Unfortunately, modern cultivation techniques have resulted in progressively reducedAMfungaldiversity and frequency in agricultural soils and potting substrates, an effect that is believed to berelated to tillage methods, the use of mineral fertilizers and nursery substrate sterilization amongother factors [19]. In consequence, the external application of mycorrhizal spores has been practiced,adding AMF inoculum either to seedlings’ growing medium or into the planting hole at time oftransplanting. Because of this, two main agronomic benefits are expected: superior growth ofseedlings in the nursery and improved performance of mature plants following planting in thefield [20]. The effects of excessive salinity on plant growth and vitality involve: reduction in theosmotic potential of the soil solution causing physiological drought, nutrient imbalance caused byreduced nutrient uptake and/or transport to the shoot, and direct cell toxicity of excessive Na orCl ion concentrations [21]. The salinity effect on plants can be described as an two-phase growthresponse [22]. In the first phase the excess salt ion concentration outside the roots is lowering theosmotic potential of the soil [22], making it harder for the plants to extract water and causing waterstress. An immediate response to this effect, which also mitigates ion flux to the shoot, is stomatalclosure [5]. The second, ion specific, phase corresponds to the excess accumulation of salt ions intissues, especially the leaf blade. The consequences of Na+ or Cl build-up in the cell walls are oftencatastrophic and include dehydration and oxidative stress [22,23], finally causing leaf dieback. If therate of leaf dieback is faster than the rate of leaf expansion, then the amount of reserve carbohydrateper plant will be reduced in proportion to the reduction in leaf area [24]. The main acclimatizationstrategy for glycophytes to excess soil salinity levels is to control ion flux into root xylem and as theresult, restrict also nutrient ion movement to the shoot [25]. Furthermore, several ions such as Pbecome rather unavailable—P precipitates with Ca2+, Mg2+ and Zn2+ ions in saline soil [26].
Unfortunately, modern cultivation techniques have resulted in progressively reducedAMfungal<br>diversity and frequency in agricultural soils and potting substrates, an effect that is believed to be<br>related to tillage methods, the use of mineral fertilizers and nursery substrate sterilization among<br>other factors [19]. In consequence, the external application of mycorrhizal spores has been practiced,<br>adding AMF inoculum either to seedlings’ growing medium or into the planting hole at time of<br>transplanting. Because of this, two main agronomic benefits are expected: superior growth of<br>seedlings in the nursery and improved performance of mature plants following planting in the<br>field [20]. The effects of excessive salinity on plant growth and vitality involve: reduction in the<br>osmotic potential of the soil solution causing physiological drought, nutrient imbalance caused by<br>reduced nutrient uptake and/or transport to the shoot, and direct cell toxicity of excessive Na or<br>Cl ion concentrations [21]. The salinity effect on plants can be described as an two-phase growth<br>response [22]. In the first phase the excess salt ion concentration outside the roots is lowering the<br>osmotic potential of the soil [22], making it harder for the plants to extract water and causing water<br>stress. An immediate response to this effect, which also mitigates ion flux to the shoot, is stomatal<br>closure [5]. The second, ion specific, phase corresponds to the excess accumulation of salt ions in<br>tissues, especially the leaf blade. The consequences of Na+ or Cl build-up in the cell walls are often<br>catastrophic and include dehydration and oxidative stress [22,23], finally causing leaf dieback. If the<br>rate of leaf dieback is faster than the rate of leaf expansion, then the amount of reserve carbohydrate<br>per plant will be reduced in proportion to the reduction in leaf area [24]. The main acclimatization<br>strategy for glycophytes to excess soil salinity levels is to control ion flux into root xylem and as the<br>result, restrict also nutrient ion movement to the shoot [25]. Furthermore, several ions such as P<br>變得相當在鹽土[26]與鈣離子,鎂離子和Zn2不可用-P析出物+離子。
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