Ancient DNA studies have established that Neolithic European populations were descended from Anatolian migrants1–8 who received a limited amount of admixture from resident hunter-gatherers3–5,9. Many open questions remain, however, about the spatial and temporal dynamics of population interactions and admixture during the Neolithic period. Using the highest-resolution genome-wide ancient DNA data set assembled to date—a total of 180 samples, 130 newly reported here, from the Neolithic and Chalcolithic of Hungary (6000–2900 BCE, n = 100), Germany (5500–3000 BCE, n = 42), and Spain (5500–2200 BCE, n = 38)—we investigate the population dynamics of Neolithization across Europe. We find that genetic diversity was shaped predominantly by local processes, with varied sources and proportions of hunter-gatherer ancestry among the three regions and through time. Admixture between groups with different ancestry profiles was pervasive and resulted in observable population transformation across almost all cultural transitions. Our results shed new light on the ways that gene flow reshaped European populations throughout the Neolithic period and demonstrate the potential of time-series-based sampling and modeling approaches to elucidate multiple dimensions of historical population interactions.

Aim Primary forests have high conservation value but are rare in Europe due to historic land use. Yet many primary forest patches remain unmapped, and it is unclear to what extent they are effectively protected. Our aim was to (1) compile the most comprehensive European‐scale map of currently known primary forests, (2) analyse the spatial determinants characterizing their location and (3) locate areas where so far unmapped primary forests likely occur. Location Europe. Methods We aggregated data from a literature review, online questionnaires and 32 datasets of primary forests. We used boosted regression trees to explore which biophysical, socio‐economic and forest‐related variables explain the current distribution of primary forests. Finally, we predicted and mapped the relative likelihood of primary forest occurrence at a 1‐km resolution across Europe. Results Data on primary forests were frequently incomplete or inconsistent among countries. Known primary forests covered 1.4 Mha in 32 countries (0.7% of Europe’s forest area). Most of these forests were protected (89%), but only 46% of them strictly. Primary forests mostly occurred in mountain and boreal areas and were unevenly distributed across countries, biogeographical regions and forest types. Unmapped primary forests likely occur in the least accessible and populated areas, where forests cover a greater share of land, but wood demand historically has been low. Main conclusions Despite their outstanding conservation value, primary forests are rare and their current distribution is the result of centuries of land use and forest management. The conservation outlook for primary forests is uncertain as many are not strictly protected and most are small and fragmented, making them prone to extinction debt and human disturbance. Predicting where unmapped primary forests likely occur could guide conservation efforts, especially in Eastern Europe where large areas of primary forest still exist but are being lost at an alarming pace.

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Salicylic acid (SA) applied at 10(-3) m in hydroponic culture decreased stomatal conductance (g(s)), maximal CO(2) fixation rate (A(max) ) and initial slopes of the CO(2) (A/C(i)) and light response (A/PPFD) curves, carboxylation efficiency of Rubisco (CE) and photosynthetic quantum efficiency (Q), resulting in the death of tomato plants. However, plants could acclimate to lower concentrations of SA (10(-7) -10(-4) m) and, after 3 weeks, returned to control levels of g(s), photosynthetic performance and soluble sugar content. In response to high salinity (100 mm NaCl), the pre-treated plants exhibited higher A(max) as a function of internal CO(2) concentration (C(i) ) or photosynthetic photon flux density (PPFD), and higher CE and Q values than salt-treated controls, suggesting more effective photosynthesis after SA treatment. Growth in 10(-7) or 10(-4) m SA-containing solution led to accumulation of soluble sugars in both leaf and root tissues, which remained higher in both plant parts during salt stress at 10(-4) m SA. The activity of hexokinase (HXK) with glucose, but not fructose, as substrate was reduced by SA treatment in leaf and root samples, leading to accumulation of glucose and fructose in leaf tissues. HXK activity decreased further under high salinity in both plant organs. The accumulation of soluble sugars and sucrose in roots of plants growing in the presence of 10(-4) m SA contributed to osmotic adjustment and improved tolerance to subsequent salt stress. Apart from its putative role in delaying senescence, decreased HXK activity may divert hexoses from catabolic reactions to osmotic adaptation.

