CHLOROPHYLL a FLUORESCENCE IN PEACH CULTIVAR MACIEL GRAFTED ON DIFFERENT ROOTSTOCKS

The objective of this study was to evaluate characteristics of chlorophyll fluorescence in peach trees cv. Maciel grafted on six rootstocks. The analysis of the chlorophyll a fluorescence, the chlorophyll content and length of the leaves began after the winter period and were repeated until approximately 150 days, totaling six samples. The early ontogeny of the leaves was characterized by some higher fluorescence parameters. High rainfall, which occurred between 61 and 112 days of the beginning of the experiment, was the environmental factor that caused the greatest change in the parameters of the JIP Test, especially those related to photosystem I. The chlorophyll content was not influenced by the effect of associations cup x rootstock. Fall in the PITOTAL were in the period of highest rainfall, behavior that was independent of the rootstock, except for plants grafted on rootstock Rubira, who had minor damage to the photosynthetic apparatus. In general, rootstocks studied in combination with cv. Maciel did not affect the absorption and utilization of light energy by photosynthetic system.