Soil Chemistry Factors Confounding Crop Salinity Tolerance—A Review

Rengasamy, Pichu

doi:10.3390/agronomy6040053

Cited by 46 publications

(20 citation statements)

References 43 publications

(50 reference statements)

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“…Soil salinity is a major limiting factor in crop productivity in irrigated and non-irrigated areas worldwide [1]. It can be caused by natural processes defined as "primary salinity" and/or by human activities ("secondary salinity") that are mainly due to improper irrigation [2]. The phenomenon of salinization is growing fast in arid and semi-arid areas [3] as a result of the relatively high temperatures In particular, RCI2A and NHX1 represent genes encoding ion transporters.…”

Section: Introductionmentioning

confidence: 99%

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Seedling Growth and Transcriptional Responses to Salt Shock and Stress in Medicago sativa L., Medicago arborea L., and Their Hybrid (Alborea)

et al. 2018

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Salinity is a major limiting factor in crop productivity worldwide. Medicago sativa L. is an important fodder crop, broadly cultivated in different environments, and it is moderately tolerant of salinity. Medicago arborea L. is considered a stress-tolerant species and could be an important genetic resource for the improvement of M. sativa’s salt tolerance. The aim of the study was to evaluate the seedling response of M. sativa, M. arborea, and their hybrid (Alborea) to salt shock and salt stress treatments. Salt treatments were applied as follows: salt stress treatment at low dose (50 mM NaCl), gradual acclimatization at 50–100 and 50–100–150 mM NaCl, and two salt shock treatments at 100 and 150 mM NaCl. Growth rates were evaluated in addition to transcriptional profiles of representative genes that control salt uptake and transport (NHX1 and RCI2A), have an osmotic function (P5CS1), and participate in signaling pathways and control cell growth and leaf function (SIMKK, ZFN, and AP2/EREB). Results showed that the studied population of M. sativa and M. arborea performed equally well under salt stress, whereas that of M. sativa performed better under salt shock. The productivity of the studied population of Alborea exceeded that of its parents under normal conditions. Nevertheless, Alborea was extremely sensitive to all initial salt treatments except the low dose (50 mM NaCl). In addition, significantly higher expression levels of all the studied genes were observed in the population of M. arborea under both salt shock and salt stress. On the other hand, in the population of M. sativa, NHX1, P5CS1, and AP2/EREB were highly upregulated under salt shock but to a lesser extent under salt stress. Thus, the populations of M. sativa and M. arborea appear to regulate different components of salt tolerance mechanisms. Knowledge of the different parental mechanisms of salt tolerance could be important when incorporating both mechanisms in Alborea populations.

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Section: Introductionmentioning

confidence: 99%

“…The following questions were addressed: (1) Is there any differentiation in the response of M. sativa and M. arborea under salt stress and salt shock? (2) What is the response of the hybrid compared to the parental species? (3) Is there any differentiation in the expression of the selected genes under salt stress and salt shock?…”

Section: Introductionmentioning

confidence: 99%

Seedling Growth and Transcriptional Responses to Salt Shock and Stress in Medicago sativa L., Medicago arborea L., and Their Hybrid (Alborea)

et al. 2018

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“…Irrigation of the soil with the high‐salinity water resulted in an acidic pH (<6.0) during the period of low rainfall and, consequently, low cation exchange (Ca 2+ , Mg 2+ , and K + ), in agreement with Rengasamy (2016). Soils with acidic pH generally contains a higher concentration of organic acids of carboxyl groups (–COOH), which increases the total acidity of the soil (Bayer et al, 1999).…”

Section: Resultsmentioning

confidence: 95%

Can Humic Substances Improve Soil Fertility under Salt Stress and Drought Conditions?

