Genotypic Differences Among Plant Species in Response to Aluminum Stress

Abstract

Genotypic differences in aluminum (Al) resistance in rye (Secale cereale L.), triticale (X Triticosecale Wittmack), wheat (Triticum aestivum L.), and buckwheat (Fygopyrum esculentum Moench) were examined using a compartmental hydroponic system. Four-day-old seedlings were grown for 24 h in 0.5 mM CaCl₂ (pH 4.5) containing 0 or 50 μM Al. Relative root elongation (RRE) at 50 μM Al. (as a percentage of that at 0 Al) was used as the index of Al resistance. On average, rye exhibited the highest Al resistance, followed by buckwheat, triticale, and wheat. However, triticale displayed the greatest genotypic differences. Al content in the root tips of triticale breeding lines negatively correlated with RRE (r = 0.5, P < 0.01), implying that the Al exclusion mechanism contributed to Al resistance. Furthermore, high Al resistance in buckwheat correlated well with the growth habitats of buckwheat, indicating that adaptation mechanisms giving good Al resistance have evolved in buckwheat. All of these results suggested that it is possible to obtain greater Al resistance in plants by screening current existing cultivars. The selection of new cultivars with increased Al resistance and sensitivity will provide important material for further studies exploring Al phytotoxic and resistant mechanisms.

Keywords:

• aluminum resistance
• buckwheat
• genotypic difference
• rye
• triticale
• wheat

ACKNOWLEDGMENTS

This work was supported partly by funds from the Education Ministry of China, the Huoyingdong Foundation, and the Natural Science Foundation of China (Contract No. 30170548, 30040035). The authors thank Prof. Shen Yuanqu (Crop Science Institute, Chinese Academy of Agricultural Science) for providing triticale seeds and Dr. Tony Miller (CPI Division of Rothamsted Research, Hertfordshire, UK) for his valuable comments on improving the manuscript.

Notes

^*Not a Chinese cultivar.

¹Data are cited from Xiong and Li (1987).

²Mean ± standard deviation (n = 14).

³Statistically different at P = 0.05.

a, b, and c indicate statistical differences.