太原东山二叠纪地层中发现最古老大孢子“球果”及其进化意义     

焦建伟 《华北地质矿产杂志》1997,12(4):315-318

与轴相连的苏铁大孢子叶第一次发现太原东册的下二叠系地层中，它出现如此之早，表明这种球果状的结构可能是所有苏铁类雌性生殖器官的祖先形式，苏铁也可能通过古地中海洋流从华北迁移到欧洲。  相似文献   

最古老的被子植物——具三心皮结构的生殖器官化石   总被引：6，自引：0，他引：6  

段淑英 《中国科学D辑》1997,(6)

被子植物雌性生殖器官化石采自辽宁省西部朝阳地区中生代的义县组,其地质时代属于晚侏罗世,这是迄今所知最古老的被子植物化石.化石为具3数花的聚伞花序,有明显的三心皮结构:即3个分裂的柱头和花柱各与1个子房相连,在早期被子植物化石中尚无可比较的属种.确定为1个新属种,名为:梁氏朝阳序Chaoyangia liangii Duan gen.et sp.nov.  相似文献   

小孢子化石鉴定煤层的价值     

斯行健 《地质论评》1951,16(Z1):52-60

所谓孢子广义的讲,是植物的生殖器官。古生代及中生代的煤层中的孢子化石,除去极少数的例外,都是属於维管束植物的。所有维管束植物都产生孢子以及和孢子同等的花粉等等。孢子可分为两种:(1)同子孢子(homosporous spores),所有的孢子,都是同样大小的。(2)异子孢子(heterosporous spores),小孢子是雄性的,内藏雄器,其中生精虫;大孢子是雌性的,内藏雌器,其中生卵球。古生代煤层中的孢子化  相似文献   

煤中一种植物生殖器官残体及其地质研究的意义          下载免费PDF全文

王士俊  霍占刚 《地质论评》1995,41(6):559-563

本文报道了发现于我国晚三叠世，侏罗纪及第三纪煤中一种植物生殖器官残体，它们类似于蕨类植物的大孢子，壁的表面具网状纹饰，但无单缝或三缝构造，有证据表明它们是裸子植物种子内的大孢子，这也是国内首次报道煤中的这种残体，利用生物显微镜和扫描电镜对上述各时代煤中的裸子植物大孢子壁的显微及来显微构造进行了初步研究，并就其所具有的古植物学，煤岩学和石油地质学意义进行了讨论。  相似文献   

Effects of Aroclor 1254 on reproductive organ weight, sperm quality and testicular mitochondria oxidative stress of Boleophthalmus pectinirostris     

HE Shanying  WU Qiuling  SUN Mengdie 《海洋学报(英文版)》2011,30(6):65-71

Boleophthalmus pectinirostris is an amphibious economic fish and wildly distributed in the southeast coast of China. In this study, Aroclor 1254 was intraperitoneally injected into B. pectinirostris with 1, 2 and 4 μg/(g·d) for 28 d to assay the reproductive organ weight, the sperm quality (sperm concentration and motility), and the testicular mitochondrial testicular mitochondria oxidative stress. The results show that the sperm number and motility in seminal vesicles, the absolute weight of testes and seminal vesicles of B. pectinirostris treated with 2 and 4 μg/(g·d) Aroclor 1254 decreased significantly as compared to the controls (p <0.05), while those treated with 1 μg/(g·d) Aroclor 1254 had no significant effects on these indictors. For the relative weight of reproductive organs, significant reduction (p <0.05) was only observed in the seminal vesicles of B. pectinirostris treated with 4 μg/(g·d). SOD activities and GSH levels in all the Aroclor 1254 treatments were significantly lower than those of the controls (p <0.05). The activities of CAT, GPx, GR and the levels of Vit C also decreased significantly in comparison with the controls (p <0.05) at the higher dose of 2 and 4 μg/(g·d) Aroclor 1254 treatments. In addition, both H₂O₂ level and MDA content in testicular mitochondria of B. pectinirostris had a close correlation with Aroclor 1254 dosage, and were significantly higher than the controls (p <0.05). Those indicate that Aroclor 1254 can induce the oxidative stress of testicular mitochondria, and impair the reproductive function of male B. pectinirostris.  相似文献   

蜈蚣藻中空变型Grateloupia filicina f．porracea（Mert·）Howe生殖器官的研究     

李伟新 《广东海洋大学学报》1984,(1):37-40

本种为青岛港及黄渤海沿岸常见种，此外也产于日本及西印度等地。曾呈奎等(1962)曾描述过产于青岛港的本种形态构造。作者自1977年开始在青岛港采到大量本种标本，同时也研究了它的形态构造及其生殖器官的系统发育过程，现报导如下：  相似文献