Abstract
BACKGROUND: Although many effects of arbuscular mycorrhizal fungi (AMF) on host plants have been well documented, whether the effects of AMF on parental generations could affect offspring performance is not fully clear. We tested whether effects of AMF on current generation of host plants would transgenerationally impact on the offspring under different phosphorus (P) soil conditions by two experiments. METHODOLOGY: The first experiment was continued for 4 consecutive years to determine whether AMF affect host plants adaptation to a low-P environment. The experiment had four treatments: low-P soil without AMF (NM-LP), low-P soil with AMF (M-LP), high-P soil without AMF (NM-HP), and high-P soil with AMF (M-HP). The second experiment was to determine the effects of AMF status of parental plants on offspring (seeds of third filial generation from the first experiment, F3 seeds) in four P levels (0, 9, 18, and 36 mg kg(- 1)) in agar without AMF. RESULTS: In the first experiment, M-LP host plants had earlier flowering time than NM-LP host plants in both parental plants and F3. Shoot biomass (P = 0.013), root biomass (P = 0.001), ratio of root biomass to shoot biomass (P < 0.001) and seed P concentration (P = 0.001) of M-LP host plants were higher than NM-LP host plants in F3. In second experiment, lateral root length and the ratio of lateral root length to main root length were highest for M-LP seedlings across all P levels for F3 seeds (P < 0.05). With P levels of 0 and 9 mg kg(- 1), average root diameter was higher for M-HP seedlings than M-LP seedlings for F3 seeds (0 mg kg(- 1): P = 0.007, 9 mg kg(- 1): P = 0.027). CONCLUSIONS: Our results show that AMF not only influences the current generation of host plants, but also greatly affects their offspring especially when their parents have grown under low-P soil condition.