Sedimentary filling characteristics and controlling factors of lacustrine microbial carbonates sequence in the Santos Basin,Brazil

Based on comprehensive analysis of seismic,logging,core,thin section data,and stable isotopic compositions of carbon and oxygen,the sedimentary filling characteristics of the Lower Cretaceous Barra Velha Formation sequence in H oil field,Santos Basin,are studied,and the high-frequency sequence stratigraphic framework is established,and the spatial distribution of reef-shoal bodies are predicted and the controlling factors are discussed.During the depositional period of the Barra Velha Formation,the study area is a slope-isolated platform-slope sedimentary pattern from southwest to northeast and the change of climate background from rift to depression periods has resulted in the variation of sedimentary characteristics from the lower third-order sequence SQ1(BVE 300 Member)of low-energy deep water to the upper third-order sequence SQ2(BVE 200 and 100 members)of high-energy shallow water in the Barra Velha Formation.The activities of extensional faults and strike-slip faults in rift period and the sedimentary differentiation from platform margin to intra-platform in depression period made the sedimentary paleogeomorphology in these two periods show features of“three ridges and two depressions”.The reef-shoal bodies mainly developed in the SQ2-LHST period,with vertical development positions restricted by the periodic oscillation of the lake level,and developed on the top of each high-frequency sequence stratigraphic unit in SQ2-LHST in the platform.The strike-slip fault activity controlled the distribution of the reef-shoal bodies on the plane by changing the sedimentary paleogeomorphology.The positive flower-shaped strike-slip faults made the formation of local highlands at the margins of and inside the shallow water platforms and which became high-energy sedimentary zones,creating conditions for the development of reef-shoal bodies.

Comparative Study of Grain Filling Characteristics in Maize

Abstract This study was conducted to illustrate the differences in grain filling characteristics between different maize materials in the Northern area of Huanghuaihai Plain, to provide a theoretical basis for the breeding of maize varieties with suitable maturation stage. The new maize hybrid Hengzao 8 was selected as an experimental material, and varieties Huamei 1 and Zhengdan 958 were selected as CK. The changes in grain size, water content, dry weight and grain filling characteristics during grain filling process were studied, and the yield components were analyzed. The grain sizes of the 3 maize materials increased rapidly within 20 d after pollination and reached their peak values on the 45^th d after pollination. Hengzao 8 had the biggest grains, while Zhengdan 958 showed the smallest grains. The 3 maize materials showed high growth speeds of dry matter from the 15^th to the 55^th d after pollination, Hengzao 8 being the fastest and Zhengdan 958 being the slowest. The growth speeds of grain dry matter dropped afterwards. The grain filling rates of the 3 materials fit the unimodal distribution; and Hengzao 8 presented the highest peak value, while Zhengdan 958 exhibited the lowest peak value. Grain size was positively correlated with water amount and negatively correlated with water content, and the grain filling rate was positively correlated with water amount. Regression analysis revealed that when the water contents of the 3 materials reached 57%, grain filling rates reached their peak values. The Logistic model showed that the maximum grain filling rate （Gmax） and the mean filling rate （Gmean） were higher in Hengzao 8 whose active grain filling stage, early stage （T1） , middle stage （T2） and late stage （T3） were shorter than other 2 varieties. The differences in 1 000-grain weight between the 3 materials were responsible for the differences in the yield. The grain filling characteristics of Hengzao 8 are decisive for achieving early maturation and high yield.

Morphological and physiological traits of large-panicle rice varieties with high filled-grain percentage

financed by the Special Program of Super Rice of Ministry of Agriculture, China （02318802013231）;the National Public Services Sectors （Agricultural） Research Projects, Ministry of Agriculture, China （201303102）;the Great Technology Project of Ningbo, China （2013C11001）