Rubber-Content of North American Plants

Rubber-Content of North American Plants

Read FREE!

Rubber-Content of North American Plants

Rubber-Content of North American Plants

Read FREE!

Excerpt

Rubber is now considered by every civilized community as one of its prime necessities. Since this important commodity is almost wholly a product of the tropics, those countries which lie entirely or mostly in the temperate zones are dependent upon importations, mostly from overseas, for their supply. This places the importing nation at a disadvantage, since it is subject at all times to labor and other economic disturbances in the rubber-producing countries, while in time of war it is dependent upon the good-will both of the producers and of whatever power happens at the moment to be in control of those seas over which the importations must travel. The United States is in a particularly hazardous position in this respect. The normal annual importation into this country is approximately 300,000,000 pounds. War-time conditions would make such increased and imperative demands that, unless this amount could be very materially augmented, it would be necessary greatly to restrict the use of rubber for ordinary commercial purposes. This inconvenience, however, would be trivial as compared with the perilous condition of the country in case importations from overseas should at the same time be seriously curtailed or stopped entirely by the enemy. It therefore behooves the United States and other countries so situated to discover some other method of supplying their needs, and it is possible that one such method lies in the improvement and cultivation of rubber plants suited to extra-tropical conditions. The responsibility for the initiation of such studies lies primarily with the botanist, since he is the one who should be the best qualified to recognize the kinds of plants most likely to yield results. It was with these considerations in mind that the present investigation was undertaken, although the general scientific interest which attaches to the formation and presence of rubber in plants was also an impelling motive.

The work described in this paper is to some extent a continuation of a survey of western North America for rubber-producing plants begun in 1917 as a war-emergency project under the State Council of Defense of California and of which there is more specific reference on p. 8. That project, however, centered around a study of the genus Chrysothamnus and related shrubs, plants in which the rubber occurs in the form of solid particles in the plant cell, whereas the present studies are concerned chiefly with the genus Asclepias (milkweeds) and similar herbaceous plants in which the rubber occurs somewhat as an emulsion in the latex, or milky sap, which in turn occupies the vessels of the highly specialized laticiferous tissues. Furthermore . . .

Search by... Author
Show... All Results Primary Sources Peer-reviewed

Oops!

An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.