scholarly journals Aluminium–silicon interactions in higher plants: an update

2020 ◽  
Vol 71 (21) ◽  
pp. 6719-6729 ◽  
Author(s):  
Martin J Hodson ◽  
David E Evans

Abstract Aluminium (Al) and silicon (Si) are abundant in soils, but their availability for plant uptake is limited by low solubility. However, Al toxicity is a major problem in naturally occurring acid soils and in soils affected by acidic precipitation. When, in 1995, we reviewed this topic for the Journal of Experimental Botany, it was clear that under certain circumstances soluble Si could ameliorate the toxic effects of Al, an effect mirrored in organisms beyond the plant kingdom. In the 25 years since our review, it has become evident that the amelioration phenomenon occurs in the root apoplast, with the formation of hydroxyaluminosilicates being part of the mechanism. A much better knowledge of the molecular basis for Si and Al uptake by plants and of Al toxicity mechanisms has been developed. However, relating this work to amelioration by Si is at an early stage. It is now clear that co-deposition of Al and Si in phytoliths is a fairly common phenomenon in the plant kingdom, and this may be important in detoxification of Al. Relatively little work on Al–Si interactions in field situations has been done in the last 25 years, and this is a key area for future development.

2018 ◽  
Vol 19 (10) ◽  
pp. 3073 ◽  
Author(s):  
Md. Rahman ◽  
Sang-Hoon Lee ◽  
Hee Ji ◽  
Ahmad Kabir ◽  
Chris Jones ◽  
...  

Aluminum (Al) toxicity is one of the major limitations that inhibit plant growth and development in acidic soils. In acidic soils (pH < 5.0), phototoxic-aluminum (Al3+) rapidly inhibits root growth, and subsequently affects water and nutrient uptake in plants. This review updates the existing knowledge concerning the role of mineral nutrition for alleviating Al toxicity in plants to acid soils. Here, we explored phosphorus (P) is more beneficial in plants under P-deficient, and Al toxic conditions. Exogenous P addition increased root respiration, plant growth, chlorophyll content, and dry matter yield. Calcium (Ca) amendment (liming) is effective for correcting soil acidity, and for alleviating Al toxicity. Magnesium (Mg) is able to prevent Al migration through the cytosolic plasma membrane in root tips. Sulfur (S) is recognized as a versatile element that alleviates several metals toxicity including Al. Moreover, silicon (Si), and other components such as industrial byproducts, hormones, organic acids, polyamines, biofertilizers, and biochars played promising roles for mitigating Al toxicity in plants. Furthermore, this review provides a comprehensive understanding of several new methods and low-cost effective strategies relevant to the exogenous application of mineral nutrition on Al toxicity mitigation. This information would be effective for further improvement of crop plants in acid soils.


2011 ◽  
Vol 79 (11) ◽  
pp. 4503-4510 ◽  
Author(s):  
Takashi Dejima ◽  
Kensuke Shibata ◽  
Hisakata Yamada ◽  
Hiromitsu Hara ◽  
Yoichiro Iwakura ◽  
...  

ABSTRACTInterleukin-17A (IL-17A)-producing γδ T cells differentiate in the fetal thymus and reside in the peripheral tissues, such as the lungs of naïve adult mice. We show here that naturally occurring γδ T cells play a protective role in the lung at a very early stage after systemic infection withCandida albicans.Selective depletion of neutrophils byin vivoadministration of anti-Ly6G monoclonal antibody (MAb) impaired fungal clearance more prominently in the lung than in the kidney 24 h after intravenous infection withC. albicans.Rapid and transient production of IL-23 was detected in the lung at 12 h, preceding IL-17A production and the influx of neutrophils, which reached a peak at 24 h after infection. IL-17A knockout (KO) mice showed reduced infiltration of neutrophils concurrently with impaired fungal clearance in the lung after infection. The major source of IL-17A was the γδ T cell population in the lung, and Cδ KO mice showed little IL-17A production and reduced neutrophil infiltration after infection. Early IL-23 production in a TLR2/MyD88-dependent manner and IL-23-triggered tyrosine kinase 2 (Tyk2) signaling were essential for IL-17A production by γδ T cells. Thus, our study demonstrated a novel role of naturally occurring IL-17A-producing γδ T cells in the first line of host defense againstC. albicansinfection.


