Despite the increased water content (fresh weight) observed in some treatments, with values ranging from 95 to 305 %, there is no relationship between this variable and plant survival during acclimatization. Analysis of shoot development (dry mass) did not exhibit significant difference between the different treatments
considered. However, an increase of leaf area (length and width) was observed in the treatments containing Paenibacillus macerans (1B and 1C). This increase of leaf area may favor rapid plant development by providing larger surface for light absorption to perform photosynthesis. This is the first study describing the presence of Paenibacillus as orchid endophytes. Paenibacillus macerans (1C) orchid endophytic auxin-producing bacteria promoted Cattleya loddigesii seedling growth during ex vitro acclimatization.
Acknowledgments This study was supported by a grant from the State of Sa ˜o Paulo Research Foundation (FAPESP/BIOTA 2004/13910-6) and A.C.F. Dias (2008/54013-8) received a graduate fellowship.