Phosphorus

About: Phosphorus is a research topic. Over the lifetime, 53120 publications have been published within this topic receiving 939731 citations. The topic is also known as: element 15 & P.

Circulation Patterns for Phosphorus, Sulfur and Calcium in the Bean Plant.

Abstract: The circulation patterns for P-32, S-35 and Ca-45 in the bean plant were determined, by radioautographic means, from single aliquots of tracer administered to the roots during a one-hour period. A portion of the radioactive isotope of phosphorus displayed sustained circulation throughout the plant during the whole of the 96-hour experimental period. The S-35 was originally mobile but circulation was rapidly curtailed by metabolic capture in young leaves. The Ca-45 did not recirculate following its initial delivery via the transpiration stream. 29 references, 5 figures.

The metabolic basis of whole-organism RNA and phosphorus content

Abstract: Understanding the storage, flux, and turnover of nutrients in organisms is important for quantifying contributions of biota to biogeochemical cycles. Here we present a model that predicts the storage of phosphorus-rich RNA and whole-body phosphorus content in eukaryotes based on the mass- and temperature- dependence of ATP production in mitochondria. Data from a broad assortment of eukaryotes support the model's two main predic- tions. First, whole-body RNA concentration is proportional to mitochondrial density and consequently scales with body mass to the14 power. Second, whole-body phosphorus content declines with increasing body mass in eukaryotic unicells but approaches a relatively constant value in large multicellular animals because the fraction of phosphorus in RNA decreases relative to the fraction in other pools. Extension of the model shows that differences in the flux of RNA-associated phosphorus are due to the size dependen- cies of metabolic rate and RNA concentration. Thus, the model explicitly links two biological currencies at the individual level: energy in the form of ATP and materials in the form of phosphorus, both of which are critical to the functioning of ecosystems. The model provides a framework for linking attributes of individuals to the storage and flux of phosphorus in ecosystems.

Phosphorus (P) Uptake Mechanisms of Crops Grown in Soils with Low P Status : II. Significance of Organic Acids in Root Exudates of Pigeonpea

Abstract: In our previous studies, pigeonpea (Cajanus cajan L.), groundnut (Arachis hypogaea L.), and rice (Oryza sativa L.) were found to have a higher ability to take up Fe- or Al-bound phosphorus (P) than soybean (Glycine max L.) and sorghum (Sorghum bicolor L.). Phosphorus absorption characteristics like I max, K m, C min, and FeIII reduction activity of roots, and root exudates in various crops were examined with a view to analyzing the mechanisms of P uptake. Phosphorus uptake ability was largely unrelated to variations in I max, K m, C min, and FeIII reduction activity of roots. Phosphorus-solubilizing activity in anionic fractions of root exudates was detected in pigeonpea but not in rice or groundnut. Malonic acid was the major component followed by oxalic and piscidic acid. These organic acids were able to release P from FePO4 and A1PO4. The higher P uptake ability of pigeonpea in soils with low P fertility presumably depends on the secretion of such organic acids from roots.