Stimulation of Root Growth Induced by Aluminum in <i>Quercus serrata</i> Thunb. Is Related to Activity of Nitrate Reductase and Maintenance of IAA Concentration in Roots
- 1 Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
- 2 Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
- 3 Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
- 4 Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
- 5 RIKEN Plant Science Center, Yokohama, Japan
- 6 RIKEN Plant Science Center, Yokohama, Japan
Abstract
Aluminum (Al) is the most abundant metal in the earth’s crust. Excess Al 3+ released by soil acidification in soil solution is thought to be a growth limiting factor to many cultivated plant species, but it has been reported to stimulate plant growth in some crop and tree species in certain concentration of Al 3+ . Previously, we had reported that Al treatment enhanced root development, uptake from growth media and in vivo nitrate reductase (NR) activity of roots. NR is one of the key enzymes in nitrogen metabolism and acts at the first step of nitrate assimilation in plants. In this study, we investigated the process of Al-induced root development in an early stage, focusing on the change in in vitro NR activity, and indole-3-acetic acid (IAA) and cytokinins concentration in roots of Quercus serrata seedlings, which were treated for 1 h with Al or Ca. In Al-treated roots, NR activity increased and IAA concentration was maintained at the same level as pretreatment, and indole-3-acetyl-L-aspartic acid (IA-Asp), which is a metabolic intermediate of IAA degradation, was not detected in roots. In Ca-treated roots, NR activity increased, but IAA concentration decreased as IA-Asp concentration increased. Thus, the maintenance of IAA concentration in Al-treated roots seems to result from suppression in the process of IAA decomposition. Al treatment increased the length and number of second lateral roots but Ca treatment did not. We concluded that root development induced by Al in the early stage was related to NR activity and maintenance of IAA concentration.
- G. R. Gobran and S. Clegg, “A Conceptual Model for Nutrient Availability in the Mineral Soil-Root System,” Canadian Journal of Soil Science, Vol. 76, No. 2, 1996, pp. 125-131. doi:10.4141/cjss96-019
- A. G?ttelin, A. Heim and E. Matzner, “Mobilization of Aluminium in the Rhizosphere Soil Solution of Growing Tree Roots in an Acid Soil,” Plant and Soil, Vol. 211, No. 1, 1999, pp. 41-49. doi:10.1023/A:1004332916188
- W. H. Smith and A. S. Pooley, “Red Spruce Rhizosphere Dynamics: Spatial Distribution of Aluminum and Zinc in the Near-Root Soil Zone,” Forest Science, Vol. 35, No. 4, 1989, pp. 1114-1124.
- T. Ohno, “Rhizosphere pH and Aluminum Chemistry of Red Oak and Honeylocust Seedlings,” Soil Biology and Biochemistry, Vol. 21, No. 5, 1989, pp. 657-660.
- R. B. Clark, “Effect of Aluminium on Growth and Mineral Elements of Al-Tolerant and Al-Intolerant Corn,” Plant and Soil, Vol. 47, No. 3, 1977, pp. 653-662. doi:10.1007/ BF0001 1034
- T. B. Kinraide, “Aluminum Enhancement of Plant Growth in Acid Rooting Media. A Case of Reciprocal Alleviation of Toxicity by Two Cations,” Physiologia Plantarum, Vol. 88, No. 4, 1993, pp. 619-625. doi:10.1111/j.1399-3054
- R. Tomioka, A. Oda and C. Takenaka, “Root Growth Enhancement by Rhizospheric Aluminum Treatment in Quercus serrata Thunb Seedlings,” Journal of Forest Research, Vol. 10, No. 4, 2005, pp. 319-324. doi:10.1007/s10310-005-0152-0
- F. C. Thornton, M. Schaedle and D. J. Ryanal, “Effect of Aluminum on the Growth of Sugar Maple in Solution Culture,” Canadian Journal of Forest Research, Vol. 16, No. 5, 1986, pp. 892-896. doi:10.1139/x86-159
- J. Huang and E. P. Bachelard, “Effect of Aluminum on Growth and Cation Uptake in Seedlings of Eucalyptus mannifera and Pinus radiate,” Plant and Soil, Vol. 149, No. 1, 1993, pp. 121-127. doi:10.1007/BF00010769
- T. Mossor-Pietraszewska, “Effect of Aluminium on Plant Growth and Metabolism,” Acta Biochimica Polonica, Vol. 48, No. 3, 2001, pp. 673-686.
- L. V. Kochian, O. A. Hoekenga and M. Pi?eros, “How Do Crop Plants Tolerate Acid Soils? Mechanisms of Aluminum Tolerance and Phosphorous Efficiency,” Annual Review of Plant Biology, Vol. 55, 2004, pp. 459-493. doi:10.1146/annurev.arplant.55.031903.141655
- R. Tomioka, A. Uchida, C. Takenaka and T. Tezuka, “Effect of Aluminum on Nitrate Reductase and Photosynthesis Activities in Quercus serrata Seedlings,” Environmental Sciences, Vol. 14, No. 3, 2007, pp. 157-165.