Boron simple and multiple omissions with Ca, Fe, Mn and Zn in castor bean plants (Ricinus communis)

Boron (B) is a micronutrients for plants, however the mechanisms of B acquiring still not completely elucidate. In tropical soils B is a problem due to the very low availability to plants. On the other hand, we found the castor bean plant that presents a high status as an oleaginous plant that could be used in biodiesel production. This work aimed to characterize B simple and multiple deficiencies visual symptoms in castor bean plants as well as the effects of the omissions in plants growth parameters and nutrients accumulation. It was used a randomized blocks design with six treatments: Hoagland solution (control), B omission (-B), B and Ca omission (-BCa), B and Fe omission (-BFe) B and Mn omission (-BMn) and four replications. Boron simple or multiple omission changed castor bean height, biomass and stem diameter. In addition, these omissions cause morphological effects and plants showed visual symptoms of deficiency. Castor bean plants require large amounts of B and farmers should attended to the levels of this nutrient in soils before cultivate this culture. The treatment -BCa presented the highest suppression in the growth parameters, shoot/root ratio and nutrient accumulation.