Biofertilizing Effects of Anabaena cylindrica Biomass on the Growth and Nitrogen Uptake of Wheat

ABSTRACT

There are a substantial number of studies on the biofertilization effects of cyanobacteria in rice paddy fields, mainly attributed to biological fixation of N₂, but not much attention has been given to their fertilizing capacity in aerobic soils. Few studies have used solid media (i.e. a soil) when testing the plant-growth-promoting effects of microalgae on plants, and particularly on wheat. The purpose of this study was to test the biofertilizing effect of a filamentous cyanobacterium, previously isolated from an agricultural soil, in order to evaluate the potential substitution of chemical fertilizers and to test its phyto-stimulating capacity. Seedlings of Triticum aestivum were grown in pots with a peat-vermiculite mixture (1:1 weight basis) in an experiment designed as a complete randomized block, consisting of four treatments and with four replicates each: a pure culture of Anabaena cylindrica concentrated by centrifugation to 2 g dry matter L⁻¹ (treatment B); spent cyanobacteria growth medium filtered at 0.22 µm (treatment F); harvested cyanobacterial mat re-suspended in distilled water (treatment WB); and distilled water as a control (treatment W). Aboveground wheat plant mass was improved by 40% in both treatments with cyanobacterial biomass (B and WB), as compared to the control (W) and filtrate (F), demonstrating that the co-cultivation with living cyanobacterial biomass was key to plant improvement. Chlorophyll contents were also increased by nearly 50% and nitrogen by over 10% in the treatment WB, clearly indicating that nutrients in the filtrate were irrelevant to the beneficial effects on plant growth.

KEYWORDS:

• Bio-fertilizer
• soil algae
• Anabaena cylindrica
• plant nitrogen
• cyanobacterial biomass

Highlights

• Application of cyanobacteria can improve growth of wheat in an aerobic soil.

• Above-ground wheat plant mass was improved by 40% in treatments with Anabaena cylindrica biomass.

An improved plant N nutrition was achieved as indicated by higher chlorophyll contents.

Acknowledgments

This work was financed by LIFE13 ENV/ES/001251 EU Project. Rajaa Kholssi benefits from a grant of the AECID (Foreign Office of Spanish Government).

Compliance with ethical standards

Conflict of interest: The authors declare that there is no conflict of interest

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the EU Project LIFE13ENV/ES/001251.