Juncus bulbosus as a pioneer species in acidic lignite mining lakes: interactions, mechanism and survival strategies

Abstract

Bulbous rush (Juncus bulbosus) initiates plant colonization in extremely acid lakes resulting from coal mining operations. Various analytical techniques (methylene blue\agar method, Ti$ + -citrate solution) X-ray diffraction (XRD), scanning electron microscopy (SEM), and Energy-dispersive X-ray (EDX) were used to assess the mechanisms and strategies employed by J. bulbosus to overcome the extreme conditions. The plant releases oxygen into the rhizosphere in turn increasing the redox potential and inducing iron oxide plaque formation. XRD showed that the iron oxide of the plaque is mainly goethite that has been developed in the presence of CO # ; SEM showed that there is a micro-space between the roots and sand grains which is inhabited by microorganisms. Furthermore, SEM-EDX studies on internal iron distribution demonstrate that iron toxicity is delayed by the physiological and biochemical structure of the plant. It is suggested that J. bulbosus uses a variety of mechanisms and strategies (morphological, physiological and biochemical adaptation) which are mainly complementary and which interact with each other to help J. bulbosus to manage its growth and survival in an extreme environment.

Influence of external zinc and phosphorus supply on Cd uptake by rice (Oryza sativa L.) seedlings with root surface iron plaque

“…These results differ from others (Chen et al 2006;Batty et al 2000;Greipsson 1994Greipsson , 1995Liu et al 2004b) but agree with our conclusions (Liu et al 2007) and those of Liu et al (2005) who also found that root tissue was the main barrier to As uptake by rice plants when arsenite was supplied. Similar results were also reported for metal uptake by other wetland plants, for example Pb and Cd uptake by Typha latifolia (Ye et al 1998), Cu, Zn and Pb uptake by water hyacinth (Vesk et al 1999), and Fe, Mn, Cu and Zn uptake by Juncus bulbosus (Chabbi 1999). The increase in Fe nutritional level in plants may partially alleviate the potential toxic effects of Cd to plant growth, as shown by the decreased Cd concentrations in roots and shoots at Fe50 than at Fe0 in both experiments (Fig.…”

“…The formation of iron plaque on the root surfaces of rice and other wetland plants is due to the release of oxygen and oxidants in the rhizosphere and the subsequent oxidation of ferrous to ferric iron and the precipitation of iron oxide or hydroxide on the root surface (Armstrong 1967;Chen et al 1980b;Taylor et al 1984). Mineralogical investigations in wetland fields have shown that the composition of iron plaque in Phalaris arundinacea is mainly ferrihydrite (∼63%) with smaller amounts of goethite (32%) and minor amounts of siderite (5%; Hansel et al 2001), or predominately goethite in Juncus bulbosus (Chabbi 1999) and rice (Chen et al 1980a). Iron plaque therefore has chemical properties similar to those of iron oxides in the soil and can thus sequester both cations and anions and alter the uptake and accumulation of elements by plants.…”

Effect of Lake Trophic Status and Rooted Macrophytes on Community Composition and Abundance of Ammonia-Oxidizing Prokaryotes in Freshwater Sediments

“…These plant species differ in nitrogen nutrition, extent of radial oxygen loss, and lifestyle, presumably resulting in differential, plant species-specific effects on rhizosphere-and root-associated AOA and AOB communities. L. uniflora prefers nitrate as the nitrogen source, while J. bulbosus prefers ammonium (41,45); oxygen release is high to moderate from the roots of L. uniflora and J. bulbosus (9,12) but is minor from the roots of M. alterniflorum (M. Herrmann, P. Stief, and A. Schramm, unpublished results); L. uniflora and J. bulbosus remain photosynthetically active throughout the year, while only the below-ground parts of M. alterniflorum are retained during winter.…”

Design of Sphingomonad-Detecting Probes for a DNA Array, and Its Application to Investigate the Behavior, Distribution, and Source of RhizospherousSphingomonasand Other Sphingomonads Inhabiting an Acid Sulfate Soil Paddock in Kalimantan, Indonesia

“…are known to be a representative acidic soil indicator, 35) and this genus can adapt to acidic soil conditions with several acid-tolerant strategies, including bacterial plaque on the rhizoplane. 36) In a similar manner, functional rhizobacteria might be involved in the surviving strategy of the wild Juncus community in the acidic soil paddocks of South Kalimantan.…”