrE doi:10.1016/j.biosystemseng.2009.12.008 Heavy metal stress in soils results in subtle changes in leaf chlorophyll concentration, which are related to crop growth and crop yield. Accurate estimation of the chlorophyll concentration of a crop under heavy metal stress is essential...

In situ optical meters are widely used to estimate leaf chlorophyll concentration, but non-uniform chlorophyll distribution causes the opticalmeasurement to vary widely among species for the same chlorophyllconcentration. Over 30 studies have sought to quantify the in situ/in vitro (optical/absolute) relationship, but neither chlorophyll extraction normeasurement techniques for ...

Plants need to allocate some of their limited resources for defense against herbivores as well as for growth and reproduction. However, the priority of resource allocation within plants has not been investigated. We hypothesized that plants with extrafloral nectaries (EFNs) invest more chlorophyll around their EFNs-to support a high rate of carbon fixation there-than in other leaf parts of youn...

Plant phenology, a sensitive indicator of climate change, influences vegetation-atmosphere interactions by changing the carbon and water cycles from local to global scales. Camera-based phenological observations of the color changes of the vegetation canopy throughout the growing season have becomepopular in recent years. However, the linkages between camera phenological metrics and leaf bioche...

Measuring plant chlorophyll concentration is a well-known and commonly used method in agriculture and environmental applications for monitoring plant health, which also correlates with many other plant parameters including, e.g., carotenoids, nitrogen, maximum green fluorescence, etc. Direct chlorophyll measurement using chemical extraction is destructive, complex and time-consuming, which has ...

in this study, the effect of four citrus rootstocks {sour orange (citrus aurantium), bakraeii (c. reticulata × c. aurantium, mexican lime (c. aurantifolia) and volkamerlemon (c. volkameriana)} on orlando tangelo leaf chlorophyll content and mineral element concentrations (n, p, k, ca, na, mg, fe, zn, mn, cl, cu, and b) have been evaluated in completely randomized design with four replications. ...