Faba bean (Vicia faba L.) varieties reveal substantial and contrasting organic phosphorus use efficiencies (PoUE) under symbiotic conditions

Background

The excessive use of inorganic P (Pi) in soils is alarming as it is causing numerous environmental problems and may lead to the depletion of rock phosphate reserves earlier than expected. Hence, to limit the over-dependence on Pi, there is the need to investigate organic phosphorus (Po), which is the dominant P form of soil P pool, as an alternate P source for plant growth.

Aim

The present study seeks to investigate organic P use efficiency of eight varieties of faba bean grown symbiotically.

Methods

The plants were grown in pots (6 kg soil) under greenhouse condition with three P source, namely, phytic acid (organic P, Po), KH₂PO₄ (inorganic P, Pi), and no-P. The P was applied at the rate of 1.79 g kg⁻¹ soil.

Results

The plants grown with Po and Pi produced similar amounts of root, shoot, and total dry matters. Despite producing statistically similar dry matters, P uptake by Pi-fertilized plants was twofold higher than by Po-fertilized plants. Meanwhile, Pi differed significantly from Po in terms of nodulation characteristics such as nodule dry biomass and individual nodule dry biomass. However, Po varied significantly from Pi in P utilization and acquisition efficiencies. Principal component analysis of Pi and Po revealed no significant variation and close association, confirming the nonsignificant differences between the two P treatments. Among the varieties tested, Tiffany tended to accumulate more dry matter, coupled with highest organic P utilization efficiency (0.48 g mg⁻¹) as well as the highest organic P beneficiary factor (80%).

Conclusion

These results provide a solid basis for further comparisons at physiological, biochemical, and molecular levels between Tiffany (Po-efficient) and Fuego (Po-inefficient) varieties, offering deep insights into and making it easier to understand the mechanisms that allow soil Po to be utilized under symbiotic conditions.     

Interrelationships between red cell nucleoside triphosphate content,and blood pH,O2-tension and haemoglobin concentration in the carp,Cyprinus carpio

As a starting point for investigations of possible control factors for the nucleoside triphosphate content in carp red cells, we utilized the natural variability in blood physico-chemical parameters to test for interrelationships. By application of two-variable regression analysis, the red cell NTP content was found to be significantly correlated with arterial P_{O 2} and pH as well as with the blood haemoglobin (Hb) concentration. These correlations show a rise in red cell NTP content with falling pH as well as with falling Hb concentration, whereas a decrease in P_{O 2} was associated with a decrease in the content of NTP, particularly at low P_{O 2} values. Evaluation based on multiple regression analysis suggested that only P_{O 2} and pH significantly affected the red cell NTP content, and that the influence of changes in Hb concentration could be accounted for by naturally occurring simultaneous changes in P_{O 2} and pH. The multifactorial control of red cell nucleoside triphosphates is discussed in relation to the role of still unknown factors.     

Effects of river regulation and diversion on marine fish and invertebrates

The effects of freshwater regulation and diversion on the adult and larval stages of fish and invertebrates in coastal marine waters are reviewed. Potential impacts of river modification are highlighted based on our present understanding of the role of fresh water on the physical, chemical and biological processes on the marine environment. These include effects on migration patterns, spawning habitat, species diversity, water quality and distribution and production of lower trophic levels. The effect of dams on anadromous and catadromous fish are also presented. We discuss in detail the marine response to specific river regulation projects on the Nile, Indus and rivers flowing into the Black Sea, San Francisco Bay and James Bay in Canada. A decline in some coastal fisheries with an overall negative impact on the biota is generally associated with reductions in freshwater flow. Extensive ecological considerations are needed during the planning stage of large-scale freshwater modification projects to minimize potential impacts.     

Effect of yellow loess on clearance rate in seven species of benthic, filter-feeding invertebrates

Attempts have been made, especially in Asia, to displace harmful algal blooms (HABs) by spraying ‘china clay’ and ‘loess’ over affected coastal waters. The impact of this technique on benthic communities and processes is not known. We examined the effects of yellow loess on clearance rates of the benthic, filter‐feeding invertebrates, Crassostrea virginica (Gmelin 1791), C. gigas (Thunberg 1793), Mytilus edulis (Linnaeus 1758), M. trossulus (Gould 1850), Argopecten irradians (Lamarck 1819), and Crepidula fornicata (Linnaeus 1758). An Obelia species of hydroid was also studied and the percent time open was analysed. Depletion rates were measured using a range of loess concentrations suspended in culture with unicellular algae (Rhodomonas lens) in 0.45 μm filtered seawater. The effects of loess on clearance rates and behaviour were species‐specific. C. virginica was not impacted until clay concentrations reached 1.0 g L^?1, while A. irradians showed a significant decrease at 0.01 g L^?1. M. edulis showed a significant decrease in clearance rates at the 1 and 10 g L^?1 concentrations. For hydroids, the percent time open was significantly lower than the control at 0.01, 0.1, and 10 g L^?1. We clearly demonstrate that loess has a significant negative impact on filter‐feeding invertebrates. The use of clay as a strategy for mitigation of HABs should be approached with extreme caution. While the control of active blooms may eventually be possible, it may not necessarily be an environmentally advisable or responsible approach to dealing with HABs.     

