Dusty secrets: REE unveil hidden trends in foliar plant nutrition under rising CO2

Dusty secrets: REE unveil hidden trends in foliar plant nutrition under rising CO₂

 

Anton Lokshin^1,2, Avner Gross², Daniel Palchan¹

 

¹Department of Civil Engineering, Ariel University, Ariel 40700, Israel

² Department of Geography and Environmental Development, Ben Gurion University of the Negev, Beer Sheva 8410501, Israel

 

The emerging phenomenon of direct foliar nutrient uptake, where dust deposits replenish plant ionome under stress, holds potential as a significant adaptation in a changing world. Dust's rapid leaf deposition, bypassing soil contact, offers a unique nutrient source, particularly relevant in soils of limited fertility. Rising CO₂, known to hinder root nutrient uptake, along with an expected decrease in soil fertility, further underscores the potential importance of this pathway. Here, we present findings from laboratory experiments in which chickpea plants were treated with atmospheric particles used as natural fertilizers. These particles, including fire ash, volcanic ash, and desert dust, were applied to plant foliage under ambient and elevated CO₂ conditions. We examined the foliar nutrient pathway from the Rare Earth Elements (REE) perspective and demonstrated that REEs serve as an excellent tool for its exploration. Analysis of the REE within the treated plants showed enrichment in Light REE compared to Heavy REE concurrent with higher biomass and improved carbon assimilation – proving the nutrients were assimilated into the plant rather than just surface retention. Finally, our results elucidate a couple of trends in the foliar nutrient uptake pathway: (1) under elevated CO₂ levels, the foliar uptake is larger, and (2) nutrient transport from dust to plant is in the following order- volcanic ash > desert dust > fire ash. Analysis of REE patterns and ratios, alongside other biological parameters, provides novel insights into the extent and dynamics of foliar nutrient uptake across dust types and CO₂ levels, shedding light on previously unexplored aspects of this crucial adaptation.