Evaluation of some cyanobacterial strains as growth promoters for sweet pepper (Capsicum annuum var. Annuum)

Three cyanobacterial strains (Spirulina, Oscillatoria and Anabaena spp.) were produced in 
forms of liquid culture and powder and evaluated as growth promoters for sweet pepper plants in a 
pot experiment. The experiment was performed in twenty four treatments including foliar 
application of cultures, filtrate and dried biomass (which were dissolved either in water or in 
culture filtrate). The negative control was water while the positive one was the recommended NPK. 
Spirulina-treated plants recorded high contents in both macroelements and microelements, whereas 
high concentrations of chlorophyll a, b and total chlorophyll were noticed in Anabaena-treated 
plants. Treatment with Spirulina showed increase in leaf and root parameters, while stem 
parameters increased by mixed culture treatment. Both Spirulina and mixed culture treatments 
showed earliness in flowering (110 days after transplantation). Plants gave fruits with marketable 
size for most treatments after 40 days of starting blooming, with protein percentages ranging from 
23.9 to 16.2%. Among the examined plants, Spirulina - treated plants were the superior in growth 
over the other treatments. Anatomical examination revealed that Spirulina - treated plants gave the 
highest increment in lamina thickness than both controls, due mainly to the elevation in spongy 
tissue thickness. Thickness of lamina positively associated with leaf fresh weight and negatively 
with leaf area.