Strategies to acquire and use phosphorus in phosphorus-impoverished and fire-prone environments

• Published in: Plant and soil Vol. 476; no. 1-2; pp. 133 - 160
• Main Authors: Lambers, Hans, de Britto Costa, Patrícia, Cawthray, Gregory R., Denton, Matthew D., Finnegan, Patrick M., Hayes, Patrick E., Oliveira, Rafael S., Power, Simon C., Ranathunge, Kosala, Shen, Qi, Wang, Xiao, Zhong, Hongtao
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.07.2022; Springer; Springer Nature B.V
• Subjects: Agriculture; Australia; Biomedical and Life Sciences; Carboxylates; cerrado; Coexistence; Convergence; Cropping systems; Ecology; Environmental aspects; Exudates; Fluorine; Fynbos; Germination; Heavy metals; landscapes; Leaves; Life Sciences; longevity; Manganese; Metalloids; Organs; Phosphorus; Phosphorus in the body; Photosynthesis; Physiological aspects; Plant diversity; Plant Physiology; Plant Sciences; Plants (botany); Releasing; Review Article; Selenium; Shrubs; silicon; soil; Soil Science & Conservation; South Africa; South America; Species; Wildfires; Australia; Cerrado Biome; South America; South Africa; Facilitation; Mycorrhizas; Sand-binding roots; Phosphorus-use efficiency; Non-mycorrhizal plants; Dauciform roots; Phosphorus-acquisition efficiency; Fire; Phosphorus; Hyperdiverse ecosystems; Carboxylates; Cluster roots
• DOI: 10.1007/s11104-022-05464-8
• ISSN: 0032-079X

Background Unveiling the diversity of plant strategies to acquire and use phosphorus (P) is crucial to understand factors promoting their coexistence in hyperdiverse P-impoverished communities within fire-prone landscapes such as in cerrado (South America), fynbos (South Africa) and kwongan (Australia). Scope We explore the diversity of P-acquisition strategies, highlighting one that has received little attention: acquisition of P following fires that temporarily enrich soil with P. This strategy is expressed by fire ephemerals as well as fast-resprouting perennial shrubs. A plant’s leaf manganese concentration ([Mn]) provides significant clues on P-acquisition strategies. High leaf [Mn] indicates carboxylate-releasing P-acquisition strategies, but other exudates may play the same role as carboxylates in P acquisition. Intermediate leaf [Mn] suggests facilitation of P acquisition by P-mobilising neighbours, through release of carboxylates or functionally similar compounds. Very low leaf [Mn] indicates that carboxylates play no immediate role in P acquisition. Release of phosphatases also represents a P-mining strategy, mobilising organic P. Some species may express multiple strategies, depending on time since germination or since fire, or on position in the landscape. In severely P-impoverished landscapes, photosynthetic P-use efficiency converges among species. Efficient species exhibit rapid rates of photosynthesis at low leaf P concentrations. A high P-remobilisation efficiency from senescing organs is another way to use P efficiently, as is extended longevity of plant organs. Conclusions Many P-acquisition strategies coexist in P-impoverished landscapes, but P-use strategies tend to converge. Common strategies of which we know little are those expressed by ephemeral or perennial species that are the first to respond after a fire. We surmise that carboxylate-releasing P-mobilising strategies are far more widespread than envisaged so far, and likely expressed by species that accumulate metals, exemplified by Mn, metalloids, such as selenium, fluorine, in the form of fluoroacetate, or silicon. Some carboxylate-releasing strategies are likely important to consider when restoring sites in biodiverse regions as well as in cropping systems on P-impoverished or strongly P-sorbing soils, because some species may only be able to establish themselves next to neighbours that mobilise P.