Faust Franziska, Schubert Sven
Institute of Plant Nutrition (iFZ), Justus Liebig University, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany.
Institute of Plant Nutrition (iFZ), Justus Liebig University, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany.
Plant Physiol Biochem. 2016 Oct;107:237-247. doi: 10.1016/j.plaphy.2016.06.009. Epub 2016 Jun 7.
Potassium ions (K(+)) and sodium ions (Na(+)) share many physical and chemical similarities. However, their interchangeability in plant nutrition is restricted. Substitution studies showed that K(+) can be replaced by Na(+) to a large extent in the nutrition of Beta vulgaris L. However, the extent of substitution without negative impacts is not unlimited. The aim of the present study was to identify the process which is most sensitive during the substitution of K(+) by Na(+) in nutrition of young sugar beet plants. We focused on transpiration, growth, and net protein synthesis. Plants were grown under controlled environmental conditions. With transfer of seedlings into nutrient solution, plants were cultivated in different substitution treatments. For all treatments the sum of K(+) and Na(+) (applied as chloride) was fixed to 4 mM. The extent of substitution of K(+) by Na(+) in the nutrient solution was varied from low (0.25% substitution: 3.99 mM K(+), 0.01 mM Na(+)) to almost complete substitution (99.75% substitution: 0.01 mM K(+), 3.99 mM Na(+)). The supply of 3.99 mM K(+) in 0.25% substitution treatment guaranteed the absence of K(+) deficiency. Transpiration was not affected by the substitution. Growth was inhibited at a substitution level of 99.75%. Net protein synthesis was already affected at a substitution level of 97.50% (0.10 mM K(+), 3.90 mM Na(+)). Hence, net protein synthesis was most sensitive to the substitution and limited the extent of substitution of K(+) by Na(+) in the nutrition of young sugar beet plants.
钾离子（K⁺）和钠离子（Na⁺）在物理和化学性质上有许多相似之处。然而，它们在植物营养中的互换性是受限的。替代研究表明，在甜菜（Beta vulgaris L.）的营养中，K⁺在很大程度上可以被Na⁺替代。然而，无负面影响的替代程度并非没有限制。本研究的目的是确定在幼嫩甜菜植株营养中K⁺被Na⁺替代过程中最敏感的过程。我们关注蒸腾作用、生长和净蛋白质合成。植株在可控环境条件下生长。随着幼苗转移到营养液中，植株在不同的替代处理下进行培养。对于所有处理，K⁺和Na⁺（以氯化物形式施用）的总和固定为4 mM。营养液中K⁺被Na⁺的替代程度从低（0.25%替代：3.99 mM K⁺，0.01 mM Na⁺）到几乎完全替代（99.75%替代：0.01 mM K⁺，3.99 mM Na⁺）不等。0.25%替代处理中3.99 mM K⁺的供应确保不存在K⁺缺乏。蒸腾作用不受替代的影响。在99.75%的替代水平下生长受到抑制。在97.50%的替代水平（0.10 mM K⁺，3.90 mM Na⁺）时净蛋白质合成就已受到影响。因此，净蛋白质合成对替代最为敏感，并限制了幼嫩甜菜植株营养中K⁺被Na⁺的替代程度。
