Non-destructive estimation of lateral root distribution in an aridland perennial

Abstract

Estimation of root distributions in natural systems remains challenging due to the difficulties in excavation and easy breakage of fine roots. Identifying lateral fine root distribution is necessary to determine the potential exploitation of spatially and temporally variable nutrient supplies that characterize most arid ecosystems. We estimated this potential by taking field measurements of lateral root distribution of the small herbaceous perennial Cryptantha flava (A. Nels.) Payson using 15 N-enriched nutrient solutions wicked into the soil at various distances from study plants. Leaves were subsequently harvested from these plants and analyzed for N isotopic ratios. C. flava plants were capable of N uptake at distances of greater than 1.0 m from the outer edge of their aboveground canopy. The considerable lateral root neighborhood area of C. flava increases the amount of spatially variable N that is exploitable in these low-N soils. The ability to acquire spatially variable N and rapidly translate N uptake into photosynthetic carbon gain are traits that aid C. flava in maintaining its position as a successful subordinate competitor in a community dominated by larger, woody perennials.

A stage‐based study of drought response in Cryptantha flava (Boraginaceae): gas exchange, water use efficiency, and whole plant performance

“…This is consistent with the root/shoot ratio declining in many species as plants grow (Coleman et al, 1994;Gedroc et al, 1996;Muller et al, 2000). Direct measurements of root responses are not feasible for C. flava because the diffuse root system extends laterally as much as a meter (Peek and Forseth, 2005) and because the ephemeral fine roots, which provide most of the absorptive surface area, are difficult to recover. Alternatively, leaf-level physiological measurements should reveal whether large plants have more difficulty meeting their water requirements than small plants.…”

“…A plant consists of one to .70 basal leaf rosettes supported by a branched woody underground stem (caudex) connected to a single taproot. Smaller roots branch off the taproot and may extend laterally as much as a meter before turning downward (Peek and Forseth, 2005;B. Casper, personal observation).…”

The lateral spread of tree root systems in boreal forests: Estimates based on 15N uptake and distribution of sporocarps of ectomycorrhizal fungi

“…Lateral root spread can be determined by excavating roots (Drexhage and Gruber, 1998), microsatellite markers (Brunner et al, 2004;Saari et al, 2005), by uptake of nutrient analogs, such as Rb, Cs, Li or Sr (Casper et al, 2003), by uptake of stable or radioactive isotopes (Peek and Forseth, 2005;Hartle et al, 2006), by ground penetrating radar or by excavation using ultrasonic air-stream (Nadezhdina and Č ermák, 2003). Excavating roots is the most direct approach and has demonstrated root lengths of more than 50 m in the case of Nuytsia floribunda, as reviewed by (Stone and Kalisz, 1991).…”

“…Furthermore, root function rather than the physical presence of roots is assessed. Uptake of nutrient analogues or of stable isotopes to estimate lateral root spread has been studied for small plants (Hawkes and Casper, 2002;Casper et al, 2003;Peek and Forseth, 2005). In forest communities, however, the sampling effort is higher due to the larger lateral root spread and the size of the trees, and there is, consequently a paucity of data from such systems.…”

Arsenic Transformation by Azospirillum Brasilense Sp245 in Association with Wheat (Triticum Aestivum L.) Roots

“…The same effect was also shown for A. brasilense Sp7 and Sp245 by Dobbelaere et al (1999). Inoculation also enhances the initiation of lateral roots, which give plants better access to soil nutrient resources (Peek and Forseth 2005). Such an effect on root morphology is characteristic of auxins, including indole-3-acetic acid (IAA).…”