Shared patterns of species turnover between seaweeds and seed plants break down at increasing distances from the sea

We tested for correlations in the degree of spatial similarity between algal and terrestrial plants communities along 5500 km of temperate Australian coastline and whether the strength of correlation weakens with increasing distance from the coast. We identified strong correlations between macroalgal and terrestrial plant communities within the first 100 km from shore, where the strength of these marine–terrestrial correlations indeed weakens with increasing distance inland. As such, our results suggest that marine‐driven community homogenization processes decompose with increasing distance from the shore toward inland. We speculate that the proximity to the marine environment produces lower levels of community turnover on land, and this effect decreases progressively farther inland. Our analysis suggests underlying ecological and evolutionary processes that give rise to continental‐scale biogeographic influence from sea to land.     

兰州盆地早第三纪植物及古气候意义

化石采自甘肃省兰州盆地咸水河组底部,经研究认为有29种,归属20属12科。它们是：樟科 Lauraceae (Daphnogene),木通科Lardizabalaceae(Akebia),小檗科Berberidaceae(Berberis),榆科Ulmaceae (Planera,Ulmus,Zelkova),桦木科Betulaceae(Alnus,Carpinus),杨梅科Myricaceae(Myrica),杨柳科Sali- caceae(Populus,Salix),紫金牛科Myrsinacese(Ardisia),蔷薇科Rosaceae (Prunus,Sorbus,Sorbaria,Spir- aea),豆科Leguminosae(Gleditsia,Sophora),漆树科 Anacardiaceae(Rhus),忍冬科Caprifoliaceae(Viburnum) 等。经植物区系组成与叶相分析显示,该植物区系的大多数成员是落叶阔叶乔、灌木,少数为常绿灌木。其中特殊的分子是 Rhus turcomanica Korov．ex Vassilvesk,该成分是早第三纪中、晚期的标志化石植物。另一化石植物 Sorbaria callicomifolia Kornilova曾出现在中亚的早渐新世,最晚至早中新世。同一层位采集的孢粉样分析结果显示：该组合仅约20种,种类相对贫乏,并以被子植物的花粉占优势。其中出现裸子植物的麻黄粉,被子植物的白刺粉及蒿粉等,这几个类型均指示沉积时期经历干旱气候。综合植物大化石及孢粉分析研究,均出现一些指示气候为亚热带干旱或周期性干旱气候的特点,并据Rhus turcomanica出现的最晚记录,推测咸水河组底部的地质时代大约是早渐新世晚期。     

中国南部石灰岩濒危植物的初步研究

本文所说中国南部石灰岩地区主要指广西、云南、贵州三省的石灰岩地区,这一地区以其植物的多样性和岩溶特有性而闻名。本文对这一地区的植被和植物保护现状、自然屎护区状况、植物濒危原因筹进行了初步考察和研究。     

Plants and insects in early old-field succession: comparison of an English site and an American site

The plant and insect communities of early, secondary succession beginning with bare ground in an Old World site (southern Britain) and a New World site (Iowa, U.S.A.) shared a number of characteristics. Both sites showed similar temporal patterns of plant species cover and species richness, although overall richness was greater at the Old World site. Annuals dominated at both sites during the first year of succession and were largely replaced by perennials in the second year. Monocotyledons were more abundant at the Old World site, especially in the second year. The two sites differed markedly in the contribution of native and introduced plant species, with the Old World site dominated by natives and the New World site by alien plant species. Insect herbivore load was greater at the Old World site, when expressed in terms of structural complexity of the vegetation, suggesting that there may be major differences in the influence of herbivores on the direction and rate of succession at the two sites.     

草莓花药培养获得无病毒植株的技术研究

以花粉发育为单核期的花药接种,在MS附加IAA 4ppm、K 2ppm、BA 2ppm的培养基上诱导愈伤组织,并可直接分化出“沙尔普斯”、“红岗利德”、“春香”3个品种的花药植株。稍加调整附加激素成分和浓度,可在“索非亚”、“宝交早生”、“戈雷拉”、“红衣”、“丽红”等品种的花药上直接经愈伤组织分化出植株。其中有“沙尔普斯”、“红岗利德”、“春香”、“宝交早生”、“索非亚”等5个品种的花药植株经过病毒检测确认不带SMoV、SCrV、SMYEV和SVBV4种病毒。对无病毒植株进行了田间对比试验,植株生长势和果实产量都明显超过对照品种。     

