生物土壤结皮与种子附属物对4种荒漠植物种子萌发的交互影响

生物土壤结皮能直接或间接地影响维管植物种子萌发与群落建成,种子本身的生物学特征（如种子附属物等）对萌发也存在一定影响。本研究选取古尔班通古特沙漠4种常见的具有不同形态附属物的藜科植物（梭梭（Haloxylon ammodendron ）、粗枝猪毛菜（Salsola subcrassa ）、心叶驼绒藜（Ceratoides ewersmanniana ）和角果藜（Ceratocarpus arenarius ））种子,设置苔藓结皮、地衣结皮和裸沙3种土壤基质,通过去除或保留种子附属物,对比研究了生物土壤结皮与种子附属物对种子萌发的影响。结果表明：粗枝猪毛菜和梭梭的苞片显著抑制了种子萌发（p <0.05）,心叶驼绒藜的柔毛和角果藜的刺状附属物对种子萌发没有显著影响（p >0.05）。与裸沙相比,苔藓结皮显著抑制了4种植物种子的萌发（p <0.05）,地衣结皮显著抑制了粗枝猪毛菜种子的萌发（p <0.01）,而对其他3种植物种子的萌发无显著影响（p >0.05）。同时,附属物与结皮对粗枝猪毛菜种子的萌发还具有交互作用,表现为显著抑制种子萌发（p <0.01）。可见,生物土壤结皮对具有不同附属物的荒漠植物种子萌发具有不同的影响,进而造成维管植物种子萌发的空间异质性,影响维管植物分布和多样性。     

辽宁本溪早石炭世植物化石

华北与东北南部地区缺失晚奥陶世至中石炭世早期地层(个别地点除外),这一论点长期以来已被中外地质学家所公认。本溪组自1926年创名以来,一直被认为属于中石炭世晚期(莫斯科期)。50年代中期,张文堂提出的论断,因无生物化石佐证,迄今未得到承认。80年代以来,吴秀元、赵修祜和刘发先后指出本溪田师付本溪组下部产纳缨尔期(或中石炭世早期)蜓和腕足类化石。 本文描述了辽宁本溪本溪组下部G层铝土矿顶板黑色页岩中所产植物化石7属12种,认为其时代为早石炭世晚期(维宪期—纳缪尔A期)。     

Effects of non-carbonaceous meteoritic extracts on the germination, growth and chlorophyll content of edible plants

We have conducted an investigation on the effects that the extracts of a non-carbonaceous meteorite could have on the germination and growth of plants and the ability of non-carbonaceous meteoritic resource to serve as nutrient source for young plants of edible types. Selected plants were two dicotyledons (Lycopersicon esculentum and Daucus carota) and one monocotyledon (Zea mays). Solution cultures were developed using seeds, seedlings and seed-embryos. Meteoritic powder was obtained from the Vigirima mesosiderite, which was analyzed by X-ray diffraction and atomic absorption spectrometry (AAS). Results showed that extracts having variable concentrations of meteoritic matter favored an earlier germination in some plant species but the increase of the concentrations produced a decreased germination. However, total germination rate was higher in the presence of meteoritic extracts than in the presence of controls in the all species. A high metabolic yield in the protein synthesis was seen in dicotyledons utilizing Type-A and B extracts having concentrations of 4.16-8.33×10³ mg l⁻¹. Phaeophytinization index and chlorophyll a/b ratio, suggesting a negative effect of the heavy metals or acidic ions over the photosynthetic activity when extracts having high meteoritic concentrations were utilized. However, a higher chlorophyll (a) production in comparison to that of chlorophyll (b) was seen in extracts (Type-A and -B) with low concentrations of meteoritic matter. On the other hand, Z. mays seed-embryos growing in extracts (Type-D) having 3.53×10⁴ mg l⁻¹ of meteoritic matter showed a protein production (9.81×10⁻² mg protein mg wet wt⁻¹) higher than that observed in seed-embryos coming from extracts having lower concentrations. However, in Murashige medium, the seed-embryos exhibited a enhanced growth and a relatively higher protein production (10.3×10⁻² mg protein mg wet wt.⁻¹). Further, chlorophyll (a+b) synthesis was higher in Murashige medium than in meteoritic extracts but chlorophyll a/b ratio was <1 in all extracts and controls. Our results suggest the usefulness of the non-carbonaceous meteoritic resource as a complementary soil component or fertilizers for culture of edible plants in space settlements and mainly for the production of young plants due to the positive metabolic effects on the chlorophyll synthesis, mitochondrial metabolism and cellular division caused by PO₄³⁻, Fe²⁺, Cu²⁺ and Ca²⁺ ions. Earlier germination responses obtained in the present experiments demonstrated the possibility to utilize germination chambers in space having wet substrates containing meteoritic-powder solutions to obtain a higher number of seedlings in a minimum degree of time. These results also reveal the biological potential of this non-carbonaceous meteoritic matter for the growth of organisms in the early Earth, Mars, and probably in other planetary bodies beyond our Solar system.     

