Mycorrhizal influence on fruit yield and mineral content of tomato grown under salt stress

Tomato (Lycopersicon esculentum Mill.} yields are known to decrease for pla nts grown in saline soils. This study was conducted to determine the effect s of arbuscular mycorrhizal fungi (AMF) inoculation on fruit yield and mine ral content of salt-tolerant and salt-sensitive tomato cultivars grown with varied levels of salt. NaCl and CaCl2 were added to soil in the irrigation water in equal molar ratios to give ECe values of 1.4 (non-stressed) and 4 .9 dS m(-1) (salt stressed). Plants were grown in a greenhouse using unster ilized, low phosphorus (P) (silty clay} soil-sand mite. Mycorrhizal root co lonization occurred whether cultivars were salt stressed or nonstressed, bu t the extent of AMF root colonization was higher in AMF inoculated than uni noculated plants. The salt tolerant cultivar 'Pello' generally had higher A MF root colonization than the salt sensitive cultivar 'Marriha'. Shoot dry matter (DM) yield, fruit fresh yield, and AMF colonization were higher for plants grown under nonstressed than for plants grown under salt stressed co nditions. Shoot DM and fruit fresh yields were higher in AMF inoculated tha n uninoculated plants grown with or without salt stress, Pello generally ha d higher fruit fresh yield per plant and fruit weight than Marriha, but the se differences were only significant for fruit weight in unioculated plants grown under salt stressed conditions. The enhancement in fruit fresh yield due to AMF inoculation was 26 and 23% under nonstressed and 28 and 46% und er salt stressed treatments for Pello and Marriha, respectively. For both c ultivars, fruit contents of P, potassium (K), zinc (Zn), copper (Cu), and i ron (Fe) were higher in AMF inoculated compared with uninoculated plants gr own under nonstressed and salt stressed conditions. Fruit Na concentrations were lower in AMF inoculated than uninoculated plants grown under salt str essed conditions. The enhancement in P, K, Zn, Cu, and Fe acquisition due t o AMF inoculation was more pronounced in Marriha than in Pello cultivar und er salt stressed conditions. The results of this study indicated that AMF i noculated plants had greater tolerance to salt stress than unioculated plan ts.