Mahmood Moniba Zahid, Odeibat Hamza Ahmad, Ahmad Rafiq, Gatasheh Mansour K, Shahzad Muhammad, Abbasi Arshad Mehmood
Department of Environmental Sciences, COMSATS University Islamabad, Abbottabad, Pakistan.
Max Planck Institute for Chemical Ecology, Jena, Germany.
Front Plant Sci. 2024 Jan 3;14:1268750. doi: 10.3389/fpls.2023.1268750. eCollection 2023.
Salinity is known to have a greater impact on shoot growth than root growth. Na buildup in plant tissue under salt stress has been proposed as one of the main issues that causes growth inhibition in crops via ionic imbalances, osmotic stress and pH disturbances. However, the evidence for apoplastic Na buildup and the role of silicon in Na accumulation at the subcellular level is still enigmatic. The current study focuses on the accumulation of Na in the apoplast and symplast of younger and older leaves of two maize varieties (Iqbal as salt-tolerant and Jalal as salt-sensitive) using hydroponic culture along with silicon supplementation under short-term salinity stress. Subcellular ion analysis indicated that silicon nutrition decreased Na concentration in both apoplastic washing fluid and symplastic fluid of maize under salt stress. The addition of silicon under NaCl treatment resulted in considerable improvement in fresh biomass, relative water content, chlorophyll content, and concentration of important subcellular ions (, Ca, Mg, and K). Knowledge of subcellular ion analysis is essential for solving the mechanisms underlying vital cellular functions e.g. in the current study, the soluble Na concentration in the apoplast of older leaves was found to be significantly greater (36.1 mM) in the salt-sensitive variety under NaCl treatment, which was 42.4% higher when compared to the Na concentration in the salt-tolerant variety under the same treatment which can influence permeability of cell membrane, signal transduction pathways and provides insights into how ion compartmentalization can contributes to salt tolerance. Calcium silicate enrichment can contribute to increased growth and improved ionic homeostasis by minimizing leaf electrolyte leakage, improving mechanical functions of cell wall and reducing water loss, and improved photosynthetic function. In current investigation, increased water content and intracellular ionic homeostasis along with reduced concentration of Na in the maize leaf apoplast suggest that calcium silicate can be used to ameliorate the adverse effects of salt stress and obtain yield using marginal saline lands.
已知盐分对地上部生长的影响大于对根系生长的影响。盐胁迫下植物组织中钠的积累被认为是导致作物生长受抑制的主要问题之一，其通过离子失衡、渗透胁迫和pH紊乱来影响作物生长。然而，关于质外体钠积累的证据以及硅在亚细胞水平上钠积累中的作用仍不明确。本研究利用水培法并在短期盐胁迫下添加硅，重点研究了两个玉米品种（耐盐品种伊克巴尔和盐敏感品种贾拉尔）幼叶和老叶质外体和共质体中钠的积累情况。亚细胞离子分析表明，硅营养降低了盐胁迫下玉米质外体洗涤液和共质体中的钠浓度。在NaCl处理下添加硅显著改善了鲜生物量、相对含水量、叶绿素含量以及重要亚细胞离子（钙、镁和钾）的浓度。亚细胞离子分析知识对于解决重要细胞功能的潜在机制至关重要，例如在本研究中，发现在NaCl处理下，盐敏感品种老叶质外体中的可溶性钠浓度显著更高（36.1 mM），与相同处理下耐盐品种中的钠浓度相比高出42.4%，这可能会影响细胞膜通透性、信号转导途径，并有助于深入了解离子区室化如何有助于耐盐性。硅酸钙富集可通过减少叶片电解质渗漏、改善细胞壁机械功能和减少水分流失以及改善光合功能，促进生长并改善离子稳态。在当前研究中，玉米叶片质外体中含水量增加、细胞内离子稳态以及钠浓度降低，表明硅酸钙可用于减轻盐胁迫的不利影响，并利用边际盐碱地获得产量。
