RhizobiumProliferation-Supporting Substances in Seed Exudates of Common Bean (Phaseolus vulgarisL.)

Abstract

Seed exudates collected from three cultivars (cv. Hokkaikintoki, Himetebou, and Kurodane‐kinugasa) of common bean (Phaseolus vulgaris L.) were fractionated based on several physicochemical properties, and the nutrient substances in the fractions effective for Rhizobium proliferation were determined. Regardless of the common bean cultivars, the low molecular weight and high polarity fraction showed the most beneficial effect on Rhizobium proliferation. After further separation of the low molecular weight and high polarity fraction, the promoting effect was detected in the non‐ionic and the cationic plus ampho‐teric subtractions. Although the amount of sugars or amino acids exuded from a seed was, respectively, similar in all the cultivars except for the sugars in Kurodanekinugasa, the content of these compounds per seed‐weight was inversely proportional to the seed size. Ten sugars and twenty‐one amino acids were, respectively, identified in the non‐ionic and cat‐ionic plus amphoteric subtractions, and there were some differences in the composition of these substances between common bean cultivars.

Divergence in δ13C of dark respired CO2 and bulk organic matter occurs during the transition between heterotrophy and autotrophy in Phaseolus vulgaris plants

“…In the case of P. vulgaris it contains several monosaccharides and oligosaccharides, almost all amino acids, some organic acids, but also proteins, enzymes and few anthocyanins and flavonoids (Morohashi & Shimokoriyama, 1972;Duke & Kakefuda, 1981;Hungria et al, 1991;Kato et al, 2005). Thus, the relatively negative isotopic signature found here for leaked organic compounds (-28.12 ± 0.076‰) is hard to relate to any particular metabolite, especially since the composition can vary considerably across varieties (Kato et al, 2005). This suggests that soluble compounds were noticeably 13 C-depleted compared with starch, which is consistent with the slight enrichment observed in seed organic matter on day 1, although the calculated isotopic impact of leaching on seed biomass is very low (i.e.…”

“…, 2005). Thus, the relatively negative isotopic signature found here for leaked organic compounds (–28.12 ± 0.076‰) is hard to relate to any particular metabolite, especially since the composition can vary considerably across varieties (Kato et al. , 2005).…”

Potential of seed and root exudates of the common beanPhaseolus vulgarisL. for immediate induction of rhizobial chemotaxis andnodgenes

“…1997). Moreover, we indicated that this promotive effect was supported by large amounts of sugars and amino acids in the seed exudates (Kato et al. 2005).…”

Proliferation of inoculatedRhizobiumand indigenous microbes around the periphery of pre-rooting common beanPhaseolus vulgarisL. seeds sown in non-sterile soils

“…1997). In addition, we showed that the promoting effect on rhizobial proliferation was supported by a large amount of sugars and amino acids in seed exudates (Kato et al. 2005).…”

“…1997) or within 24 h after culturing in the composed medium containing the seed exudates (Kato et al. 1997; Kato et al. 2005).…”