Discovery unleashes growth in salty soils

14 May 2019

A hormone produced by stressed plants could combat damage caused by salty soils, considerably increasing plant growth.

A team of researchers from The University of Queensland and Western Sydney University has identified a naturally-occurring chemical in plants – known as 1-aminocyclopropane-1-carboxylate, or ACC – that reduces the symptoms of salt stress when applied to soil.

Dr Hongwei Liu, who conducted the research during his PhD work at UQ, said he was excited to strike a blow against salinity, which affects more than 220 million hectares of irrigated farming and food-production land worldwide.

“It’s a worldwide environmental threat, impacting the overall health of our ecosystem, greatly reducing crop production and threatening global food security,” he said.

“Salty irrigation water is repeatedly applied to crops, leading to progressively higher levels of salt in the soil, reducing crop yields, increasing susceptibility to drought and damaging soil microbiology.

“Scientists have long tried to find ways to breed salt-tolerance or remove salt and this new research is promising.”

Dr Liu said applying ACC to crops planted in salty soils prevented the formation of compounds causing plant damage under salty conditions, increasing beneficial soil enzyme and microbial activity.

This enabled the plants to cope with the salt, increasing growth in lettuces by nearly five-times and in plant models by more than 30 times, growing in extremely salty soil under lab conditions.

Professor Peer Schenk from UQ’s School of Agriculture and Food Sciences said there was significant potential for the compound to help manage crop production in otherwise unusable soils.

"Growers have traditionally used a range of long-term and slow-acting materials such as gypsum, manures, tillage and other methods to reduce the exposure of plants to the salts in soils, but these are costly and frequently ineffective, and provide limited benefits over years or decades,” he said.

“This solution could be much more cost-effective, is naturally produced by plant roots, and contributes to long-term soil health, plant-microbe relationships and carbon storage.”

While there is still more research required, Dr Liu believes ACC’s future is bright.

“More work still needs to be done to see if the method works for different soil types and crops under different climatic conditions, as well as testing any potential environmental impact.

“But I believe that our study contributes to a better understanding of plant-microbe interactions, opening the door for commercial use of ACC in agriculture, improving the fertility of salty soils worldwide.”

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