| Abstract: | Information on desiccation sensitivity of Euterpe edulis seeds under two drying rates is presented. The sensitivity was studied during the course of germination and normal germination. The water
content was evaluated for both seeds and embryos. Results showed the following: (a) For both drying treatments and for both germination and normal germination, desiccation sensitivity values were higher for measurements based on the water content of the embryo than for those of the seed. (b) For both drying treatments,
desiccation sensitivity were higher for normal germination than for germination based on both the embryo
and seed water contents. (c) Under the slow drying treatment and for measurements based on the seed water
content, critical water content was visible for normal germination but not for germination; (d) Critical water
contents for germination and normal germination were more clearly established in the fast drying treatment
than they were in the slow drying method based on both the embryo and seed water contents. Critical water
contents were not associated with changes in electrolyte leakage, which suggests that conductivity is not a
good indicator of physiological seed quality. From the beginning of both drying treatments, changes in nuclei
and vacuoles were observed, but, when seed water content was reduced to below critical values, the cells
became severely plasmolyzed, the vacuoles highly distorted, and the nuclei formed an almost homogeneous
mass with the chromatin and the nucleoplasm, which suggests irreversible DNA damages. |
