Arbuscular mycorrhizal colonisation of roots of grass species differing in invasiveness

Abstract

Recent research indicates that the soil microbial community, particularly arbuscular mycorrhizal fungi (AMF), can influence plant invasion in several ways. We tested if 1) invasive species are colonised by AMF to a lower degree than resident native species, and 2) AMF colonisation of native plants is lower in a community inhabited by an invasive species than in an uninvaded resident community. The two tests were run in semiarid temperate grasslands on grass (Poaceae) species, and the frequency and intensity of mycorrhizal colonisation, and the proportion of arbuscules and vesicles in plant roots have been measured. In the first test, grasses representing three classes of invasiveness were included: invasive species, resident species becoming abundant upon disturbance, and non-invasive native species. Each class contained one C3 and one C4 species. The AMF colonisation of the invasive Calamagrostis epigejos and Cynodon dactylon was consistently lower than that of the non-invasive native Chrysopogon gryllus and Bromus inermis, and contained fewer arbuscules than the post-disturbance dominant resident grasses Bothriochloa ischaemum and Brachypodium pinnatum. The C3 and C4 grasses behaved alike despite their displaced phenologies in these habitats. The second test compared AMF colonisation for sand grassland dominant grasses Festuca vaginata and Stipa borysthenica in stands invaded by either C. epigejos or C. dactylon, and in the uninvaded natural community. Resident grasses showed lower degree of AMF colonisation in the invaded stand compared to the uninvaded natural community with F. vaginata responding so to both invaders, while S. borysthenica responding to C. dactylon only. These results indicate that invasive grasses supposedly less reliant on AMF symbionts have the capacity of altering the soil mycorrhizal community in such a way that resident native species can establish a considerably reduced extent of the beneficial AMF associations, hence their growth, reproduction and ultimately abundance may decline. Accumulating evidence suggests that such indirect influences of invasive alien plants on resident native species mediated by AMF or other members of the soil biota is 1 probably more the rule than the exception.Keywords: arbuscular mycorrhizal fungi (AMF), Calamagrostis epigejos, Cynodon dactylon, grasses, invasive plants, semiarid temperate grassland.Nomenclature: Tutin et al. (1964Tutin et al. ( -1993.Abbreviations: AMF -Arbuscular Mycorrhizal Fungi; a% -percentage arbuscule occurence of the AMF colonised root section; A% -percentage arbuscule occurence of the whole root; F% -frequency of root segments colonised by AMF; M% -intensity of mycorrhizal colonisation; v% -percentage vesicle occurence of the AMF colonised root section; V% -percentage vesicle occurence of the whole root;

Deficit Watering Reduces Plant Growth to a Smaller Extent With Arbuscular Mycorrhizal Association Than Without It for Non-Invasive Grass Species but Not for Invasive Grass Species

“…Similarly, C. epigejos showed poor mycorrhizal colonization on coal mine spoil banks and moderate growth response to mycorrhizal infection in a pot experiment (Rydlová and Vosátka, 2001). Our earlier field study (Endresz et al, 2013) also suggested that the invasive Calamagrostis and Cynodon are not dependent on AMF symbionts, while the non-invasive Chrysopogon is (Danthonia was not examined then). In a semiarid steppe, Calamagrostis and Cynodon consistently displayed a lower degree of AMF colonization than resident grasses, including Chrysopogon, and the native bunchgrasses Festuca vaginata and Stipa borysthenica attained lower degree of AMF infection in stands invaded by Calamagrostis or Cynodon than in intact community (Endresz et al, 2013).…”

“…Our earlier field study (Endresz et al, 2013) also suggested that the invasive Calamagrostis and Cynodon are not dependent on AMF symbionts, while the non-invasive Chrysopogon is (Danthonia was not examined then). In a semiarid steppe, Calamagrostis and Cynodon consistently displayed a lower degree of AMF colonization than resident grasses, including Chrysopogon, and the native bunchgrasses Festuca vaginata and Stipa borysthenica attained lower degree of AMF infection in stands invaded by Calamagrostis or Cynodon than in intact community (Endresz et al, 2013). Since in the same study we found Calamagrostis to have higher degree of AMF infection in nutrient poor sand grassland than in humus rich loess grassland, and others (Kovács and Szigetvári, 2002;Lingfei et al, 2005) reported intense AMF colonization for Cynodon, these two invasive species can be considered as facultative mycorrhizal plants.…”

Impacts of Invasive Plants on Soil Fungi and Implications for Restoration

“…However, it is unclear how quickly these legacy effects occur or attenuate after an invasive plant is removed, as well as how soon the community may return to the structure and functioning of the previously native state [42]. In certain instances, after an invasive is removed, any changes in AMF abundance and diversity are fleeting, because differences in abundance and richness return rapidly with the return of the native vegetation type [14,38]. In contrast, in other studies [37] even a highly mycorrhizal invasive plant may not rapidly alter the AMF community, even after 29 weeks.…”

Recovery of arbuscular mycorrhizal fungi root colonization after severe anthropogenic disturbance: four species assessed in old-growth Mediterranean grassland

“…AMF communities affect plant communities in complex ways: like plants, not all AMF species play the same role in ecosystems (Hart et al 2003). The effects of AMF on plants are species-specific (Hoeksema et al 2010;Endresz et al 2013), but also depend on environmental conditions (Grime et al 1987;Hartnett and Wilson, 1999;Kytöviita et al 2003), and higher AMF root colonization is not always linked with better vegetation recovery (Richter et al 2002). Further research is required to explore how different ecosystem components can affect overall ecosystem recovery, and how they could be used to facilitate or to accelerate this recovery in a restoration context (Allen, 1989;Herrera et al 1993;Callaway et al 2001;Kardol et al 2009).…”