Using High-Throughput Phenotyping to Explore Growth Responses to Mycorrhizal Fungi and Zinc in Three Plant Species.

S J Watts-Williams,C Brien,N Jewell,T R Cavagnaro,T Garnett,B Berger

doi:10.34133/2019/5893953

Abstract

There are many reported benefits to plants of arbuscular mycorrhizal fungi (AMF), including positive plant biomass responses; however, AMF can also induce biomass depressions in plants, and this response receives little attention in the literature. High-throughput phenotyping (HTP) technology permits repeated measures of an individual plant's aboveground biomass. We examined the effect on AMF inoculation on the shoot biomass of three contrasting plant species: a vegetable crop (tomato), a cereal crop (barley), and a pasture legume (Medicago). We also considered the interaction of mycorrhizal growth responses with plant-available soil zinc (Zn) and phosphorus (P) concentrations. The appearance of a depression in shoot biomass due to inoculation with AMF occurred at different times for each plant species; depressions appeared earliest in tomato, then Medicago, and then barley. The usually positive-responding Medicago plants were not responsive at the high level of soil available P used. Mycorrhizal growth responsiveness in all three species was also highly interactive with soil Zn supply; tomato growth responded negatively to AMF inoculation in all soil Zn treatments except the toxic soil Zn treatment, where it responded positively. Our results illustrate how context-dependent mycorrhizal growth responses are and the value of HTP approaches to exploring the complexity of mycorrhizal responses.

Highlights

Arbuscular mycorrhizal fungi (AMF) are known to play a major role in the uptake of plant nutrients, the impacts of forming arbuscular mycorrhizal (AM) associations on plant growth can vary widely [1]
Both the barley and tomato roots were well colonised by the arbuscular mycorrhizal fungi (AMF) in inoculated treatments, for all Zn addition treatments
In what we believe to be the first application of High-throughput phenotyping (HTP) of this type in studies of AM, we have examined the effect of AMF inoculation and varying soil Zn concentrations on the growth of three contrasting species: a vegetable crop, cereal crop, and pasture legume

Summary

Introduction

Arbuscular mycorrhizal fungi (AMF) are known to play a major role in the uptake of plant nutrients, the impacts of forming arbuscular mycorrhizal (AM) associations on plant growth can vary widely [1]. Studied plant species such as maize (Zea mays), leek (Allium porrum), and Medicago (Medicago truncatula) often display marked positive growth responses when colonised by AMF, under soil nutrient deficient conditions [8, 9]. There has been some focus in the literature on plant species such as wheat (Triticum aestivum) and barley (Hordeum vulgare) being nonresponsive or even negatively responsive to AMF inoculation [10,11,12,13]. Growth responses are not consistent between different genotypes of the same species of plant [13, 14], nor between different

Objectives

Methods

Results

Discussion

Conclusion