et al. 2019

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Semiarid soils may be poor in organic carbon, a necessary source of energy for soil microorganisms that affect plant growth. Although the addition of organic carbon may improve soil chemical characteristics, the concentration of humic compounds in the organic component may vary and affect soil chemical composition. We evaluated the effect of two sources of humic compounds on a dystrophic yellow Oxisol cultivated with passion fruit (Passiflora edulis Sims f. edulis) and irrigated with saline water during a severe drought in the Brazilian semiarid region. Soil fertility was evaluated during two seasons. A bovine biofertilizer and an organic commercial amendment (Humistar) were used as sources of humic compounds. Salinity resulted in reduced soil fertility, mainly during the lower rainfall period. The combination of humic substances and salinity increased soil salinity. Humistar, more concentrated in humic acid than fulvic acid, increased both acidity and salinity of the Oxisol under study during the lower rainfall period. Our results contradict the general idea that organic matter can mitigate the harmful effects of salts in semiarid soils because the addition of organic sources to the soil, mainly during a severe drought period, may reduce soil fertility. Although this response may depend on the concentration of humic acids in the amendment, our results suggest that the correction of soil chemistry with the application of either amendment to Oxisols under semiarid conditions, mainly during severe drought, is not economically feasible. Core Ideas Saline irrigation reduces the fertility of Oxisols, mainly in low‐rainfall periods. The combination of humic substances and salinity increased salinity of Oxisols. During low‐rainfall periods, humic substances reduced Oxisol fertility.

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“…In glycophytes (salt‐sensitive plants), soil salinity results in the uptake of sodium (Na + ) and chloride (Cl − ) ions by plant roots, leading to a decrease in growth as a result of inhibition of cell division and elongation (Zhong and Lauchli, ; Bernstein and Kafkafi, ). Soil salinity can also inhibit the uptake of important macro‐elements, including potassium (K), calcium (Ca), phosphorous (P), magnesium (Mg) and sulphur (S), and the uptake of microelements, such as ion (Fe), zinc (Zn) and boron (B), leading to nutrient deficiency (Grattan and Grieve, ; Rengasamy, ). Although many of the gene pathways and transporters for both Na + uptake and exclusion in the roots have been identified, tools to quantitatively measure Na + and K + spatially in plant tissues have been limited due to the inherent difficulties of measuring soluble ions.…”

Section: Introductionmentioning

confidence: 99%

A laser ablation technique maps differences in elemental composition in roots of two barley cultivars subjected to salinity stress

2019

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Summary In saline soils, high levels of sodium (Na+) and chloride (Cl−) ions reduce root growth by inhibiting cell division and elongation, thereby impacting on crop yield. Soil salinity can lead to Na+ toxicity of plant cells, influencing the uptake and retention of other important ions [i.e. potassium (K+)] required for growth. However, measuring and quantifying soluble ions in their native, cellular environment is inherently difficult. Technologies that allow in situ profiling of plant tissues are fundamental for our understanding of abiotic stress responses and the development of tolerant crops. Here, we employ laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS) to quantify Na, K and other elements [calcium (Ca), magnesium (Mg), sulphur (S), phosphorus (P), iron (Fe)] at high spatial resolution in the root growth zone of two genotypes of barley (Hordeum vulgare) that differ in salt‐tolerance, cv. Clipper (tolerant) and Sahara (sensitive). The data show that Na+ was excluded from the meristem and cell division zone, indicating that Na+ toxicity is not directly reducing cell division in the salt‐sensitive genotype, Sahara. Interestingly, in both genotypes, K+ was strongly correlated with Na+ concentration, in response to salt stress. In addition, we also show important genetic differences and salt‐specific changes in elemental composition in the root growth zone. These results show that LA‐ICP‐MS can be used for fine mapping of soluble ions (i.e. Na+ and K+) in plant tissues, providing insight into the link between Na+ toxicity and root growth responses to salt stress.

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Soil Chemistry Factors Confounding Crop Salinity Tolerance—A Review

Cited by 46 publications

References 43 publications

Seedling Growth and Transcriptional Responses to Salt Shock and Stress in Medicago sativa L., Medicago arborea L., and Their Hybrid (Alborea)

Seedling Growth and Transcriptional Responses to Salt Shock and Stress in Medicago sativa L., Medicago arborea L., and Their Hybrid (Alborea)

Can Humic Substances Improve Soil Fertility under Salt Stress and Drought Conditions?

A laser ablation technique maps differences in elemental composition in roots of two barley cultivars subjected to salinity stress

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