Bean plant feeding

The first indication of the active role of plants in producing volatile chemicals to attract the natural enemies of their herbivorous attackers was found by Dicke, Sabelis, and coworkers (7, 24) in their studies of predatory mites that prey on plant-feeding mites. They found that when herbivorous spider mites feed on lima bean leaves, the plant releases a blend of volatiles that attracts predatory mites. The blend produced differs between plant species and varies depending on the species of spider mite that is attacking the plant. The blends even differ between plant cultivars infested with the same spider mite species, and the predatory mites can detect these differences (25,26). Artificially damaged leaves are not attractive to the predatory mites. 

Recent studies have shown that exposure of plants to sulfur dioxide can in fact affect their susceptibility to Insect attack. Bean plants exposed to low levels of SO2 were preferred for feeding by the Mexican bean beetle (58). 

Highly toxic substances, such as cyanides, are sometimes feeding cues and stimulants for specialized insects. For example, instar larvae of the southern armyworm (Spodoptera eridania) strongly prefer cyanogenic foods, such as foliage of the lima bean, a plant with comparatively elevated cyanide content — up to 31 mg/kg in some varieties — in the form of linamurin (Brattsten et al. 1983). Feeding was stimulated in southern army worms at dietary levels up to 508 mg KCN/kg... 

Nutrition research on winged bean has mainly focused upon the tough, mature seed, which is rich in protein and oil. The seeds are occasionally consumed in Indonesia and Papua NewGuinea (59, 60). A survey of 240 winged bean accessions from 16 countries showed that the protein and oil contents range between 20.7-45.9% and 7.2-21.5% respectively (13). Studies on the evaluation of seed flour as an alternative feed source for livestock has only recently begun. The two most commonly used plant protein sources in broiler (chicken) diets to date have been soybean and peanut cake (62). 

Plants respond to the mechanical or insect herbivore damage of their tissues." During herbivorous attacks, some plants emit a specific blend of volatiles, which may result in defense responses retarding development of the herbivores or attraction of herbivore enemies to feed upon them. In lima bean leaves, the spider mite-induced volatiles, as well as infestation and artificial wounding, activate the ethylene and JA signaling pathways. ... 

Mithofer A, Wanner G, Boland W (2005) Effects of feeding Spodoptera Uttoralis on lima bean leaves. II. Continuous mechanical wounding resembling insect feeding is sufficient to elicit herbivory-related volatile emission. Plant Physiol 137 1160-1168... 

Mannans have been found in some kinds of plants such as endosperms of copra and ivory palm nuts, guar beans, locust beans, coffee beans and roots of konjak Amorphophallus konjac). Most of these saccharides are used only in the food and feed processing industries. Recently, it has been reported that manno-oligosaccharides are useful as one of the best growth factors for Bifidobacterium sp. and Lactobacillus... 

Various experiments in Vanilla plant cell cultures, however, gave different results [14-18, 30, 51]. This might be due to the fact that different biosynthetic pathways operate in the beans and in the cell culture. In fact most of the work in cell cultures showed only conversion of non-glucosylated products. Ferulic acid feeding resulted in increased vanillin levels. The fact that the V. planifolia cell cultures do not produce vanillin in any significant amount means that the results from studies using vanilla cell cultures for elucidation of the pathway should be considered with caution. Finally, it cannot be excluded that different pathways may contribute to the vanillin production in the beans. Scheme 9.1 shows that vanillin can be formed through different ways in a complex network of compounds. 

For some herbivores, the responses to herbivore-induced plant odors differ under different circumstances. For instance, the spider mite I urticae is more attracted to healthy lima bean leaves than leaves that emit volatiles induced by spider mite infestation (Dicke, 1986 Dicke and Dijkman, 1992). However, Pallini etal. (1997) found that the same mite is attracted to cucumber plants that are already infested by conspecifics. In contrast, T urticae avoids the odor of cucumber plants under attack by the western flower thrips, FranJdiniella occidentalis, which is a herbivore but also feeds on spider mites. Bark beetles can cause strong reactions in their host trees, resulting in the emission of a blend of volatile terpenoids that, in combination with aggregation pheromenes, is used in mass attacks. These same substances may attract predators (Byers, 1989) and parasitoids (Sullivan et al, 2000 Pettersson, 2001 Pettersson et al, 2001) to infested trees. 

Large holes in leaves. Cause Bean leaf beetles. Adults feed above ground larvae eat roots plants may turn yellow and wilt. 

---