Effect of Soil Acidity Factors on Nodulation and Growth of Vigna unguiculata in Solution Culture1
- J. S. Hohenberg and
- D. N. Munns2
Effects of low pH, low Ca, and high Al were tested on nodulation of Vigna unguiculata cultivars by the tolerant Rhizobium strain CB 756 in solution culture. Both pH (4.5) and Al (100 µM) caused delays in nodulation, particularly at low Ca (0.3 mM). At high Ca (3.0 mM) cultivar and treatment differences diminished with time. Cultivars differed in nodulation delay. In cultivar TVu 990 nodulation was most tolerant of acidity alone; in California Blackeye-5 it was tolerant to Al; and in TVu 1190 it was sensitive to both stresses. Nodulation in three other cultivars was sensitive to Al. “Starter N” improved nodulation and plant growth. Cultivars whose growth was Al tolerant (in +N media) recovered more rapidly from effects of nodulation delay. Three types of symbiotic failure were observed. In TVu 1190, nodulation failure at high (100 µM) Al caused N deficiency. In TVu 990, host plant sensitivity to Al decreased N2 fixation despite adequate nodule numbers. In Blackeye 5, nodulation was tolerant to Al and plant N was maintained, so that relative yields of +N and symbiotic plants were similarly decreased by Al.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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