Determination of isoprene and alpha-/beta-pinene oxidation products in boreal forest aerosols from Hyyti?l?, Finland: diel variations and possible link with particle formation events.

Biogenic volatile organic compounds (VOCs), such as isoprene and alpha-/beta-pinene, are photo-oxidized in the atmosphere to non-volatile species resulting in secondary organic aerosol (SOA). The goal of this study was to examine time trends and diel variations of oxidation products of isoprene and alpha-/beta-pinene in order to investigate whether they are linked with meteorological parameters or trace gases. Separate day-night aerosol samples (PM(1)) were collected in a Scots pine dominated forest in southern Finland during 28 July-11 August 2005 and analyzed with gas chromatography/mass spectrometry (GC/MS). In addition, inorganic trace gases (SO(2), CO, NO(x), and O(3)), meteorological parameters, and the particle number concentration were monitored. The median total concentration of terpenoic acids (i.e., pinic acid, norpinic acid, and two novel compounds, 3-hydroxyglutaric acid and 2-hydroxy-4-isopropyladipic acid) was 65 ng m(-3), while that of isoprene oxidation products (i.e., 2-methyltetrols and C(5) alkene triols) was 17.2 ng m(-3). The 2-methyltetrols exhibited day/night variations with maxima during day-time, while alpha-/beta-pinene oxidation products did not show any diel variation. The sampling period was marked by a relatively high condensation sink, caused by pre-existing aerosol particles, and no nucleation events. In general, the concentration trends of the SOA compounds reflected those of the inorganic trace gases, meteorological parameters, and condensation sink. Both the isoprene and alpha-/beta-pinene SOA products were strongly influenced by SO(2), which is consistent with earlier reports that acidity plays a role in SOA formation. The results support previous proposals that oxygenated VOCs contribute to particle growth processes above boreal forest.     

土壤有机碳汇内涵与核算方法辨析

在"碳达峰、碳中和"战略需求下,土壤有机碳汇作为生态系统碳汇的重要组成部分,土壤碳库容量以及如何开展土壤有机碳汇核算日益成为生态碳汇的研究热点。梳理了国内外土壤有机碳汇及核算相关研究成果,解析了土壤有机碳汇的概念内涵,提出了以稳定性有机碳作为土壤有机碳汇的表征指标及获取方法。从土壤发生学角度提出了土壤碳汇阈值的概念,土壤中有机碳的含量随着分解转化最终会达到动态平衡,此时稳定有机碳含量值约是常数,这个常数就是稳定碳库的库容,在特定的成土因素下,碳库的核算值不会超过平衡时的常态值。在客观上,体现在非人类干扰状态下不同土壤类型自然状态下的稳定性有机碳含量。参照土壤有机质平衡理论,提出了土壤碳汇核算的定量化方法,为土壤碳汇的度量和核算提供了一套技术思路。下一步土壤有机碳汇的核算应在科学研究基础上多角度凝聚共识,制定碳汇核算标准,确定不同尺度下可操作、可重复以及可复制的土壤有机碳汇核算技术与方法。     

高等植物光合同化物的运输与分配

高等植物光合同化物的运输受维管束发育状况影响较大,有时会限制产量。而同化物在各库器官间的分配主要决定于库本身的特性,它常用库强度和优先权来描述。库强度是库容量和库活力的乘积,库容量用细胞数目来度量,而库活力常用相对生长速度来度量。近年来人们也用酶少戌一来度量库活力或库强度。而库的优先权描述的是各库器官需求同化物的优先次序,种子被认为是优等权最高的库。同化物的运输分配不仅决定于植物本身源、流、库的特     

Spatial patterns of China's carbon sinks estimated from the fusion of remote sensing and field-observed net primary productivity and heterotrophic respiration

Accurately assessing the carbon sink and spatial distribution pattern of China's terrestrial ecosystems is of great significance to the implementation of climate change and carbon neutrality strategy. However, the views of various studies are still very controversial due to the differences in carbon sink estimation methods and data sources. In this study, vegetation net primary productivity (NPP) and ecosystem heterotrophic respiration (Rh) estimation models were constructed based on machine learning methods by fusing multisource data, such as remote sensing and ground observation data. The magnitude and spatial pattern of carbon sink in China from 2000 to 2018 were then revealed, and the carbon sink capacity of various ecosystems was quantitatively assessed. The main conclusions include the following: (1) The use of scale-matched carbon input and output data can help reduce the system error in carbon sink estimation. (2) China's terrestrial ecosystem carbon sink since the twenty-first century is approximately 0.458 Pg C/yr, which is equivalent to 22.72% of China's anthropogenic carbon emissions. (3) Deciduous forest has a higher carbon sink capacity than evergreen forest, while coniferous forest has a more stable carbon sink capacity than broad-leaved forest. The magnitude and spatial distribution of carbon sink in China reported in this study provides a scientific reference for achieving carbon neutrality and sustainable development.     

