Conduit diameter and drought‐induced embolism in Salvia mellifera Greene (Labiatae)

• DOI: 10.1111/j.1469-8137.1994.tb02964.x
• Publication Date: 2006-04-29T11:21:53Z
• Authors: K. R. HARGRAVE; K. J. KOLB; F. W. EWERS; S.D. DAVIS
• Keywords: Electrical conduit; Tracheid; Water Transport; Water Stress

SUMMARY The relationship between conduit (vessel and tracheid) diameter water‐stress‐induced air embolism was examined using a double staining technique. Comparisons were made irrigated control plants at water potentials of −13 MPa stressed about −8 MPa. Water stress induced either by natural drought conditions or laboratory drying shoots from previously shrubs. Stem segments perfused with 0.1 % basic fuchsin to mark the initially conductive conduits, and, following high pressure perfusion 10 DIM citric acid remove embolisms, 0.1% alcian blue embolized conduits. Hydraulic conductance per gradient ( k h ) measured before after embolisms removed. Diameters non‐embolized conduits then microscopically in transverse stem sections. In controls there little mean diameters not significantly different for SM. non‐emboltzed For both artificially dehydrated naturally droughted 91% drop due embolism, 30 μm vs. 21 vs With increasing an increased probability embolism. Wider may have larger pores their pit membranes, thus vulnerability Alternatively, wider merely more pits, statistical chances having particularly large pore air‐exposed membrane. Narrow vessels tracheids provide interwoven auxiliary transport system that appears be importance when many wider, efficient become embolized.