Agriculture Reference
In-Depth Information
As shown above‚ plants may absorb elements for which they have no nutritional
requirement or absorb nutrient elements to concentrations far in excess of nutritional
needs. Many of these elements may be taken up in substantial quantities. Halophytes‚ for
example‚ may accumulate substantial quantities of sodium and chloride. The summed
mean concentrations of these elements in the leaves of a variety of mangrove species
ranged up to 5.06 % of dry biomass (Walsh‚ 1974) while those of arid-climate
Atriplex
species (Chenopodiaceae) are known to occur in concentrations in excess of 10 % of dry
weight (Sharma
et al
.‚ 1972).
Plants may be classified as excluders‚ indicators or accumulators‚ depending whether
their tissue concentrations of particular elements increase more slowly‚ in parallel with‚
or more rapidly than those in the surrounding medium. Glycophytes (non-halophytic
