Micronutrients in Pinus caribaea morelet. III. Corresponding, Fe, Mn and Zn sufficiency and deficiency internal levels

Abstract

A pot experiment was conducted in a green house, in Piracicaba, SP, Brazil, in order to determine the effects of Fe, Mn and Zn omission on growth, the corresponding internal levels and the efficiency of micronutrients use for young plants of P. caribaea var. hondurensis, P. caribaea var. bahamensis and P. caribaea var. caribaea. The following nutritional treatments were used: complete, without Fe, without Mn and without Zn. Washed sand was used as a substrate, being the plants watered twice a day with the corresponding nutrient solution. After the deficiency symptoms establishment, the plants were cut and separated in parts, dried at 75oC, weighed, ground and analysed for Fe, Mn an Zn concentrations. Upper and lower needles internal levels of these micronutrients were obtained. Under deficiency P. caribaea var. bahamensis was the most efficient variety in Fe use; P. caribaea var. caribaea was the most efficient variety in Cu use, and the least in Mn use; P. caribaea var. hondurensis was the least efficient variety in Fe use. All the caribean pine varieties used had very low need of Zn.