Agriculture Reference
In-Depth Information
nodules, which could be their equivalent of a good steak. Bean leaf beetles, a pest
of soybeans, can also attack other parts of the plant, including nodules (Lundgren &
Riedell, 2008). Angiosperm parasites such as
Orobanche crenata
can decimate entire
crops of grain legumes. Paradoxically, legume roots may secrete a class of substances
known as strigolactones, which can stimulate the germination of plant parasites, but
these substances are also important for the recognition between the legume and AM
fungi (Yoneyama et al., 2008). On the other hand, it has recently been found that some
strains of
R. leguminosarum
in associationwith pea plants produce phenolic compounds
that decrease the germination of parasite seeds (Mabrouk et al., 2007). Nematodes,are
best known as pests of plants and animals, but many of them live saprophytically in
soil and contribute to nutrient cycling. Some of these are attracted to legume roots
in response to volatiles produced by the roots and carry with them rhizobia capable
of nodulating these roots (Horiuchi et al., 2005). Rhizobia also produce plant growth-
promoting substances, and these may enhance the ability of host plants to grow in soils
contaminated with heavy metals such as arsenic (Reichman, 2007).
