Limitations and Potential of in situ Rhizobox Sampling for Assessing Microbial Activity in Fruit Tree Rhizosphere

Abstract

Controlled in situ sampling of tree rhizosphere is still a major challenge in detailed rhizosphere studies. Rhizoboxes have been widely used to describe the rhizosphere of annual crops, but have been rarely applied to trees. In this manuscript we aimed at assessing pH and microbial activity gradients associated with fruit tree rhizospheres. Rhizoboxes were introduced during the spring season around plum trees in an organic orchard receiving three different fertilization treatments. Relatively thin and incomplete root mats developed within rhizoboxes which had been placed 40 cm from the tree trunk. Roots developed only in a few of the rhizoboxes that had been placed at 150 cm from the trunk. No significant gradients of pH or microbial activity were observed in all fertilization treatments. Absence of gradients could be the result of the incomplete cover of the root mats, or could indicate that the rhizosphere of such trees is very limited in space, such that the degree of slice resolution was insufficient. Yet, the experimental approach taken in this study reveals other potential research applications, by enabling root sampling under controlled conditions of growth period and the medium which is used for rhizobox packing.

Distance-dependent varieties of microbial community structure and metabolic functions in the rhizosphere of Sedum alfredii Hance during phytoextraction of a cadmium-contaminated soil

“…However, functionally, rhizosphere should not be limited to specific volumes but rather characterized by gradients of soil characteristics, from the root surface to the surrounding soils (Aviani et al 2006). Distance-dependent changes of root activities might lead to the distance-dependent varieties of root-microbe-soil interrelations (He et al 2009).…”

Strategies and methods for studying the rhizosphere—the plant science toolbox

“…As an example, Boukcim et al (2001Boukcim et al ( , 2006 characterized root growth and architecture of young plants of Cedrus atlantica in rhizoboxes as a function of nitrogen nutrition and ectomycorrhizal inoculation. However, in some cases rhizobox studies have been carried out even with older trees (Dinkelaker et al 1997;Aviani et al 2006).…”

Transfer Mechanism, Uptake Kinetic Process, and Bioavailability of P, Cu, Cd, Pb, and Zn in Macrophyte Rhizosphere Using Diffusive Gradients in Thin Films

“…ex L, Gramineae), 1 one perennial emerged macrophyte, and one submerged macrophyte (Myriophyllum verticiilaturn), 47 are both widely distributed in Lake Erhai in Yunnan province (China) (Figure S2−1). On the basis of the method proposed by Aviani et al (2006), 56 in this research, a rhizobox (RB) with multilayers in vertical direction, a sediment-root compartment (R-zone) and a bulk sediment compartment (B-zone), has been designed for the cultivation of Zizania latifolia (ZL) and Myriophyllum verticiilaturn (MV) in lake, the separation of rhizosphere and non-rhizosphere zones, DGT tests and the collection of sediment and root samples. DGT technique and RB are designed to reveal the kinetic exchange between porewater/ solid interface, the mobility and bioavailability of P, Cu, Cd, Pb, and Zn in macrophyte rhizosphere and the bioaccumulation.…”