basil plants (ocimum basilicum l.) were sprayed with salicylic acid (1mm) and exposed to ultraviolet-c (uv-c) radiation (40 wm-2) after emergence of six developed leaves. plants were grown for 18 days and exposed to uv-c for 5 mind-1 alternatively. chlorophyll a, chlorophyll b and carotenoide were considered for analysis of photosynthetic pigments. the results showed that the photosynthetic pig...

Effect of cobalt (Co) stress on morphological parameters and pigments of Arachis hypogaea L. were studied. Growth parameters such as, root and shoot length, number of nodules, total leaf area and root and shoot dry weights; photosynthetic pigments viz., chlorophyll ‘a’, chlorophyll ‘b’, total chlorophyll and carotenoid contents were analysed. Growth parameters and pigments have beneficial value...

BACKGROUND AND AIMS Theory for optimal allocation of foliar nitrogen (ONA) predicts that both nitrogen concentration and photosynthetic capacity will scale linearly with gradients of insolation within plant canopies. ONA is expected to allow plants to efficiently use both light and nitrogen. However, empirical data generally do not exhibit perfect ONA, and light-use optimization per se is littl...

Gross ecosystem productivity (GEP) in tropical forests varies both with the environment and with biotic changes in photosynthetic infrastructure, but our understanding of the relative effects of these factors across timescales is limited. Here, we used a statistical model to partition the variability of seven years of eddy covariance-derived GEP in a central Amazon evergreen forest into two mai...

Responses of leaf water relations and photosynthesis to summer drought and autumn rewetting were studied in two evergreen Mediterranean oak species, Quercus ilex spp. rotundifolia and Quercus suber. The predawn leaf water potential (Ψ(lPD)), stomatal conductance (gs) and photosynthetic rate (A) at ambient conditions were measured seasonally over a 3-year period. We also measured the photosynthe...

Desert vegetation plays significant roles in securing the ecological integrity of oasis ecosystems in western China. Timely monitoring of photosynthetic/non-photosynthetic desert vegetation cover is necessary to guide management practices on land desertification and research into the mechanisms driving vegetation recession. In this study, nonlinear spectral mixture effects for photosynthetic/no...

In a chlorophyll mutant (virescent) and wild-type cotton (Gossypium hirsutum L.), a number of photosynthetic parameters have been measured and compared with those published for other chlorophyll mutants. (a) The photosynthetic rates at 230 w/m(2) (400-700 nm) from a tungsten lamp were 36.8 mg CO(2) fixed/dm(2).hr (virescent) and 39.5 mg CO(2) fixed/dm(2).hr (wild-type). On a chlorphyll basis, t...

The physiological basis for the advantage of alternate partial root-zone irrigation (PRI) over common deficit irrigation (DI) in improving crop water use efficiency (WUE) remains largely elusive. Here leaf gas exchange characteristics and photosynthetic CO(2)-response and light-response curves for maize (Zea mays L.) leaves exposed to PRI and DI were analysed under three N-fertilization rates, ...

Plants or algae take many benefits from oxygenic photosynthesis by converting solar energy into chemical energy through the synthesis of carbohydrates from carbon dioxide and water. However, the overall yield of this process is rather low (about 4% of the total energy available from sunlight is converted into chemical energy). This is the principal reason why recently many studies have been dev...

Fast repetition rate (FRR) fluorometry is an optical technique for estimating photosynthetic properties of phytoplankton from measurements of variable fluorescence yield. I determined the minimum error in such estimates contributed by inherent instrument biases, improper measurement protocols, and the type of optimization algorithm used to infer photosynthetic variability from changes in variab...