Mungbean (Vigna radiata (L.) Wilczek) or green gram as a dryland grain legume is exposed to varied timings and severity of drought stress, resulting in variability in photoassimilate production. In order to evaluate some physiological responses in one mungbean cultivar to timing and severity of drought stress, a 3-replicate RCBD (randomized complete block design) field experiment was carried ou...

* Here, we evaluated how increased shading and declining net photosynthetic capacity regulate the decline in net carbon balance with increasing leaf age for 10 Australian woodland species. We also asked whether leaves at the age of their mean life-span have carbon balances that are positive, zero or negative. * The net carbon balances of 2307 leaves on 53 branches of the 10 species were estimat...

With the rapid development of nanotechnology and widespread use of nanoproducts, concerns have arisen regarding the ecotoxicity of these materials. In this paper, the photosynthetic toxicity and oxidative damage induced by nanoFe3O4 on a model organism, Chlorella vulgaris (C. vulgaris) in aquatic environment, were studied. The results showed that nano-Fe3O4 was toxic to C. vulgaris and affected...

Net photosynthetic rates of Spirodela polyrrhiza turions, at low O(2) levels, were 6.2 and 38.8 micromoles O(2) per gram fresh weight per hour at 1 millimolar HCO(3) (-) and CO(2) saturation, respectively, and much lower in a regular low-pH growth solution. Air equilibration O(2) concentrations decreased rates considerably, except at CO(2) saturation. The surfacing rate of turions in various in...

A bio-optical mooring, which was deployed for 240 days during 1987 in the western Sargasso Sea (-35øN, 70øW), provided among other things a detailed record of the seasonal distribution of chlorophyll a fluorescence and the scalar irradiance of photosynthetically available radiation. This data base was augmented by shipboard measurements of chlorophyll a concentration, chlorophyll a fluorescence...

Photosynthetic data collected from Pisum sativum L. and Phaseolus vulgaris L. plants at different stages of development were related to symbiotic N(2) fixation in the root nodules. The net carbon exchange rate of each leaf varied directly with carboxylation efficiency and inversely with the CO(2) compensation point. Net carbon exchange of the lowest leaves reputed to supply fixed carbon to root...

Four mutants with delayed leaf senescence were selected from seed of durum wheat mutagenized with ethylmethane sulphonate. Changes in net photosynthetic rate, efficiency of photosystem II and chlorophyll concentration during the maturation and senescence of the flag leaves of both mutant and parental plants were determined under glasshouse conditions. The four mutant lines maintained photosynth...

Leymus chinensis is a dominant, rhizomatous perennial C3 species in the grasslands of Songnen Plain of Northern China, and its productivity has decreased year by year. To determine how productivity of this species responds to different precipitation regimes, elevated CO2 and their interaction in future, we measured photosynthetic parameters, along with the accumulation and partitioning of bioma...

To evaluate the effects of O3 on the net photosynthetic rate in flag leaves of rice (Oryza sativa L.) based on stomatal O3 flux and reactive oxygen species (ROS) scavenging enzyme activities, the Japanese rice cultivar Koshihikari was exposed to O3 for 1 month after heading in O3-exposure chambers. During the exposure period, rice plants were exposed to charcoal-filtered air or O3 at 60 or 100 ...

Relationships between net plant CO(2) exchange rate (CER) and canopy development were examined in ;jubilee' tomato over the initial 4 weeks of vegetative growth. A comparison was made between two plant groups that were alternatively exposed to 200 or 800 microeinsteins per square meter per second midday irradiation to establish a differential in net CER. Plants exposed to higher irradiation dem...