Salt hyperaccumulation in Amaranthaceae: understanding the physiology behind salinity adaptation in nature

Abstract

Salt hyperaccumulating plants have drawn significant attention for their potential use in phytoremediation due to their ability to absorb ions from the soil and store them in their aboveground tissues, particularly in their succulent leaves. Several species, including S. fruticosa, S. nudiflora, S. baryosma, C. ambrosoides, C. murale, C. album, A. nummularia, A. amnicola, A. lentiformis, A. aspera, A. tomentosa, and H. recurvum, belong to this category of hyperaccumulators. Elevated levels of salt stress have a detrimental impact on the growth and development of plants. This is attributed to the heightened accumulation of ions, resulting in both ionic and osmotic stress. Specifically, the ratios of Na⁺/K⁺, Na⁺/Ca²⁺+Mg²⁺, and Cl^-/SO₄^2- tend to skew towards higher values under increased salinity conditions from normal to 16 dS m^-1. Furthermore, the total ionic content per plant showed a noticeable increase, escalating from 152.43 to 306.8 units. Notably, ash content and total dissolved solids also exhibited augmentation with rising levels of salinity (from control to 16 dS m^-1). EC and pH varied with the different species in comparison to the values before plantation. Sodium adsorption ratio (SAR) varied from 23.16 to 24.87 with the species. These halophytes are to be a source of genes for developing salinity-resistant crops that can be oppressed during conventional and molecular plant breeding programs. Considering their unique traits, these halophytes hold promise as a source of genes for developing salt-resistant crops, and they can be integrated into conventional and molecular plant breeding programs to combat salinity-related challenges.