山楂层积期间脱落酸含量与种子萌发的关系

温带果树的种子必须经历一段时间的后熟才能发芽和正常生长,许多树种的种子只有经历低温层积才能发芽。山楂属蔷微科,在约旦有广泛分布。不论层积与否,酸处理对划破种皮的山楂种子无影响(Qrunfleh,1991)。大多数山楂种子的胚具休眠性,所以需用层积处理等催芽措施。据Bausher(1974)报道,成熟的桃种子的ABA浓度足以促使其休眠,但至今还没有对山楂种子萌发的最有效的手段。

层积时间和深度及贮藏年限对黄瑞香种子萌发的影响

为了找到探索有效打破黄瑞香种子休眠、提高种子发芽率的方法,以黄瑞香种子为试材,研究3种不同层积期、4种不同层积深度以及不同贮藏年限对黄瑞香种子发芽率的影响。结果表明,贮藏1 a或2 a对黄瑞香种子发芽率的影响差异不显著;不同层积期、不同层积深度对黄瑞香种子发芽率有显著影响。层积期10月20日发芽率最高,11月9日发芽率最低;层积深度80 cm效果最好,40 cm发芽率最低;黄瑞香种子生理休眠属深度生理休眠。由于各因素间对打破种子休眠无交互作用,因此层积期为1 0月20日至10月30日、层积深度为60~100 cm,可获得较高的发芽率。

Neoproterozoic stratigraphic correlation of Subei-Huainan in China

Subei-Huainan in the southeastern margin of the North China platform is a key area of convergence of China’s north-south stratigraphic correlation of Neoproterozoic.Due to the lack of fossils,the Neoproterozoic stratigraphic correlation is still a difficulty in this area.The division of Neoproterozoic strata and the establishment of the correlation framework of the stratigraphic sequences have been done through recognizing the regularity of meter-scale cycles by measuring the outcrop of Neoproterozoic strata and using the Fischer diagram and the sea-level curve of transgressive-regressive by the maximum flooding sedimentary and molar teeth carbonate sedimentary.The maximum flooding sedimentary which becomes cycle sequence comparison of sign is isochronous in the same basin and is a key of cycle sequence comparison although paleogeographic environment and sedimentary sequence may be different in the sedimentary strata of the same geologic time.Molars carbonates,having specific geological distrution time and depositional environment and mainly developing in the ramp environment of the platform edge in the 1500-650 Ma,are the new symbol of the stratigraphic correlation in the Neoproterozoic.Because of the missing of the fossil record,the maximum flooding and the molar-teeth carbonate sedimentary,as the new research ideas,are used in stratigraphic division and correlation.

Heavy mineral stratigraphy of sediments from the southern outer shelf of the East China Sea since the last glaciation using fuzzy C-means cluster method

Correspondence analysis and fuzzy C-means cluster methods were used to divide the stratigraphy of heavy mineral assemblages, and the sediment sources and depositional dynamics of the environment reconstructed. The assemblages were taken from marine sediments from the late Pleistocene to the Holocene in Core Q43 situated on the outer shelf of the East China Sea. Based on the variable boundaries of the mineral assemblage at 63 and 228 cmbsf （cm below sea floor）, the core might have previously been divided into three sediment strata marked with units Ⅰ, Ⅱ and Ⅲ, which would be consistent with the divided sediment stratum of the core using minor element geochemistry. The downcore distribution of heavy minerals divided the sedimentary sequence into three major units, which were further subdivided into four subunits. The interval between 0 and 63 cmbsf of the core （unit Ⅰ）, which spans the Holocene and the uppermost late Pleistocene, is characterized by a hornblende-epidote-pyroxene assemblage, and contains relatively a smaller amount of schistic mineral and authigenic pyrite. In comparison, the interval between 63 and 228 cmbsf （unit Ⅱ）, is representative of the Last Glacial Maximum （LGM）, and features a hornblende-epidote-magnetite-ilmenite assemblage containing the highest concentrations of heavy minerals and opaque minerals. However, the interval between 228 and 309 cmbsf （unit Ⅲ）, which spans the subinterglacial period, is characterized by a hornblende-authigenic-pyrite-mica assemblage. Relative ratios of some heavy minerals can be used as tracers of clastic sediment sources. The lower part of the sediment core shows the highest magnetite/ilmenite ratio and relatively high hornblende/augite and hornblende/epidote ratios. The middle core shows the highest hornblende/augite and hornblende/epidote ratios, and the lowest magnetite/ilmenite ratio. The upper part exhibits a slightly higher magnetite/ilmenite ratio, and also the lowest hornblende/augite and hornblende/epidote ratios. The distribution of the mineral ratio is consistent with stratigraphic division in heavy mineral data using correspondence analysis and fuzzy C-means clustering. Variations in heavy mineral association and mineral ratio in core Q43 revealed changes in provenance and depositional environment of the southern outer shelf of the East China Sea since the late Pleistocene, well corresponding to interglacial and glacial cycles.

