Saline-alkali land constitutes a crucial strategic reserve for farmland resources. The rational development, utilization, and protection of saline-alkali land resources, along with the comprehensive utilization of such land, hold great significance for China’s agricultural and ecological security. Suaeda salsa, a typical salt-tolerant plant, is widely distributed in saline-alkali areas across China. It plays a crucial role in maintaining soil stability, enhancing the soil environment, promoting soil biodiversity, and protecting water sources and quality in saline-alkali regions. However, it remains unclear how different lighting and water level environments affect the non-structural carbohydrates of S. salsa. Based on this, a study was conducted using S. salsa seedlings grown in saline-alkali soil and nutrient soil, respectively, to investigate the effects of different light conditions, water levels, and substrate types on their growth. The experiment included four light–water treatments: high light (17,216.93 lx) × high water level (23.76 cm) (A), high light × low water level (16.18 cm) (B), low light (6,622.35 lx) × low water level (C), and low light × high water level (D). These were combined with two types of growing substrates (saline-alkali soil and nutrient soil) and two growth stages (mature stage and growth stage). Biomass and physiological characteristics of different organs, such as roots, stems, and leaves, were measured to analyze the effects of light, water, substrate, and growth stage on the content and allocation of non-structural carbohydrates in S. salsa. The results indicate that variations in light and water levels significantly affect the content of non-structural carbohydrates (NSCs) in the leaves of S. salsa. Under low water level conditions (B1 and C1), the soluble sugar content in the leaves increased significantly. In contrast, under high water level and high light conditions (A1), starch content in both leaves and roots showed a marked increase. Moreover, the total NSC content in S. salsa grown in saline-alkali soil during the growth stage was highest in A1 and significantly greater than in all other treatments. These findings suggest that under high water level conditions, plants accumulate more starch in leaves and roots as a response to potential hypoxia stress. Under low water level conditions, however, they tend to enhance soluble sugar content to maintain osmotic regulation. Variations in NSC content under different light conditions also reflect adaptive adjustments to insufficient light availability. This study systematically reveals, for the first time, the interactive effects of light, water level, and substrate on carbon allocation in S. salsa. The results provide new theoretical insights into the ecological adaptation strategies of plants in saline-alkali environments and offer practical references for the environmental restoration and sustainable utilization of saline-alkali lands. Graphical Abstract

The Effects of Light and Water Level on the Non-Structural Carbohydrates of Suaeda Salsa

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发表日期：

2025年12月15日

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Qikang Wang,
Fulin Xu,
Hailong Xu,
Cuilian Xu,
Yan Lan,
Nan Wu

摘要

Saline-alkali land constitutes a crucial strategic reserve for farmland resources. The rational development, utilization, and protection of saline-alkali land resources, along with the comprehensive utilization of such land, hold great significance for China’s agricultural and ecological security. Suaeda salsa, a typical salt-tolerant plant, is widely distributed in saline-alkali areas across China. It plays a crucial role in maintaining soil stability, enhancing the soil environment, promoting soil biodiversity, and protecting water sources and quality in saline-alkali regions. However, it remains unclear how different lighting and water level environments affect the non-structural carbohydrates of S. salsa. Based on this, a study was conducted using S. salsa seedlings grown in saline-alkali soil and nutrient soil, respectively, to investigate the effects of different light conditions, water levels, and substrate types on their growth. The experiment included four light–water treatments: high light (17,216.93 lx) × high water level (23.76 cm) (A), high light × low water level (16.18 cm) (B), low light (6,622.35 lx) × low water level (C), and low light × high water level (D). These were combined with two types of growing substrates (saline-alkali soil and nutrient soil) and two growth stages (mature stage and growth stage). Biomass and physiological characteristics of different organs, such as roots, stems, and leaves, were measured to analyze the effects of light, water, substrate, and growth stage on the content and allocation of non-structural carbohydrates in S. salsa. The results indicate that variations in light and water levels significantly affect the content of non-structural carbohydrates (NSCs) in the leaves of S. salsa. Under low water level conditions (B1 and C1), the soluble sugar content in the leaves increased significantly. In contrast, under high water level and high light conditions (A1), starch content in both leaves and roots showed a marked increase. Moreover, the total NSC content in S. salsa grown in saline-alkali soil during the growth stage was highest in A1 and significantly greater than in all other treatments. These findings suggest that under high water level conditions, plants accumulate more starch in leaves and roots as a response to potential hypoxia stress. Under low water level conditions, however, they tend to enhance soluble sugar content to maintain osmotic regulation. Variations in NSC content under different light conditions also reflect adaptive adjustments to insufficient light availability. This study systematically reveals, for the first time, the interactive effects of light, water level, and substrate on carbon allocation in S. salsa. The results provide new theoretical insights into the ecological adaptation strategies of plants in saline-alkali environments and offer practical references for the environmental restoration and sustainable utilization of saline-alkali lands.

Graphical Abstract