Source–sink dynamics: how sinks affect demography of sources

Models of source–sink population dynamics have to make assumptions about whether, and eventually how, demographic parameters in source habitats are dependent on the demography in sink habitats. However, the empirical basis for making such assumptions has been weak. Here we report a study on experimental root vole populations, where estimates of demographic parameters were contrasted between source patches in source–sink (treatment) and source–source systems (control). In the presence of a sink patch (simulated by a pulsed removal of immigrants), source‐patch populations failed to increase over the breeding season, mainly due to a high spatially density‐dependent dispersal rate from source to sink patches. The per capita recruitment rate was almost two times higher in source–sink than in the source–source systems, but this did not compensate for the loss rate due to dispersal from source to sink patches. Sex ratio in the source–sink systems became less female biased, probably as a result of an enhanced frequency of dispersal movements in females. Good knowledge of the degree of density‐and habitat‐dependent dispersal is critical for predicting the dynamics of source–sink populations.     

Effects of the source:sink ratio on the phenotypic plasticity of stem water potential in olive (Olea europaea L.)

The aims of this work were to quantify (i) the effect of the source:sink ratio on stem water potential (SWP) and (ii) the phenotypic plasticity of SWP and its relationship to oil yield components in olive. Trees with a 3-fold variation in the source:sink ratio (crown volume/fruit number per tree) were monitored in 2007-2008 and 2008-2009 in a fully irrigated orchard in Mendoza, Argentina. The combination of rainfall, irrigation, and evaporative demand led to a steady SWP largely above -1.65 MPa in 2007-2008 and a marked seasonal decline from -1.13 MPa to -2.04 MPa in trees with a medium and low source:sink ratio in 2008-2009. Plasticity was quantified as the slope of the norm of reaction for each trait. Across seasons, trees with a high source:sink ratio had a higher SWP than their counterparts with a medium and low source:sink ratio. Plasticity of SWP was highest in olives with a low source:sink ratio (slope=1.28) and lowest for trees with a high source:sink ratio (slope=0.76). The average SWP for each source:sink ratio and season was unrelated to both the source:sink ratio and yield components. On the other hand, the plasticity of SWP was positively associated with fruit number and negatively associated with the source:sink ratio, fruit weight, and fruit oil weight. The plasticity of the SWP was unrelated to SWP per se. It is concluded that understanding the effect of the source:sink ratio on plant water relations would benefit from a dual perspective considering the trait per se and its plasticity. A dual approach would also allow for more robust plant-based indicators for irrigation.     

Modulation of lateral transport of membrane components by spatial variations in diffusivity and solubility.

The effect of spatially varying diffusivity and solubility on the efficiency of intramembrane transport is investigated by obtaining solutions to the generalized lateral diffusion equation in which both the diffusion coefficient, D(r), and the partition coefficient, K(r), are functions of position. The mean-time-to-capture by a sink, tc, of particles diffusing in a plane is obtained analytically for the case of a sink surrounded by gradients in D(r) and K(r) with radially symmetrical geometry. It is shown that for particles originating at random locations, tc is shortened dramatically, if in an annular region around the sink, D and K are significantly greater than in the remainder of the plane. Similarly, a viscous boundary layer surrounding a sink is demonstrated to represent a significant barrier for diffusing particles. To investigate more complex geometries, a finite difference numerical integration method is used and is shown to provide comparable results for tc with modest computational power. The same method is used to calculate the tc for particles originating at a source that is joined to the sink by a channel. The increase in the rate with which particles travel from a source to a sink when they are joined by a high diffusivity and/or solubility channel is illustrated by several numerical examples and by graphical representations that show the equilibrium particle density (and hence the effective particle flow) in the presence of different sink, source, and channel combinations. These results are discussed in terms of fluidity domains and other membrane heterogeneities.     

