Journal of Agricultural Science and Sustainable Production (Jan 2017)
The Effect of Some Bacterial Isolates on Root Growth and Nutrient Uptake in Corn (Zea mays L.)
Abstract
Root initiation can be influenced by microbial inoculation and microbial auxin. Auxin production is known as one of plant growth promoting characteristics of bacteria. This hormone has main role in root-initiation. Thus, in a factorial experiment the ability of some bacterial isolates (25 isolates) were assessed in in-vitro condition. Results showed that auxin-production by the isolates in NF medium containing 0 and 100 mg.kg-1 of tryptophan varied from 0.75-2.28 mg.l-1 The highest and lowest amount of auxin were measured by Az-3 and Az-48, respectively. Furthermore, in order to study the effect of isolates inoculation on root initiation and general growth of corn, a completely randomized design experiment were carried out. In the whole period of experiment all nutrient solution were added to the pots via Hogland solution, since the sterile sand or inert medium were used as the bed of pot culture. Maximum volume of roots were observed in the isolates Az-13 and Az-73 by the volume of 47.67 and 38.67 cm3 respectively, whereas Az-8 had the highest root dry matter. Maximum total dry weight was gained by isolate Az-48. Nutrient analysis in dry tissue of corn showed that Az-48 had highest uptake of nitrogen, phosphorus, potassium and iron with the value of 80.66, 10.85, 241.2 and 4.67 mg.pot-1 Our results showed that although Az-48 had lowest auxin-production ability in in-vitro assay but in pot culture it was very efficient and it seems that other mechanisms play the role in this increment.
