
%0 Journal Article
%A Lush, WM 
%A Evans, LT 
%T Longitudinal Translocation of <sup>14</sup>C-Labelled Assimilates in Leaf Blades of <I>Lolium temulentum</I>
%J Functional Plant Biology
%D 1974/09/01
%V 1
%N 3
%P 433-443
%K 
%R https://doi.org/10.1071/PP9740433
%U https://www.publish.csiro.au/paper/PP9740433 
%X The distribution of 14C activity in leaf blades of L. temulentum following application of 14CO2 to a small area near the middle of the blades was studied over periods of up to 6 h. The profiles of 14C activity towards the leaf base comprised several regions. The very steep logarithmic profiles within a few centimetres of the area exposed to 14CO2, and symmetrical about it, were shown to be probably due to diffusion of gaseous 14CO2 within the leaves prior to its photosynthetic fixation.    The major profile region represented the movement of a pulse of 14C activity, in the hour following exposure to 14CO2, down the leaf at speeds of 40-84 cm/h. The activity in this pulse was attenuated along the pathway, the attenuation decreasing with increase in distance moved. In leaves harvested more than 1 h after exposure to 14CO2, there was an irregular transition zone between these two logarithmic profile regions which may represent a later or slower-moving component of translocation. In leaves harvested less than 30 min after exposure to 14CO2, there was an increase in slope at the profile front which was not attributable to changes in phloem cross-section relative to leaf catchment area.    No steady acropetal movement of 14C activity was detected, but some activity was found in the distal areas of even the earliest-harvested leaves. Long, parallel-veined leaves of grasses may well provide suitable systems for more detailed analysis of translocation profiles. 
