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Roles of leaf water potential and soil‐to‐leaf hydraulic conductance in water use by understorey woody plants
Author(s) -
Ishida Atsushi,
Yamamura Yasuo,
Hori Yoshimichi
Publication year - 1992
Publication title -
ecological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.628
H-Index - 68
eISSN - 1440-1703
pISSN - 0912-3814
DOI - 10.1007/bf02347090
Subject(s) - turgor pressure , transpiration , water potential , vapour pressure deficit , osmotic pressure , stomatal conductance , understory , agronomy , environmental science , soil water , botany , deciduous , horticulture , chemistry , biology , canopy , soil science , photosynthesis
Abstract Diurnal changes of leaf water potential and stomatal conductance were measured for 12 deciduous shrubs and tree saplings in the understorey of a temperate forest. Sunflecks raised the leaf temperature by 4°C, and vapor pressure deficit to 2 kPa. Although the duration of the sunflecks was only 17% of daytime, the photon flux density (PFD) of sunflecks was 52% of total PFD on a sunny summer day. Leaf osmotic potential at full turgor decreased in summer, except in some species that have low osmotic potential in the spring. Plants that endured low leaf water potential had rigid cell walls and low osmotic potential at full turgor. These plants did not have lower relative water content and turgor potential than plants with higher leaf water potential. There were three different responses to an increase in transpiration rate: (i) plants had low leaf water potential and slightly increased soil‐to‐leaf hydraulic conductance; (ii) plants decreased leaf water potential and increased the hydraulic conductance; and (iii) plants had high leaf water potential and largely increased the hydraulic conductance.