A mathematical model of infiltrative tumour growth taking into account cell proliferation, death and motility is considered. The model is formulated in terms of local cell density and nutrient (oxygen) concentration. In the model the rate of cell death depends on the local nutrient level. Thus heterogeneous nutrient distribution in tissue affects tumour structure and development. The existence ...

Two major difficulties exist in the use of Aspergillus niger v. Tiegh for identification and study of the roles of micronutrients, although these are certainly not unique with this fungus. The water, sucrose, and salts employed may be assumed never to be completely free from impurities of micronutrients. Moreover, increases in yield with apparently non-nutritive elements may be due to biologica...

Objective: Evaluate the nutrient concentration at foliar level of chrysanthemums grown in tezontle sand using three concentrations Steiner Universal Nutrient Solution.
 Design/Methodology/Approach: A completely randomized design was used, each treatment represented a solution and had 11 repetitions, study variables were: nutrients: N, P, K, Ca, Mg S, plant height (AP), stem diameter (DT), ...

Biosolids, materials resulting from domestic sewage treatment, are surface applied to forest soils to increase nutrient availability. Retaining streamside management zones (SMZs) can limit nutrient pollution of streams. We delineated 15 m SMZs along three intermittent streams in an 18-year-old Pinus taeda L. plantation. We applied biosolids outside the SMZ on one side of each of the streams mai...

Global nutrient cycles have been altered by the use of fossil fuels and fertilizers resulting in increases in nutrient loads to aquatic systems. In the United States, excess nutrients have been repeatedly reported as the primary cause of lake water quality impairments. Setting nutrient criteria that are protective of a lakes ecological condition is one common solution; however, the data require...

A non-destructive cultivation system was developed to study the dynamics of phosphorus (Pi) uptake by mycorrhizal and non-mycorrhizal maize plantlets. The system consisted of a plant container connected via silicon tubes to a glass bottle containing a nutrient solution supplemented with Pi. The nutrient solution is pumped with a peristaltic pump to the upper part of the container via the silico...

Commercial hydroponics is a modern technology involving plant growth on inert media in place of the natural soil, in order to uncouple the performance of the crop from problems associated with the ground, such as soil-borne diseases, nonarable soil, poor physical properties, etc. Various non-toxic porous materials are used as plant growth substrates, including rockwool, perlite, pumice, expande...