Publication Date
1997
Description
The objective of this study was to provide information on how current photosynthate allocated to the root system in perennial ryegrass (Lolium perenne L.) is distributed among individual roots at differing nodal positions. Mature single ryegrass tillers were transplanted in September 1993 to glass house pots and three months later four of the plants were supplied with 14CO2. Individual roots from these radioactively-labeled plants were identified according to their nodal position on the tiller axis and amount of radiocarbon in each root quantified for root tip segments and for the remainder of the root axis. Similar plants were destructively harvested and the number of roots, and mean weight and mean length of individual roots at each node recorded. Counting basipetally from the node of the first fully expanded leaf, root initiation occurred by node two, and final root mass and length was attained by node six. Of the total radiocarbon recovered from the root system, approximately 70% was found in roots attached to the first five nodes. The greatest allocation to root tips was at node one (17.7% of radiocarbon recovered) while the greatest allocation to root axes was at node three (12.1% of radiocarbon recovered). Implications for understanding of timing of root development in relation to nodal position on the tiller axis are discussed.
Included in
Agricultural Science Commons, Agronomy and Crop Sciences Commons, Plant Biology Commons, Plant Pathology Commons, Soil Science Commons, Weed Science Commons
Allocation of Carbon-14 to Roots of Different Ages in Perennial Ryegrass (Lolium perenne L.)
The objective of this study was to provide information on how current photosynthate allocated to the root system in perennial ryegrass (Lolium perenne L.) is distributed among individual roots at differing nodal positions. Mature single ryegrass tillers were transplanted in September 1993 to glass house pots and three months later four of the plants were supplied with 14CO2. Individual roots from these radioactively-labeled plants were identified according to their nodal position on the tiller axis and amount of radiocarbon in each root quantified for root tip segments and for the remainder of the root axis. Similar plants were destructively harvested and the number of roots, and mean weight and mean length of individual roots at each node recorded. Counting basipetally from the node of the first fully expanded leaf, root initiation occurred by node two, and final root mass and length was attained by node six. Of the total radiocarbon recovered from the root system, approximately 70% was found in roots attached to the first five nodes. The greatest allocation to root tips was at node one (17.7% of radiocarbon recovered) while the greatest allocation to root axes was at node three (12.1% of radiocarbon recovered). Implications for understanding of timing of root development in relation to nodal position on the tiller axis are discussed.
