Upward Course Research Articles

Concentric vascular bundle in some ascidial stalks of Clerodendron infortunatum Gaertn.

SOME ascidial stalks of Clerodendron infortunatum described earlier1 contain a few vascular bundles which are concentric—some amphivasal and others amphicribral in structure. The amphivasal vascular bundles are seen near the tip of the ascidial stalk. In tracing the origin of this amphivasal vascular bundle from the base to the tip in serial sections, it was observed that the basal collateral vascular bundle becomes gradually a horse-shoe shaped one which ultimately becomes amphivasal in shape (see photomicrograph). At an upper level this concentric vascular bundle reverts successively to the horse-shoe shaped and collateral types. During the transition stage of the vascular bundle from collateral to concentric structure, its upward course is diverted towards the pith. Here the amphivasal vascular bundle is seen embedded within three to six layers of cells of the pith. Next, the concentric bundle turns outward again and takes its place by the side of the neighbouring collateral vascular bundles, by which time it has assumed its collateral form.

C&EN ANNUAL REVIEW of DEVELOPMENTS IN THE CHEMICAL AND PROCESS INDUSTRIES

Board index of industrial chemicals production (1935-39=100) continue its steady climb from a postwar low of 388 in August 1949 to a new high of 457 in September 1950. It is perhaps characteristic of the chemical industry that this September level exceeded by a considerable margin the World War II peak of 412, reached in June 1945. All indications are that the index continued to rise during the quarter just ended and will carry its upward course into the coming year, although perhaps at a slower rate since increases from now on must come almost entirely from new capacity. Virtually all branches of the industry shared in the production gains, some more than others. Among the inorganics, major increases were recorded for ammonia calcium carbide, chlorine and caustic soda (despite a three-months strike affecting two major producers), chrome colors, aod hydrochloric, nitric, phosphoric, and sulfuric acids. Of the major organics, acetic acid, acetic anhydrides, benzene ...

A Half Century

In this Guest Editorial the inventor of the modern electron tube, and of many other contributions to radio during the last half century, here describes the upward course of radio and offers counsel, based on experience, to his fellow workers of today and to the government officials entrusted with present administrative responsibilities.

Morphology of the Gynobase in Mertensia

The conformation of the ring-like disc or gynobase surrounding the gynoecium varies greatly among the genera of Boraginaceae. The morphology of the gynobase ha's been taken for granted by most systematists, and has been used descriptively in connection with description of nutlet attachment. No morphological or evolutionary significance has been attached to the gynobase. In other families, anatomical and morphological studies have demonstrated that many discs, nuptial nectaries, and floral squamellae may be interpreted in terms of the other appendages of the flower. For example, it is believed that the sheathing disc about the carpel in many Leguminosae represents an abortive set of stamens.1 Structures adjacent to the gynoecium which have been observed in many Apocynaceae are interpreted as carpellodes.2 The heteromorphic nature of the gynobase of Mertensia is apparent on gross examination (Figs. 15, 16). The four unequal lobes of the gynobase alternate with the four nutlets of the pistil. Opposed to the carpels are two small obtusely triangular pointed lobes. Alternated with the carpels are the two large lobes which equal or surpass the nutlets in size. For a better understanding of the morphology of the gynobase it is necessary to describe briefly the anatomy of the flower in Mertensia. The vascular anatomy of the flower is not especially complicated in Mertensia. In most respects the description given here applies to other members of the Boraginaceae which I have examined (Figs. 1-13). The pedicel contains a circle of ten strands, alternately large and small (Fig. 1). The five smaller traces swing outward and upward to supply the sepals (Fig. 4). These strands split radially into 3 parts after they leave the stele. Lateral strands of adjacent calyx lobes do not fuse. The sepal gaps close, and then the petal and stamen traces begin to depart (Fig. 5). Each stamen receives one trace. There are five petal traces, and these split radially into three members after leaving the stele. The petal and stamien trace gaps close and the stele becomes provascular except for the strands which are to supply the carpels (Fig. 7). Each carpel is provided with three traces. The two ventrals of each carpel swing inward and upward toward the center of the flower, each eventually ascending through the placenta into the funiculus (Figs. 10-12). The dorsal bundle pursues a devious upward course which leads into the style. The median lateral bundles seen in the nutlet walls apparently arise from the placental bundles, curve upward into the wall of the nutlet and then gradually die out.

The Vascular Anatomy of the Seedling of Dioon edule

1. The vascular cylinder of the embryo is a protostele, but becomes a siphonostele in the seedling. It is very short and squarish in cross-section, one of the diagonals of the section being at right angles to the inner faces of the cotyledons, and the other parallel with them. Near each of the four corners is a group of protoxylem cells, the long diameter of whose section extends along the diagonal. 2. The four protoxylem groups extend downward to form the protoxylem of the root. 3. From each protoxylem group a foliar strand runs outward for a short distance and then branches, the branches separating at a wide angle and continuing outward until under the cotyledon, when they ascend it; the result is four strands for each cotyledon. The two protoxylem groups on the diagonal perpendicular to the inner faces of the cotyledons give rise to the two inner strands of each cotyledon; while the two protoxylem groups on the diagonal parallel with the inner faces of the cotyledons give rise to the two outer strands of the cotyledons, that is, one branch runs into the outer edge of the one and the other branch (from the same group) runs into the edge of the other cotyledon (opposite the first). 4. For each leaf or scale four strands leave the vascular cylinder at points not definitely located but well-distributed; two strands of each organ leave the cylinder approximately on the same side as the leaf for which they are destined, and run more or less directly through the cortex into the central or abaxial part of the petiole without branching; while the other two strands of each organ leave the cylinder approximately on the opposite side and describe a wide curve around it, the one in one direction and the other in the other, and finally ascend in the dorsal or adaxial part of the petiole, branching repeatedly. The girdle on the side toward which the spiral may be said to turn is generally the longer one. 5. When the cotyledonary vascular strands leave the vascular cylinder they are endarch, gradually become mesarch in their upward course, and finally approach the exarch condition. 6. The foliar vascular strands also are endarch at their separation from the vascular cylinder, and in their upward course become mesarch and finally exarch. In the very young leaf this transition extends through the whole base and petiole uniformly; but in the adult leaf it is comparatively rapid through the base up to the lower part of the petiole, where only a few centrifugal elements remain, and which remain uniform until in the rachis, where the transition is completed, so that in the pinna only centripetal xylem is left. 7. In the lower stretches of the foliar strands a considerable amount of the centrifugal wood is primary xylem. 8. In the foliar strands of the embryo and seedling, the xylem tissue, so far as developed, from below upward passes from an inner to a central position in reference to the whole bundle. 9. The girdle is established very early, and is horizontal from the beginning.