Aluminum effects on photosynthesis and elemental uptake in an aluminum‐tolerant and non‐tolerant wheat cultivar

Abstract

The effects of aluminum (Al) on photosynthesis and elemental uptake were studied in two wheat cultivars (Triticum aestivum L. cvs Yecora E, Nestos) differing in their tolerance to Al. Concentrations of calcium (Ca), magnesium (Mg), potassium (K), and iron (Fe) in the plant tissues of both cultivars grown in nutrient solutions (pH 4.5) decreased at all Al levels (0, 37.1, 74.1, and 148 μM). The tolerant cultivar Yecora E retained larger concentrations of all elements measured in roots and above ground parts compared with the non tolerant cultivar Nestos. Concentrations of Ca and Mg in leaves of the cultivar Nestos under high Al treatment were within the deficiency range. Changes in the shape of the chlorophyll fluorescence induction curves showed that Al‐stress altered thylakoid photofunctioning even in the more tolerant cultivar. Aluminum stress resulted in partial inhibition of photosynthetic electron transport at photosystem II and closure of photosystem II reaction centers. Chloroplast elemental loss and concomitant intrathylakoid acidification are postulated as mediating mechanisms for Al stress‐induced inhibition of photosynthesis.

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