Nutrient stress

The nutrient stress hypothesis can be tested by comparing diet-tissue A N values of animals on low versus normal and high protein diets. Our controlled diet experiments, although primarily designed to trace carbon from different dietary macronutrient fractions (proteins versus carbohydrates, fats and sugars) to animal tissues under different levels of nutrient stress (Ambrose and Norr 1993) may be suitable for testing this hypothesis because they contain diets with 5, 20 and 70% protein by weight. 

Under stable conditions of extremely low productivity imposed by mineral nutrient stress (position 7 in Fig. lb) there is little seasonal change in biomass. Leaves and roots often have a functional life of several years and there is usually an uncoupling of resource capture from growth (Grime, 1977 Chapin, 1980). Because of the slow turnover of plant parts, differentiating cells occupy a small proportion of the biomass and morphogenetic... 

Fig. 2. Comparison of the effects of various stress treatments upon reproductive effort in Poa annua. The intensity of each stress treatment is characterised by comparing the growth increment of stressed plants to that of control (unstressed) plants over the same experimental period. , control O, water stress (polyethylene glycol) A, mineral nutrient stress (dilute concentrations of Rorison solution) shading by neutral filters (Smit, 1980).

Smit, P.T. (1980). Phenotypic Plasticity of Four Grass Species under Water, Light and Nutrient Stress. BSc thesis. University of Utrecht. 

On the other hand, there is also evidence that polyphenolic synthesis in trees is reduced under nutrient stress. For example, in an organic/conventional... 

The produchon of oxidase enzymes in native strains is often not constitutive, since these enzymes are only required under specific conditions, such as nutrient stress. This imposes limitations on their application in continuous bioprocesses and one way of dealing with this issue is to develop improved expression systems. Laccase from Trametes sp. C30, which in its native strain is inducible and only weakly expressed, has been cloned and expressed in yeast to provide a functional recombinant enzyme with the same high activity and low redox potential as the native enzyme [68]. 

Water and nutrient stress may often increase allelochemical production. In a recent review, Gershenzon (22) has pointed out that numerous allelochemicals of various chemical groups are often produced and stored in much higher concentrations by plants under water or nutrient stress than by plants growing under optimal conditions. 

B Tannins were consulted but nevertheless they were negative feeding cues. E Tannins may well have contributed to nutrient stress at a time when high martality occurred. Tannins in feces indicated their ability to pass through the gut unaltered. 

Puri B. K. (2005). Treatment of Huntington s disease with eicosapentaenoic acid. In Yehuda S. and Mostofsky D. I. (eds.), Nutrients, Stress and Medical Disorders. Nutrition and Health (Series) Humana Press Inc, Totowa, pp. 279-286. 

G. W. Hart Dynamic cycling of O-GlcNAc on nucleocytoplasmic proteins a nutrient/stress sensor globally regulating cellular mechanism... 

Van Donk, E. and Hessen, D.O., Grazing resistance in nutrient-stressed phytoplankton, Oecologia, 93, 508, 1993. 

Another kind of environmental interaction may result when in a homeostatic adjustment to the pollutant, the plant sacrifices part of its capacity to respond to environmental fluctuations. For example, the metabolic adjustment to fluorides may increase the susceptibility to nutrient stress. This hypothesis could explain why some symptoms of chronic fluoride toxicity resemble those produced by Mn, Fe, or Zn deficiencies. If air pollution is one environmental factor that alters the susceptibility of the plant to other environmental stress, it would also be logical to expect an interaction between pollutants if the receptor is exposed to two or more of them. Such interactive effects have been found. Sub-threshold concentrations of SOL> and 03 or S02 and N02 produce foliar lesions when plants are exposed to both pollutants (34). Additionally, plants exposed to S02 differ from non-fumigated plants in their resistance to subsequent fumigations (35). Thus the plants susceptibility or capacity to adapt to a pollutant is altered by concurrent exposures to another or consecutive exposures to the same one. 

Gershenzon, J. (1984) Changes in the levels of plant secondary metabolites under water and nutrient stress, in Recent Advances in Phytochemistry. 18. Phytochemical Adaptations to Stress (eds B.N. Timmermann, C. Steelink and F.A. Loewus). Plenum, New York, pp. 273-320. 

Flynn, K. J., and Flynn, K. (1995). DinoflageUate physiology Nutrient stress and toxicity. In Harmful Marine Algal Blooms (Lassus, P., Arzul, G., Erard, E., Gentien, P., and MarcaiUou, C., eds.). 

Kudela, R., Roberts, A., and Armstrong, A. (2002). Laboratory analyses of nutrient stress and toxin production in Pseudo-nitzschia spp. from Monterey Bay, California. In 10th International Conference on Harmful Algal Blooms (Steidinger K, ed.). Intergovernmental Oceanographic Commission of UNESCO, St. Petersberg, PL. 

Lake Washington Point-source (wastewater) nutrient stress. Mitigated via diversion of nutrient source downstream and chance biological control of phytoplankton. Rapid recovery. 

K-selected, nutrient-stress tolerant (S) species and the attuning, lightharvesting, attenuated, disturbance-tolerant ruderal (R) species. 

Poorter, H. (1998). Do slow-growing species and nutrient stressed plants respond relatively strongly to elevated COj Global Change Biol. 4, 693-697. 

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