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Assimilation and Movement of Radioactive Carbon in Alfalfa and Reed Canarygrass 1
Author(s) -
Wolf D. D.
Publication year - 1967
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1967.0011183x000700040011x
Subject(s) - phalaris arundinacea , biology , photosynthesis , fructose , carbon dioxide , agronomy , rhizome , botany , fodder , dry matter , light intensity , horticulture , food science , wetland , ecology , physics , optics
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 C 14 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 CO 2 assimilation as influenced by several light intensities was measured by C 14 in leaves after exposing plants to labeled carbon dioxide. Each reduction of light intensity resulted in reduced C 14 in leaves. Light saturation (maximum C 14 O 2 uptake) throughout the profile did not occur with 50% of full sun intensity. Measurable uptake of C 14 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 C 14 from glucose. Carbon‐14 from glucose, the predominant building block of nonstructural carbohydrates in alfalfa, moved to a lesser degree than C 14 from fructose.