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This paper reports chromosome number and karyotype analysis of
Cycas panzhihuaensis endemic to China. The material was collected from Dukou, Sichuan. It is a diploid species, with 2n=22=2m+4sm+4st+l2t. The karyotype of Cycas
panzhihuaensis is different from that of the other species of the genus Cycas, which
was known to be 2n=4m+8st+10t. The former is a new karyotype in the genus. The
authors briefly discuss karyotype evolution of the genus Cycas in this papar. 相似文献
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德保苏铁居群特征及保护措施 总被引:3,自引:0,他引:3
报道了德保苏铁(CycasdebaoensisY.C.ZhongetC.J.Chen)的居群结构调查情况,并与百色地区林业局1998年的调查结果进行比较。结果表明,德保苏铁分布区狭窄,仅产于广西壮族自治区德保县扶平乡约15.3hm2的石灰岩山坡;由于人为原因,其数量已从1998年的2000多株锐减到2001年的1085株,尤其是成年植株数量剧减,由此导致年龄结构趋于幼年化,呈现正金字塔的假象;雌雄比从1∶10变为1∶5,这些现状表明德保苏铁的保护刻不容缓。 相似文献
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The population of cone-bearing cycad, Cycas panzhihuaensis L. Zhou et S. Y. Yang, was male-biased. Although the number of male individuals was almost equal to that of female individuals, the clonal and cone production of male individuals was 1.31 and 2.21 times as much as that of female individuals respectively. The sequence of pollen shedding was from the base to the top of the cone and microsporophyll. The peak of daily pollen shedding occurred at noon and in the afternoon. The airborne pollen concentration decreased quickly within 2.55 m and finally maintained at a low level along with the distance from emitting male cone. The megastrobilus was transformed into a receptive state at the beginning of pollination due to the regular morphological changes of megasporophylls. Two kinds of ants and one kind of cockroaches were found to be active within the megas- trobili during pollination, albeit causing no tissue damage. The microstrobili gave off a strong odor of fennel that could dispel all the insects nearby. The sterile foliar structure of the megasporophyll was able to secret aqueous droplets at dawn which might function as transporting adhered pollen grains by dislodging and accumulating them on or near micropyles during the process of droplets falling. Resuits from field observation showed that pollination of C. panzhihuaensis might be accomplished by different pollinators. Pollen grains were firstly wind-transported from microstrobili to megastrobili and then insects and secreted droplets on the megasporophyll either directly or indirectly carried the pollen grains to ovules within a megastrobilus. However, insects might play as a subsidiary pollinator due to the preferential concentration of airborne pollen grains transported to the megasporophylls. 相似文献
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Cycas debaoensis is one of the critically endangered cycad species endemic to China. In this study, we described the development of six microsatellite markers from the genome of C. debaoensis using the protocol of fast isolation by AFLP of sequences containing repeats (FIASCO) and two microsatellite markers derived from the database of expressed sequence tags (dbEST). Polymorphism of each locus was assessed in 60 adult individuals of the cycad. The average allele number of the microsatellites was 2.6 per locus, ranging from two to five. The observed and expected heterozygosities varied from 0.0833 to 0.7333 and from 0.0805 to 0.7188, respectively. Despite its rarity, only one locus (Y177) deviated from Hardy-Weinberg equilibrium due to the excessive homozygosity. The marker transferability of the eight primer pairs was tested on other four congeneric species that also occur in China. 相似文献
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Min Zhang Zheng-Feng Wang Shu-Guang Jian Wan-Hui Ye Hong-Lin Cao Peng Zhu Ling Li 《Conservation Genetics》2009,10(4):1175-1176
Cycas hainanensis is an endangered cycad species endemic to Hainan Island, China. To enrich our scientific conservation for this species, we
developed eight microsatellite markers using repetitive DNA enriched libraries. The number of alleles per microsatellite locus
varied from 8 to 17. The expected (H
E
) and observed (H
O
) heterozygosities varied from 0.4754 to 0.8846 and from 0.3636 to 0.9600, respectively. These markers will be employed to
determine whether the ex situ C. hainanensis individuals in Sourh China Botanical Garden capture a representative portion of genetic diversity of the wild populations. 相似文献
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<正> 杏黄兜兰Paphiopedilum armeniacum S. C. Chen et F. Y. Liu是一种珍贵的兰科植物。分布于云南碧江县,生于岩壁上。是我国植物学家张敖罗于1979年7月采到,1982年经陈心启和刘芳媛定名的新种。属名Paphiopedilum 源自希腊字paphio(维纳斯的形容词)和pedilum(拖鞋),用以形容该属植物状若拖鞋的唇瓣。种加词armeniacum在拉丁语中为“杏树”,这里意为“杏黄色的”,该词另一个意思是“亚美尼亚(西亚的一个国名)的”。1992年2月杏黄兜兰在昆明市园林局主办的云南兰花展览会 相似文献
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P. Vorster 《植物分类学报:英文版》1997,35(6):550-551
The names Cycas hongheensis and C. parvula were not validly published in 1994 when they were first proposed, but were validated in 1996 by a different author. 相似文献
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对台湾苏铁Cycas taiwaniana的形态特征、分布和模式产地做了增补和修订。目前台湾苏铁仅分布在我国福建省的中南部,且仅有一株野生植株生长在平和县。台湾苏铁的模式株仍生长在漳州市陈元光庙前。 相似文献
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青城细辛的花器官发生 总被引:1,自引:0,他引:1
利用扫描电镜观察了青城细辛(Asarum splendens)的花器官发生过程。青城细辛的花器官为轮状结构,向心发生,依次为两轮3基数的花被原基,两轮6基数的雄蕊原基和一轮6基数的心皮原基。两轮花被原基互生,只有外轮(先发生的一轮)花被原基完全发育,而内轮(后发生的一轮)花被原基在发育过程中逐渐退化。两轮雄蕊原基为离心发生:位于内侧的一轮雄蕊原基先发生,每两个原基正对第一轮发生的花被原基,外侧的一轮雄蕊原基后发生,与内轮雄蕊原基互生。心皮与内侧的一轮雄蕊互生。 相似文献
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LIU Nian 《植物分类学报:英文版》1998,36(6):552-554