Salinity-induced ethylene accumulation caused by high production of 1-aminocyclopropane-1-carboxylic acid (ACC) hinders rice plant growth and development. Nevertheless, ACC deaminase may alleviate salt stress and high ethylene production in rice cultivars under salinity stress. Pyridoxal 5′-phosphate (PLP), an ACC deaminase co-factor, could be a useful ACC inhibitor in plants; however, it has not been studied before. In the present study, the effects of PLP on the growth and morphophysiological characteristics of rice cultivars (Jinyuan 85 (JY85) and Nipponbare (NPBA) were investigated under salinity stress (control (CK), low salinity (LS), and high salinity (HS) in hydroponic conditions. The experiment was laid out in a completely randomized design (CRD) under factorial arrangement of treatments. The results showed that, compared with no PLP, exogenous application of PLP significantly inhibited ACC and ethylene production in the roots, leaves and panicles of both cultivars under salinity, and PLP was more effective at improving the physiological characteristics of both cultivars under salinity stress. Further, root morphophysiological traits and pollen viability were triggered in the PLP treatment compared to the no-PLP treatment under various salinity levels. ACC production inhibited by PLP was useful for improving the 1000-grain weight, grain yield per plant, and total plant biomass under the CK, LS and HS treatments in both rice cultivars. These results revealed that PLP, as an ACC deaminase cofactor, is a key tool for mitigating ethylene-induced effects under salinity stress and for enhancing the agronomic and morphophysiological traits of rice under saline conditions.

1-氨基环丙烷-1-羧酸（ACC）的大量生产导致盐分诱导的乙烯积累，阻碍了水稻的生长和发育。然而，ACC脱氨酶可以减轻盐分胁迫下水稻品种的盐分胁迫和较高的乙烯产量。ACC脱氨酶辅助因子Pyridoxal 5'-phosphate（PLP）可能是植物中有用的ACC抑制剂。但是，以前没有研究过。在本研究中，研究了盐分胁迫（对照），低盐度（LS）和高盐度（P）对水稻（Jinyuan 85（JY85）和Nipponbare（NPBA））的生长和形态生理特性的影响。在无水栽培条件下，采用完全随机设计（CRD）进行实验，结果显示与无PLP相比，外源施用PLP显着抑制盐分胁迫下两个品种根，叶和穗的ACC和乙烯生成，PLP在改善盐胁迫下两个品种的生理特性方面更有效。此外，与在不同盐度水平下的无PLP处理相比，在PLP处理中触发了根的形态生理特征和花粉生存力。在两个水稻品种的CK，LS和HS处理下，PLP抑制的ACC产量可用于改善1000粒重，单株籽粒产量和总植物生物量。这些结果表明，PLP作为ACC脱氨酶的辅助因子，是缓解盐分胁迫下乙烯诱导的作用以及增强盐分条件下水稻的农艺和形态生理特性的关键工具。