The morphological effects of lead

Calcium and magnesium are very abundant in soils, and soils deficient in Ca are rare, calcium status is maintained when lime is added to correct acidity. Plant cells contain relatively large concentrations of Ca, but most of it is bound in the cell-wall as the pectate (about 60%) or sequestered in different organelles (Clarkson, 1984). Ca affects the permeability of the cytoplasmic membrane and its deficiency leads to malformation of the growing parts of the plant. Hewitt and Smith (1975) have discussed the early experiments on the morphological effects of Ca deficiency. Calcium is often found in combination with organic acids, for example oxalic acid, a soluble, toxic metabolic by-product is converted to insoluble calcium oxalate. 

Bulk Density. The bulk densities determined by the tapping method for three powders were 0.424, 0.426 and 0.425 g/ml. From a theoretical viewpoint, particles with a smaller diameter should contribute to a tighter packing and thus lead to an increase in bulk density. This difference was not noted. Again, this could result from the difference in particle morphology. The increased tendency to expand or form internal voids in small size fractions (8) may have offset the expected effect of particle size itself. Therefore, no significant difference was observed. 

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