Seasonal Colonization of Arbuscular Mycorrhiza Fungi in the Roots of Camellia sinensis (Tea) in Different Tea Gardens of India

Abstract

Microscopic study of sterilized and stained root segments showed presence of four species namely Glomus fasciculatum, G. mosseae, Gigaspora margarita, and Acaulospora scrobiculata belonging to three genera of mycorrhizal fungi. Maximum AM colonization was observed during April-September and minimum was observed for December-January months of the year. Comparative study of AM fungi colonization at four sites during rainy season showed maximum colonization (100%) at Archadia site having soil with high organic matter, less acidity, and low phosphorus (P) whereas minimum (64.59%) at IIP with low organic matter, more acidity, and high P content. However, no variation in nitrogen content was observed at all four sites. Study suggested a positive relation of percentage root colonization with soil organic matter and negative relation with acidity and P content of soil. Study concludes that the percentage AM colonization is the function of seasonal variation in physicochemical properties of soil and presence of AM inoculums in the soil at a particular time.

Managing plant-environment-symbiont interactions to promote plant performance under low temperature stress

“…Some studies have shown that mycorrhizal fungi spore germination and hyphae colonization are almost completely inhibited at 10 °C (Gpey 1991;Wang et al 2002;Sharma et al 2013), although the growth of some fungal species may be severely inhibited, but not completely ceased at such low temperatures, for example at 10 °C for Glomusintraradices and at 5 °C for Glomus caledonium (Table 1) (Wang et al 2002;Sharma et al 2013). AMF capable of growing in cold soils may show contradictory results from beneficial to parasitic relationships (Charest et al 1993;Sharma et al 2013). This could be due to inability of AMF to uptake and transfer nutrients to the host plant, while consuming plant carbon reservoir (Sharma et al 2013).…”

“…AMF capable of growing in cold soils may show contradictory results from beneficial to parasitic relationships (Charest et al 1993;Sharma et al 2013). This could be due to inability of AMF to uptake and transfer nutrients to the host plant, while consuming plant carbon reservoir (Sharma et al 2013). The optimum ambient temperature for developing many AMF would be between 20 to 30 °C with upper and lower activity thresholds of 34 and 16 °C , respectively, for most strains (Wang et al 2002).…”

“…The optimum ambient temperature for developing many AMF would be between 20 to 30 °C with upper and lower activity thresholds of 34 and 16 °C , respectively, for most strains (Wang et al 2002). Unlike endomycorrhizal arbuscular mycorrhizae (AM), ectomycorrhizae mycelium may remain active at 0 °C (Sharma et al 2013). Interestingly, Zhou et al (2012 study showed that the combined treatment of AMF (Glomus versiforme) along with 50 mg L -1 foliar spray with the synthetic plant growth retardant paclobutrazol (PBZ) effectively reduced chilling injury of Teak (Tectona grandis) seedlings subjected to 6, 3, and 0 °C for 12 hours.…”

“…Under cold dry climatic conditions, AMF colonization was greatly affected by temperature and rainfall and accordingly varied during the growth seasons (Allen 1983). AM extraradical hyphae have the potential to survive under freezing temperatures (Allen 1983;Kytöviita, 2005;Sharma et al 2013). Due to the similarities between cold and drought adaptation mechanisms, extraradical AM mycelia are well adapted to tolerate prolonged periods of both cold and drought stresses in habitats with frequent prolonged dry spells such as sand dunes and deserts.…”

“…Fungal spores have unique adaptation mechanisms that enable them to complete fungal life cycle, withstanding harsh conditions, particularly extreme temperatures. For instance, AM spores remain viable after exposure to −80 °C (Sharma et al 2013). However, under freezing temperatures, it is hypothesized that the effectiveness and nature of symbiotic relationship may be strongly altered and even shifted from endomyrrhizal (i.e., AMF) to ectomycorrhizal fungi relationship (Sharma et al 2013).…”