Relações hídricas em espécies lenhosas no campus Pampulha/UFMG, Belo Horizonte, MG

Abstract

- 0.25 MPa), and I. edulis the smallest (psiPD = - 1.5 MPa). J. princeps showed higher water potential values during the day (psiMD > - 1.5 MPa) and lower values were observed for S. macrophylla and I. edulis (psiMD < - 3.0 MPa). The daily amplitudes of the water potential ( = psiPD - psiMD) were positively related with the vapour pressure deficit (VPD), and the largest values were observed in S. macrophylla and I. edulis. The conductance usually decreased in the beginning of the afternoon, and I. edulis presented smaller restriction to the transpiration. The largest conductance values were observed in a cloudy day of the rainy season. A quadratic regression (r² = 0.635, p < 0.01), suggests that species with larger density not necessarily present larger , once a great restriction to the loss of water can happen as observed for L. tomentosa, a species with high wood density.]]>

Weak relationships between leaf phenology and isohydric and anisohydric behavior in lowland wet tropical forest trees

“…Evergreen and deciduous species are opposite extremes in the leaf economics spectrum, and the correlation between sap conductivity and leaf phenology is strong (Freschet et al 2010 (Freschet et al 2010), which reflects the close interrelation between leaf and stem characteristics with regard to responses to environmental conditions (Santiago et al 2004, Ishida et al 2008, Meinzer et al 2008, Freschet et al 2010, M endez-Alonzo et al 2012, Kr€ ober et al 2015. However, another study failed to establish a direct relationship between deciduousness and WD (Silva & Lemos Filho 2001). This lack of correlation is mainly observed in deciduous and semi-deciduous species, with high (≥0.5 or 0.8 g/cm³, depending on the study published) or low WD values (< 0.3 or 0.5 g/m³) (Borchert 1994a, Silva & Lemos Filho 2001, Choat et al 2005, Lima & Rodal 2010, Valdez-Hern andez et al 2010, Lima et al 2012, M endez-Alonzo et al 2013.…”

“…However, another study failed to establish a direct relationship between deciduousness and WD (Silva & Lemos Filho ). This lack of correlation is mainly observed in deciduous and semi‐deciduous species, with high (≥0.5 or 0.8 g/cm³, depending on the study published) or low WD values (< 0.3 or 0.5 g/m³) (Borchert , Silva & Lemos Filho , Choat et al . , Lima & Rodal , Valdez‐Hernández et al .…”

“…Unlike these seasonal variations in VPD, the high water potential of the soil observed in the wet forest at REBIO União indicates the absence of seasonal water restrictions. Even without seasonal variation in water supply in the soil, the daily and seasonal variations in VPD favor water retention by plants (Lemos Filho & Mendonça Filho , Silva & Lemos Filho ).…”