1988 ◽  
Vol 39 (3) ◽  
pp. 319 ◽  
Author(s):  
RC Bruce ◽  
LA Warrell ◽  
DG Edwards ◽  
LC Bell

In the course of three experiments, soybean (Glycerine max (L.) Merr.) cv. Forrest was grown in 21 soils (four surface soils and 17 subsoils) amended with liming materials (CaCO3 and Mg CO3) and soluble Ca salts (CaSO4.2H20 and CaCl2.2H2O). In most soils, the soluble salts increased concentrations and activities of Al species in solution to levels that restricted root growth, and MgCO3, induced a Ca limitation to root growth. Root lengths after three days were related to so11 and soil solution attributes.Suitable diagnostic indices for the prediction of Ca limitations to root growth were either Ca saturation of the effective cation exchange capacity or Ca activity ratio of the soil solution, which was defined as the ratio of the activity of Ca to the sum of the activities of Ca, Mg, Na, and K. Values corresponding to 90% relative root length (RRL) of soybean were 0.05 for the Ca activity ratio and 11% for Ca saturation. Calcium activity and Ca concentration in the soil solution and exchangeable Ca were less useful for this purpose.Soil Al saturation was not a good predictor of Al toxicity, but soil solution measurements were. The activities of Al3+ and AlOH2+ gave the best associations with RRL, and values corresponding to 90% RRL were 4 8M and 0.5 8M respectively. The results suggested that Al(OH)3� , Al(OH)2+, and AlSO4+, were not toxic species. Soil solution pH and soil pH measured in water were more sensitive indicators of root growth than soil pH measured in 0.01 M CaCl2.Using a Ca activity ratio of 0.05 and an Al3+ activity of 4 8M as diagnostic indices, none of the 20 soils in two experiments were toxic in Al, while 13 (all subsoils) were deficient in Ca. Thus the first limitation on root growth was Ca deficiency and not Al toxicity, in spite of high Al saturations and relatively low pH in these soils. However, Al toxicity could be induced by increasing the ionic strengths of soil solutions.


1991 ◽  
Vol 31 (5) ◽  
pp. 653 ◽  
Author(s):  
J Brockwell ◽  
JA Andrews ◽  
RR Gault ◽  
LG Gemell ◽  
GW Griffith ◽  
...  

Following numerous reports of nodulation failures in pigeonpea [Cajanus cajan (L.) Millsp.] crops in New South Wales, a series of experiments was conducted in glasshouses and at 6 locations in the field. When inoculated seed was grown in moist vermiculite or in sand beds in the glasshouse, pigeonpea nodulated, and fixed N2, normally; but at 3 sites in the field, we could detect neither nodulation nor N2 fixation, despite adequate inoculation or a population of suitable rhizobia in the soil. At another site there was only sporadic occurrence of effective nodules. Nitrogen was fixed at 2 of the 3 field sites on acid soils, but at 1 site it appeared that nodulation was due to a naturally occurring population of soil rhizobia and not to the inoculant. When comparisons were made, pigeonpea was invariably inferior to symbiotically related legumes, cowpea and adzuki bean, in nodulation and N2 fixation. This inferiority was associated with substantially poorer rhizobial colonisation of pigeonpea rhizospheres. The experimental findings confirmed the anecdotal evidence that pigeonpea is an erratically nodulating grain legume on neutral and alkaline soils.


2020 ◽  
Vol 73 (3) ◽  
pp. 9349-9359
Author(s):  
Jorge Enrique Cuervo-Alzate ◽  
Nelson Walter Osorio

Tropical soils are characterized by acidity and poor plant nutrient availability, limiting their agricultural productivity. These soils are commonly amended with lime, but its low solubility impairs its effectiveness to enhance soil fertility. The use of gypsum has gained attention among farmers due to its higher solubility and mobility in the soil, local accessibility, and low price. Therefore, this study was conducted to determine the effects of Agricultural Gypsum (AG) addition on ten Colombian acid soils that had poor fertility and contrasting their physical and chemical characteristics. Surface (0-20 cm) soil samples were air-dried, sieved (<2 mm), and transferred into plastic vases, 40 g (dry base) per vase. Increasing rates of gypsum were added by duplicate: 0.0, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0, and 16.0 g kg-1. Then, the soils were incubated for two weeks and watered to maintain 50% of their maximum water holding capacity. Soil pH, Al+3, Ca+2, Mg+2, K+, S-SO4-2, and P-H2PO4-2 were measured using standard methods. The results showed that AG addition significantly (P<0.05) increased soil exchangeable Ca+2-K+, Ca+2 saturation, S-SO4-2 concentration, and exchangeable Al+3, particularly with doses above 4.0 g kg-1. In contrast, soil Al+3 saturation, P-H2PO4-2 and pH significantly decreased as the AG doses increased, while soil exchangeable Mg+2 levels were not significantly affected. The use of gypsum incubation tests could be promissory for its effects on soil amelioration associated mainly to increase soil exchangeable Ca2+ and S-SO 42- and to decrease Al3+ saturation.