森林生态效益补偿优先级机制研究及应用——基于碳汇总量与变化量视角

森林生态效益补偿制度对于提高森林建设者积极性、促进森林生态效益提升具有重要意义。然而,我国森林生态效益补偿实践中依然存在仅以森林面积为补偿依据导致激励错位的问题。基于此,结合国家"双碳"目标,提出一种基于碳汇总量与变化量双向视角的综合森林生态效益补偿优先级机制,选取我国重要生态功能区秦巴山区为案例,分别从森林碳汇总量与变化量视角量化各区县生态补偿优先级,并构建二者结合的综合优先级模型,以促进在生态补偿实践中的资金分配公平性与激励性。研究发现,(1)在研究期内大多区县森林碳汇总量增长,但存在个别区县森林碳汇功能降低的现象,具体原因存在差异;(2)碳汇总量优先级与碳汇变化量优先级清单存在差异。总量优先级高的区县,变化量优先级较低,因此,生态补偿应综合考虑各区县森林碳汇在两个维度的表现;(3)综合优先级排名结果呈现"高值-中值-低值"的不同区间特征,该补偿机制在综合优先级高值区激励区县扩建森林、新增森林碳汇,在中值区激励区县保育森林,在低值区鼓励区县结合森林现状从扩建与保育两个方向提升森林碳汇功能。以森林碳汇保育与增汇成果为导向,有效探索碳汇功能在生态补偿中的实践价值,为我国区域森林生态效益补偿实践的公平性与科学性提供研究基础。     

Effect of Reduction of Sink Strength in Developing Seeds on Vein Loading Patterns of Photoassimilate in Source Leaves of Pisum sativum L

The effect of sink strength reduction in developing seeds onvein loading of photoassimilate has been studied in Pisum sativumL. The sink strength was manipulated by means of the ‘openseed coat technique’. Sink strength of the operated ovuleswas controlled by the osmolality of a substitute medium replacingthe embryo. A high osmolality of the medium (400 mM mannitol)or a low osmolality of the medium (without mannitol) was usedto maintain a high or low sink strength, respectively. To studythe effect of sink strength reduction on vein loading, macro-autoradiographywas used. After applying ¹⁴CO₂ to the source leaf for 10 to20min autoradiographs of plants with different sink strengthshowed differences in distribution of ¹⁴C-photoassimilate overthe mesophyll and the veins. Under low sink strength conditionsvein loading of ¹⁴C-photoassimilate was reduced. After longertime spans (40 to 60 min) no clear differences in vein loadingwere visible in the autoradiographs. However, measurement of¹⁴C in plant parts along the path of transport from source tosink showed a decrease of the rate of export of ¹⁴C from thesource leaf under low sink strength conditions. Apparently,accumulation of ¹⁴C-photoassimilate into the phloem and exporttowards sink regions can be reduced by lowering the sink strength.A signal must have been transferred from sink all the way tothe source regions. The mechanism of such a signal is discussed. Key words: Pisum sativum, phloem loading, photoassimilate transport, seed development, sink-source interactions     

Effect of light and ontogenetic stage on sink strength in bean leaves

Light (about 3,000 foot-candles) neither increased nor decreased the sink strength of young, rapidly expanding leaves of Phaseolus vulgaris L. cv. Black Valentine, as measured by the comparative rates of import of ¹⁴C-labeled photosynthates by sink leaves in the light versus dark in short term experiments. Although irradiated sink leaves accumulated more ¹⁴C activity, the difference was fully accounted for by photosynthetic reabsorption of respiratory CO₂ derived from substrates translocated to the sink leaves.

Maximum sink strength was attained when the sink leaf reached 7 to 8 cm² in area (9 to 10% of its fully expanded size). Thereafter sink strength declined rapidly and asymptotically to a near zero value at about 45% final area. During this period, however, the rapid decline in translocation was offset by a rapid rise in the photosynthetic rate of the sink leaf, maintaining a near constant relative rate of dry weight increase until the sink leaf had expanded to about 17% of its final area. Although the increasing photosynthetic capacity was associated with a decreasing import capacity, suggesting that the rate of translocation to the sink leaf was controlled by the developing capacity of the sink leaf for photosynthesis, it was not possible to vary the total (true) translocation rate to the sink leaf by varying the photosynthetic rate of the sink leaf in short term light-dark experiments. Despite a high ratio of source to sink in these experiments, no evidence accrued that translocation into young bean leaves was ever sink-limited.