Sedimentary response to volcanic activity in the Okinawa Trough since the last deglaciation

To investigate the relationship between volcanic activity and sediment record on regional and temporal scales,158 surface sediment samples were collected from the East China Sea Shelf to the northern Okinawa Trough (OT),and two cores recovered in the northern and southern OT,respectively.Mineralogy,grain-size,and geochemical analyses of those samples show that:1) volcanic glass,volcanic-type pyroxene,hypersthenes,and magnetite increase in sediment influenced by volcanic activity;2) sediment grain sizes (and also silt content) increase in ash layers;and 3) the contents of Na2O and Zr are higher,while terrigenous elements,e.g.,TFe2O3 and K2O,and biogenous compositions,e.g.,CaO and Sr,are relatively lower in ash layers than those of non-ash layers.The distribution of volcanic ash has three distinguishing characteristics:1) volcanic ash is more abundant in the northern and central OT than the southern OT;2) volcanic ash increases from continental shelf to the trough;3) the sediment during the last 12 000 a suggests stronger volcanic events than during 15 000-12 000 a.The eruptive locations,frequency,and volume of calderas are among the most important factors controlling the distributions of volcanic ash.In addition,the main Kuroshio warm current that extends northward probably impeded the diffusion of volcanic ash to the west and south in the OT.However,a southward current probably carried some volcanic ash toward southern OT.

辽宁山楂种子休眠与后熟期的生理生化研究

试验得知辽宁山楂种子层积后熟期长的主要原因是坚硬的种壳不开裂所致。层积过程中吸氧量、过氧化氢酶活性、ＧＡ３／ＡＢＡ、ＩＡＡ／ＡＢＡ、ＺＲ／ＡＢＡ比值与层积时间呈显著正相关，与ＡＢＡ含量极显著负相关；糖代谢、蛋白质代谢、脂肪代谢在层积过程中也发生相应的变化，但不显著。

The effects of cryosurgery upon the pulmonary parenchyma with single or double freeze-thaw cycles in rabbits

Objective:The aim of our study was to observe the different effects including diameter of cryosurgery region and incidence of pneumothorax and pleural effusion when cryosurgery upon the pulmonary parenchyma with single or double freeze-thaw cycles in rabbits.Methods:Fifty rabbits were divided into two groups and they were all subjected to cryosurgery.The group one was single freeze-thaw cycle cryosurgery and the other group was double cycles.Pneumothorax and pleural effusion were observed after cryosurgery immediately with computer tomograph.The surviving animals were killed at 3 days after cryosurgery and histology observe were obtained.Results:There was no animal dead in the test.Histologically,a hemorrhagic infarct developed in the region of cryosurgery.The incidence of pneumothorax was 28% in group one and 12% in group two.The diameter of cryosurgery region was(4.3 ± 0.8) cm in rabbits who received double cycles cryosurgery and 3.1 ± 0.8 cm in single cycle.Conclusion:It is safety to cryosurgery upon pulmonary parenchyma with one or two cycles and the histological changes are similar.The diameter of cryosurgery region with two cycles was bigger than one.