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The responses of root morphology and phosphorus-mobilizing exudations in wheat to increasing shoot phosphorus concentration

Soil P deficiency is a major constraint to crop yield in many parts of the world and as such the adaptations of root growth and rhizosphere processes for soil phosphorus (P) acquisition have been investigated intensively in wheat (Triticum aestivum). However, only a few studies have paid attention to shoot P status. A recent study by Shen et al. and published in AoBP investigated responses of root morphology and P-mobilizing exudation to increasing shoot P concentration.

Responses of wheat to increasing shoot P concentrations
Responses of (A) total root length, (B) specific root length, (C) citrate exudation and (D) malate exudation to varying shoot P concentrations.

Root morphological and physiological traits of wheat showed different behaviours to P deficiency. Phosphorus-deficient wheat maintained root growth over shoot growth by preferentially allocating more carbon to roots; increasing total root length and producing more fine roots. Wheat did not increase rhizosphere acidification or acid phosphatase secretion in low P soil, occasionally found in plants under P deficiency. Citrate exudation of roots was enhanced by P deficiency, whilst malate exudation was reduced. It was concluded that maintaining root biomass and length is the major strategy used by wheat to deal with extreme P deficiency, rather than root exudation.

Researcher highlight

Qi Shen

Qi Shen obtained a BSc. in Resources and Environmental Science from the China Agricultural University in 2016. In 2018, she completed a MSc. in Agricultural Resources and Environment (plant nutrition) under the supervision of Associate Professor Haigang Li at China Agricultural University. Qi is soon going to start a PhD research project under the supervision of Dr. Patrick Finnegan, Professor Hans Lambers and Dr. Kosala Ranathunge in the School of Biological Sciences at The University of Western Australia.

Qi is interested in responses of plants under low phosphorus status that could be useful for future food security and changing environmental conditions. She has worked with important crop species in China and has investigated rhizosphere responses of these plants with different phosphorus supply. In her PhD, Qi will work on native Australian plants and other important crop species with a focus on plant phosphorus nutrition.