Production of submerged aquatic plant communities of Doodhadhari lake Raipur, (M.P. India)

The biomass of submerged aquatic plant communities was studied periodically during two annual growth periods. Najas minor contributed 78% to the total standing biomass. Ceratophyllum demersum, Hydrilla, Nelumbo nucifera, Trapa bispinosa and Potamogeton crispus contributed towards the rest of the biomass. The production was 0.64 g./m.²/day for the growing seasons of one year.     

人工降雨对湿地植物叶表面颗粒物滞留的影响

现阶段植物滞尘作为治理大气颗粒物污染的有效方法已被广泛接受与应用。已有研究表明,降雨等方式对植物叶表面颗粒物的滞留有着显著的影响,可有效地将颗粒物从叶表面去除,使植物再次具有滞留颗粒物的能力。由于自然降雨难以量化,现有研究大多采用模拟降雨的方式,将降雨特性量化为降雨强度、降雨历时等可控变量,但较少将降雨高度这一变量纳入研究。且大多以森林生态系统或者城市生态系统中常见的乔、灌、草等植物为主要研究对象,而忽略了处于水陆过渡带的湿地生态系统中植物的特殊性。湿地生态系统不仅可通过植物叶片等结构滞留颗粒物,还可依靠增强空气相对湿度促进颗粒物的吸收和积累,导致湿地植物滞尘规律的特殊性。因此,选择北京地区湿地生态系统内的4种常见植物（香蒲、菖蒲、芦苇和黄花鸢尾）作为研究对象,通过人工模拟降雨的方式,将降雨特性量化为降雨高度与降雨强度两个变量,共设置1 m （11 m）、2 m （10 m）两个不同降雨高度,30 mm/h、45 mm/h、60 mm/h三种不同降雨强度,并将颗粒物划分粗颗粒物（10—100 μm）、细颗粒物（3—10 μm）、超细颗粒物（0.4—3 μm）三种粒径范围。通过滤膜法获得单位叶面积颗粒物去除量,探讨人工降雨对湿地植物叶表面颗粒物滞留的影响。主要研究结果如下：（1）颗粒物去除量在粗颗粒物（10—100 μm）粒径范围内最高;（2）所试4种湿地植物中,菖蒲的颗粒物去除量位居前列;（3）只有在一定的范围内,植物叶表面颗粒物去除量才随降雨强度的增加而增加;（4）不同降雨高度下所试湿地植物叶表面颗粒物去除量无明显规律,降雨高度之间无显著差异（P>0.05）。     

城市建成区自生草本植物群落的物种多样性与功能多样性——以深圳市为例

城市自生草本植物的物种多样性和功能多样性直接影响城市生态系统的功能和稳定性,但目前相关研究依然很缺乏。以深圳市为例,基于建成区600个1hm²样地的现场调查数据,分析自生草本植物的群落结构、物种多样性、群落功能特征及功能多样性。结果显示:①调查共记录自生草本植物61科178属273种,其中多年生草本占54.6%,乡土植物占65.6%。②占明显优势的功能特征有中小型叶(91.85%)、草质叶(42.59%)、纸质叶(32.96%)、叶片无毛或近无毛(56.67%)、中等密度绒毛(40.37%)、叶面较粗糙(52.59%)、花期4-6个月(50.78%)、果期4-6个月(49.22%)、干果(86.03%)。③群落类型间功能丰富度FDp、功能离散度Rao二次熵差异极显著(P ＜ 0.01)、功能均匀度FEve差异显著(P ＜ 0.05)。④公园绿地的物种多样性指数明显高于其他三类绿地;不同绿地类型间的功能丰富度和功能离散度在滞尘、降噪、降温增湿及生物多样性保护方面都有极显著差异(P ＜ 0.01),功能均匀度只在滞尘及生物多样性保护方面差异极显著(P ＜ 0.01)。⑤各功能多样性指数均与Margalef指数、Simpson指数及Shannon-Wiener指数呈极显著正相关关系(P ＜ 0.01)。研究结论和方法为维护城市生态系统稳定性、建设生态宜居城市、促进城市可持续发展提供理论依据。     

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.     

Effect of temperature on the progamic phase in high-mountain plants

Progamic processes are particularly temperature-sensitive and, in lowland plants, are usually drastically reduced below 10 °C and above 30 °C. Little is known about how effectively sexual processes of mountain plants function under the large temperature fluctuations at higher altitudes. The present study examines duration and thermal thresholds for progamic processes in six common plant species (Cerastium uniflorum, Gentianella germanica, Ranunculus alpestris, R. glacialis, Saxifraga bryoides, S. caesia) from different altitudinal zones in the European Alps. Whole plants were collected from natural sites shortly before anthesis and kept in a climate chamber until further processing. Flowers with receptive stigmas were hand-pollinated with allopollen and exposed to controlled temperatures between -2 and 40 °C. Pollen performance (adhesion to the stigma, germination, tube growth, fertilisation) was quantitatively analysed, using the aniline blue fluorescence method. Pollen adhesion was possible from -2 to 40 °C. Pollen germination and tube growth occurred from around 0 to 35 °C in most species. Fertilisation was observed from 5 to 30-32 °C (0-35 °C in G. germanica). The progamic phase was shortest in G. germanica (2 h at 30 °C, 12 h at 5 °C, 24 h at 0 °C), followed by R. glacialis (first fertilisation after 2 h at 30 °C, 18 h at 5 °C). In the remaining species, first fertilisation usually occurred after 4-6 h at 30 °C and after 24-30 h at 5 °C. Thus, mountain plants show remarkably flexible pollen performance over a wide temperature range and a short progamic phase, which may be essential for successful reproduction in the stochastic high-mountain climate.     

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。