Aluminum Tolerance of Soybean Varieties in Relation to Calcium Nutrition
- C. D. Foy,
- A. L. Fleming and
- W. H. Armiger
Differential aluminum tolerance of ‘Perry’ and ‘Chief’ soybean varieties, determined previously from growth on acid Bladen soil, was confirmed in nutrient solutions containing Al as the known growth-limiting factor. Differences in Al tolerance between the two varieties were steadily increased as the Ca level of the nutrient solution was reduced from 50 to 8 to 2 ppm.
Aluminum toxicity in soybeans was associated with decreases in concentrations of Ca in the tops and roots of both varieties, but this effect of Al was much more pronounced in the Al-sensitive Chief variety than in the more tolerant Perry. Greater Al sensitivity of the Chief variety was associated with greater susceptibility to a petiole collapse symptom. This symptom was related to a lower Ca concentration in the leaves and petioles, and specifically, related to a lower Ca concentration in the small petiole zone actually showing the collapse. Soil and solution studies indicated that the Ca deficiency observed in acid Bladen soil was Al induced. Aluminum appears to interfere to different degrees in the uptake and use of Ca by these two soybean varieties. The petiole collapse appeared to be a secondary effect of Al injury, and the presence of the symptom was not required for yield reduction by Al. The fact that soybean varieties differ in Al tolerance suggests that plant breeders may be able to develop varieties that can root more effectively in acid, Al-toxic subsoils. Varieties differing in Al tolerance also provide valuable tools for fundamental studies on the physiological nature of Al toxicity in plants. The petiole collapse symptom associated with Al sensitivity may be useful to plant breeders in screening genetic populations of soybeans for Al tolerance.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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