Observations on the Development and Germination of the Seed in Certain Polygonaceae

Abstract

The Polygonaceae have been included by Harz (7, p. 1072) under the ''Curvembryonaten"' which he speaks of as being furnished with an abundant perisperm, and laterally placed embryo. The term '"'perisperm"' is applied to the remaining portion of the nucellus ina mature seed. Harz (p. 1102) carefully figures and describes the buckwheat seed, considering the entire storage region as perisperm, and stating that the same relation holds in species of Rumex. | Johnson (11, p. 334), evidently influenced by the work of Harz, was led to believe that there is a rather close relationship between the Polygonaceae and the Piperaceae, in which family he observed perisperm. In these Piperaceae he looks upon the very abundant perisperm as the real storage region, it being separated from the embryo by a layer of endosperm, which, instead of acting as a storage region, serves to digest and pass on food material to the embryo from the perisperm. In an earlier paper (10, p. 368) Johnson had already

Embryogeny and vegetative developmental anatomy of Polygonum pensylvanicum L.

“…Endosperm development in several other species of this family was reported by Woodcock (1914) and Lonay (1922).…”

“…Endosperm development in several members of the Poly gonaceae was reported by Stevens (1912), Woodcock (1914), and Lonay (1922). The progressive degeneration of the nucellar tissue and the various stages of endosperm development in F. esculentum was described and illustrated by Stevens.…”

“…L. and several species of Polygonum, Rumex, and Polygonella by Woodcock (1914). The fruit of the Polygonaceae is usually a flattened three or four angled or winged achene (Fernald, 1950).…”

“…According to these authors the microscopic structure of the pericarp of P. pensylvanicum is similar to that de scribed for P. convolvulus. Woodcock (1914) described the early stages of "seed" germination in several members of the Polygonaceae. In Rumex crispus L. the first gross evidence of germination is the rapid elongation of the embryo, which forces the apex of the fruit coat to form a split through which the radicle emerges.…”

Toxicity of soil fumigants in relation to seed dormancy

“…Evidence for the sequence of events involved in the termination of seed dormancy in Polygonum pensylvanicum is incomplete. Woodcock (56) in 191k gave an excellent account of the morphology and anatomy of certain Polygonaceae seed and suggested that in Polygonum articulatum and Polygonum scandens the aleurone layer secretes an enzyme xdiich con verts the insoluble starch of the endosperm into a form available for the germinating embryo. Ransom (39) studied after-ripening requirements for seed of several species of Polygonaceae, He found that seed of Polygonum pensylvanicum treated for 5 months at i|.3°-W°F under saturated conditions germinated 81i percent, whereas in diy storage no after-ripening occurred.…”