PT Journal
AU Sanchez-Diaz, M
   Garcia, J
   Antolin, M
   Araus, J
TI Effects of Soil Drought and Atmospheric Humidity on Yield, Gas Exchange, and Stable Carbon Isotope Composition of Barley
SO Photosynthetica
PY 2002
BP 415
EP 421
VL 40
IS 3
DI 10.1023/A:1022683210334
WP https://ps.ueb.cas.cz/artkey/phs-200203-0025.php
DE CO2 balance; Hordeum vulgare; transpiration efficiency; water stress; water use efficiency
SN 03003604
AB The combined effects of water status, vapour pressure deficit (VPD), and elevated temperature from heading to maturity were studied in barley. Plants growing at high VPD, either under well-watered or water deficit conditions, had higher grain yield and grain filling rate than plants growing at low VPD. By contrast, water stress decreased grain yield and individual grain dry matter at any VPD. Water regime and to a lesser extent VPD affected δ<sup>13</sup>C of plant parts sampled at mid-grain filling and maturity. The differences between treatments were maximal in mature grains, where high VPD increased δ<sup>13</sup>C for both water regimes. However, the total amount of water used by the plant during grain filling did not change as response to a higher VPD whereas transpiration efficiency (TE) decreased. The net photosynthetic rate (P<sub>N</sub>) of the flag leaves decreased significantly under water stress at both VPD regimes. However, P<sub>N</sub> of the ears was higher at high VPD than at low VPD, and did not decrease as response to water stress. The higher correlation of grain yield with P<sub>N</sub> of the ear compared with that of the flag leaf support the role of ear as the main photosynthetic organ during grain filling under water deficit and high VPD. The deleterious effects of combined moderately high temperature and drought on yield were attenuated at high VPD.
ER