     

Effects of an attractive sink leading into maladaptive habitat selection

Habitat sinks can attract dispersing animals if high mortality or breeding failure are difficult to detect (e.g., when due to human hunting or pollution). Using a simple deterministic model, we explore the dynamics of such source-sink systems considering three scenarios: an avoided sink, no habitat preference, and an attractive sink. In the second two scenarios, there is a threshold proportion of sink habitat above which the whole population decreases to extinction, but this extinction threshold varies with habitat preference and the relative qualities of the two habitat types. Hence, it would be necessary to know the habitat preferences of any species in a source-sink system to interpret data on population increases and declines. In the attractive sink scenario, small changes in the proportion of sink habitat may have disproportionate effects on the population persistence. Also, small changes in growth rates at the source and the sink severely affect the threshold and the time of extinction. For some combinations of demographic parameters and proportion of habitat sink, the decline affects the source first; thus, during some time, it will be hidden to population monitoring at the sink, where numbers can even increase. The extinction threshold is also very sensitive to the initial population sizes relative to carrying capacity. Attractive sinks represent a novel aspect of source-sink dynamics with important conservation and management implications.     

Field evidences for the positive effects of aerosols on tree growth

Theoretical and eddy covariance studies demonstrate that aerosol‐loading stimulates canopy photosynthesis, but field evidence for the aerosol effect on tree growth is limited. Here, we measured in situ daily stem growth rates of aspen trees under a wide range of aerosol‐loading in China. The results showed that daily stem growth rates were positively correlated with aerosol‐loading, even at exceptionally high aerosol levels. Using structural equation modeling analysis, we showed that variations in stem growth rates can be largely attributed to two environmental variables covarying with aerosol loading: diffuse fraction of radiation and vapor pressure deficit (VPD). Furthermore, we found that these two factors influence stem growth by influencing photosynthesis from different parts of canopy. Using field observations and a mechanistic photosynthesis model, we demonstrate that photosynthetic rates of both sun and shade leaves increased under high aerosol‐loading conditions but for different reasons. For sun leaves, the photosynthetic increase was primarily attributed to the concurrent lower VPD; for shade leaves, the positive aerosol effect was tightly connected with increased diffuse light. Overall, our study provides the first field evidence of increased tree growth under high aerosol loading. We highlight the importance of understanding biophysical mechanisms of aerosol‐meteorology interactions, and incorporating the different pathways of aerosol effects into earth system models to improve the prediction of large‐scale aerosol impacts, and the associated vegetation‐mediated climate feedbacks.     

Experimental evidence that source genetic variation drives pathogen emergence

A pathogen can readily mutate to infect new host types, but this does not guarantee successful establishment in the new habitat. What factors, then, dictate emergence success? One possibility is that the pathogen population cannot sustain itself on the new host type (i.e. host is a sink), but migration from a source population allows adaptive sustainability and eventual emergence by delivering beneficial mutations sampled from the source''s standing genetic variation. This idea is relevant regardless of whether the sink host is truly novel (host shift) or whether the sink is an existing or related, similar host population thriving under conditions unfavourable to pathogen persistence (range expansion). We predicted that sink adaptation should occur faster under range expansion than during a host shift owing to the effects of source genetic variation on pathogen adaptability in the sink. Under range expansion, source migration should benefit emergence in the sink because selection acting on source and sink populations is likely to be congruent. By contrast, during host shifts, source migration is likely to disrupt emergence in the sink owing to uncorrelated selection or performance tradeoffs across host types. We tested this hypothesis by evolving bacteriophage populations on novel host bacteria under sink conditions, while manipulating emergence via host shift versus range expansion. Controls examined sink adaptation when unevolved founding genotypes served as migrants. As predicted, adaptability was fastest under range expansion, and controls did not adapt. Large, similar and similarly timed increases in fitness were observed in the host-shift populations, despite declines in mean fitness of immigrants through time. These results suggest that source populations are the origin of mutations that drive adaptive emergence at the edge of a pathogen''s ecological or geographical range.     

Magnesium deficiency results in accumulation of carbohydrates and amino acids in source and sink leaves of spinach

Accumulation of assimilates in source leaves of magnesium‐deficient plants is a well‐known feature. We had wished to determine whether metabolite concentrations in sink leaves and roots are affected by magnesium nutrition. Eight‐week‐old spinach plants were supplied either with a complete nutrient solution (control plants) or with one lacking Mg (deficient plants) for 12 days. Shoot and root fresh weights and dry weights were lower in deficient than in control plants. Mg concentrations in deficient plants were 11% of controls in source leaves, 12% in sink leaves and 26% in roots, respectively. As compared with controls, increases were found in starch and amino acids in source leaves and in sucrose, hexoses, starch and amino acids in sink leaves, whereas they were only slightly enhanced in roots. In phloem sap of magnesium‐deficient and control plants no differences in sucrose and amino acid concentrations were found. To prove that sink leaves were the importing organs they were shaded, which did not alter the response to magnesium deficiency as compared with that without shading. Since in the shaded sink leaves the photosynthetic production of metabolites could be excluded, those carbohydrates and amino acids that accumulated in the sink leaves of the deficient plants must have been imported from the source leaves. It is concluded that in magnesium‐deficient spinach plants the growth of sink leaves and roots was not limited by carbohydrate or amino acid supply. It is proposed that the accumulation of assimilates in the source leaves of Mg‐deficient plants results from a lack of utilization of assimilates in the sink leaves.     

