Rooting structure, effects

Effects on Rooting Structure and Interactions Among Plants... 

Besides making implicit use of these really puzzling properties of the relativistic Kepler problem, the second major impact of Sommerfeld s article lies in several notions introduced which lie at the foundation of relativistic quantum chemistry and have since been instrumental in the field the notion of scalar (kinemat-ical) relativistic effects versus fine-structure effects, the introduction of the fine-structure constant, a = jhc, and the expansion of the relativistic expressions in powers of the square of this constant. The idea that relativistic effects decisively influence the structure of the outer electrons of the atoms is at the root of relativistic quantum chemistry. 

For Pauling, electronegativity is a constant of the atom, irrespective of the combination in which it is involved. Pauling s electronegativities, which are obtained from Ihermochemical data, include the average structure effects of the atom in the combination. They have the dimension of a square root of energy. Pauling stressed... 

Protoanemonin, which has been isolated from Anemone pulsatilla and Ranunculus spp., was reported to inhibit root growth by slowing down metabolism and blocking mitosis 35). Erickson and Rosen 35) observed cytological effects in corn root tips at concentrations of 10M and lower. Cells undergoing division appeared to accumulate in the interphase or prophase stages. Metaphase, anaphase, and telophase stages were not observed. Cytoplasmic and vacuolar structures were disturbed and the presence of mitochondria could not be demonstrated in treated tissue. Thimann and Bonner 141) reported that protoanemonin was 10 to 30 times more inhibitory than coumarin in coleoptile and split pea stem tests, and that BAL prevented the inhibitory action. 

The permeation of soil at the root-soil interface by mucilage from the root cap may affect structure, and it may oppose the damaging effects of compression and shearing, but little is known. Another suggested role is that the mucilage assists root-cap cells or acts in concert with them to decrease the friction between the growing root tip and soil (51) or, conversely, that the mucilage acts as a lubricant. 

In addition to the interactions between plants and microorganisms, a third factor, the soil, also plays a role in determining root exudation and the activity and diversity of rhizosphere microbial populations. In this section, physical and structural aspects of the soil are discussed in relation to their effects on root exudation and microbial populations. Consideration is also given to the role of agricultural management practices on rhizosphere processes. In addition, the role of other biotic factors, such as microfaunal predation, is discussed in relation to nutrient cycling in the rhizosphere. 

I. Nir, S. Klein, and A. Poljakoff-Mayber, Effect of moisture stress on submicro-scopic structure of maize roots, Australian Journal of Biological Science 22 1 (1969). 

B. Analysis of Fe Stress Effects on Microbial Community Structure on Barley Roots... 

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