Using bioacoustic tools to clarify species delimitation within the Blakiston's Fish Owl(Bubo blakistoni)complex

Although Blakiston's Fish Owl(Bubo blakistoni)is widely treated as a single species,marked differences in the structure of pair duets between continental and in...     

Southern Ocean iron enrichment experiment: carbon cycling in high- and low-Si waters

The availability of iron is known to exert a controlling influence on biological productivity in surface waters over large areas of the ocean and may have been an important factor in the variation of the concentration of atmospheric carbon dioxide over glacial cycles. The effect of iron in the Southern Ocean is particularly important because of its large area and abundant nitrate, yet iron-enhanced growth of phytoplankton may be differentially expressed between waters with high silicic acid in the south and low silicic acid in the north, where diatom growth may be limited by both silicic acid and iron. Two mesoscale experiments, designed to investigate the effects of iron enrichment in regions with high and low concentrations of silicic acid, were performed in the Southern Ocean. These experiments demonstrate iron's pivotal role in controlling carbon uptake and regulating atmospheric partial pressure of carbon dioxide.     

Density of Mars' south polar layered deposits

Both poles of Mars are hidden beneath caps of layered ice. We calculated the density of the south polar layered deposits by combining the gravity field obtained from initial results of radio tracking of the Mars Reconnaissance Orbiter with existing surface topography from the Mars Orbiter Laser Altimeter on the Mars Global Surveyor spacecraft and basal topography from the Mars Advanced Radar for Subsurface and Ionospheric Sounding on the Mars Express spacecraft. The results indicate a best-fit density of 1220 kilograms per cubic meter, which is consistent with water ice that has approximately 15% admixed dust. The results demonstrate that the deposits are probably composed of relatively clean water ice and also refine the martian surface-water inventory.     

Fat mobilization in adipose tissue is promoted by adipose triglyceride lipase

Mobilization of fatty acids from triglyceride stores in adipose tissue requires lipolytic enzymes. Dysfunctional lipolysis affects energy homeostasis and may contribute to the pathogenesis of obesity and insulin resistance. Until now, hormone-sensitive lipase (HSL) was the only enzyme known to hydrolyze triglycerides in mammalian adipose tissue. Here, we report that a second enzyme, adipose triglyceride lipase (ATGL), catalyzes the initial step in triglyceride hydrolysis. It is interesting that ATGL contains a "patatin domain" common to plant acyl-hydrolases. ATGL is highly expressed in adipose tissue of mice and humans. It exhibits high substrate specificity for triacylglycerol and is associated with lipid droplets. Inhibition of ATGL markedly decreases total adipose acyl-hydrolase activity. Thus, ATGL and HSL coordinately catabolize stored triglycerides in adipose tissue of mammals.     

Venus: an upper limit on intrinsic magnetic dipole moment based on absence of a radiation belt

On the basis of the absence of energetic electrons (E(e) 45 kiloelectron volts) and protons (E(p) 320 kiloelectron volts) associated with Venus to within a radial distance of 10,150 kilometers from the center of the planet and using a physical similitude argument and the observational and theoretical knowledge of the magnetosphere of Earth, we conclude that the intrinsic magnetic dipole moment of Venus is almost certainly less than 0.01 and probably less than 0.001 of that of Earth. Corresponding upper limits on the magnetic field at the equatorial surface of Venus are about 350 and 35 x 10(-5) gauss, respectively.     

Separation of metallic from semiconducting single-walled carbon nanotubes

We have developed a method to separate metallic from semiconducting single-walled carbon nanotubes from suspension using alternating current dielectrophoresis. Our method takes advantage of the difference of the relative dielectric constants of the two species with respect to the solvent, resulting in an opposite movement of metallic and semiconducting tubes along the electric field gradient. Metallic tubes are attracted toward a microelectrode array, leaving semiconducting tubes in the solvent. Proof of the effectiveness of separation is given by a comparative Raman spectroscopy study on the dielectrophoretically deposited tubes and on a reference sample.