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Lima Bean (lima + bean)

Distribution by Scientific Domains
Life Sciences80%

Selected Abstracts

Air pollution impedes plant-to-plant communication by volatiles

ECOLOGY LETTERS, Issue 9 2010
James D. Blande
Ecology Letters (2010) 13: 1172,1181 Abstract Volatile organic compounds (VOCs) emitted by damaged plants convey information to undamaged neighbouring plants, and previous research has shown that these signals are effective over short distances in nature. Many herbivore-induced VOCs react with ozone, which is the most important tropospheric air pollutant in rural areas. We used extrafloral nectar (EFN) secretion as a phenotypic indicator of between-plant communication in Phaseolus lunatus L. (Lima bean) and show that an ozone-rich (80 ppb) atmosphere reduces the distance over which signalling occurs. We found that ozone degrades several herbivore-induced VOCs, a likely mechanism reducing communication distances. Direct exposure to 80-ppb ozone did not affect the VOC emissions from P. lunatus. In addition, we demonstrated that high ozone concentrations, 120 and 160 ppb, induced EFN secretion in exposed plants, whereas more moderate concentrations, 80 and 100 ppb, did not. This suggests that ozone can play a complex role in the indirect defence of P. lunatus. [source]

Trade-offs between direct and indirect defences of lima bean (Phaseolus lunatus)

JOURNAL OF ECOLOGY, Issue 5 2008
Daniel J. Ballhorn
Summary 1Plant defence theory predicts trade-offs among defence traits as a result of resource limitation or pleiotropic effects. Although theoretically widely accepted, empirical demonstrations of such trade-offs are surprisingly scarce and mechanistic explanations are usually lacking. 2We quantified cyanogenesis (the release of hydrogen cyanide (HCN)) as a direct defence and the emission of volatile organic compounds (VOCs) as an indirect defence against herbivores. To elucidate whether the trade-offs occur at the genetic or phenotypic level we investigated cultivated and wild-type accessions of lima bean (Fabaceae: Phaseolus lunatus L.) and compared different leaf developmental stages. Genetic relationships among the accessions were studied using amplified fragment length polymorphism (AFLP) analysis. 3Cyanogenesis and the release of VOCs differed significantly among the accessions and were negatively correlated: high cyanogenic accessions released low amounts of VOCs and vice versa. The same remained true for the ontogenetic stages, since primary leaves of all accessions hardly ever produced HCN at all, yet regularly showed high release rates of VOCs. 4Low and high cyanogenic accessions of lima bean formed distinct clades in an AFLP-based dendrogram, while wild-types and cultivars did not separate. The first pattern indicates that the underlying defensive syndromes are genetically conserved, while the latter is likely to be caused by a multiple origin of cultivated lima beans or an extensive gene flow among cultivated and wild plants. 5Synthesis. Trade-offs between cynogenesis and VOC release were obvious both between accessions and at the ontogenetic level, and thus cannot be explained by pleiotropy. We contend that allocation restrictions and/or adaptations to different enemy pressures are most likely to explain why lima bean can invest into cyanogenesis or VOCs, but not both. [source]

A Thermostable Chitinase with Chitin-Binding Activity from Phaseolus limensis

JOURNAL OF FOOD SCIENCE, Issue 6 2008
S.Y. Wang
ABSTRACT:, A 28.6-kDa chitinase with chitin-binding activity was isolated from the large lima bean (Phaseolus limensis) seeds. The procedure entailed extraction, ammonium sulfate precipitation, affinity chromatography on Affi-gel blue gel, and high-performance liquid chromatography (HPLC) on SP-Toyopearl. There was an almost 108-fold increase in specific activity of the purified chitinase compared with that of the crude extract. The enzyme exhibited a pI of 7.8 by isoelectric focusing electrophoresis. The optimum pH and the optimum temperature for activity toward N-acetyld-glucosamine were 5.4 and 40 to 50 °C, respectively. The enzyme was stable up to 55 °C. It exerted a potent inhibitory action toward fungal species, including Fusarium solani, Pythium aphanidermatum, and Sclerotium rolfsii. [source]

Trade-offs between direct and indirect defences of lima bean (Phaseolus lunatus)

JOURNAL OF ECOLOGY, Issue 5 2008
Daniel J. Ballhorn
Summary 1Plant defence theory predicts trade-offs among defence traits as a result of resource limitation or pleiotropic effects. Although theoretically widely accepted, empirical demonstrations of such trade-offs are surprisingly scarce and mechanistic explanations are usually lacking. 2We quantified cyanogenesis (the release of hydrogen cyanide (HCN)) as a direct defence and the emission of volatile organic compounds (VOCs) as an indirect defence against herbivores. To elucidate whether the trade-offs occur at the genetic or phenotypic level we investigated cultivated and wild-type accessions of lima bean (Fabaceae: Phaseolus lunatus L.) and compared different leaf developmental stages. Genetic relationships among the accessions were studied using amplified fragment length polymorphism (AFLP) analysis. 3Cyanogenesis and the release of VOCs differed significantly among the accessions and were negatively correlated: high cyanogenic accessions released low amounts of VOCs and vice versa. The same remained true for the ontogenetic stages, since primary leaves of all accessions hardly ever produced HCN at all, yet regularly showed high release rates of VOCs. 4Low and high cyanogenic accessions of lima bean formed distinct clades in an AFLP-based dendrogram, while wild-types and cultivars did not separate. The first pattern indicates that the underlying defensive syndromes are genetically conserved, while the latter is likely to be caused by a multiple origin of cultivated lima beans or an extensive gene flow among cultivated and wild plants. 5Synthesis. Trade-offs between cynogenesis and VOC release were obvious both between accessions and at the ontogenetic level, and thus cannot be explained by pleiotropy. We contend that allocation restrictions and/or adaptations to different enemy pressures are most likely to explain why lima bean can invest into cyanogenesis or VOCs, but not both. [source]