Variability in Alfalfa for Growth and Mineral Uptake and Efficiency Ratios under Aluminum Stress
- V. C. Baligar ,
- J. H. Elgin and
- C. D. Foy
Alfalfa (Medicago sativa L.) is an important forage legume that is known to be sensitive to soil acidity. A nutrient solution experiment was conducted under controlled growth conditions to evaluate the effects of Al (0, 75, and 150 µmol L−1) on growth, nutrient uptake, and mineral nutrient efficiency ratios (ER = shoot dry weight produced per unit element in shoot) in 15 selected alfalfa cultivars and lines. Growth of shoots and roots differed with Al levels and cultivars/lines. At 75 µmol L−1 the mean reductions of shoot and root dry matter yield were 29 and 6% of the control, respectively. Shoot nutrient contents showed significant positive correlations with shoot and root weights, and negative correlations with Al level and shoot Al concentrations. The ER values were used to classify cultivars and lines into efficient and inefficient utilizers of absorbed nutrients. With the exception of the ER for Ca, negative correlations were observed between Al level and ER. The cultivars and lines used in this study showed intraspecific genetic diversity for dry matter yield and ER values for the elements when plants were grown with or without AL.
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