Effects of plant growth regulators and NaCl on early developmental stages of Striga hermonthica

A series of laboratory experiments were carried out in order to investigate the effect of plant growth regulators (PGRs) and NaCl on germination and haustorium initiation of Striga hermonthica. Therefore, manipulation of seed germination and pre-attachment stages are mandatory for successful management. In the present study, conditioned Striga seeds in water treated with 2, 4-D produced high germination 76% in response to GR24. Induction of germination by BAP varied from low (30%) to moderate (50%). Moreover, conditioned seeds treated with the combination of auxins and NaCl reduced germination by 90-100% as compared to the control. Furthermore, germination of Striga was relatively higher in the presence of kinetine and BAP in presence or absence of the GR24. In addition, both the cytokinies in combine with NaCl induced haustorium initiation in a dose dependent manner. Both axuins in combination with NaCl displayed negative response for haustorium initiation, in absence of haustorium factor. Striga seeds conditioned in presence of PGRs plus NaCl and subsequently treated with germination stimulant displayed considerable germination reduction (35-100%). Kinetine in combination with NaCl completely inhibited Striga germination in response to the synthetic germination stimulants GR24 in a concentration dependent manner. Withrespect to haustorium, all treatments reduced Striga germilings, significantly as compared to control (88%) in response to DMBQ. Auxin, 2, 4-D applied to Striga seeds after seeds conditioned in water was completely inhibited (100%) haustoria as compared to the control. Furthermore, Osmotic potential may significantly affect germination and haustorium initiation of Striga hermonthica. The results are consistent with a model in which both germination and subsequent morphogenesis in Striga are associated with exogenous and endogenous phytohormones.