Physcomitrella patens Reute mCherry as a tool for efficient crossing within and between ecotypes

• Physcomitrella patens is a monoecious moss that is predominantly selfing in the wild. Laboratory crossing techniques have been established and crosses between the sequenced Gransden ecotype and the genetically divergent Villersexel ecotype were used for genetic mapping. The recently introduced ecotype Reute has a high fertility rate and is genetically more closely related to the Gransden ecotype than the Villersexel ecotype. Reute sexual reproduction phenology is similar to Gransden, which should allow successful crossing.
• Using the Reute ecotype and an existing Gransden mutant as a test case, we applied a normalised crossing approach to demonstrate crossing potential between these ecotypes. Also, using a standard transformation approach, we generated Reute fluorescent strains expressing mCherry that allow an easy detection of crossed offspring (sporophyte).
• We show that Reute can be successfully crossed with a self‐infertile DR5:DsRed2 mutant generated in the Gransden background. Using newly established Reute fluorescent strains, we show that they can efficiently fertilise Reute as well as Gransden wild type. The resulting progeny display Mendelian 1:1 segregation of the fluorescent marker(s), demonstrating the suitability of such strains for genetic crossing.
• Overall our results demonstrate that Reute is highly suitable for genetic crossing. The Reute mCherry strain can be used as a suitable background for offspring selection after crossing.

     

不同生态型芦苇种群对盐胁迫的生长和光合特性

土壤盐渍化是影响我国土壤利用效率的主要因素之一,芦苇是改良土壤盐渍化的良好实验材料,但芦苇有着多种的生态型,比较各生态型芦苇的耐盐差异成为亟待解决的问题。通过设置淡水(0.00%)与加盐(质量浓度2.00%)处理控制实验,测量芦苇的生长指标和光合指标,比较河口型芦苇与内陆型芦苇耐盐性,寻找合适生态型的芦苇作为改良土壤盐渍化的生物材料。在实验中,与淡水条件相比,加盐(2.00%)处理条件下,河口型芦苇和内陆型芦苇的株高(height)、蒸腾速率(E)均显著性下降,但是两种生态型的芦苇的水分利用效率(WUE)明显提高;河口型的芦苇相对生长速率(RGR)和气孔导度(Gs)都明显高于内陆型芦苇。在淡水环境中,河口型芦苇的相对生长速率(RGR)和净光合速率(A)都显著性地高于内陆型芦苇。结果表明两种生态型的芦苇在进化过程中存在一定程度上的分化,盐胁迫会抑制两种芦苇的生长,两种生态型芦苇的相对生长速率和气孔导度在盐胁迫下出现明显地差异,表明两种生态型的芦苇对盐度的响应机制有所差异。相比于内陆型芦苇,河口型芦苇有着更强的耐盐性,内陆型及河口型芦苇的表型性状差异主要是由于其原生境的差异所决定的。     

贵州喀斯特区C4植物物种组成与水分生态型划分

该研究通过查阅文献、核对贵州大学林学院标本库及现场群落调查与标本采集,并运用碳同位素比值法研究典型C_4植物水分利用特性,探索C_4植物在喀斯特植被恢复中的地位,进而揭示贵州喀斯特地区C_4植物资源的基本特征。结果表明:贵州喀斯特区共有C_4植物141种,隶属于74属15科,分别占全国科属种的62.50%、46.25%、24.48%,以禾本科(Gramineae)和莎草科(Cyperaceae)为主;区内C_4植物种均为一年生或多年生草本,多年生植物种略多于一年生植物种;水分生态型整体偏旱生,旱生和中生植物分别占总数的24.82%和31.21%;喀斯特区C_4植物具有高水分利用效率,但不同水分生态型间差异不显著;贵州喀斯特区C_4植物资源具有资源丰富、利用途径广泛、能长期利用、竞争力强、能大面积分布、偏旱生且水分利用幅度广的基本特征,适合喀斯特区生境,自然状态下多为恢复早期物种,有利于喀斯特区生态恢复。在贵州喀斯特恶劣生态环境下C_4植物有较好的生态适应性,并表现出较高的药用、食用、饲用、景观应用等价值,对其开发利用对贵州经济、社会发展及生态恢复有重要意义。     

