Stomatal regulation and adaptation to salinity in glycophytes and halophytes

Soil salinity is one of the major abiotic stresses, which negatively affects the productivity of plants in both cultivated and natural environments. Salinity stress increases osmotic stress and ROS accumulation and breaks the ionic balance in plant cells. In stomatal guard cells, these factors cause ABA biosynthesis and stomatal closure, resulting in the reduction of CO2 assimilation and crop yield loss. Halophytes are the plants capable to thrive in an extremely saline environment, thus consider as one of the vital resources for breeding salt-tolerant crops. Understanding the common and specific adaptive mechanisms to salinity of halophytes and glycophytes (most crop species) is one of the effective approaches to mining the salt tolerance-associated genetic resources. Here, we first reviewed the physiological traits conferring salinity tolerance traits (stomatal density, stomatal aperture, photosynthetic characteristics, and ion content) between halophytes and glycophytes. Comparative genomic and transcriptomic analysis of key membrane transporters regulating stomatal opening and closure is then conducted to explore the adaptation mechanisms of halophytes and glycophytes to salinity stress. In summary, future research is suggested to focus more on halophytes to gain a better mechanistic understanding of salt tolerance before applications in glycophytic crop breeding

The utilization of Ricinus communis in the phytomanagement of heavy metal contaminated soils

Soil contamination with toxic metals is a major global concern due to their effects on plants and the ecosystem. In contaminated soils, some plant species have the ability to remediate heavy metals. Ricinus communis L., is an industrial crop plant gaining popularity in the remediation of heavy metal contaminated soils owing to its strong and deep penetrating roots aiding high metal accumulation and large biomass level. Ricinus communis can tolerate high amounts of metals by adopting different strategies, which include the production of antioxidant enzymes, subcellular localization, and exudation of organic acid. At the molecular level, R. communis can tolerate metal stress by activating stress-responsive genes. Proper selection of metal-tolerant R. communis cultivars is effective in the remediation of metal-contaminated soils, owing to their high capacity for metal tolerance. Exogenous application of mineral fertilization and the use of microbes and chelating agents increase metal solubility and availability for plant uptake in soil. Also, good agronomic practices such as co-planting of R. communis with other leguminous crops enhance R. communis growth and metal tolerance, thereby improving remediation of metal-contaminated soils. This review, therefore, critically discusses the recent approaches in using R. communis to remediate metal-contaminated soils.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author