Effects of arbuscular mycorrhizal fungi on the growth, nutrient uptake and glycyrrhizin production of licorice (Glycyrrhiza uralensis Fisch)

Abstract

The growth of licorice in arid areas faces nutritional and environmental stresses. Arbuscular mycorrhizal (AM) fungi have been shown to increase the abilities of plants to develop. However, little is known regarding the role of AM fungi in licorice (Glycyrrhiza uralensis) growth. In the present study, by inoculation with two AM fungi, Glomus mosseae (Nicolson & Gerdemann) Gerd. & Trappe and Glomus veriforme (P. Karst.), the effects on licorice growth in sand were examined by measuring plant height, number of leaves, shoot and root fresh weight, and by analyzing morphological parameters of the root system in sand. The influence of the two microorganisms on the accumulation of mineral nutritions and bioactive components in licorice were also investigated. The results showed that mycorrhyzae were of the Arum-type and their colonization frequency (F %), colonization intensity (M %) and colonization intensity (m %) of AM fungi inoculation were found to be 80.0-84.6%, 49.4-60.0% and 58.4-71.9%, respectively. The inoculation significantly improved plant growth during early and late growth stages in comparison with the control. Moreover, inoculation of G. mosseae and G. versiforme, alone or in combination, improved plant phosphorus acquisition in the leaf over noninoculation plants. In addition, mycorrhiza formation enhanced the glycyrrhizin concentration in roots, but resulted in a considerable reduction of the root oxidase activity. The results indicate that the inoculation with AM fungi could be a useful approach to increase the licorice pharmic quality.

The enhancement of drought tolerance for pigeon pea inoculated by arbuscular mycorrhizae fungi

“…In comparison with the stress-free conditions, drought led to gradual decreases in RA of both AMD and NAMD seedlings, however, the status of the former was significantly higher than the latter after 10 days water deficit ( Figure 4D), implying that AM might considerably improve root metabolism, and could effectively alleviate oxidative stress, consequently strengthened the tolerance potential to water deficit. The higher RA herein might be an adaptive mechanism to moderate drought stress, which could facilitate drought tolerance by scavenging oxidative radicals (Liu et al 2007).…”

“…Under drought stress, AM may highly promote the growth of host plant, which is well described (Liu et al 2007, Parniske 2008. To AM-colonized plants, the improvement of the root surface and/or the external hyphae per se may highly elevate the uptake of water and nutrients (Augé 2004, Porcel and Ruiz-Lozano 2004, Liu et al 2007, consequently resulting in the increased tolerance to drought.…”

“…To AM-colonized plants, the improvement of the root surface and/or the external hyphae per se may highly elevate the uptake of water and nutrients (Augé 2004, Porcel and Ruiz-Lozano 2004, Liu et al 2007, consequently resulting in the increased tolerance to drought. In the current case, AM seedlings possessed an obviously greater root system ( Figure 1C) besides the extraradical AM fungal mycelia, giving rise to an obvious superiority in PH (Figure 2A), SD ( Figure 2B), leaf WC ( Figure 2C), as well as leaf number and weight (available upon query) compared with the non-AM plant under both presence and absence of water deficit, verifying the earlier findings in soybean (Porcel and Ruiz-Lozano 2004), citrus (Wu et al 2010), and licorice (Liu et al 2007). …”

“…SS, Pro or MDA in leaves was quantified based on the method by Chandler and Thorpe (1987), Vasquez-Tello et al (1990) or Wen et al (2010), respectively. The RA were determined according to the description by Liu et al (2007).…”

“…The beneficial effects of AM symbioses on improving growth and water-stress tolerance are well documented (Augé 2004, Wu and Xia 2006, Liu et al 2007, Parniske 2008. Under water deficit, the amelioration of water status in AM-colonized plants may be ascribed to direct water uptake and transport via external hyphae (Augé 2004), regulation of stomatal conductance (Goicoechea et al 1997), as well as indirect effects of elevated P level (Fitter 1988, Xavier andGermida 2003), higher antioxidative status (Porcel and Ruiz-Lozano 2004), and osmotic adjustment (Ruiz-Lozano 2003, Porcel and Ruiz-Lozano 2004, Wu and Xia 2006.…”