Rubisco decrease is involved in chloroplast protrusion and Rubisco-containing body formation in soybean(Glycine max.) under salt stress

摘要

Salt stress often induces declination of net photosynthetic rate (Pn), partially resulted from Rubisco degradation. The chloroplast protrusions (CPs) is one of the pathways of Rubisco exclusion from chloroplasts. To explore the relationship between the Rubisco contents and CP_s under salt stress, Pn, maximum photochemical efficiency of PSII (F_v/F_m), carboxylation efficiency (CE) and concentration of Rubisco, number of CPs and Rubisco-containing Body (RCBs) were investigated with two differently saltresponding varieties in this experiment. We observed that 150 mM salt treatment resulted in not only significant decrease in Pn, CE and Rubisco content, but also obvious increase in the number of CP_s and RCB_s in salt-sensitive variety. Under salt stress formation of CP_s resulted in production of much more RCB_s, which could immigrate into and combine with vacuole. It may be a kind of important mechanism for rapid degradation of Rubisco under salt stress. Our conclusion provides a new sight for how Rubisco can be fast degraded under salt stress.