The Effect of Growth Regulators, CCC and B9, on Protein and Total Nitrogen of Bean Leaves (Phaseolus vulgaris) during Development

Total-N and protein-N were greatest in developing primary leavesof intact plants of Phaseolus vulgaris before the leaves werefully expanded. Treating plants with CCC or B9 delayed the timewhen total-N and protein-N diminished. Removing the growingpoint made nitrogen accumulate in the leaves and the total-Ndid not diminish until they were fully expanded. Treatment withCCC did not affect the amount of total-N or protein-N in decapitatedplants. Apparently nitrogen moves more slowly from primary leavesof CCC-treated plants because the shoot grows more slowly anddemands less nitrogen. Similarly, leaves of decapitated plantshave more nitrogen because there is no shoot. When primary leaveswere detached and rooted, protein continued to increase in themalthough they were fully expanded before they developed roots,again probably because the demand for nitrogen was small. Changesin protein were correlated with changes in chlorophyll duringdevelopment. Maximum photosynthesis per leaf probably occurs before leavesare fully expanded, and the protein changes in the leaf maybe closely related to the trend of photosynthesis during thelife of a leaf.