Open AccessPhysiological response of Miscanthus genotypes to salinity stress under elevated CO 2
Author(s) -
Liang Kehao,
Peng Xiaoying,
Liu Fulai
Publication year - 2022
Publication title -
gcb bioenergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.378
H-Index - 63
eISSN - 1757-1707
pISSN - 1757-1693
DOI - 10.1111/gcbb.12948
Subject(s) - miscanthus , salinity , abscisic acid , photosynthesis , stomatal conductance , transpiration , halophyte , perennial plant , chemistry , agronomy , water use efficiency , bioenergy , horticulture , botany , biology , zoology , biofuel , ecology , biochemistry , gene
Miscanthus is a class of C 4 perennial grasses, which can be cultivated on marginal land even with high salinity. However, the future environment may be altered by elevated atmospheric CO 2 concentration ([CO 2 ]) and knowledge is limited about the interactive impacts of CO 2 enrichment and salinity on this C 4 bioenergy crop. In this study, three Miscanthus genotypes ( M. sacchariflorus , M. × giganteus , and M. lutarioriparius ) were grown under either ambient (400 ppm) [CO 2 ] ( a [CO 2 ]) or elevated (800 ppm) [CO 2 ] ( e [CO 2 ]) at five salinity levels (0, 50, 100, 150, and 200 m m NaCl denoted as S0, S1, S2, S3, and S4, respectively), and the impacts of e [CO 2 ] on plant physiological responses to salt stress were investigated. Our results suggested that e [CO 2 ] had no obvious effect on net photosynthetic rate ( A n ), but significantly reduced the stomatal conductance ( g s ), thus improving water use efficiency regardless of salinity levels. In addition, e [CO 2 ] could improve water potential of plants under both control and saline conditions, but the magnitude of increase was highly genotypic dependent. The maximum quantum yield of photosystem II ( F v / F m ) was not altered by e [CO 2 ], which, however, could alleviate the negative effect of salt on F v / F m . Furthermore, salt stress increased the concentration of abscisic acid (ABA) in xylem sap and leaves, while the effect of e [CO 2 ] on ABA level was closely associated with genotypes. e [CO 2 ] reduced Na + concentration and had positive influences on maintaining Na + /K + ratio, thus favoring ionic homeostasis, although such effect was genotype dependent. Collectively, our data suggested that e [CO 2 ] could partially mitigate the detrimental effects of salinity, conferring higher salt tolerance of Miscanthus .