Research progress in physiological and molecular biology mechanism of drought resistance in rice

Rice is one of the most important crops, providing staple food for about half population of the world. Drought stress affects plant growth and development seriously. This article reviewed the research progress of the physiological and molecular biology mechanism including osmotic adjustment, scavenging oxidative radicals, endogenous hormones, drought-resistance genes and epigenetic modification, it may be afford interrelated reference for increasing rice drought resistance and breeding drought resistance rice varieties.

Research on the Status Quo and Supervision Mechanism of Food Safety in China

Food safety supervision mechanism is a strong guarantee to promote the smooth implementation of China's food safety laws and regulations,and it is implemented through legal,administrative,economic,moral and other integrated policy instruments,as well as media publicity,quality traceability,network tracking,information disclosure and other non-administrative means. Along with strengthening supervision and control means,the people's food safety in China is safeguarded,and the healthy development of the food industry is promoted.

Research of total levels on DNA methylation in plant based on HPLC analysis

HPLC analysis is important for determination of total level on DNA methylation in plants. It can be used to help characterise epigenetic changes during growth, development and stress. HPLC methods have been optimised for mammalian and microbial DNA, but not for plants. This article examines several important factors in the HPLC analysis of plant DNA methylation including extraction and purification of DNA and HPLC conditions choice by using leaves of rice seedling. The experimental results showed that RNA of nucleic acid was removed by using RNase A. This study also identified critical components of HPLC analysis. With the optimized method of HPLC conditions, the better result was achieved in the chromatogram of cytosine and 5-methylcytosine in genomic DNA acid hydrolysis. The study would offer a comprehensive guide for the stringent analysis of DNA methylation in plants.

Mineralogical Characteristics and in-situ Sulfur Isotopic Analysis of Gold-Bearing Sulfides from the Qilishan Gold Deposit in the Jiaodong Peninsula,China

Large-scale gold mineralization during the Early Cretaceous is identified in the Jiao-dong Peninsula of China.Sources of ore-forming fluids remain debated.We study the Qilishan gold deposit in the northwestern Jiaodong Peninsula with detailed mineralogical observation and in-situ sulfur isotope analyses,in order to reveal the gold occurrence and the origin of ore-forming fluids.The Qilishan gold deposit is mainly clastic altered rock-type in mineralization,and ore minerals are visible native gold,electrum,pyrite,chalcopyrite and galena,gangue minerals as quartz,sericite and calcite.The gold occurrence includes inclusion and intergranular types,formed within pyrites and chalcopy-rites and along their fissures.In-situ sulfur isotope analysis of gold-bearing sulfides suggests that the Qilishan deposit is enriched in heavy sulfur,withδ34S values mainly from+8.0‰to+12.0‰.δ34S val-ues increase gradually with the fluid evolution from the early to late stages,which is interpreted to be related to the loss of sulfur via sulfide precipitation.The crystallization of sulfides from hydrothermal fluids may have triggered the instability of Au(HS)2,and finally led to gold precipitation.Combined with sulfur isotope compositions of other gold deposits(n=43)and wall-rocks in the Jiaodong Peninsu-la,it is proposed that the ore-forming fluids were probably not directly originated from metamorphic wall-rocks(e.g.,Jiaodong Group).Moreover,the relatively long time interval rules out the possibility that the gold mineralization(ca.120 Ma)was associated with granitic magma activities(mostly 160-150 Ma).Possible ore genesis scenario is that,long-term subduction of slabs(e.g.,the Paleo-Pacific)with gold-enriched pyritic materials and crustal sedimentary rocks resulted in both high Au contents and positiveδ34S values of sulfur in the lithospheric mantle below the North China Craton.Subse-quently,devolatilization of the metasomatized mantle produced auriferous fluids that migrated up-ward along translithospheric fault systems,and gold finally precipitated in favorable structural posi-tions,generating the world-class Jiaodong deposits in the Early Cretaceous.