Analysis on the Effects of Potassium Deficiency on the Growth and Physiological Characteristics of Coconut Seedlings

Potassium ions (K<sup>+</sup>) are crucial for plant growth and crop yield. However, the effects of low potassium on the growth and physiological characteristics of coconut seedlings remain poorly understood. Therefore, in this study, we conducted a hydroponic pot experiment to compare the changes in growth and leaf physiological traits of coconut seedlings under low potassium (K<SUB>L</SUB>) and normal potassium (K<sub>ck</sub>) conditions. Low potassium significantly reduced plant height, biomass, SPAD values of chlorophyll, as well as potassium (K) content, soluble protein (SP) and soluble sugar (SS) levels in coconut seedlings. Under low potassium conditions, the content of malondialdehyde (MDA) in the leaves of coconut seedlings increased significantly, while the proline (PRO) content decreased markedly. The activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were significantly reduced. The levels of endogenous hormones such as auxin (IAA), gibberellin (GA), and zeatin (ZR) declined significantly, while the content of abscisic acid (ABA) increased significantly. The results indicate that low potassium has a substantial impact on the growth and physiological characteristics of coconut seedlings. Therefore, in coconut cultivation, it is essential to ensure the scientific and moderate supplementation of potassium fertilizers to meet their growth and physiological requirements.