TROCAS GASOSAS E RELAÇÕES HÍDRICAS EM LARANJEIRAS COM CLOROSE VARIEGADA DOS CITROS

The citrus variegated chlorosis (CVC) is an anomaly, possibly caused by the xylem limited bacterial group of Xylella fastidiosa. The leaves of CVC affected orange trees showed water deficiency symptoms that were associated to decreases of photosynthesis, transpiration, stomatal conductance and water potential, as compared to leaves of unaffected trees. The decreases of photosynthesis might be related to the lower values of leaf stomatal conductance affected plants. On the other hand, decreases of conductance appears to be related to CVC induced water deficiency. Considering that stomatal functioning was not affected, it is suggested that the water deficiency symptoms of CVC affected plants occurs due to increases of water flow resistence through xylem vessels. Additional index terms: Photosynthesis, stomatal conductance, Xylella fastidiosa, Citrus sinensis.