Progress in Studying Salt Secretion from the Salt Glands in Recretohalophytes: How Do Plants Secrete Salt?

Abstract

To survive in a saline environment, halophytes have evolved many strategies to resist salt stress. The salt glands of recretohalophytes are exceptional features for directly secreting salt out of a plant. Knowledge of the pathway(s) of salt secretion in relation to the function of salt glands may help us to change the salt-tolerance of crops and to cultivate the extensive saline lands that are available. Recently, ultrastructural studies of salt glands and the mechanism of salt secretion, particularly the candidate genes involved in salt secretion, have been illustrated in detail. In this review, we summarize current researches on salt gland structure, salt secretion mechanism and candidate genes involved, and provide an overview of the salt secretion pathway and the asymmetric ion transport of the salt gland. A new model recretohalophyte is also proposed.

Making Plants Break a Sweat: the Structure, Function, and Evolution of Plant Salt Glands

“…For example, Na + transporters, including SOS1, would need to be regulated together with plasma membrane proton ATPases to excrete salt to the surface against an electrochemical gradient while Na + /K + membrane transporters like HKT1 would be useful for the influx of Na + into the secretory bladder cell from neighboring cells. Additional membrane transporters associated with Na + and Cl - transport that may play an important role in developing functional salt glands are reviewed in Shabala et al (2015) and Yuan et al (2016a). Further refinements could be made by taking advantage of the knowledge that increased GL3 expression increases trichome density on leaves (Payne et al, 2000; Morohashi et al, 2007).…”

Molecular mechanisms underlying stress response and adaptation

“…These salt glands have four secretory pores in the center of the cuticle that secrete NaCl . Using high‐throughput RNA sequencing, candidate genes have been identified in the Limonium bicolor salt gland that are highly associated with salt secretion . In addition, an efficient method has been developed to screen for mutants capable of adapting to abnormal salt gland density .…”

Comparison of two halophyte species (Salsola soda and Portulaca oleracea)for salt removal potential under different soil salinity conditions

“…Some plants tolerate salt (Munns and Gilliham, 2015;Karakas et al, 2016) while others accumulate or exclude salt (Yuan et al, 2016). As a result, plants that thrive under saline conditions became an option for the remediation of saline-affected soils.…”