Interaction with salinity of GA3-induced leaf elongation,petiole pithiness and bolting in celery

GA₃ sprayed on celery plants, which received a continuous supply of 0, 0.2, 0.4, 0.6 or 1.0% NaCl solutions to the roots, caused a pronounced increase in leaf elongation.Along with enhanced elongation, GA₃ increased breakdown of parenchymatous tissue in the petiole, but this effect was drastically suppressed in the salt-treated plants. In a similar fashion, the effect of GA₃ on the elongation of the flowering-stem (bolting) was significantly diminished in salt-treated plants. In no case did the salinity treatment totally abolish the bolting-process induced by GA₃.Changing the temperature of the lower part of the root system altered the magnitude of GA₃ effect on bolting. As the temperature was lowered from 30 to 6° C, the ability of GA₃ to cause bolting was greatly reduced.The results are discussed in view of the possible interaction between salinity and the GA₃ effect on petiole elongation, cellular breakdown and bolting.