TY - JOUR AU - Alexander, Alex G. AU - Biddulph, Orlin PY - 1975/01/01 Y2 - 2024/03/29 TI - Effects of Growth-Regulatory Chemicals on the Action Spectra for 14C Assimilation and Transport in Sugarcane Leaves JF - The Journal of Agriculture of the University of Puerto Rico JA - JAUPR VL - 59 IS - 1 SE - Articles DO - 10.46429/jaupr.v59i1.10625 UR - https://revistas.upr.edu/index.php/jaupr/article/view/10625 SP - 15-25 AB - Pretreatment of sugarcane with the growth hormone gibberellic acid (GA<sub>3</sub>) and the growth depressant Polaris [N,N-bis (phosphonomethyl) glycine] significantly altered the action spectra for <sup>14</sup>C assimilation and transport by leaf tissues. Leaf segments enclosed in a <sup>14</sup>CO<sub>2</sub> atmosphere were illuminated with discrete wavelengths of equal quantum flux from 400 to 710 nanometers (nm). Both compounds significantly lowered <sup>14</sup>C assimilation in the blue, from 437 to 480 nm. Polaris accentuated a green depression at 550 nm while lowering assimilation peaks in the red at 600-640 nm and at 670 nm. Translocation of <sup>14</sup>C, as percentages of the total nuclide assimilated, was vastly increased by both materials in the blue-violet (400 nm) and by GA<sub>3 </sub>in the blue (437-480 nm). Polaris increased transport from the blue-green to yellow (520-600 nm). A high sensitivity of control plants to far-red light (710 nm) was unaffected by either material. These results support the theory that chemical ripening may involve sugar synthesis and transport processes in addition to growth-regulatory effects in sink tissues. ER -