Arbuscular mycorrhizas modify tomato responses to soil zinc and phosphorus addition
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Arbuscular mycorrhizas (AM) play an important role in plant P and Zn nutrition; however, relatively few studies have directly investigated the interactive effects of these nutrients on plants. Therefore, we undertook a glasshouse experiment to study the effects of Zn and P on AM formation and functioning. A mycorrhiza defective tomato mutant (rmc) and its mycorrhizal wild-type progenitor (76R) were used in this experiment. Plants were grown in soil amended with five Zn concentrations, ranging from deficient to toxic, and two levels of P addition. The addition of Zn and P to the soil over a range of concentrations had profound effects on plant growth and nutrition and mycorrhizal colonization. Mycorrhizal benefits were the greatest when plants were grown under low soil P and Zn. Furthermore, the effect of soil Zn supply on plant growth, nutrition, and AM colonization was strongly influenced by the concentration of P in the soil. Thus, studies of AM and Zn (or other nutrients of interest) should take into account the impact of soil P concentration on the role of AM in plant Zn acquisition, under both deficient and toxic soil Zn concentrations.
KeywordsArbuscular mycorrhizas (AM) Zinc Phosphorus Mycorrhiza defective tomato mutant (rmc) Solanum lycopersicum (Tomato)
The authors wish to thank Ms. Leesa Hughes for her excellent technical assistance and members of the “Cav-Lab” for valuable discussions. We also gratefully acknowledge Dr. Susan Barker and Prof. Sally Smith for continued access to the rmc and 76R genotypes of tomato. This research was in part funded by the Monash University, School of Biological Sciences. TRC also wishes to acknowledge the Monash Research Accelerator program for financial support.
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