# Continuous cropping changes the absorption and accumulation of elements in Casuarina equisetifolia, thus affecting its physiological properties

## TL;DR

Continuous planting of Casuarina equisetifolia reduces its ability to absorb and transport essential elements, leading to worse plant growth and physiological performance.

## Contribution

This study reveals how continuous monoculture affects elemental uptake and physiological traits in Casuarina equisetifolia.

## Key findings

- Continuous planting reduced root and leaf enrichment of elements like Na, Ni, N, K, Mg, Lu, Rb, and Zn.
- Element transport of Mo, N, Nb, and Sr decreased significantly with more continuous plantings.
- Physiological indices like root activity and photosynthetic rate declined with increased continuous planting.

## Abstract

Continuous monoculture affects elemental uptake in Casuarina equisetifolia (C. equisetifolia). In this study, C. equisetifolia with different numbers of continuous plantings was used to determine multi-element contents in rhizosphere soil, roots, and leaves using inductively coupled plasma-mass spectrometry (ICP-MS), and to assess the physiological indices of the roots and leaves. The effects of continuous planting on the uptake and transport of elements, and physiological characteristics of C. equisetifolia were also analyzed. The results showed that continuous planting of C. equisetifolia significantly reduced the enrichment capacity of its roots and leaves for certain elements. Specifically, continuous planting reduced Na and Ni enrichment in roots and N, K, Mg, Lu, Rb, and Zn enrichment in leaves. In terms of elemental transport, continuous planting resulted in a significant decrease in the transport of Mo, N, Nb, and Sr by C. equisetifolia. Physiological indice results showed that root activity, root cation exchange capacity, chlorophyll content, and net photosynthetic rate in C. equisetifolia tended to decrease significantly with an increase in the number of continuous plantings. In conclusion, continuous planting reduced the uptake, enrichment, and transport of beneficial elements in C. equisetifolia, which in turn inhibited root growth, decreased photosynthetic capacity, and ultimately stunted plant growth. This study provides an important reference for planting management and elemental regulation in continuous planting systems of C. equisetifolia.