Conservação e viabilidade de grãos de pólen de Carnaúba (Copernicia prunifera (MILL.) H.E. MOORE)

Abstract

Among the species of palmáceas, the Copernicia prunifera, stands out in the northeastern region of Brazil. However, there is a shortage of scientific information about carnauba, especially with regard to research aimed at the genetic improvement of culture. The objective of this work was to evaluate the different phases of the development of the floral bud (closed, semi open and open), to estimate the pollen viability by colorimetric tests and in vitro germination and to evaluate the conservation of pollen grains of Copernicia prunifera when submitted to the reduction in temperature of storage. Inflorescence samples were randomly collected from 10 matrices at different stages of development, collected in Russas-Ceará. Then, for the evaluation of flower morphology the size of the floral bud was measured in three different stages: closed, open and semi-open. To evaluate the pollen viability two dyes were used lugol and 1% acetic carmine. The in vitro germination rate of the pollen grains was verified using three different culture media: Medium 1 (M1): 100 g L-1 of sucrose; 10 g L-1 of agar; Medium 2 (M2): 100 g L-1 sucrose; 500 mg L-1 of H3BO3; 10 g L-1 of agar; Medium 3 (M3): 100 g L-1 sucrose; 300 mg L-1 of CaCl2; 10 g L-1 of agar. Pollen grain storage was tested in three different environments: refrigerator (12 ° C), freezer (6 ° C) and room temperature (26 ° C). The evaluation of the viability of the pollen was done by germinating the pollen tube in three different culture media, with the following compositions: Medium 1 (M1): 100 g L-1 of H3BO3; 300 mg L-1 Ca (NO3) 4(H2O); 10 g L-1 agar, Medium 2 (M2): 100 g L-1 sucrose; 500 mg L-1 of H3BO3; 10g L-1 agar, Medium 3 (M3): 100g L-1 sucrose; 10g L-1 of agar. By the Tukey test at 5% probability there is no statistical difference between the treatments tested for the evaluation of the pollen viability by the colorimetric test. Regarding the storage of the carnauba pollen grain, it is indicated that it is at a temperature ranging from 6 ° C to 12 ° C and the pollen viability can be tested during the storage period using culture medium 2 (100g L -1 of Sucrose, 500mg L-1 of H3BO3, 10g L-1 of agar).