HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Wolf, D. D. Search for Related Content PubMed Articles by Wolf, D. D. Agricola Articles by Wolf, D. D.

Assimilation and Movement of Radioactive Carbon in Alfalfa and Reed Canarygrass¹

Alfalfa (Medicago sativa L.) and reed canarygrass (Phalaris arundinacea L.) were exposed in the field to radioactive carbon dioxide. Plants were treated at several maturity stages and C¹⁴ was measured in various plant parts at several dates following exposure. Carbon-14 moved to the tap root during the 15-min exposure time and accumulated with time in the tap root to a greater extent when exposed in the more mature stage (bud stage of alfalfa and early head stage of reed canarygrass) than when exposed in the vegetative stage.

Relative CO₂ assimilation as influenced by several light intensities was measured by C¹⁴ in leaves after exposing plants to labeled carbon dioxide. Each reduction of light intensity resulted in reduced C¹⁴ in leaves. Light saturation (maximum C¹⁴O₂ uptake) throughout the profile did not occur with 50% of full sun intensity. Measurable uptake of C¹⁴ occurred with 0.1% of full sun but may have been due in part to dark fixation.

Labeled carbon fed into one tiller of a plant as fructose and glucose was translocated throughout the underground rhizome system of a reed canarygrass clone and throughout all parts of an alfalfa plant. Carbon-14 from fructose, the predominant building block of nonstructural carbohydrates in reed canarygrass, moved to a lesser degree than C¹⁴ from glucose. Carbon-14 from glucose, the predominant building block of nonstructural carbohydrates in alfalfa, moved to a lesser degree than C¹⁴ from fructose.

Key Words: carbohydrates • Medicago sativa • Phalaris arundinacea • C¹⁴O₂ • radioactive sugars

² Assistant Professor of Agronomy, formerly at University of Connecticut, now at Virginia Polytechnic Institute, Blacksburg.

Received for publication December 23, 1966.