Rapporti Fra Endosperma ed Embrione Nella Germinazione di Pinus Pinea L.: Nota i: Effetti del Grado di Maturita del Seme

Endosperm embryo interrelationships during germination of PINUS PINEA L. 1rst note. — Seeds and excised embryos have been cultured in vitro in the dark. Experiments with ripe seeds and embryos have been paralleled with exper. with unripe ones (6 months before natural seed dispersal). The results are as follows:Both ripe and unripe seeds germinate in the dark into green seedlings.In both types of seedlings the rootlet is the only part which rapidly increases in length, actually growing, but the growth speed of the root is greater in ripe seeds than in the unripe ones.Both ripe and unripe excised embryos grow slowly, with greenles cotyledons and dwarf roots, showing a very slight geotropic curve.The root stops growing more sharply in ripe embryos than in unripe ones.The hypothesis is raised that the rootlet reaches its full growing power, under the endosperm control, and that this control encreases more and more, as the seed approaches its full maturity.