Effect of soil pH on growth, nutrient uptake, and mycorrhizal colonization in exotic invasive Lygodium microphyllum

Abstract

Lygodium microphyllum is an invasive exotic plant species taking over many sites in freshwater and moist habitats in Florida. Managing it has been a significant challenge for land resource managers and researchers due to its extensive rapid invasion. To assess the effects of soil pH on growth, nutrient uptake, and mycorrhizal colonization in the roots of L. microphyllum, we conducted a 60-day greenhouse experiment by growing it in pots filled with pH-adjusted soils to a range from 4.5 to 8.0. L. microphyllum was able to survive and grow at all soil pH levels; however, final biomass, relative growth rate, photosynthesis, and specific leaf area were all greater in soil pH 5.5-6.5 compared to the other treatments. Correspondingly, nitrogen concentration was also related to these four plant parameters. Root colonization by mycorrhizal fungi was higher in soil pH 5.5-7.5 and lowest for plants growing in 4.5 or 8.0 and was correlated with plant growth parameters as well as elemental concentration in the leaves. Soil pH 8.0 was not strong enough for a pronounced growth decline, thus further increasing soil pH could provide a desired outcome and merit further investigation, although its potential negative impact on native flora (both plants and microorganisms) would need to be assessed.

Soil biotic and abiotic conditions negate invasive species performance in native habitat

“…In the invaded regions of South Florida L. microphyllum displays most of the ecological characteristic associated with successful invasive plants (Westbrooks 1998): it has the ability to grow in varying hydrological (Gandiaga et al 2009), nutrient (Volin et al 2010), and light conditions (Volin et al 2004). It tolerates a wide range of soil pH (Soti et al 2014(Soti et al , 2015, and has a strong symbiotic relationship with arbuscular mycorrhizal fungi (AMF) (Soti et al 2014). Comparative analysis of soil samples from both its native range and invaded region have shown that L. microphyllum, which had adapted to close-to-neutral soils in Florida, grows in highly acidic soils in its native range in Australia (Soti et al 2014).…”

Differential responses to global change of aquatic and terrestrial invasive species: evidences from a meta‐analysis

“…Soti et al. () found that low pH negatively affected the growth of the invasive macrophyte Lygodium microphyllum . Further, small zooplankton species’ composition in fishless bog lakes was negatively affected when pH was experimentally decreased (Arnott and Vanni ).…”

“…The uptake of CO 2 by water causes a chemical reaction to take place producing carbonic acid (H 2 CO 3 ), which lowers the pH of water (Bradshaw 2007) and causes changes in carbonate and bicarbonate ions. Soti et al (2015) found that low pH negatively affected the growth of the invasive macrophyte Lygodium microphyllum. Further, small zooplankton species' composition in fishless bog lakes was negatively affected when pH was experimentally decreased (Arnott and Vanni 1993).…”

Production of Arbuscular Mycorrhizal Fungi using In vitro Root Organ Culture and Phenolic Compounds

“…Mycorrhizal colonization degree in L. microphyllum roots was significantly low in extremely alkaline and acidic soils. Roots of soil pH ranging from 5.5 to 7.5 recorded high mycorrhizal colonization degree 49 .…”