Inheritance of Boron Efficiency in Oilseed Rape

Field experiments were conducted to study the inheritance of boron efficiency in oilseed rape (Brassica napus L.) by evaluating the boron (B) efficiency coefficient (BEC, the ratio of the seed yield at below the critical boron level to that at the boron-sufficient level) with 657 F2:3 lines of a population derived from a cross between a B-efficient cultivar, Qingyou 10, and a B-inefficient cultivar, Bakow. Qingyou 10 had high BEC as well as high seed yield at low available soil B. On the contrary, Bakow produced low seed yield at low B status. Boron deficiency decreased the seed yield of the F2:3 lines to different extents and the distribution of BEC of the population showed a bimodal pattern. When the 657 F2:3 lines were grouped into B-efficient lines and B-inefficient lines according to their BEC, the ratio of B-efficient lines to B-inefficient lines fitted the expected ratio (3:1), indicating that one major gene controlled the B-efficiency trait. 127 F2:3 lines selected from the population at random, with distribution of BEC similar to that of the overall population, were used to identify the target region for fine mapping of the boron efficiency gene.

Paleosalinity and lake level fluctuations of the 3rd Member of Paleogene Shahejie Formation,Chezhen Sag,Bohai Bay Basin

The Chezhen Sag,located in the north-western Jiyang Depression,is one of the most important oil-bearing sags in the Bohai Bay Basin.Due to the low degree of exploration in the sag,paleosalinity and sedimentary environment of the sag in the 3rd Member of Paleogene Shahejie Formation(Es3)is not clear.Recovering the paleosalinity and lake level fluctuations is helpful for understanding organic matter rich rocks sedimentation.Therefore,a detailed geochemical,mineralogical and paleontological analysis of the Es3 in the Chezhen Sag was conducted.Index like Sr/Ba ratios,B/Ga ratios,equivalent boron content and methods concluding Adams'formula and Couch's method were adopted to reveal the paleo-salinity and lake level variations.The results indicate that the lower submember(Lower Es3)was deposited in a salt water with high salinity,accompanied by dry climate and transgression event.The middle submember(Middle Es3)and upper submember(Upper Es3)record a freshwater to brackish environment.The paleosalinity and paleoclimate changes are consistent with the global sea level variations.The type and content of sporopollen indicate a dry climate in Lower Es3,which further confirms the reliability of the reconstruction results of paleosalinity.Combined with the paleoclimate and previous marine paleontological evidence,we proposed that the high salinity period is associated with a high lake level and a large-scale transgression event in Lower Es3.According to salinities and corresponding Lake depths,we established a sedimentary environment variation model of the Es3 Member in Chezhen Sag.