title: Elemental stoichiometry indicates predominant influence of potassium and phosphorus limitation on arbuscular mycorrhizal symbiosis in acidic soil at high altitude.
abstract: The functioning of high-altitude agro-ecosystems is constrained by the harsh environmental conditions, such as low temperatures, acidic soil, and low nutrient supply. It is therefore imperative to investigate the site-specific ecological stoichiometry with respect to AM symbiosis in order to maximize the arbuscular mycorrhizal (AM) benefits for the plants in such ecosystems. Here, we assess the elemental stoichiometry of four Capsicum genotypes grown on acidic soil at high altitude in Arunachal Pradesh, India. Further, we try to identify the predominant resource limitations influencing the symbioses of different Capsicum genotypes with the AM fungi. Foliar and soil elemental stoichiometric relations of Capsicum genotypes were evaluated with arbuscular mycorrhizal (AM) colonization and occurrence under field conditions. AM fungal diversity in rhizosphere, was estimated through PCR-DGGE profiling. Results demonstrated that the symbiotic interaction of various Capsicum genotypes with the AM fungi in acidic soil was not prominent in the study site as evident from the low range of root colonization (21-43.67%). In addition, despite the rich availability of carbon in plant leaves as well as in soil, the carbon-for-phosphorus trade between AMF and plants appeared to be limited. Our results provide strong evidences of predominant influence of the potassium-limitation, in addition to phosphorus-limitation, on AM symbiosis with Capsicum in acidic soil at high altitude. We also conclude that the potassium should be considered in addition to carbon, nitrogen, and phosphorus in further studies investigating the stoichiometric relationships with the AMF symbioses in high altitude agro-ecosystems.
authors.affiliation: Defence Research Laboratory, Defence Research & Development Organisation, Post Bag 2, Tezpur 784001, Assam, India.
authors.forename: Mohammad Haneef
authors.initials: MH
authors.lastname: Khan
authors.affiliation: Defence Research Laboratory, Defence Research & Development Organisation, Post Bag 2, Tezpur 784001, Assam, India. Electronic address: mk_meghvansi@yahoo.co.in.
authors.forename: Mukesh K
authors.initials: MK
authors.lastname: Meghvansi
authors.affiliation: Defence Research Laboratory, Defence Research & Development Organisation, Post Bag 2, Tezpur 784001, Assam, India.
authors.forename: Rajeev
authors.initials: R
authors.lastname: Gupta
authors.affiliation: Defence Research Laboratory, Defence Research & Development Organisation, Post Bag 2, Tezpur 784001, Assam, India.
authors.forename: Vijay
authors.initials: V
authors.lastname: Veer
mesh_terms: D000531:Altitude; D002212:Capsicum / Q000382:microbiology* / Q000502:physiology; D002244:Carbon / Q000378:metabolism; D017753:Ecosystem; D038821:Mycorrhizae / Q000502:physiology*; D009584:Nitrogen / Q000378:metabolism; D010758:Phosphorus / Q000172:deficiency*; D018515:Plant Leaves / Q000382:microbiology / Q000502:physiology; D018517:Plant Roots / Q000382:microbiology / Q000502:physiology; D011188:Potassium / Q000378:metabolism*; D058441:Rhizosphere; D012987:Soil / Q000737:chemistry; D013559:Symbiosis
chemical_list: D012987:Soil; D010758:Phosphorus; D002244:Carbon; D009584:Nitrogen; D011188:Potassium
keywords: Acidic soil; Arbuscular mycorrhizal fungi; High altitude; Resource limitation; Rhizosphere; Stoichiometry