中国特有种大理白前对高寒环境的形态适应特征

高寒草甸具有辐射强、低气压、风大、昼夜温度骤变等不利于植物生长的环境特征,为了探讨中国特有种大理白前(Cynanchum forrestii)对高寒环境的生态适应,以川西南九龙县高寒草甸(海拔3 100~3 500 m)的大理白前为对象,采用光学显微镜技术和扫描电镜技术研究了大理白前的形态解剖特征,并采用TCC法分析了花粉和种子的生活力。结果表明:大理白前的叶、茎、花均被有丰富的单列细胞组成的表皮毛;叶片和茎的表皮角质层较厚;叶的气孔较大而下生,栅栏组织和海绵组织发达;茎表皮细胞小、细胞壁厚,皮层由7层细胞组成,排列紧密,细胞内储藏有丰富的物质,维管柱所占比例较大,木射线数量较多,髓部发达且储藏物质丰富;根维管组织发达,皮层细胞储藏有丰富的物质;种子和花粉活力较高、合生花冠、合蕊柱、种子具有种毛,以及种皮厚而坚硬等特征为提高繁殖效率提供了保障。上述结果表明,大理白前具有一整套适应高寒环境的外部形态和内部结构特征,使其保持较高的抗辐射、抗旱和抗寒能力,为大理白前在高寒环境中成功生存和繁衍奠定了结构基础。

Research on Pollen Grains of Tetraploid Lines and Diploid Control Line of Chrysanthemum cinerariifolium (Trev.) Vis.

[Objective] The aim was to study characters of pollen grains of tetraploid lines and diploid control line of Chrysanthemum cinerariifolium (Trev.) Vis.,morphological characters,fertility of pollen grain and germination percentage of seeds. [Method] Pollen grains were prepared by sulphuric acid-acetyl oxide decomposition method. The lengths of polar axis and equatorial axis of pollen grains were determined with general optical microscope. The morphology of pollen grains was observed with SEM (scanning electron microscope) and the typical visual fields of 2 500× (or 2 000×),7 000× were taken pictures. [Result] Comparing with the diploid control line,the pollen grains of five tetraploid lines which were tested were different from the diploid line in morphology,sculpture,etc.. 4 of the 5 tested samples were significant larger than the diploid line in size and one was similar to the diploid line. [Conclusion] This research provided references for breeding tetraploid improved varieties of Chrysanthemum cinerariifolium (Trev.) Vis. with good fertility and high germination percentage.

Analysis of Fertility Differences of Peiai 64S in Hunan and Hainan

[Objective] The purpose was to study and analyze the difference of Peiai 64 S fertility expression in two different climatic regions, Hainan and Hunan in 2010, and confirm the suitable region for its production of hybrid seeds. [Method] Eight sowing times were designed, March 20 and 30, April 10 and 30, May 15, June 1, 10 and 20, respectively in Changsha of Hunan. Thirteen sowing times were designed in Hainan, January 28, February 12 and 27, March 14 and 29, April 13 and 28, May 13 and 28, June 12, July 1, 12 and 27, respectively. Peiai 64S was gradually managed and recorded heading stage during cultivation, and the effects of different climate influencing factors, such as daily mean temperature, daily maximum temperature, daily minimum temperature, duration of day at 0-25 d before heading （namely pollen mother cell meiophase）, on pollen fertility were analyzed to confirm sensitive periods of light and temperature. [ResuLt] There was a big difference in sensitive period among the same cytoplasmic male sterile （CMS） in different climatic regions. The sensitive period of Peiai 64S was in first four phases, phases V, VI, VII, VIII （0-13 d） in Changsha of Hunan, which was in last four phases, phases I, II, III, IV （13-25 d） in Haikou of Hainan. Under natural conditions, Peiai 64S pollen sterility rate were all more than 99.5% and seed-setting rates all less than 0.5% in Haikou, so production of hybrid seeds was safe. Its pollen sterility rate was 21.3%- 100.0% in Hunan, so its security coefficient of hybrid seeds production was lower than that in Hainan. [Conclusion] The security coefficient of hybrid seeds production of CMS Peiai 64S is lower than that in Hainan.

