科研之友
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摘要
the objective of this study was to evaluate the germination of %26quot;pau-de-balsa%26quot; (ochroma lagopus sw., bombacaceae) seed as a function of maturation stages of fruits, the germination of seeds harvested from trees with different diameters at height breast (dbh), and the germination of seed with different treatments to break dormancy. in the first experiment, the germination of seeds from fruits of different maturation stages, green, greenish (green yellowish), black (closed fruit) and dehiscent black (fruit opened with displayed seed cotton), was evaluated. in the second, the germination of seeds from trees with the same age (17 months) and with different dbh, small (5.4 cm), medium (9.1 cm) and large (13.2 cm) was evaluated. in the third, the germination of seeds subjected to dormancy breaking treatments, control, water for 24 and 48 hours, water at 80oc and left to cool, h2so4 for 1/2 and 1 minute and with and without seed cotton; seed cotton burned on metallic sieve, and sowing of seeds with seed cotton was evaluated. the seeds were germinated on paper in germination chambers at 20oc, 30oand 25oc in the first, second and third experiments, respectively. the pau-de-balsa seeds germinated better and faster when the fruits were black or black dehiscent, or when collected on trees with small or medium diameter, or treated with water at 80oc, or treated with sulfuric acid for 1/2 or 1 minute with or without seed cotton. the treatments with sulfuric acid has the advantage to breaking dormancy and dissolving the seed cotton. the seeds newly collected and germinated no presented seedcoat dormancy.
