# Electrophysiological Regulation of Nutrient Transport in Mangrove Species Under Salinity Stress: A Comparative Physiological Analysis of Aegiceras corniculatum (L.) Blanco and Kandelia obovata Sheue, H.Y. Liu & J.W.H. Yong

## TL;DR

This study explores how two mangrove species regulate nutrient transport under salt stress using electrophysiological traits, revealing differences in their adaptive strategies.

## Contribution

The study introduces electrophysiological traits as a novel framework to understand nutrient transport in mangroves under salinity stress.

## Key findings

- K. obovata showed a 63.7% increase in nutrient active flow under low salinity, while A. corniculatum had a 7.9% reduction.
- K. obovata exhibited higher growth and photosynthetic performance compared to A. corniculatum under salinity stress.
- Nutrient transport capacity was non-significant in control and low-salt treatments, indicating resistance to low salt stress.

## Abstract

Salinity is a major environmental constraint that influences nutrient acquisition and internal transport in coastal plant species. However, the electrophysiological mechanisms underlying nutrient flow regulation in mangroves remain poorly understood. This study investigates the active transport flow of nutrients (NAF) and nutrient plunder capacity (NPC) in two ecologically significant mangrove species, Aegiceras corniculatum (L.) Blanco (A. corniculatum) and Kandelia obovata Sheue, H.Y. Liu & J.W.H. Yong (K. obovata), using intrinsic electrophysiological leaf traits including inherent impedance (IZ), inherent capacitive reactance (IXC), inherent inductive reactance (IXL), and inherent capacitance (IC). A randomized block design was employed using three different saline treatments with control, such as control (0 mM), low (T1,100 mM), medium (T2, 250 mM), and high (T3, 450 mM). The results of the fitting equations show a positive correlation between resistance (Re), capacitive reactance (XC), and inductive reactance (XL) with clamping force (CF); all values of R2 are ≥0.98, and p-values are <0.0001. Nutrient transport capacity (NTC) was non-significant in control and low-salt treatment for both mangrove species, indicating resistance to low levels of salt stress. NAF results of A. corniculatum showed a slight reduction of 7.9% under low salinity, while K. obovata displayed strong positive responses NAF increasing by 63.7% compared to the control. Additionally, the NPC of A. corniculatum species was not significantly affected at low and medium salt levels but declined at high salt levels. In contrast, K. obovata exhibited a higher growth rate and better photosynthetic performance than A. corniculatum. Our findings provide novel mechanistic insights into how electrophysiological regulation governs nutrient transport under salinity stress and highlight interspecies differences in adaptive strategies, with implications for understanding mangrove resilience in saline environments.