Aluminium localization and toxicity symptoms related to root growth inhibition in rice (Oryza sativa L.) seedlings

Abstract

We correlated root growth inhibition with aluminium (Al(3+)) localization and toxicity symptoms in rice roots using seedlings of two genotypes (tolerant and sensitive) that were exposed to different AlCl(3) concentrations. Al(3+) localization was evaluated by hematoxylin in primary roots and by morin in cross-sections of the root tips. Neutral invertase enzyme activity and callose (1 -- 3, beta-D-glucan) accumulation were observed and compared with Al(3+) accumulation sites. Root growth was inhibited by Al(3+) in a concentration-specific manner and proportional to the increase of hematoxylin staining, being more pronounced in the sensitive genotype. Morin staining showed the presence of Al(3+) deep within the roots of the sensitive genotype, indicating that the metal was able to penetrate beyond the first few cell layers. In the tolerant genotype, Al(3+) penetration was restricted to the first two cell layers. Ruptures in exodermis and epidermis layers by lateral root protrusions in both genotypes allowed Al3+ to enter into the roots. More intense activity of invertase in roots of the tolerant genotype was also observed, which could be related to greater root growth of this cultivar when submitted to Al(3+) stress. Moreover, Al(3+)-induced callose accumulation was a late response occurring in the same areas where Al(3+) was present.

Leaf cDNA-AFLP analysis reveals novel mechanisms for boron-induced alleviation of aluminum-toxicity in Citrus grandis seedlings

“…Al-toxicity led to an increase in invertase activity, mainly in the tolerant rice genotype (Alvim et al, 2012). We found that the expression of acid invertase (TDF #216-3) was detected only in 20 μM Bþ1.2 mM Al-treated leaves (Table 1), which might be involved in B-induced alleviation of Al-toxicity.…”

Salicylic Acid Alleviates Aluminum Toxicity in Tomato Seedlings (Lycopersicum esculentum Mill.) through Activation of Antioxidant Defense System and Proline Biosynthesis

“…Panda et al [21] reported that long-term Al treated plants could not uptake water due to the interaction of Al with root cell nuclei, inhibiting cell division and cytoskeleton formation. It was proposed that in resistant cultivar SIRI, the release of Al 3+ binding compounds in to the apoplastic region and at the root tip surface can effectively chelate Al 3+ , avoiding to some extent its penetration into cells and preventing successive tissue damage [22]. Figure 5.…”

Chlorophyll fluorescence parameters and photosynthetic pigments of four Glycine max varieties under Aluminium chloride stress

“…Soy bean grains are among the world's most important in terms of protein content of 35-40 % and oil content of 15-22%. Soy bean grains are also rich in essential amino acids, vitamins and minerals (Alvim et al, 2012). Considerable attention has been focused on assessing the impact of aluminium (Al) stress on cultivated plants because its stress is often the primary factor limiting crop production in acid soils (Kochian, 1995).…”

“…Cai et al (2011) observed that Aluminium affects plants physiologically including the quantity of chlorophyll pigments, suppression of photosynthetic activities at the photosynthetic apparatus and plant mineral nutrient uptake. The use of aluminium-tolerant plants is part of crop management strategy for agricultural production in acid soils (Alvim et al, 2012). In Kenya, Western region led in soy bean production with nearly 50% in 2003.…”

“…The area that is potentially suitable for soybean production in Kenya ranges from 157,000 ha to 224,000 (Chianu et al, 2008). At low pH, the release of toxic aluminium soluble forms (particularly Al 3+ ) is enhanced by the dissolution of Al-containing compounds, thus becoming available to interact with plants and other organisms (Samac and Tesfaye, 2003;Alvim et al, 2012. Very little research on the effects of aluminium chloride stress has been done on soy bean varieties grown in Kenya.…”