Petiole colapse in soybeans leaves

Abstract

In an experiment evaluating soybean (Glycine max (L.) Merrill) cultivars for tolerance to insects conducted at the Centro Experimental in Campinas, SP, Brazil, the colapse of petioles was observed only in leaves in the middle part of the plant of the cultivar IAS-5. Leaves affected and normal ones as well as a soil sample at the 0-20 cm depth were sampled. The calcium concentration in the soil showed to be sufficient to supply the needs of the plant, whereas the leaf analyses showed that the calcium concentration in the leaves affected was approximately five times lesser than that in normal ones. The water deficit at the initial development of the plant might have caused restrain in calcium absorption and reduced the leaf size of those emitted on the occasion. Water deficit together with high temperatures at the initial reproductive period could have caused petiole colapse of the leaves.