Search

In order to reveal the developmental process of the deuterogenic placenta of Adinandra latifolia from the family Pentaphylacaceae, and the relationship between deuterogenic placenta, carpellary placenta and free central placenta, the flower buds and mature fruits of A. latifolia were observed in detail by scanning electron microscope(SEM)and stereoscopic microscope. Floral buds at different stages of development were collected and fixed in formalin-aceticacid-alcohol, and then dehydrated through an ethanol/amylacetate series, critical point dried with CO2, Au/Pt sputter coated, prepared samples were examined with SEM. Mature fruits were dissected under a stereoscopic microscope directly without preparation. The results showed that during the floral development, 5 carpel primordia were growth rapidly after the stamens initiation, and then ovary was combined with the axial placenta on the upper part and cavity on the bottom part. After the placenta grew on the carpels(named carpellary placenta), several mounds appear at the top of the receptacle within the position opposite to the carpel in the lower cavity. The mounds combined gradually into a hemispherical deuterogenic placentation. And some fertile ovules appeared on the surface of both the carpellary placenta and deuterogenic placenta. Finally, in mature fruits the fertile ovules turn to seeds on both types of placenta in which vascular bundles are discrete. Therefore, deuterogenic placenta appeared independently and was later than the carpellary placenta. The development of deuterogenic placenta in A. latifolia was different from that of the free central placenta in both Caryophyllaceae and Phytolaccaceae(the axial placenta turned into a free central placenta by the septa disappear), but it is basically identical to that of Primulaceae, Theophrastaceae, Maesaceae, Myrsinaceae from Ericales(the free central placenta formed on top of the receptacle directly). [ABSTRACT FROM AUTHOR]

In order to ensure the safety of filling stope and ore mining efficiently, it is necessary to study the interaction between the filling and surrounding rock in different strength periods, which influences the stability of filling stope.The paraffin was selected as the contact material to simulate the early strength of the filling body, and also considering the complexity of the stress environment in the contact zone, the non-uniform stress in the contact zone between the wall rock and the early-strength backfill was simulated.In order to effectively characterize the regional instability in the contact zone and realize the transformation from qualitative analysis to quantitative evaluation, the PVC plastic foil was placed on the contact face between the surrounding rock and the early strength filling body.Combined with the microscopy imaging, electron microscope scanning, AE monitoring and strain monitoring, the laboratory experiment of the interaction between the surrounding rock and the early strength filling body under different load conditions was studied.The strain change, crack growth deformation evolution, stability failure of cemented backfill and surrounding rock complex were monitored and analyzed.The results show that the deformation of the contact zone increases rapidly, the strain value fluctuates greatly and the abrupt change is obvious.After loading, the paraffin in the contact zone shows three different damage characteristics: one is spiral damage, the second is the parallel type of damage, the third shows the characteristics of cross-damage, and the strain around the contact zone shows a steady increasing trend. The results also show the complex mechanical and deformation characteristics of filling body and surrounding rock, which has a certain guiding significance to ensure the stability of the stope with the early strength filling body.The synchronization between crack propagation and internal damage is realized.The study provides a research idea for further studying the mechanical properties of backfill and surrounding rock complex under two-dimensional and three-dimensional loads. [ABSTRACT FROM AUTHOR]