Foliar application of cyanobacterial formulations stimulates plant growth and fruit quality in tomato under protected cultivation

ABSTRACT

Cyanobacterial biofertilizers enhance plant and soil productivity across crops, through soil-seed application at the field level; however, their use as foliar treatment is less investigated. This study evaluated the role of foliar sprays, initiated 4 weeks after transplantation of nursery-raised seedlings in beds, and effected at weekly intervals for a period of eight weeks. towards enhancing plant growth, yield and quality of tomato grown in a climate-controlled polyhouse. Sprays were composed of aqueous formulations of carrier alone, and those amended with the formulations of plant-growth-promoting cyanobacterium Anabaena laxa (A. laxa) or biofilm Anabaena torulosa -Trichoderma viride (An-Tr) or suspension of 100 µM Fe EDTA. A. laxa brought about a significant increase in nitrate reductase and glutamine synthetase activity in leaves by 13%–17%, along with 3-fold stimulation in carbonic anhydrase activity. Cyanobacterium-amended foliar agents significantly enhanced soil dehydrogenase, urease activity, along with increments in organic carbon, Fe, Zn in soil and stimulated yield, fresh weight and quality of fruits. Both cyanobacterial formulations were promising in enhancing plant growth, fruit yield and quality, however, A. laxa also significantly improved microbiological activity and nutrient enrichment in soil. Future research is focused towards optimising the dose and storage life of such foliar agents for protected horticulture.

KEYWORDS:

• Biostimulants
• C–N assimilation
• IAA
• Quality traits
• Soil fertility

Acknowledgements

A. B. conducted the sampling, analyses, compiled the data and its statistical analyses; R. P. conceptualised, planned, and supervised the experiments, wrote the draft, and performed final editing of the manuscript; B. R., V. K. and R. M. N. assisted in the sampling and analyses of plant-soil parameters; S. G. R. supervised the fruit analyses and provided critical suggestions; A. K. S. was involved in the fertigation scheduling and supervision of crop growth and yields; Y. S. S. supervised nutrient analyses and provided useful inputs to the experimental work. All the authors approved the final version submitted. Shri Gulab Singh is gratefully acknowledged for his help in the nutrient analyses and Shri Parveshji for the maintenance of crop.

Disclosure statement

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

Consent to participate

All the authors have participated in the investigation and writing of the manuscript.

Consent for publication

All the authors have consented to the publication.

Data availability statement

All the data are provided as Tables and Figures.

Additional information

Funding

The authors are grateful for the funds facilitated through the Indian Council of Agricultural Research (ICAR) Network Project on Microorganisms ‘Application of Microorganisms in Agricultural and Allied Sectors’ (AMAAS), New Delhi. The authors thank the Division of Agronomy and Division of Microbiology, ICAR-IARI, for providing funds and necessary facilities.