Effects of mosaic biological soil crusts on vascular plant establishment in a coastal saline land of the Yellow River Delta, China

Abstract

Aims The effects of biocrusts on vascular plants are rarely evaluated in coastal saline lands. Our aim was to examine whether and how a mosaic of biocrusts affect seed germination of two typical herbaceous plants in a coastal saline land of the Yellow River Delta, to enhance our understanding by which substrate heterogeneity influences plant community dynamics. Methods We conducted growth chamber experiments to investigate the effects of biocrusts and uncrusted soil from bare patch-, Phragmites australis-, Suaeda glauca- and Tamarix chinensis-dominated habitats on seed germination percentage and mean germination time of two herbaceous plants: the perennial Phragmites australis and the annual Suaeda glauca. We also explored the mechanisms underlying the effects of substrate on seed germination. Important Findings Compared to uncrusted soil, biocrusts increased water content, nutrient accumulation and concentration of most salt ions, but they reduced soil pH value. Biocrusts with mosses directly decreased soil pH value and concentration of Mg 2+, resulting in an indirect increase in seed germination percentage of S. glaucas. The low soil pH value also resulted in an indirect decrease in seed germination speed of P. australis in their own habitats. Bare patch directly increased accumulation of Cl −, resulting in an indirect decrease in seed germination speed of P. australis. These results suggest that biocrusts with mosses in P. australis habitats offer a window of opportunity for germination of S. glaucas. Biocrusts combined with habitat type have the potential to influence plant community structure through an effect on seed germination and establishment.

Halophytes play important role in phytoremediation of salt-affected soils in the bed of Urmia Lake, Iran

“…Feng et al 9 , reported that osmotic adjustment can be controlled by biosynthesis of compatible solutes and accumulation/compartmentalization or exclusion of ions. Most plant species, especially halophytes, can maintain the water potential and necessary osmotic gradient for water uptake by accumulating different inorganic ions equal to or more than their concentration in soil solution 49 .…”

“…Several studies have examined the effect of soil salinity on plant yields and growth parameters 8 , 9 which could cause huge losses in plant productivity 10 , 11 . Salt accumulation in soils without suitable vegetation can increase wind erosion and cause the surface sediments to form a sleazy texture 12 .…”

“…Salt accumulation in soils without suitable vegetation can increase wind erosion and cause the surface sediments to form a sleazy texture 12 . Transporting saline sediments with a high concentration of sodium chloride (NaCl) and other potentially fine-grain saline and toxic components could be dangerous for the ecological and environmental security, the establishment of vegetation, and human health in arid and semi-arid regions 9 , 13 .…”

Agro-Physiological and Genetic Characterization of Halophyte Species and Their Impact on Salt-Affected Soil

“…Slama et al (2015) and Delavar et al (2020) mentioned that halophytes can regulate soluble substances like glycine betaine and proline to increase cell volume and maintain osmotic balance under salinity. These organic compounds likely play a role in leaf osmotic adjustment and the protection of membrane stability at severe salinity (Feng et al, 2021). Salt-marsh halophytes cope with salt by excluding entry into roots, sequestering salts intracellular (leading to succulence), and excreting salt via glands, usually on leaf surfaces (Nhu et al, 2020).…”