Plant life on gypsum: a review of its multiple facets

The adaptation of plants to particular soil types has long intrigued biologists. Gypsum soils occupy large areas in many regions of the world and host a striking biological diversity, but their vegetation has been much less studied than that developing over serpentine or saline soils. Herein, we review all aspects of plant life on gypsum ecosystems, discuss the main processes driving their structure and functioning, and highlight the main conservation threats that they face. Plant communities in gypsum habitats typically show distinctive bands at very small spatial scales, which are mainly determined by topography. Plants living on gypsum soils can be classified into three categories: (i) wide gypsophiles are specialists that can penetrate the physical soil crust during early life stages and have physiological adjustments to cope with the chemical limitations imposed by gypsum soils; (ii) narrow gypsophiles are refugee plants which successfully deal with the physical soil crust and can tolerate these chemical limitations but do not show specific adaptations for this type of soils; and (iii) gypsovags are non‐specialist gypsum plants that can only thrive in gypsum soils when the physical crust is absent or reduced. Their ability to survive in gypsum soils may also be mediated by below‐ground interactions with soil microorganisms. Gypsophiles and gypsovags show efficient germination at low temperatures, seed and fruit heteromorphism within and among populations, and variation in seed dormancy among plants and populations. In gypsum ecosystems, spatio‐temporal changes in the composition and structure of above‐ground vegetation are closely related to those of the soil seed bank. Biological soil crusts (BSCs) dominated by cyanobacteria, lichens and mosses are conspicuous in gypsum environments worldwide, and are important drivers of ecosystem processes such as carbon and nitrogen cycling, water infiltration and run‐off and soil stability. These organisms are also important determinants of the structure of annual plant communities living on gypsum soils. The short‐distance seed dispersal of gypsophiles is responsible for the high number of very narrow endemisms typically found in gypsum outcrops, and suggests that these species are evolutionarily old taxa due to the time they need to colonize isolated gypsum outcrops by chance. Climate change and habitat fragmentation negatively affect both plants and BSCs in gypsum habitats, and are among the major threats to these ecosystems. Gypsum habitats and specialists offer the chance to advance our knowledge on restrictive soils, and are ideal models not only to test important evolutionary questions such as tolerance to low Ca/Mg proportions in soils, but also to improve the theoretical framework of community ecology and ecosystem functioning.     

植物转录抑制子的结构特征及其作用机理

转录因子依转录调控能力可分为激活子和抑制子。植物转录抑制蛋白的分类依据很多,从作用方式上可分为主动抑制子和被动抑制子两大类：根据与DNA结合的方式则可分为锌指类、MYB类、AP2／EREBP类、bHLH类和bZlP类等。植物主动抑制子通过其含有的抑制域对转录直接起抑制作用。抑制域又可分很多类,但多数为含有类似EAR基序的保守性基序,其上具有几个保守性亮氨酸残基。植物转录抑制子主要通过对激活子或基本转录复合物产生作用及改变染色体结构3种方式来抑制目标基因的转录。有关植物转录抑制子的研究虽很欠缺,但以拟南芥SUPERMAN等抑制子的EAR基序为代表的研究表明,抑制域是阐明植物转录抑制子功能和下游基因表达调控机理的核心对象,而融合抑制子沉默技术（CRES-T）也为人为调控基因沉默带来了新的技术手段。     

紫茎泽兰叶片水浸液对蚕豆的化感效应

外来入侵植物可以通过淋溶、自然挥发、根系分泌和植株凋落物分解等途径向周围环境释放化感物质,抑制伴生植物的生长、发育。该研究以不同浓度紫茎泽兰(Eupatorium adenophorum)叶片水浸液处理蚕豆(Vicia faba)种子,研究紫茎泽兰叶片水浸液对蚕豆根尖细胞微核、染色体畸变、细胞凋亡、蚕豆幼苗叶片叶绿素和N含量、光合生理特性、生物量的影响。结果表明:(1)紫茎泽兰叶片水浸液处理显著抑制蚕豆根尖的伸长和细胞的有丝分裂,并诱导蚕豆根尖细胞染色体畸变和细胞微核的产生,有丝分裂指数随着叶片水浸液浓度增加而减小,根尖细胞微核率随叶片水浸液浓度增加而增大,高浓度叶片水浸液处理对蚕豆根尖细胞的凋亡及坏死有明显影响。(2)紫茎泽兰叶片水浸液处理引起蚕豆幼苗叶片的叶绿素和N含量显著降低,并导致蚕豆幼苗最大净光合速率和生物量的显著下降。总之,紫茎泽兰叶片水浸液可能引起蚕豆根尖的氧化损伤和抑制根尖的伸长,且叶片水浸液的抑制作用呈现一定的剂量效应。紫茎泽兰叶片水浸液对蚕豆根尖的损伤和抑制作用可能影响了植株对氮素的吸收,进而对蚕豆幼苗光合生理表现以及生物量积累产生显著负面效应。