1982 ◽  
Vol 13 (2) ◽  
pp. 115-128 ◽  
Author(s):  
N. Christophersen ◽  
A.O. Stuanes ◽  
R.F. Wright

600 mm of artificial, “unpolluted” precipitation with a chemical composition of assumed preindustrial quality ([H+] = 9 μeql−1, [SO4] = 11 μeql−1) was sprayed on a “mini-catchment” (98 m2) over a period of 3½ weeks. The mini-catchment is a granitic bowl partially covered with shallow, acid soils. It is located in the Storgama area, Telemark county, southern Norway, an area which today receives acidic precipitation ([H+] = 54 μeql−1, [SO4] = 59 μeql−1). The treatment resulted in lowered values for [H+], [Al] and [SO4] in runoff within a week. Excluding the spring snowmelt, [H+] ≈ 50 μeql−1 (pH = 4.3) under natural conditions, whereas during the experiment [H+] levelled off at 30 μeql−1 (pH = 4.5). Correlation analysis suggests that SO4 and organic anions are related to the runoff acidity. The level of total organic carbon in runoff was, however, elevated compared to undisturbed conditions. Under the present natural conditions S04 is the most important anion. The amount of water-extractable sulfate in the soil is equivalent to about ½ of the present yearly input. The response in the sulfate output to a reduced input is difficult to predict because of processes which transform sulfur to and from various compounds in the soil and vegetation. Several years may be required before a new steady state is reached after a substantial decrease in input. Long-term experiments in which the catchment is shielded against natural precipitation are required to obtain more certain estimates of the response in runoff composition.


Author(s):  
Claudia Teixeira Guimaraes ◽  
Jurandir Vieira de Magalhaes

Abstract Citrate transporters belonging to the multidrug and toxic compound extrusion (MATE) family of membrane transporters in sorghum and maize, SbMATE and ZmMATE1, respectively, play a major role in aluminium (Al) tolerance. However, these MATE members show regulatory differences, as well as peculiarities in their genetic effect and mode of action. These aspects, which are discussed in this chapter, have to be considered to design successful breeding programmes in order to achieve maximum Al tolerance and, consequently, to improve grain and biomass production in regions of the world with Al toxicity. As shown in this chapter, target genes with major effects and molecular tools are available for marker-assisted breeding for improving Al tolerance both in sorghum and maize. However, wide adaptation to acid soils should be sought by pyramiding genes controlling different traits such as drought tolerance, P acquisition, resistance to diseases and other stresses commonly found in each agroecological environment.


2015 ◽  
Vol 45 (6) ◽  
pp. 1013-1020 ◽  
Author(s):  
Joseila Maldaner ◽  
Fernando Teixeira Nicoloso ◽  
Luciane Almeri Tabaldi ◽  
Denise Cargnelutti ◽  
Etiane Caldeira Skrebsky ◽  
...  

Aluminum (Al) toxicity is a limiting factor for crop production in acid soils, which cover approximately 60% of the Brazilian territory. This study aimed to evaluate the effects of Al on growth and tissue Al concentration of two Pfaffia glomerata accessions (BRA and JB/UFSM). Plantlets were grown in a hydroponic system with five Al concentrations (0, 50, 100, 150 and 200mg L-1) for 7 days. Most of the evaluated parameters presented significant interaction between both P. glomerata accessions and Al levels in nutrient solution and, in general, Al treatments negatively affected plant growth, especially roots. Moreover, BRA accession showed higher Al accumulation in its tissues than JB/UFSM and, consequently in BRA accession the growth was impaired substantially. Furthermore, the results suggest that, between P. glomerata accessions studied, BRA is less appropriated for medicinal uses when grown in soils with high Al levels, due to the higher accumulation of tissue Al content.


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