Wheat zinc trials get radioactive edge

RADIOACTIVE CEREAL: Tom Cresswell, ANTSO, Casey Doolette, University of SA, and PhD candidate Thea Lund Read have been using nuclear monitoring to test for zinc absorption.
RADIOACTIVE CEREAL: Tom Cresswell, ANTSO, Casey Doolette, University of SA, and PhD candidate Thea Lund Read have been using nuclear monitoring to test for zinc absorption.

Nuclear science could help wheat crops by tackling the issues of zinc and other micronutrient deficiencies in soil.

Researchers from the Future Industries Institute at the University of SA are collaborating with a group of scientists at the Australian Nuclear Science and Technology Organisation to investigate a new class of micro and nano-scale zinc fertilisers for broadacre crops.

This involves analysing the growth of 140 wheat plants flown from SA to Lucas Heights, Sydney, in a specially-designed greenhouse laboratory.

University of SA research associate Casey Doolette and PhD candidate Thea Lund Read at the Future Industries Institute are assessing if nano and micro zinc particles applied to leaves, can provide a more sustained supply of zinc to the crops.

The purpose of the study is to determine what form of zinc is the most efficient for supplying the nutrient to broadacre crops, with the ultimate aim of optimising crop management to increase crop yield and quality.

Nuclear science was used to understand how zinc is transported through the crop, and is based on the use of what are known as radiotracers to track the distribution of elements, in this case, zinc.

The tracer principle involves making a product slightly radioactive so that with certain equipment you can image it after it has arrived at a location in a plant or in a person. In this study, the zinc particles were made radioactive using the OPAL research reactor.

The imaging technique used by the team has allowed for single plants, grown in the greenhouse at ANSTO for this study, to be measured at multiple points of time without having to harvest them.

ANSTO biologist Nicholas Howell captured a series of x-ray like images called auto-radiographic images of the plants, which show how the distribution of zinc changes in live leaves, over time.

ANSTO environmental research scientist Tom Cresswell was also part of the study, and applied his expertise in using radioactive isotopes as tracers in marine organisms to the plants.

“We use this technique to study all manner of things at the atomic level. It is slightly different working with plants, but the concept and application is essentially the same,” Dr Cresswell said.

“By using zinc-65 as a radiotracer, it is possible to detect exactly where the zinc goes after it has been absorbed by the plant.

“We would also be interested in knowing how much zinc is not taken up by the plant, as that zinc would be released into the environment with rainfall, and from the perspective of an ecotoxicologist, it is important to know if the zinc is affecting freshwater runoff.”

Dr Doolette said ideally the applied zinc would accumulate in the grains of the plant, where it has the most nutritional benefit as food.

“By determining the most efficient form of zinc for direct foliar application, crop management strategies can be optimised to increase crop yield and quality,” Dr Doolette said.

For more information on ANSTO, see www.ansto.gov.au