The growth response of greenhouse cucumber (Cucumis sativus L.) to infection by vesicular–arbuscular mycorrhizal (VAM) fungi and to 4, 12 and 20 mg L−1 of phosphorus (P) nutrition was characterized over 38 d of plant establishment. Although maximum growth rates were not reached with the P levels studied, foliar concentrations of P were consistent with those published for healthy cucumber plants. Plants were highly receptive to colonization by Glomus mosseae, G. dimorphicum and G. intraradices. Infection by all species decreased as P nutrition increased; however, growth rates of primary yield components (e.g., stem and leaf dry weights, leaf area) of VAM-infected plants were greater than those of noninfected plants at all levels of P nutrition. The VAM-enhanced growth was similar to that induced by increases in P nutrition. The VAM-infected plants had lower concentrations of soluble nitrogen (N) than noninfected plants early in development; however, N concentrations were equal by 38 d after planting. Total soluble carbohydrate concentration of leaves of noninfected plants increased 62% faster than that of leaves of VAM-infected plants, possibly due to decreased export and a higher degree of P stress in the non-infected plants. Relative to noninfected plants, higher concentration of soluble carbohydrates in roots of VAM-infected plants may indicate increased sink demand to support the symbiosis. Since VAM stimulated growth at levels of P nutrition considered nondeficient by tissue analysis, use of VAM to accelerate the early development of transplants may be advantageous to the greenhouse industry. Key words:Cucumis sativus L., phosphorus, vesicular–arbuscular mycorrhizal fungi, mineral nutrition
Arbuscular mycorrhizal fungi regulate the oxidative system, hormones and ionic equilibrium to trigger salt stress tolerance in Cucumis sativus L.
