Open Access Highly Accessed Methodology

Protocol: optimising hydroponic growth systems for nutritional and physiological analysis of Arabidopsis thaliana and other plants

Simon J Conn1, Bradleigh Hocking12, Maclin Dayod12, Bo Xu12, Asmini Athman12, Sam Henderson12, Lucy Aukett1, Vanessa Conn12, Monique K Shearer13, Sigfredo Fuentes1, Stephen D Tyerman12 and Matthew Gilliham12*

Author Affiliations

1 School of Agriculture, Food & Wine and The Waite Research Institute, University of Adelaide Waite Campus, PMB1, Glen Osmond, South Australia 5064, Australia

2 Australian Research Council Centre of Excellence in Plant Energy Biology, Glen Osmond, South Australia 5064, Australia

3 Australian Centre for Plant Functional Genomics, Glen Osmond, South Australia 5064, Australia

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Plant Methods 2013, 9:4  doi:10.1186/1746-4811-9-4

Published: 5 February 2013

Abstract

Background

Hydroponic growth systems are a convenient platform for studying whole plant physiology. However, we found through trialling systems as they are described in the literature that our experiments were frequently confounded by factors that affected plant growth, including algal contamination and hypoxia. We also found the way in which the plants were grown made them poorly amenable to a number of common physiological assays.

Results

The drivers for the development of this hydroponic system were: 1) the exclusion of light from the growth solution; 2) to simplify the handling of individual plants, and 3) the growth of the plant to allow easy implementation of multiple assays. These aims were all met by the use of pierced lids of black microcentrifuge tubes. Seed was germinated on a lid filled with an agar-containing germination media immersed in the same solution. Following germination, the liquid growth media was exchanged with the experimental solution, and after 14-21 days seedlings were transferred to larger tanks with aerated solution where they remained until experimentation. We provide details of the protocol including composition of the basal growth solution, and separate solutions with altered calcium, magnesium, potassium or sodium supply whilst maintaining the activity of the majority of other ions. We demonstrate the adaptability of this system for: gas exchange measurement on single leaves and whole plants; qRT-PCR to probe the transcriptional response of roots or shoots to altered nutrient composition in the growth solution (we demonstrate this using high and low calcium supply); producing highly competent mesophyll protoplasts; and, accelerating the screening of Arabidopsis transformants. This system is also ideal for manipulating plants for micropipette techniques such as electrophysiology or SiCSA.

Conclusions

We present an optimised plant hydroponic culture system that can be quickly and cheaply constructed, and produces plants with similar growth kinetics to soil-grown plants, but with the advantage of being a versatile platform for a myriad of physiological and molecular biological measurements on all plant tissues at all developmental stages. We present ‘tips and tricks’ for the easy adoption of this hydroponic culture system.

Keywords:
Hydroponics; Plant nutrition; Arabidopsis; Gas exchange; ACA2; CAX1; CAX2; VHA-α; Transient transformation