Effect of Funneliformis mosseae on growth, mineral nutrition, biochemical indexes and chlorophyll content of Ziziphus spina-christi seedlings at different salinities

Abstract

Vast area of the land around the world is saline. Knowledge of plant behavior and their interaction with mychorrizal fungi in saline areas may help seedling establishment in such environments. This study aimed to determine the effects of the inoculation of the fungus Funneliformis mosseae (FM) on Ziziphus spina-christi (Rhamnaceae) plants grown under salt stress. Mycorrhizal and non-mycorrhizal seedlings were exposed to different levels of NaCl in the soil (0, 50, 100, and 150 mM). The following parameters were measured in both inoculated and non-inoculated plants: root colonization rate, seedling height, root diameter, root and shoot dry weights, chlorophyll a and b, total nitrogen (N), phosphorus (P), potassium (K) and sodium (Na + ) content, proline accumulation in roots and leaves, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities. The results showed that soil salinity hampered the root colonization by the fungus, and decreased basal diameter, seedling height, root and shoot dry weights, as well as some nutrients and chlorophyll a concentration, while increased leaves and roots Na IntroductionSoil salinity is a chronic problem increasing worldwide, especially in arid and semiarid areas (Al-Karaki 2006). At least 6% of the global landmass is affected by salinity (FAO 2007). Three types of physiological stress affect plant growth in saline soils: (i) toxic effects of specific ions, such as sodium and chloride, on plant cells (Juniper & Abbott 1993); (ii) physiological drought in soil with low osmotic potential, due to the plant efforts to maintain a lower internal osmotic potential, thus preventing water egression from roots into the soil; and (iii) imbalances of the nutrient content caused by the decreased nutrient uptake and/or transport to the leaves (Adiku et al. 2001).To mitigate the effects of soil salt on plant growth, many strategies have been developed, including the use of seedlings with roots colonized by arbuscular mycorrhizal fungi (AMF -Wu et al. 2010, Yang et al. 2014. AMF have symbiotic relationship with the roots of over 80% of the terrestrial plant species, including halophytes, hydrophytes and xerophytes (Hejiden et al. 1998). Indeed, It has been demonstrated that AMF colonization increases the tolerance of some plants to salt (Tian et al. 2004). AMF are mutually symbiotic and provide a direct physical link between the soil and plant roots (Gaur & Adholeya 2004). AMF promotes salinity tolerance by increasing nutrient uptake (Evelin et al. 2012, Beltrano et al. 2013, improving rhizospheric and soil conditions (Asghari et al. 2005), increasing photosynthesis and water use efficiency (Hajiboland et al. 2010), the accumulation of compatible solutes (Evelin et al. 2012) and enzymatic antioxidants such as superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) as a defense system to protect the plant cell from oxidative stress (Wu et al. 2010, Lu et al. 2014.Funneliformis mosseae (FM) is an arbuscular mycorrhiza used to alleviate salt stress in Arachis hypogaea (...