An improved evaluation of photoassimilate flux through a pedicel of tomato plant (Lycopersicon esculentum Mill.) was examined in an application of ethylenediaminetetraacetic acid (EDTA) solution for collecting phloem exudate, where the cut end of the pedicel was immersed into the EDTA solution bath in a vial held on the pedicel. A part of the solution in the vial loaded with phloem exudate was sampled at a certain interval by using a micro syringe, and just after every sampling the solution bath was replenished with the fresh EDTA solution to keep the initial volume. Sugar concentration in the sampled solution and volumes of the solutions sampled and replenished were measured, and then photoassimilate flux exuded through the pedicel during the successive samplings was evaluated by analysis of sugar balance in the solution bath, where backflow through the pedicel was taken into account. The chelate effect of the EDTA solution was kept reliable for about a whole day, and photoassimilate flux was most enhanced in the solution bath of 20 mM EDTA and under the larger rates of replenishment with the fresh EDTA. Dynamic changes in the photoassimilate flux caused by lighting and leaf excision were evaluated clearly at a short sampling interval of 20 min. The results suggest that the improved EDTA method can be applied to short term analysis of dynamics of phloem translocation affected by change in pressure potential gradient through phloem from source leaves to the pedicel.
|Number of pages||9|
|Publication status||Published - 1997|
All Science Journal Classification (ASJC) codes
- Agricultural and Biological Sciences(all)
- Plant Science
- Environmental Science(all)