Rapid inhibition of root growth in wheat associated with aluminum uptake as followed by changes in morin fluorescence
2001
Brauer, D.
Acidic soils limit the land available for crop production and increase the cost of production in many regions of the United States and the world. The use of Aluminum (Al)-resistant germplasm is one means of reducing the impact of acidic soils and development of such germplasm is limited by our understanding of the processes that confer resistance. This study sought to associate changes in root growth rate with Al entry into the tissue of two cultivars of wheat (Triticum aestivum L.) differing in sensitivity to Al. Changes in the spectral characteristics of morin were characterized to determine if a dual excitation or emission assay for Al could be developed. It was not possible to develop such a protocol. However, an assay based on changes in fluorescence intensity of morin was adopted from the work of Vitorello and Haug. Addition of Al to a total concentration of 5 micromolar resulted in a 50% decrease in root elongation rate with the Al-sensitive cultivar, Scout, but little change in root elongation with the Al-resistant cultivar, Atlas. Inhibition of root growth occurred without a noticeable lag. The addition of Al to the external solution of bathing Scout roots caused an increase in the fluorescence of intracellular morin, indicative of Al entry into the root cells. No increase in morin fluorescence was observed with Atlas roots exposed to 5 micromolar Al. Therefore, there was an association between morin fluorescence, thus presumably Al entry, and inhibition of root growth.
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