Effectivity of arbuscular mycorrhizal fungi collected from reclaimed mine soil and tallgrass prairie

Abstract

<p> <span style="font-family:;" "=""><span style="font-family:Verdana;">We examined suitability of arbuscular mycorrhi</span><span style="font-family:Verdana;">zal fungi (AMF) associated with cool-season non</span><span style="font-family:Verdana;">native forages on reclaimed surface-mined land in southeast Ohio for establishment of native warm-season grasses. The goal of establishing these grasses is to diversify a post-reclamation landscape that is incapable of supporting native </span><span style="font-family:Verdana;">forest species. A 16-week glasshouse study com</span><span style="font-family:Verdana;">pared AMF from a 30-year reclaimed mine soil (WL) with AMF from native Ohio tallgrass prairie soil (CL). Four native grasses were examined from seedling through 16 weeks of growth. Comparisons were made between CL and WL AMF on colonized (+AMF) and non-colonized plants (–AMF) at three levels of soil phosphorus (P). Leaves were counted at 4 week intervals. Shoot and root biomass and percent AMF root colonization were measured at termination. We found no difference between WL and CL AMF. Added soil P did not reduce AMF colonization, but did reduce AMF efficacy. Big bluestem (</span><i><span style="font-family:Verdana;">Andropogon gerardii</span></i><span style="font-family:Verdana;"> Vitman), Indiangrass (</span><i><span style="font-family:Verdana;">Sorghastrum nutans</span></i><span style="font-family:Verdana;"> (L.) Nash), and tall dropseed (</span><i><span style="font-family:Verdana;">Sporobolus asper</span></i><span style="font-family:Verdana;"> (Michx.) Kunth) benefited from AMF only at low soil P while slender wheatgrass (</span><i><span style="font-family:Verdana;">Elymus trachycaulus</span></i><span style="font-family:Verdana;"> (Link) Gould ex Shinners) exhibited no benefit. Establishment of tallgrass prairie dominants big blue-stem and Indiangrass would be supported by the mine soil AMF. It appears that the non-native forage species have supported AMF equally functional as AMF from a regionally native tallgrass prairie. Tall dropseed and slender wheatgrass were found to be less dependent on AMF than big bluestem or Indiangrass and thus would be useful in areas with little or no AMF inoculum.</span></span> </p

Mycorrhizas influence functional traits of two tallgrass prairie species

“…Although A. gerardii was strongly dependent on mycorrhizas as we hypothesized, it was not literally an "obligate" mycotroph as previously suggested (Hetrick et al 1986(Hetrick et al , 1988(Hetrick et al , 1990Hartnett et al 1993). In our study, noninoculated A. gerardii were able to equal the growth of inoculated plants with as little as an estimated 18.1 lgÁg À1 P supplied weekly (totaling 28 mgÁL À1 soil over our entire experiment), making it a facultative mycotroph as found recently by others (Miller et al 2002;Grman 2012;Thorne et al 2013). When the total amount of P applied throughout an experiment is summed, our results are similar to those of Grman (2012) who found mycorrhiza disadvantage for A. gerardii at total P additions above 86 mgÁL À1 soil and Thorne et al (2013) who found disadvantage above 49 mgÁL À1 soil total P addition.…”

“…Thorne et al. () used field collected soil, but Grman () used a nutrient‐poor sand‐soil mixture like ours, so base substrate differences in P availability undoubtedly contribute to the somewhat different threshold values for mycorrhiza disadvantage. Although Hetrick et al.…”

“…; Grman ; Thorne et al. ). When the total amount of P applied throughout an experiment is summed, our results are similar to those of Grman () who found mycorrhiza disadvantage for A. gerardii at total P additions above 86 mg·L −1 soil and Thorne et al.…”

“…, , ), recent studies that repeatedly supplied A. gerardii with soluble P have found it too is able to grow without mycorrhizas (Grman ; Thorne et al. ), hence both species are facultatively mycotrophic (see Janos ). Nevertheless, recent work investigating C3 and C4 grasses has concluded that C3 grasses exhibit less of a growth response to mycorrhizas than C4 grasses or exhibit no response at all (Reinhart et al.…”

“…Thus, those authors concluded that C3 grasses generally are less dependent on mycorrhizas than are C4 grasses (Hetrick et al 1988;Hartnett et al 1993). Although early research suggested that of A. gerardii and E. canadensis, only the latter could grow without mycorrhizas (e.g., Hetrick et al 1986Hetrick et al , 1988Hetrick et al , 1989, recent studies that repeatedly supplied A. gerardii with soluble P have found it too is able to grow without mycorrhizas (Grman 2012;Thorne et al 2013), hence both species are facultatively mycotrophic (see Janos 2007). Nevertheless, recent work investigating C3 and C4 grasses has concluded that C3 grasses exhibit less of a growth response to mycorrhizas than C4 grasses or exhibit no response at all (Reinhart et al 2012;Yang et al 2016).…”