Hibiscus hamabo Rootstock-Grafting Improves Photosynthetic Capacity of Hibiscus syriacus under Salt Stress

Hibiscus syriacus, a woody ornamental plant with great economic value, is vulnerable to salinity. Hence, its cultivation in saline areas severely restricted. Although grafting H. syriacus onto hamabo rootstock can greatly improve syriacus’s salt resistance, the photosynthetic response of and stress remains largely unknown. To address this question, self-rooted (Hs), self-grafted (Hs/Hs), hamabo-grafted (Hs/Hh) were exposed 0 or 300 mM NaCl. Salt significantly reduced net maximum rates, chlorophyll content, (Fv/Fm) actual (ΦPSII) photochemical quantum yield photosystem II (PSII), as well apparent electron transport rate, Hs Hs/Hs. However, these reductions alleviated when was grafted hamabo. In line changes fluorescence parameters, expression genes encoding subunits PSII PSI Hs/Hh higher than that Hs/Hs under conditions. Moreover, upregulated involved Calvin–Benson–Bassham cycle These results indicate ameliorate inhibition salinity on capacity mainly resulting from limitations pigments, efficiency, cycle.