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The role of nitric oxide (NO) in photosynthesis is poorly understood as indicated by a number of studies in this field with often conflicting results. As various NO donors may be the primary source of discrepancies, the aim of this study was to apply a set of NO donors and its scavengers, and examine the effect of exogenous NO on photosynthetic electron transport in vivo as determined by chlorophyll fluorescence of pea (Pisum sativum) leaves. Sodium nitroprusside-induced changes were shown to be mediated partly by cyanide, and S-nitroso-N-acetylpenicillinamine provided low yields of NO. However, the effects of S-nitrosoglutathione are inferred exclusively by NO, which made it an ideal choice for this study. Q A 2 reoxidation kinetics show that NO slows down electron transfer between Q A and Q B , and inhibits charge recombination reactions of Q A 2 with the S 2 state of the water-oxidizing complex in photosystem II. Consistent with these results, chlorophyll fluorescence induction suggests that NO also inhibits steady-state photochemical and nonphotochemical quenching processes. NO also appears to modulate reaction-center-associated nonphotochemical quenching.Plants, as well as animals, respond to ambient levels of nitric oxide (NO), and also generate NO themselves via various enzymatic and nonenzymatic pathways (Yamasaki, 2000;Neill et al., 2003;Río et al., 2004). Indeed, in the past years, a growing amount of research has provided evidence for the multiple physiological roles of this gaseous free radical in plants (for review, see Wendehenne et al., 2004;Delledonne, 2005). The turnover of NO depends on its concentration, the ambient redox status, and the concentration of target molecules. In biological systems, NO is capable of targeting thiol-and metal-containing proteins (Lamattina et al., 2003). Photosynthetic and mitochondrial electron transport chains are abundant in transition metalcontaining complexes, and NO and its derivative peroxynitrite are known to inhibit the mitochondrial electron transport chain (Millar and Day, 1996;Yamasaki et al., 2001). Yet, the effect of exogenous NO on photosynthetic activity in intact leaves has so far been poorly addressed, with often conflicting results.Previous research suggests that NO gas decreases net photosynthesis rates in oat (Avena sativa) and alfalfa (Medicago sativa) leaves (Hill and Bennett, 1970). Lum et al. (2005) have identified a number of intracellular targets of NO signalization including mitochondria, peroxisomes, and chloroplasts. They found that the NO donor sodium nitroprusside (SNP) decreases the amount of Rubisco activase and the b-subunit of the Rubisco subunit-binding protein in mung bean (Phaseolus aureus).NO is also able to influence the photosynthetic electron transport chain directly. An important action site of NO is PSII. Electron paramagnetic resonance and chlorophyll fluorescence measurements using NO gas treatment of isolated thylakoid membrane complexes have clearly demonstrated that NO can reversibly bind to several sites in PSII and...

The increase in the speed of land-cover change experienced worldwide is becoming a growing concern. Major socio-economic transitions, such as the breakdown of socialism in Europe, may lead to particularly high rates of landscape transformations. In this paper we examined the loss of semi-natural grasslands in Hungary between 1987 and 1999. We studied the relationship between 9 5 potential driving forces and the fate of grasslands using logistic GLMs.Grassland loss was found to be very high (1.31 % per year), which is far higher than either before or after this period. The most influential predictors of grassland loss were environmental and landscape characteristics (soil type, area of remnant grassland patches), and the socio-economic context (distance to paved road, and nearest settlement, human population density). Several 10 processes and relationships can only be understood from a historical perspective (e.g. large extent of afforestation, strong decrease of soil water table). Grassland loss during the study period emerged as a consequence of survival strategies of individual farmers seeking adaptation to the changing environmental and socio-economic conditions, and not urbanization and agricultural intensification which are the main underlying drivers for the ongoing landscape transformations in 15 most parts of the developed world.Though globalization increasingly influences local land use decisions , reconstructing and modelling recent landscape changes cannot be done without a proper understanding of local history and culture. Our analysis shows the importance of large-area yet high resolution landscape change research, which may reveal unexpected patterns of land cover change, undetected at coarser scales. 20Keywords: East-Central Europe, land-cover change, logistic GLMs, proximate and underlying driving forces LANDSCAPE ECOLOGY, 28: (5) pp. 789-803. (2013) 3

Ancient DNA studies have established that European Neolithic populations were descended from Anatolian migrants who received a limited amount of admixture from resident hunter-gatherers. Many open questions remain, however, about the spatial and temporal dynamics of population interactions and admixture during the Neolithic period. Using the highest-resolution genome-wide ancient DNA data set assembled to date—a total of 177 samples, 127 newly reported here, from the Neolithic and Chalcolithic of Hungary (6000–2900 BCE, n = 98), Germany (5500–3000 BCE, n = 42), and Spain (5500–2200 BCE, n = 37)—we investigate the population dynamics of Neolithization across Europe. We find that genetic diversity was shaped predominantly by local processes, with varied sources and proportions of hunter-gatherer ances try among the three regions and through time. Admixture between groups with different ancestry profiles was pervasive and resulted in observable population transformation across almost all cultural transitions. Our results shed new light on the ways that gene flow reshaped European populations throughout the Neolithic period and demonstrate the potential of time-series-based sampling and modeling approaches to elucidate multiple dimensions of historical population interactions.