A core set of metabolite sink/source ratios indicative for plant organ productivity in Lotus japonicus

Plant growth is an important process in physiological as well as ecological respect and a number of metabolic parameters (elemental ratios as well as steady-state levels of individual metabolites) have been demonstrated to reflect this process on the whole plant level. Since plant growth is highly localized and is the result of a complex interplay of metabolic activities in sink and source organs, we propose that ratios in metabolite levels of sink and source organs are particularly well suited to characterize this process. To demonstrate such a connection, we studied organ-specific metabolite ratios from Lotus japonicus treated with mineral nutrients, salt stress or arbuscular mycorrhizal fungi. The plants were displaying a wide range of biomass and of flower/biomass ratios. In the analysis of our data we looked for correlations between shifts in sink/source metabolite ratios and plant productivity (biomass accumulated at the time of harvest). In addition we correlated shifts in metabolite ratios comparing competing generative and vegetative sink organs with shifts in productivity of the two organs (changes in flower/biomass ratios). In our analyses we observed clear shifts of carbohydrates and of compounds connected to nitrogen metabolism in favour of sink organs of particularly high productivity. These shifts were in agreement with general differences in metabolite steady-state levels when comparing sink and source organs. Our findings suggest that differentiation of sink and source organs during sampling for metabolomic experiments substantially increases the amount of information obtained from such experiments.     

Distribution of Assimilates from Various Source Leaves During the Development of Gladiolus grandiflorus

The distribution pattern of the products of photosynthesis wasstudied in gladiolus plants (Gladiolus grandiflorus cv Eurovision)in four stages of development I, plants having a very younginflorescence still enclosed between the leaves; II, plantswith a young inflorescence just emerged from the leaves, III,plants at full bloom, IV, plants with young fruits. The first,third or sixth foliage leaf was labelled with ¹⁴CO₂, and subsequentdistribution in the plant was determined Results were expressedas a percentage of translocated ¹⁴C accumulated by each partof the plant which gives a measure of its ‘sink strength’,or as ‘relative sink activity’ (RSA) which is independentof the size of the indicated organ. There are two competing sinks in the developing gladiolus—theinflorescence and the new corm. When RSA is the criterton theinflorescence constitutes the main sink irrespective of thesource leaf from the first stage until flowering. With the subsequentwilting of the flowers and fruit set RSA of the inflorescencedeclines rapidly and the new corm becomes the main sink When‘sink strength’ is the criterton it appears thatthe inflorescence acts as a very weak sink when it is youngand becomes increasingly stronger until flowering and then declinessteeply. Sink strength of the corm declines during the developmentof the inflorescence and then increases again steeply with wiltingof the flowers and fruit set. There are small differences betweenthe various source leaves. The young new corm acts as a strongsink for the lower foliage leaf and progressively weaker forupper leaves. Gladiolus grandiflorus, flower development, corm, assimilates distribution, sink strength, relative sink activity     

Development of Sink Capacity of the "Storage Root" in a Radish Cultivar with a High Ratio of "Storage Root" to Shoot

The mechanisms that control sink capacity are poorly understood.in radish, a major sink is the "storage root", which beginsto thicken early in development, mainly as a result of thickeningof the hypocotyl. We investigated changes in the accumulationof dry matter, sink activity (increase in dry weight of thehypocotyl per unit of dry weight present per unit of time),carbohydrate content, levels of metabolites, activities of enzymesrelated to the breakdown of sucrose, and the profile of solubleproteins, as well as changes in anatomy, using hypocotyls ofa cultivar with a high ratio of "storage root" to shoot. Wefound that sink activity was strongly related to the level andactivity of sucrose synthase but not to the activity of invertase.We also found a significant correlation between sucrose contentand the level and activity of sucrose synthase. Our resultssuggest that sucrose synthase, but not invertase, might be criticalfor the development of the sink activity of the radish hypocotyland that the level of sucrose might regulate the expressionof sucrose synthase. A discussion of sink capacity is presentedthat includes consideration of structural changes in the hypocotyl. (Received December 14, 1998; Accepted January 27, 1999)     