Mismatch in the distribution of floral ecotypes and pollinators: insights into the evolution of sexually deceptive orchids

Plants are predicted to show floral adaptation to geographic variation in the most effective pollinator, potentially leading to reproductive isolation and genetic divergence. Many sexually deceptive orchids attract just a single pollinator species, limiting opportunities to experimentally investigate pollinator switching. Here, we investigate Drakaea concolor, which attracts two pollinator species. Using pollinator choice tests, we detected two morphologically similar ecotypes within D. concolor. The common ecotype only attracted Zaspilothynnus gilesi, whereas the rare ecotype also attracted an undescribed species of Pogonothynnus. The rare ecotype occurred at populations nested within the distribution of the common ecotype, with no evidence of ecotypes occurring sympatrically. Surveying for pollinators at over 100 sites revealed that ecotype identity was not correlated with wasp availability, with most orchid populations only attracting the rare Z. gilesi. Using microsatellite markers, genetic differentiation among populations was very low (G_ST = 0.011) regardless of ecotype, suggestive of frequent gene flow. Taken together, these results may indicate that the ability to attract Pogonothynnus has evolved recently, but this ecotype is yet to spread. The nested distribution of ecotypes, rather than the more typical formation of ecotypes in allopatry, illustrates that in sexually deceptive orchids, pollinator switching could occur throughout a species' range, resulting from multiple potentially suitable but unexploited pollinators occurring in sympatry. This unusual case of sympatric pollinators highlights D. concolor as a promising study system for further understanding the process of pollinator switching from ecological, chemical and genetic perspectives.     

Root Dynamics of Cultivar and Non‐Cultivar Population Sources of Two Dominant Grasses during Initial Establishment of Tallgrass Prairie

Dominance of warm‐season grasses modulates tallgrass prairie ecosystem structure and function. Reintroduction of these grasses is a widespread practice to conserve soil and restore prairie ecosystems degraded from human land use changes. Seed sources for reintroduction of dominant prairie grass species include local (non‐cultivar) and selected (cultivar) populations. The primary objective of this study was to quantify whether intraspecific variation in developing root systems exists between population sources (non‐cultivar and cultivar) of two dominant grasses (Sorghastrum nutans and Schizachyrium scoparium) widely used in restoration. Non‐cultivar and cultivar grass seedlings of both species were isolated in an experimental prairie restoration at the Konza Prairie Biological Station. We measured above‐ and belowground net primary production (ANPP and BNPP, respectively), root architecture, and root tissue quality, as well as soil moisture and plant available inorganic nitrogen (N) in soil associated with each species and source at the end of the first growing season. Cultivars had greater root length, surface area, and volume than non‐cultivars. Available inorganic N and soil moisture were present in lower amounts in soil proximal to roots of cultivars than non‐cultivars. Additionally, soil NO₃–N was negatively correlated with root volume in S. nutans cultivars. While cultivars had greater BNPP than non‐cultivars, this was not reflected aboveground root structure, as ANPP was similar between cultivars and non‐cultivars. Intraspecific variation in belowground root structure and function exists between cultivar and non‐cultivar sources of the dominant prairie grasses during initial reestablishment of tallgrass prairie. Population source selection should be considered in setting restoration goals and objectives.     

Ringed seal (Pusa hispida) seasonal movements,diving, and haul‐out behavior in the Beaufort,Chukchi, and Bering Seas (2011–2017)

