Recovery of the photosynthetic capacity of Campomanesia adamantium (Myrtaceae) after water deficit

Campomanesia adamantinum O. Berg, a plant native to Cerrado, has the potential to adapt to a stressful environment because it grows in a region with a long dry period and prone to frequent fires, leading to water deficit. Thus, this study aimed at assessing the gas exchange capacity of C. adamantium seedlings under water deficit conditions and its potential to recover after rewatering. The seedlings were grown under two different conditions: group 1 was the control, in which plants were grown under well-moisturized conditions with 70 % water-holding capacity, and group 2, in which plants were grown with no irrigation and precipitation and were rewatered when the photosynthetic rate reached levels close to zero. The plants subjected to water deficit conditions demonstrated markedly decreased stomatal conductance and transpiration from 23rd up to the 31st day; at the 31st day, the photosynthetic rate, water-use efficiency, and Rubisco carboxylation activity reached levels of almost zero, but when the plants were rewatered, the metabolism recovered rapidly. The internal carbon concentration values were not influenced by the variations in stomatal conductance. In general, during most of the evaluated periods, the chlorophyll index of C. adamantium did not change when irrigation was suspended, highlighting the potential of this species to be used for the recovery of degraded areas in the Cerrado domain.