Changes of calmodulin (CaM) distribution in the embryo sac of rice (Oryza sativa subsp. Japonica) at various stages before and after fertilization have been investigated by using immunogold electron microscopy. Before...Changes of calmodulin (CaM) distribution in the embryo sac of rice (Oryza sativa subsp. Japonica) at various stages before and after fertilization have been investigated by using immunogold electron microscopy. Before pollination, both cytoplasm and vacuoles of the egg cell, synergids and central cell were labeled by gold particles. A small amount of gold particles were localized in the nucleus, endoplasmic reticulum, mitochondria and dictyosomes. From pollination to fertilization, CaM amount increased in these cells, especially rich in the starch of amyloplasts. Increase of gold particles in the central cell began about 2 h earlier than that in the egg cell. There was no distinct difference of CaM amount between the degenerated and the persistent synergids. It is interesting to observe an obvious change of CaM distribution form during pollination and fertilization from scattered single particles to clustered particles, and back again to single particles after the fertilization finished. CaM was also localized extracellularly in the embryo sac wall as well as in the wall and intercellular space of nucellus cells. The extracellular CaM also changes in its amount and form after pollination. These results suggest that CaM, either intra- or extra-cellular, may play important roles in fertilization and zygote formation.展开更多
为了探讨热激蛋白在低温锻炼诱导的耐热性形成过程中的保护功能,进一步分析葡萄幼苗对温度逆境产生交叉适应性的细胞学机制,试验以葡萄(Vitis vinifera L. cv. Jingxiu)幼苗为试材,采用胶体金免疫电镜定位技术,定位观察了小分子热激蛋白...为了探讨热激蛋白在低温锻炼诱导的耐热性形成过程中的保护功能,进一步分析葡萄幼苗对温度逆境产生交叉适应性的细胞学机制,试验以葡萄(Vitis vinifera L. cv. Jingxiu)幼苗为试材,采用胶体金免疫电镜定位技术,定位观察了小分子热激蛋白17.6(sHSP17.6)在葡萄叶片中的亚细胞分布情况,结果表明,低温锻炼预处理可增强其在高温胁迫条件下的表达水平,细胞核和叶绿体中代表sHSP17.6的免疫金颗粒密度比相应的对照细胞明显增多,尤其是胁迫处理3 h时。这一结果为sHSP17.6参与低温锻炼诱导的耐热性提供了更直观的细胞学证据。展开更多
为了研究砂岩在渗流−应力耦合作用下的变形局部化破坏特征,利用可视化三轴伺服控制试验系统,结合三维数字图像相关技术(three-dimensional digital image correlation,简称3D-DIC),开展不同排水条件下的砂岩三轴压缩试验,对岩石力学、...为了研究砂岩在渗流−应力耦合作用下的变形局部化破坏特征,利用可视化三轴伺服控制试验系统,结合三维数字图像相关技术(three-dimensional digital image correlation,简称3D-DIC),开展不同排水条件下的砂岩三轴压缩试验,对岩石力学、渗流及其变形局部化特性进行分析,并利用电镜扫描对砂岩破坏后其破裂面微观形貌进行分析。结果表明:排水条件下砂岩的峰值强度和弹性模量高于不排水条件下的值,且随着渗透水压增大,砂岩的峰值强度、弹性模量和泊松比均随之增大,出现贯通裂纹的时间点和渗透率最大值出现的时间点则会提前;当渗透水压相同时,不排水条件下砂岩表面变形场云图的局部化带比排水条件下的更宽,即岩石的宏观裂纹更明显,排水条件下水流将岩石内部的矿物颗粒带走,形成孔洞,其破裂面的表面比不排水条件下更光滑,而不排水条件下颗粒表面明显有片状岩屑附着;所有排水条件下径向变形局部化启动点始终高于轴向变形局部化启动点,平均提高了1.23%,变形局部化径向、轴向启动应力水平均随渗透水压的增大而增大,即启动的时间点更提前,排水条件下砂岩的径向启动应力水平、轴向启动应力水平均高于不排水条件下的值,平均分别提高了1.85%和2.21%,渗透水压相同时,不排水条件下启动应力及应力水平受水压的影响比排水条件更明显。展开更多
文摘Changes of calmodulin (CaM) distribution in the embryo sac of rice (Oryza sativa subsp. Japonica) at various stages before and after fertilization have been investigated by using immunogold electron microscopy. Before pollination, both cytoplasm and vacuoles of the egg cell, synergids and central cell were labeled by gold particles. A small amount of gold particles were localized in the nucleus, endoplasmic reticulum, mitochondria and dictyosomes. From pollination to fertilization, CaM amount increased in these cells, especially rich in the starch of amyloplasts. Increase of gold particles in the central cell began about 2 h earlier than that in the egg cell. There was no distinct difference of CaM amount between the degenerated and the persistent synergids. It is interesting to observe an obvious change of CaM distribution form during pollination and fertilization from scattered single particles to clustered particles, and back again to single particles after the fertilization finished. CaM was also localized extracellularly in the embryo sac wall as well as in the wall and intercellular space of nucellus cells. The extracellular CaM also changes in its amount and form after pollination. These results suggest that CaM, either intra- or extra-cellular, may play important roles in fertilization and zygote formation.
文摘为了研究砂岩在渗流−应力耦合作用下的变形局部化破坏特征,利用可视化三轴伺服控制试验系统,结合三维数字图像相关技术(three-dimensional digital image correlation,简称3D-DIC),开展不同排水条件下的砂岩三轴压缩试验,对岩石力学、渗流及其变形局部化特性进行分析,并利用电镜扫描对砂岩破坏后其破裂面微观形貌进行分析。结果表明:排水条件下砂岩的峰值强度和弹性模量高于不排水条件下的值,且随着渗透水压增大,砂岩的峰值强度、弹性模量和泊松比均随之增大,出现贯通裂纹的时间点和渗透率最大值出现的时间点则会提前;当渗透水压相同时,不排水条件下砂岩表面变形场云图的局部化带比排水条件下的更宽,即岩石的宏观裂纹更明显,排水条件下水流将岩石内部的矿物颗粒带走,形成孔洞,其破裂面的表面比不排水条件下更光滑,而不排水条件下颗粒表面明显有片状岩屑附着;所有排水条件下径向变形局部化启动点始终高于轴向变形局部化启动点,平均提高了1.23%,变形局部化径向、轴向启动应力水平均随渗透水压的增大而增大,即启动的时间点更提前,排水条件下砂岩的径向启动应力水平、轴向启动应力水平均高于不排水条件下的值,平均分别提高了1.85%和2.21%,渗透水压相同时,不排水条件下启动应力及应力水平受水压的影响比排水条件更明显。
