METHOD FOR RAPID ASSESSMENT OF ALUMINUM TOLERANCE OF PEA (Pisum sativum L.)

Abstract

A b s t r a c tCrops vary considerably in their resistance to acidic soils, and many legumes, including pea (Pisum sativum L.), considered to be sensitive or moderately sensitive crops compared to cereals. The main factor determining the phytotoxicity of acidic soils is the increased concentration of mobile aluminum ions in the soil solution. Accumulation of aluminum in root tissues interferes with cell division, initiation of growth of lateral roots and uptake of minerals and water by plants. Under laboratory conditions the resistance of plants to aluminum is estimated by the degree of damage to the roots by aluminum using dyes (hematoxylin, eriochrome cyanine R) and the ability of roots to restore growth after toxic effect of this metal. This work dedicated to the development of rapid assessment of aluminum tolerance especially for peas, which is as follows: the seeds were germinated in the growth chamber in the nutrient solution for 3 days (7000 lx illumination, temperature of 19 С at night and 21 С during the day, photoperiod 16 h), treated with a toxic concentration of aluminum chloride (3 mg Al/l) for 24 hours, incubated in fresh nutrient solution without aluminum for 2 days and stained with 0.1 % eriochrome cyanine R for 10 min. Zone of root tissue damage by aluminum painted in the color purple. Plant resistance to aluminum was determined by the length of the root re-growth area after exposure to the toxicant. Using 19 varieties of pea from the N.I. Vavilov Research Institute of Plant Industry collection (VIR collection) it was shown that pea has high variability in tolerance to aluminum. Varieties with a minimum (1.01.5 mm) length of the root re-growth (k-2759, k-3654 and k-3283) were characterized by intense purple color of the root, but varieties with a maximum (14.014.5 mm) length of the root re-growth (k-4376, k-9504 and k-7307) had a faint but detectable staining. The proposed method makes it possible to identify genotypes contrasting in aluminum tolerance, is highly reproducible and can be used for screening and study of intraspecific variability in this trait of pea plants at very early developing stage.

Aluminum exclusion from root zone and maintenance of nutrient uptake are principal mechanisms of Al tolerance in Pisum sativum L.

“…The recently proposed root re-elongation assay to rapidly assess Al tolerance in pea (Vishnyakova et al 2015) was used to screen 106 genotypes. For this purpose, seeds (25 seeds per genotype) were germinated in the dark for 3 days at 21°C in special containers filled with nutrient solution (lM): KH 2 PO 4 , 400; KNO 3 , 1200; MgSO 4 , 250; CaCl 2 , 60; pH 4.5.…”

“…Staining of roots with eriochrome cyanine R was repeatedly used for rapid assessment of Al tolerance in different plant species using root re-elongation assay. Recently we adapted this method to estimate root reelongation of pea treated with Al and have already published these results (Vishnyakova et al 2015). Eriochrome cyanine R is a dye that forms color complexes with cations such as Al and Fe.…”

“…Al-tolerant soybean genotypes possessed higher P efficiency (Liao et al 2006;Liang et al 2013), responded more actively to toxic Al by citrate, malate and oxalate exudation (Silva et al 2001;Liao et al 2006), and responded to Mg or Ca treatments by alleviating Al toxicity (Silva et al 2001). However, intraspecific variability in Al tolerance of pea was not studied, except our recent report describing significant genotypic variation in root re-elongation of 19 pea genotypes following Al exposure (Vishnyakova et al 2015).…”

Genetic diversity of VIR Raphanus sativus L. collections on aluminum tolerance

“…With an increase of concentration, intraspecific differences in the crops begin to appear. The intensity of staining with eriochrome cyanine R characterizes the con centration of mobile forms of aluminum, which in turn cor relates with aluminum tolerance (Vishnyakova et al, 2015). If, after treatment with aluminum, the concentration of its active forms is low, then the mitotic activity of cells is restored at the root, the root grows back, and after the staining zone, an unstained growth appears (Kosareva, 2012).…”

“…Plant resistance can be assessed in laboratory tests by the degree of damage of the seedlings roots by aluminum using hematoxylin (Canado et al, 1999) and eriochrome cyanine R (Aniol, 1981). This method was successfully applied to assess the intraspecific variability of aluminum tolerance in rice (Awasthi et al, 2017), peas, maize, wheat, and sorghum (Anas, Yoshida, 2004;Kosareva, 2012;Vishnyakova et al, 2015) with hematoxylin, and with wheat, rye, triticale (Aniol, 1981;Aniol, Gustafson, 1984), aegilops, oats, maize (Kosareva, Semenova, 2004;Kosareva, 2012) and peas (Vishnyakova et al, 2015) with eriochrome cyanine R.…”