Alyssum

Yields of flax were reduced when a small percentage of Camelina alyssum plants was present. Griimmer and Beyer (62) reported that at least four, and possibly six, substances of phenolic configuration... 

However, some plants can accumulate more than 0.1% of Pb, Co, Cr, and more than 1% of Mn, Ni and Zn in the shoots. These accumulator plants are called hyperaccumulators. To date, there are approximately 400 known metal hyperaccumulator plants in the world (Baker and Walker, 1989). Thlaspi caerulescens, Alyssum murale, A. lesbiacum, A. tenium are Zn and Cd hyperaccumulators. Brassica juncea, a high-biomass plant, can accumulate Pb, Cr(III), Cd, Cu, Ni, Zn, Sr, B and Se. Thlaspi caerulescens accumulates Ni. Hybrid poplar trees are reported to phytoremediate Cd and As contaminated soils. A Chinese brake fem, Pteris vittata, is an As hyperaccumulator (Ma et al., 2001). 

Kramer U, Grime GW, Smith JAC, Hawes CR, Baker AJM. Micro-PIXE as a technique for studying nickel localization in leaves of the hyperaccumulator plant Alyssum lesbiacum. Nucl Instr Methods B 1997 130 346-350. 

Alkanna orientalis (L.) Boiss. var. orientalis (L.) Boiss. Brassicaceae (Cruciferae) Alyssum saxatile L. -6.0 -7.8 -6.6... 

Kerkeb, L., Kramer, U., 2003, The role of free histidine in xylem loading of Nickel in Alyssum lesbiacum eealBrassica juncea. Plant Physiol. 131 716-724. 

Susceptible plants Brassicas, particularly as seedlings. Also ornamentals such as nasturtium, alyssum, anemone, and godetia. 

The nickel content of most natural vegetation is 0.05-5 ppm on a dry weight basis (NAS 1975). Near source areas, nickel on plants may be elevated because of direct foliar deposition. Some species of plants have the ability to hyperaccumulate nickel (Brooks 1980). The concentration in the leaves of Alyssum bertolonii contained 120 ppm nickel (12%). These plants are thought to produce organic ligands that complex with nickel. 

Fig. 4-1. Histogram showing nickel concentrations in the gznm Alyssum. There are two distinct populations including hyperaccumulators with > 1000 pg g l Ni in dried tissue.

Most hyperaccumulators are themselves endemic to the type of soil in which they are found. A classical case of this is the Alyssum genus that is widespread in Southern Europe and Asia Minor. Section Odontarrhena of the genus contains about 50 taxa that are endemic to ultramafic (serpentine) soils (Brooks, 1887 Brooks et al., 1979). Due to their endemism they invariably indicate the presence of serpentine soils and thereby act as geobotanical indicators of potential mineralisation in the substrate. Another example is the presence of the Zn hyperaccumulators Viola calaminaria and Thlaspi calaminare confined to Zn deposits in Western Germany and Eastern Belgium. 

Chemical analysis of the plant material can often be of assistance to the plant taxonomist. Cases of doubtful identity can sometimes be resolved. For example, the various species of Alyssum are rather similar morphologically. A simple col-ourimetric test of herbarium material can quickly confirm, or deny a given classification by the taxonomist. 

Hyperaccumulation of Ni appears to be a strategy where genera such as Alyssum have been able to evolve a physiological tolerance to phytotoxic nickel-rich soils, and avoid competition from other species by flourishing in environments so hostile, that often Alyssum is the only coloniser of the area. 

The only other genus with such a large number of hyperaccumulators of Ni is Thlaspi, a plant that seems to occupy the same ecological niches in Southern Europe as does Alyssum. Unlike the latter however, Thlaspi is much more widespread in Central and Western Europe, and has poor representation in Anatolia. Reeves and Brooks (1983 b) found 12 species with hyperaccumulator status. 

Alyssum likes full sun and well-drained average soil. Direct-sow in loose soil 5 weeks before last frost. Do not cover seeds thev... 

Alyssum, sweet. See Lobularia Amaranthus, 17 Amblyseius. citrus and, 72 Ambly.seius californicus, 457 Amblyseius cucumeris. buying and releasing, 4S5... 

---