攀枝花苏铁分布区地质、第四纪冰川及苏铁渡冰河期之谜的探讨

攀枝花苏铁渡第四纪冰期之谜?应用"小区气候假说"或"植物南移假说"均难以作出合理的解析。本文在综合研究攀枝花苏铁生物学特征、攀枝花地质、古生物、第四纪冰期的基础上,认为攀枝花苏铁是古苏铁植物种群中某一属种演比衍生的物种。第四纪冰期临近时一些种子和孢子花粉落入溶洞中,在适宜於休眠的环境条件下处休眠状态。冰川消退后。少数溶洞随 U 形谷陡壁崩塌而破坏.种子和孢子花粉逸出。其中个别萌发长成植株,繁衍而成现存的攀枝花苏铁种群。

陇东地区新石器时代的早期农业及环境效应

通过陇东地区新石器时代2处文化层剖面及5处文化点的花粉、炭屑、种子的综合研究,重建了陇东地区新石器时代农业发展过程及其环境效应.研究显示,陇东地区早期农业经历了由单一黍作农业向黍、粟混作,并结合水稻、大豆等多样化农业发展过程.旱作农作物黍在仰韶文化早,中期占有绝对的优势,而粟在仰韶文化晚期开始明显增加,在齐家文化时期达到最大值.陇东地区仰韶文化晚期大豆开始栽培,稻作农业在陇东地区出现不晚于4800cal a BP,并延续到约4000cal a BP的齐家文化.新石器时代陇东黄土高原塬面以灌丛草原植被为主,沟谷地带存在云杉-铁杉-栎为主的针阔叶混交林,新石器时代农业活动减少自然植被盖度,促使灌丛草原趋向于单一的蒿属草原.农业活动减弱或消退后,以沙棘、蔷薇科、麻黄、豆科、蒿属、藜科为主的灌丛草原植被得以恢复.

Mating patterns and pollen dispersal in a Japanese larch(Larix kaempferi) clonal seed orchard： a case study

Pollination dynamics highly determines the genetic quality of seed orchard crops. However, there is less research about the effect of mating patterns on seed productivity of orchard crops. So far, clonal seed orchards have been producing genetically improved seedlings used for most Japanese larch(Larix kaempferi(Lamb.) Carr.) plantations in China. In the present study, a total of 17 highly variable simple sequence repeat(SSR) markers were used for genotyping a progeny trial population consisting of 647 open-pollinated progenies germinated from seeds which were collected from 63 maternal clones with 140 potential paternal clones in a Japanese larch clonal seed orchard in China. Paternity analysis was used in the present case study in order to evaluate the level of paternal gametic contribution, estimate pollen contamination and selfing rates, and investigate pollination patterns,pollen dispersal patterns and the impact of mating patterns on seed productivity of orchard crops. We observed 93.7% of the success rate of the parental assignment, unequal paternal gametic contribution(0–12.4%) with 6.3% of the progenies derived from pollen contamination or unsampled pollen donors, and absence of evidence for selfing. We also found that pollination rate highly depended on the distance between pollen donors and maternal parents, the majority of the identified crossing(65.7%)occurred between clones within a 150-m radius, and large variations in growth performance existed among the paternal halfsiblings. Progeny growth performance(diameter at breast(DBH) and height(HGT)) was measured at Age-20 in order to investigate the impact of mating patterns on timber production of orchard crops. As either the paternal or maternal, two clones(i.e., clones Z38 and Z62) were identified to have produced progenies with higher average stem volume breeding values than that of all of the progenies. Specifically, the genetic gains for volume were 3.53% for the two clones as paternal parents, and 8.26% as the maternal parents at Age-20. Thus, both elite clones were ideal candidates for the construction of next-generation clonal seed orchards due to their synchronous reproductive phenology with greater crossing rate and higher genetic gain. These results improved the pedigree information to provide solid evidence of mating patterns for future design and effective management of seed orchards and for the development of viable long-term breeding strategies for other coniferous species.