Rooting, Water Uptake, and Xylem Structure Adaptation to Drought of Two Sorghum Cultivars

Autor: Yukihiro Sugimoto, Imad‐eldin A. Ali, Y. Cohen, M. Luxová, A. A. Salih, Shinobu Inanaga, Alexander Lux
Rok vydání: 1999
Předmět:
Zdroj: Crop Science. 39:168-173
ISSN: 1435-0653
0011-183X
DOI: 10.2135/cropsci1999.0011183x003900010027x
Popis: Several mechanisms have been proposed to explain the high tolerance of sorghum [Sorghum bicolor (L.) Moench] to drought. This paper reports a field study on the effects of soil moisture stress on the rooting habits, transpiration rate, and xylem anatomy of two sorghum cultivars, Tabat (drought susceptible) and Gadambalia (drought tolerant). Two levels of water stress, -0.02 MPa (wet) and -0.75 MPa (dry), were applied. Tabat had a higher root length density (RLD), higher late metaxylem (LMX) vessels per nodal root, higher leaf area, and higher transpiration rate than Gadambalia. In Tabat, soil moisture stress reduced RLD by 30%, nodal roots by 31%, number of LMX vessels in the root by 42%, leaf area by 13%, and transpiration rate by 11%. In Gadambalia soil moisture stress did not affect RLD at depths ≥0.2 m, number of nodal roots, or number of LMX vessels per nodal root. However, leaf area and transpiration rate were reduced by 3 and 11%, respectively. Under dry conditions, Gadambalia displayed a higher water extraction efficiency than Tabat throughout the profile (0-0.9 m). In Gadambalia, unlike Tabat, the stem was highly sclerified. A 1- to 3-cell-thick layer of schlerenchyma was observed beneath the epidermis. The peripheral vascular bundles were surrounded with a 3- to 6-cell-thick schlerenchyma sheath. However, in roots anatomical differences were less prominent. Drought tolerance in Gadambalia is associated with higher water extraction efficiency, fewer nodal roots per plant, fewer LMX vessels per nodal root, a smaller leaf area, and a well developed sclerenchyma.
Databáze: OpenAIRE
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