Technique For Chromosome Observation in Coffea Embryos

SUMMARY

Growing embryos excised from developing fruits are soaked in one of the three solutions: saturated solution of paradichlorobenzene, for 6–8 hours; 0.002 M 8—oxyquinoline, for 6–8 hours; of 0.2% colchicine, for 3–4 hours. After this they are fixed in 1:1 ethanol-acetic acid overnight and then hydrolyzed in a mixture of 7 parts of 2% orcein in 70% acetic acid and 3 parts of N hidrochloric acid, for 3 hours at 40° C. Next they are placed in a drop of 1% of acetic orcein on a slide and covered with a cover slip; pressure is then applied to flatten the tissue and separate the cells. Well coloured prophases, prometaphases and polar view metaphases with shortened and scattered chromosomes were observed in embryos of several species of Coffea.