Measurements of downwelling spectral irradiance were made during the fall of 1982 in the North Pacific Ocean (near 33øN, 142øW). These data are used to produce vertical profiles of downwelling irradiance for visible energy (400-700 nm) and photosynthetic available radiation (PAR). The profiles demonstrate that the attenuation of visible energy and PAR are primarily functions of chlorophyll pigm...

Plants have an ability to prevent chlorophyll accumulation, which would mask the bright flower color, in their petals. In contrast, leaves contain substantial amounts of chlorophyll, as it is essential for photosynthesis. The mechanisms of organ-specific chlorophyll accumulation are unknown. To identify factors that determine the chlorophyll content in petals, we compared the expression of gene...

Peridinin-chlorophyll-protein, a water-soluble light-harvesting complex that has a blue-green absorbing carotenoid as its main pigment, is present in most photosynthetic dinoflagellates. Its high-resolution (2.0 angstrom) x-ray structure reveals a noncrystallographic trimer in which each polypeptide contains an unusual jellyroll fold of the alpha-helical amino- and carboxyl-terminal domains. Th...

Passive optical hyperspectral remote sensing of plant pigments offers potential for understanding plant ecophysiological processes across a range of spatial scales. Following a number of decades of research in this field, this paper undertakes a systematic meta-analysis of 85 articles to determine whether passive optical hyperspectral remote sensing techniques are sufficiently well developed to...

the toxicity of four potentially toxic trace elements (cu, ni, pb and zn) to annual atriplex (a.hortensis and a. rosea) was examined to determine if this plant showed sufficient tolerance to be used tophytoremediate soils polluted with these heavy metals. the soils, which contained up to (per kilogram) 501mg cu, 1674 mg ni, 1334 mg pb and 3588 mg of zn were sampled around metal-contaminated sit...

abstract- to investigate the effect of draught stress on water relations, stomatal density, chlorophyll content and yield of rapeseed, an experiment was done with four levels of drought stress including l1 (field capacity, fc), l2 (70% available water content, awc), l3 (50% awc), and l4 (30% awc), within three growth stages- including stem elongation (t1), onset of flowering (t2) and silique fo...

Photosystem II Herbicides, Chlorotic Herbicides, Chlorophylls, Carotenoids, Phytochrome, Inhibitors Etioplasts of radish seedlings treated with photosystem II (DCMU, bentazon) and chlorotic herbicides (amitrole, SAN 6706) were tested on their ability to perform the phytochrome mediated chlorophyll and carotenoid biosynthesis. The cytoplasmic influence on the chloroplastic action of herbicides w...