Isolation and identification of some cyanobacteria and their plant growth promoting effect on wheat (Triticum aestivum L.), Ethiopia

Abstract

Cyanobacteria are gram negative photosynthetic prokaryotic microorganisms otherwise known as Blue Green Algae (BGA). Numerous cyanobacteria were isolated and identified worldwide and most of them are known to possess the ability to discharge plant growth promoting substances as well as fixing atmospheric nitrogen. Therefore, the present study mainly focussed on evaluating the plant growth promoting activity of cyanobacterial isolates using wheat as an experimental crop by seed germination and pot experiments. In the present study, five different cyanobacterial species were isolated and identified as Pseudanabaena galeata KA1, Oscillatoria perornata KA2, Phormidium acutum KA3, Rivularia sp. KA4 and Lyngbya sp. KA5 based on the morphometric characters using microscopic investigations. The heterocystous cyanobacterium Rivularia sp. KA4 at 0.3% aqueous concentration showed significantly (p<0.05) highest results in the morphological parameters as well as in the biochemical parameters under seed germinations experiment. The same heterocystous cyanobacterium Rivularia sp. KA4 at 2g dried application significantly (p<0.05) boosted the morphological growth parameters (plant height, number of leaves, leaf length, leaf width, number of roots, root length, shoot fresh and dry weight) and biochemical parameters (chlorophyll a, chlorophyll b, total chlorophyll and carotenoid) of the experimental crop under pot experiment when compared to all other cyanobacterial species, chemical fertilizer treatment, and control. Therefore, the heterocystous cyanobacterial isolate Rivularia sp. KA4 at 3% aqueous extracts can be used to do the pretreatment of wheat seeds and the same heterocystous cyanobacterium Rivularia sp. KA4 can also be used as biofertilizers in both dried as well as liquid form for the cultivation of T. aestivum.