Hydrogen Stable Isotope Analysis of Water Acquisition Ability of Deep Roots and Hydraulic Lift in Sixteen Food Crop Species

Water Competition of Intercropped Pearl Millet with Cowpeaunder Drought and Soil Compaction Stresses

“…The deuterated water was poured to the soil surface with a measuring cylinder. About 15 h after the application of the deuterated water, xylem sap from the labeled plants was collected following the method of Zegada-Lizarazu and Iijima (2004). The deuterium abundances in xylem sap were measured by mass spectrometry (DELTA plus , Finnigan Mat Instruments, Inc., Germany).…”

“…These values were converted into the concentration of deuterated water (atom % excess) and used to determine the water sources of intercropped and monocropped plants. Further details of the procedures for the determination of deuterium abundances are given in Zegada-Lizarazu and Iijima (2004). The application of heavy water was regarded as recent rainfall or recently irrigated water.…”

“…Variations in the relative abundance of deuterium in plant xylem sap have been used as an indicator of water uptake from a simulated rainfall event (recently irrigated water) and existing soil water Dawson, 1993;Zegada-Lizarazu and Iijima, 2004;Araki and Iijima, 2005;Iijima et al, 2005). Water is the only source of hydrogen for plants, and no isotopic fractionation occurs during the movement of water from the roots to the shoot base.…”

Deep Root Water Uptake Ability and Water Use Efficiency of Pearl Millet in Comparison to Other Millet Species

“…In pearl millet, root elongation in deep soil layers has also been investigated in semiarid environments (Sivakumar and Salaam, 1994;Zaongo et al, 1994;Bruck et al, 2003); however, the function of deep roots, such as water uptake, is not well documented. In our previous investigation, the deuterium labelling of deep soil water provided evidence that fi nger millet, Job's tears, and barnyard millet increased their water extraction from deep wet layers when topsoil was subjected to drought stress, but common millet, pearl millet, and foxtail millet did not (Zegada-Lizarazu and Iijima, 2004). Further study on the deep-water uptake ability of pearl millet is required to elucidate the drought tolerance of pearl millet.…”

Rhizodeposition of Mucilage, Root Border Cells, Carbon and Water under Combined Soil Physical Stresses in Zea mays L.

“…The enrichment of 13 C (atom % excess) of the samples was calculated from the atom % of the samples subtracted by natural abundance of 13 C values measured for control soil. For the deuterium analysis, water contained in the soil sample was extracted by centrifugation (Zegada-Lizarazu and Iijima, 2004). The isotopic ratios of deuterium water are presented in standard delta notation (δ D) in parts per thousand (‰) relative to standard (SMOW: Standard Mean Ocean Water) as expressed by the following equation, stated by Araki and Iijima (2005).…”