论文部分内容阅读
In higher plants, NAD(P)H dehydrogenase (NDH) complex reduces plastoquinones and drives cyclic electron flow (CEF) around photosystem I (PSI).It also produces extra ATP for photosynthesis and improves the fitness to abiotic environmental stress.To elucidate the role of CEF in salt tolerance of photosynthetic apparatus, we measured Na+ concentration, the increase in chlorophyll fluorescence, expression of NDH B and H subunits, and genes relative to Na+ transport into vacuole or/and cell.The results showed that in the salt tolerant soybean (S 111-9) exhibited much higher CEF activity and ATP accumulation in light, while Na+ concentration was similar in the leaves under salt stress.In Sl11-9 ndhB and ndhH were highly up-regulated under salt stress and their proteins were maintained higher or up-regulated significantly.An increase in accumulation of Na+ in vacuole happened more commonly in S111-9, while accumulation of Na+ in chloroplast appeared in the salt-sensitive Melrose.Some genes associated to Na+ transport into vacuole or/and cell, such as genes encoding CBL10-CIPK24-NHX and CBL4-CIPK24-SOS1 complex, were more highly expressed in Sl11-9.Therefore, we proposed that the enhanced NDH dependent CEF promotes to supply extra ATP for sequestering Na+ in vacuole.This is an important mechanism for salt tolerance in soybean and also provides a new sight to understand the resistance of plant to salt stress.