Continued Arctic warming and sea‐ice loss will have important implications for the conservation of ringed seals, a highly ice‐dependent species. A better understanding of their spatial ecology will help characterize emerging ecological trends and inform management decisions. We deployed satellite transmitters on ringed seals in the summers of 2011, 2014, and 2016 near Utqia?vik (formerly Barrow), Alaska, to monitor their movements, diving, and haul‐out behavior. We present analyses of tracking and dive data provided by 17 seals that were tracked until at least January of the following year. Seals mostly ranged north of Utqia?vik in the Beaufort and Chukchi Seas during summer before moving into the southern Chukchi and Bering Seas during winter. In all seasons, ringed seals occupied a diversity of habitats and spatial distributions, from near shore and localized, to far offshore and wide‐ranging in drifting sea ice. Continental shelf waters were occupied for >96% of tracking days, during which repetitive diving (suggestive of foraging) primarily to the seafloor was the most frequent activity. From mid‐summer to early fall, 12 seals made ~1‐week forays off‐shelf to the deep Arctic Basin, most reaching the retreating pack‐ice, where they spent most of their time hauled out. Diel activity patterns suggested greater allocation of foraging efforts to midday hours. Haul‐out patterns were complementary, occurring mostly at night until April‐May when midday hours were preferred. Ringed seals captured in 2011—concurrent with an unusual mortality event that affected all ice‐seal species—differed morphologically and behaviorally from seals captured in other years. Speculations about the physiology of molting and its role in energetics, habitat use, and behavior are discussed; along with possible evidence of purported ringed seal ecotypes.     

景观生态分类概念释义及研究进展

景观生态分类通过建立等级分类系统,能够全面反映一定区域景观的空间分异和组织关联,揭示其空间结构与生态功能特征,是景观生态评价和规划管理的基础.本文首先对景观生态分类的概念进行剖析,然后从分类系统的制定及对分类因子选择的发展进程、分类方法的改进和创新、景观生态类型制图及应用领域等方面阐述国内外景观生态分类的进展和现状,并在总结以前研究存在不足的基础上,进一步指出今后景观生态分类研究的重点和发展趋势.

Abstract：

Landscape ecological classification (LEC), through establishing hierarchical classifi-cation system, can comprehensively reflect the spatial heterogeneities and their associations of definite regional landscape,, and reveal its spatial structural characteristics and ecological func-tions, being the basis of landscape evaluation, landscape planning, and landscape management. In this paper, the concept of LEC was paraphrased, and the research progress of LEC was reviewed and analyzed from the aspects of framing classification systems, selecting indices, im-proving classification methods, mapping landscape ecotypes, and applications. The problems of LEC research and its development trend were pointed out.     

Asymmetric impacts of two herbivore ecotypes on similar host plants

1. Ecotypes may arise following allopatric separation from source populations. The simultaneous transfer of an exotic plant to a novel environment, along with its stenophagous herbivore, may complicate more traditional patterns of divergence from the plant and insect source populations. 2. The present study evaluated herbivory effects by two Cyrtobagous salviniae ecotypes on two species of Salvinia: the larger S. molesta and the smaller S. minima. Evaluations were based on relative growth rates, biomass production, coverage, and nutrient cycling in a series of complementary and comparative laboratory and outdoor tank experiments. 3. In general, the experiment results indicated that the smaller Florida ecotype of C. salviniae impacted both Salvinia species more than the larger Brazil ecotype. Herbivory, especially by the Florida ecotype, also improved water quality and accelerated nutrient cycling by increasing the rates of litterfall from the standing crops of salvinia. 4. The smaller size of the Florida ecotype may be adaptive by allowing maximal exploitation of host plants via internal larval feeding, which presumably reduces predation risk while increasing damage to the plant. These findings provide support for relying on the suppressive effects of the Florida ecotype in Florida, rather than introducing the Brazil ecotype to counter new infestations of S. molesta.     

新疆罗布麻生态类型及其纤维品质研究

新疆塔里木河及叶尔羌河流域是我国能够提供商品精干罗布麻的主要地区。由于野生罗布麻生长高矮不一,形态各异,与其纤维品质的相关性较大。通过40个株号的罗布麻植株形态和纤维长度等的的测定,分析各类型罗布麻的纤维长度和罗布麻植株各部分纤维长度情况。研究结果表明：罗布红麻高杆类型主茎纤维最长,罗布麻放牧类型纤维最短。罗布麻植株各部分纤维长度是主茎上的大于分枝,主茎中部的最长,基部和梢部最短。为野生罗布麻资源开发利用提科学依据。