鲜切花高产优质气象影响因子分析

以主要鲜切花品种马蹄莲、香石竹为材料，用常规观测气象资料与其产量波动和质量进行相关分析。结果表明：日照时数和气温对笠年春季出花数有滞后作用。马蹄莲花茎高度与日平均气温１０～２５℃有效积温成对数关系，达优质花高度还需一定营养体大小。气温和日照时数对香石竹产量波动有一定影响     

Evapotranspiration from a wet temperate grassland and its sensitivity to microenvironmental variables

The eddy covariance and energy balance method was employed to determine evapotranspiration (LE) over a wet temperate C3–C4 co‐existing grassland in Japan. After sensible heat flux (H) was estimated via the eddy covariance technique, LE was calculated as the residual of the energy budget with calibration against the direct measurements of LE by a lysimeter. Daily mean LE varied from 0·8 to 10·5 MJ d⁻¹, with a peak at 16·5 MJ d⁻¹ in late July to early August. Day‐to‐day and seasonal variability in LE was affected appreciably by net radiation (R_n), atmospheric vapour pressure deficit (VPD), canopy surface conductance (g_c) and leaf area index (LAI). Before the canopy closure, LE responded to LAI in a linear manner. However, LE decreased with increasing LAI later in summer. Daytime variation in the decoupling coefficient (Ω) demonstrates that the canopy decoupled from the atmosphere in the morning and LE was primarily driven by the available energy, while in the afternoon the canopy partially coupled to the atmosphere so that LE was sensitive to VPD and g_c. Throughout the whole measurement period, Ω was generally larger than 0·5, suggesting that the available energy contributes more to LE than VPD. Copyright © 2004 John Wiley & Sons, Ltd.     

秦巴山地植物南北变化与过渡模式研究

秦岭—大巴山是中国重要的南北地理分界线和生态过渡带,建立秦巴山地南北方向上植物种类组成及重要值的详细变化序列和过渡模式,对于深入认识中国南北过渡带的过渡性、复杂性及暖温带与亚热带分界线具有十分重要的科学意义。本文通过野外实地调查获取秦巴山地东、中、西部3条南北穿越样线163个采样点的植被序列数据,分析了物种丰富度、相对重要值及优势种多度的纬向变化,并将亚热带与温带物种相对重要值的差值（SND-RIV）用于表现南北方物种的优势程度,以分析和归纳植物的空间变化模式。结果表明：① 东部（三门峡—宜昌）、中部（西安—达州）、西部（天水—广元）亚热带物种丰富度及相对重要值自北向南递增,温带物种自北向南递减。东部温带物种丰富度及相对重要值在神农架和伏牛山由于海拔高度的影响出现两个峰值,中部亚热带物种在大巴山地区最高,西部亚热带物种在陇南以南超过温带物种;② 东部南北方物种的交错过渡带最宽,约180 km;中部大约在秦岭南坡至大巴山北坡之间,约100 km;西部交错过渡带偏南,约50~60 km。③ 东、中、西部山地植物纬向过渡模式和驱动因子有明显差异。东、西部自南向北亚热带物种的减少主要与年均降水量减少有关,年平均气温影响较小;中部年平均气温的作用比湿润指数稍大。本文揭示了秦巴山地东、中、西部植物的南北变化及过渡模式,提升了对中国南北过渡带复杂性和多样性的科学认识。     

Geographical and Botanical Variation in Concentrations of Molybdenum in Natural Pasture Plants and Surface Water and Yak Molybdenum Ingestion in North Tibet,China

The North Tibet plateau is the world highest plateau with a unique alpine grassland and water environment. To obtain a better understanding of the correct supply of Molybdenum (Mo) to livestock in north Tibet, we investigated the content and geographical variation of Mo in different families of pasture plants (n=1017) and water (n=40), then discuss the Cuprum (Cu):Mo ratio in different plant families, and calculate the total Mo intake of the yak in north Tibet. The average Mo concentration in five families preferred for grazing are: Compositae (2.71 μg g^-1), Leguminosae (2.70 μg g^-1), Gramineae (2.48 μg g^-1), Cyperaceae (1.63 μg g^-1), and Rosaceae (1.51 μg g^-1). There was a strong geographical variation in Mo concentration (p < 0.001). The mean value of Mo in north Tibet surface water from 15 sites is 0.89 µg L^-1. The Mo ingestion by yak through these plants and water in north Tibet is about 9586 µg day^-1 which means the toxicity of Mo does not exist in the average daily diet. However, the large geographical variation found may cause some toxicity of Mo in the average daily intake of north Tibet pasture plants in some areas. The Cu:Mo ratio of 2:60 is considered the limit for risk of Mo hyperactivity, while extremely high Cu:Mo ratios may lead to chronic copper poisoning. Our survey of plant samples found 43.29% below and 29.3% above the limiting Cu:Mo ratio of 60 indicating some risk to north Tibet livestock.     

三峡库区珍稀濒危植物

三峡库区共有高等陆生植物6088种，珍稀濒危植物56种，其中Ⅰ级保护物种4种，Ⅱ级保护物种23种，Ⅲ级保护物种29种，处于濒危状态的7种，渐危状态的27种，稀有状态的22种。在分析三峡库区珍稀濒危植物种类组成、地理成分、现状分布的基础上，探讨了库区珍稀濒危植物致危原因及目前所采取的保护措施中所存在的问题，并提出了相应的保护对策。     

Typology of Municipal Wastewater Treatment Technologies in Latin America

This paper presents an analysis of the wastewater treatment plants in six Latin American and Caribbean countries. Based on a sample of 2734 municipal treatment facilities, the applied processes are classified by sizes (influent flow) and type of technologies. The distribution of the technologies is also presented for each of the six countries. In addition, a representative municipal wastewater characterization, based on influent data from 174 treatment plants, is proposed. Results show that stabilization ponds, activated sludge, and the upflow anaerobic sludge blanket reactors represent 80% of the treatment facilities of the sample, providing treatment to 81% of the total flow considered. Moreover, 67% of the plants in the sample are small (flow <25 L/s) and the very small facilities (influent flow <5 L/s) are extensively applied in the region (34% of the sample), especially in Mexico and Brazil. The use of very small treatment plants may result in low energy efficiency systems and on possible incompliance of the discharge standards. This common practice in several countries in Latin America should be revised in order to improve the environmental performance of such facilities.