The Annual Carbohydrate Cycle of Alpine Plants as Related to Growth

M ooney, H. A., and W. D. B illings. (Duke U., Durham, N. C.) The annual carbohydrate cycle of alpine plants as related to growth. Amer. Jour. Bot. 47(7): 594–598. Illus. 1960.—Analyses were made of the carbohydrate content of roots, rhizomes, and shoots of certain plants in the alpine tundra region of the Medicine Bow Mountains, Wyoming, from the beginning of one growing season until the start of the following one. Principal species investigated were Saxifraga rhomboidea, Polygonum bistortoides, and Geum turbinatum. Results were correlated with phenological events as observed in the field. Growth of these plants was found to be very rapid, commencing in some instances under a cover of old snow. The underground organs contained relatively large amounts of carbohydrate reserves. A great part of this stored carbohydrate was utilized in growth prior to snowmelt and during the grand period of shoot growth immediately following snowmelt. In Polygonum, 50% of the rhizome reserves was used in a 1‐wk. period in early growth. Except for this short period of rapid depletion in rhizomes and roots during early growth, high carbohydrate levels were maintained both in the shoot and in the underground organs during most of the growing season. Generally, the lowest carbohydrate reserve level in both root and shoot occurred before flowering, a relatively high level was maintained in the shoot from flowering until after fruiting, while peak storage in underground parts was reached at the start of fall dormancy. The carbohydrate cycle in these alpine plants is quite similar to that in certain arctic plants.