基于文献计量的土地利用变化与碳汇评估交叉研究进展

在"碳中和"的背景下,土地利用变化与碳汇评估的结合日趋紧密,受到了景观生态学、人文地理学等多个学科的关注,二者的交叉研究已成为当下研究热点。对土地利用变化和碳汇评估进行研究,对于实现碳中和、碳达峰具有重要意义。以2003-2023年Web of Science 的核心数据集3556篇英文文献和中国知网CNKI数据库363篇中文文献为研究对象,采用CiteSpace软件制作科学知识图谱,梳理了土地利用变化和碳汇评估交叉研究的概况、研究领域及方向和发展脉络及趋势。研究发现,近20年来土地利用变化和碳汇评估交叉研究的刊文量呈逐年增长趋势,根据关键词聚类情况可将文献主要分为三类议题:1)土地利用类型碳汇评估;2)生态系统服务碳汇评估;3)土壤和植被碳汇评估。其中,土地利用类型碳汇评估是土地利用变化和碳汇交叉研究的重点。研究热点从碳汇评估方法研究逐渐向气候变化及土地利用变化下的碳汇预测模拟转变。在研究方法上,遥感数据分析方法得到不断改进,同时人工智能和机器学习方法也逐渐开始为更多学者采用。在未来的研究中,应发挥学科交叉的优势,完善该领域的研究深度和广度,加强综合性的碳汇评估研究,强化对政策的响应并提出合理的国土空间规划建议,为早日实现碳达峰、碳中和目标提供科学依据和参考。     

我国主要海域海水养殖碳汇能力评估及其影响效应——基于我国9个沿海省份面板数据

随着海水养殖业的碳汇功能逐渐被认识和肯定,海水养殖不再单是一项经济活动,而是对环境具有正向影响的碳汇生态活动。以我国沿海9个省份为例,选取海水养殖业碳汇主要贡献的贝类和藻类海产品,并按照各自的碳汇方式对我国沿海地区2008—2015年海水养殖碳汇能力测算,进一步将9个沿海省份按照主要海域划分为渤海、黄海、东海、南海,利用LMDI模型从海水养殖的结构效应和规模效应角度分析碳汇能力的区域差异和主要影响因素。研究结果显示,黄海沿岸海水养殖碳汇能力最强,南海沿岸海水养殖的碳汇转化比例最高,规模效应与我国沿海地区海水养殖碳汇能力始终呈正相关,结构效应的作用显著但不稳定。基于上述结论,我国沿海地区碳汇养殖业应首先提升碳汇养殖技术、稳定海水养殖产量,其次注重优化养殖结构,对碳汇潜力巨大的贝类多加关注。     

Experimental evidence for an alkali ecotype of <Emphasis Type="Italic">Lolium multiflorum</Emphasis>, an exotic invasive annual grass in the Central Valley,CA, USA

One of the characteristics of highly invaded ecosystems is that exotic species are often poor invaders of edaphically severe sites, which become refuges for native flora. To investigate the invasive potential of Lolium multiflorum (Per.) into alkali sites in California, an ex-situ reciprocal transfer experiment was carried out using seeds from populations of L. multiflorum taken from three sites differing in alkalinity (and inundation), including alkali sink soils (pH 8.5) and sink matrix soils (pH 7.4) located within meters of each other, and non-sink soils (pH 5.0) located several km away. Survivorship, plant height, leaf number and seed production were assessed. In addition, a native composite, Hemizonia pungens (Hick.), commonly found on alkali sinks was also sampled at the sink and sink matrix microsites. Lolium multiflorum plants grown from alkali sink and sink matrix seeds produced fewer leaves and seeds but were taller than plants grown from non-alkali seeds, the latter perhaps an adaptation to frequently inundated soils. Non-alkali genotypes fared poorly in sink soils for all traits, both in comparison to their growth on non-sink soils, and in comparison to the sink and sink edge genotypes. This suggests the existence of L. multiflorum ecotypes adapted to inundated alkali sinks, a genotypic difference that occurs on a broad spatial scale (kilometers), but not so obviously on the micro-site scale (meters) between sink and sink matrix populations. These data suggest that the absence of exotic invasives from alkali sites may be temporary if they are evolving tolerance for these severe sites, and this may threaten the future of the native alkali specialists that currently find refuge in these sites.