Co-cultivation of cyanobacteria for raising nursery of chrysanthemum using a hydroponic system

Abstract

The present investigation aimed to utilize plant growth–promoting diazotrophic cyanobacteria as an option to raise the chrysanthemum varieties Pusa Aditya and Jaya in a nursery by co-culturing hydroponically. Fresh stem cuttings of chrysanthemum were planted in BG 11 medium (−N) which was inoculated to log-phase cultures of Anabaena torulosa (BF1), Anabaena doliolum (BF4), and Anabaena laxa (RPAN8) individually. Analyses of chrysanthemum growth and biometric/biochemical parameters after 30 days of co-cultivation revealed that co-culturing treatments performed significantly better, as compared with BG11 medium alone. Anabaena laxa brought about an increment of 27–40% in IAA production in the root tissues of both varieties grown in hydroponics. Quantification of biofilm formation on roots (measured as OD550) illustrated a two- to four-fold increment in the co-culture treatments. PEP carboxylase activity was significantly enhanced in root and shoot tissues of cuttings in Jaya, and the medium chlorophyll enhanced by several folds in both varieties. Significant increases in root dry biomass were recorded, which positively correlated with root protein (r = 0.992) in Pusa Aditya, illustrating the superiority of co-culturing as a promising option for nursery propagation. The economic benefits of BG 11 medium (without combined N) as a novel growth medium for growing the cyanobacterium and raising chrysanthemum nursery, in co-culturing mode, were also highlighted. Anabaena torulosa (BF1) performed well in both Pusa Aditya and Jaya, while Anabaena laxa (RPAN8) was significantly superior in Jaya. Future research is focused towards integration of such novel and cheap organic inputs in maintaining disease-free and nutrient-enriched plants in long-term experiments up to flowering stage.