Carthamus species in the ancient Near East and south-eastern Europe: archaeobotanical evidence for their distribution and use as a source of oil

We present an overview of archaeobotanical Carthamus spp. finds from Neolithic to medieval sites in the Near East and adjacent areas. A particular focus is put on the cultivated form of the genus. Safflower appears first in a number of early Bronze Age (3000 b.c.) sites in northern and central Syria. From there it apparently spread to Egypt, the Aegean and south-eastern Europe. The Near Eastern Bronze Age evidence shows a striking exclusiveness in the distribution patterns of safflower and flax, with flax being restricted to Levantine and Iranian sites. This may reflect the contrasting ecological requirements of the two crops, with safflower being well adapted to drought and salinity and thus to arid conditions. At the same time the geographically complementary evidence may indicate a similar use of the two crops and most probably suggests that the safflower was also used for oil almost from the beginning of its cultivation. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Evidence of the domestication history of flax (Linum usitatissimum L.) from genetic diversity of the sad2 locus

A phylogenetic analysis was conducted on 34 alleles of 2.5 kb sized stearoyl-ACP desaturase II (sad2), obtained from 30 accessions of cultivated and pale flax (Linum spp.), to elucidate the history of flax domestication. The analysis supports a single domestication origin for extant cultivated flax. The phylogenetic evidence indicates that flax was first domesticated for oil, rather than fibre. The genetic diversity of the sad2 locus in cultivated flax is low when compared to that of the pale flax assayed. An absolute archaeological date could be applied to the synonymous substitution rate of sad2 in cultivated flax, yielding a high estimate of 1.60–1.71×10⁻⁷ substitutions/site/year. The occurrence of nonsynonymous substitutions at conserved positions of the third exon in alleles from cultivated flax suggests that the locus may have been subjected to an artificial selection pressure. The elevated synonymous substitution rate is also compatible with a population expansion of flax since domestication, followed by a population decline in historic times. These findings provide new insight into flax domestication and are significant for the continuous exploration of the flax germplasm for utilization.     

Flax cultivation and textile production in Neolithic wetland settlements on Lake Constance and in Upper Swabia (south-west Germany)

At present there are substantial amounts of archaeological and archaeobotanical data from the Late Neolithic wetland settlements of southern Germany on the oil and fibre plant flax (Linum usitatissimum L.). This is the result of 30 years of intensive excavations and research in 53 settlement areas. This article, on the one hand, will present the significance of flax remains, products made of flax and the inventory of relevant tools for evidence of and reconstruction of the flax production processes. On the other hand, based on the quantitative analysis of flax remains, the changing significance of this important cultivated plant during the course of the Late Neolithic will be demonstrated. From this it will be evident that textile production and in particular flax processing were part of a decisive upheaval in cultural development that initiated the transition to the middle phase of the Late Neolithic in the fields of agriculture and technology.     

Miscanthus sacchriflorus exhibits sustainable yields and ameliorates soil properties but potassium stocks without any input over a 12‐year period in China

The perennial C₄ Miscanthus spp. is used in China for bio‐fuel production and its ecological functions. However, questions arise as to its economic and environmental sustainability in abandoned farmland where the costs should be very low. Little is known about its yield performance and effects on soil properties when it was harvested annually without any inputs in China. To address these questions, an experiment was implemented for 12 years on annually harvested Miscanthus sacchariflorus planted in 2006 and managed without fertilization, irrigation, or any other inputs. We determined biomass yields each year, biomass allocation, and soil properties before and after its cultivation. Biomass yields of M. sacchariflorus reached a peak value (29.67 t/ha) 3 years after cultivation and was maintained at a stable level (averaged 22.22 t/ha) during 2012–2017. Its root shoot ratio increased due to more biomass allocated below‐ground with time. Long‐term cultivation of M. sacchariflorus increased organic carbon contents, pH (for the absence of fertilization), microbial carbon, nitrogen and phosphorus contents, and soil carbon nitrogen ratios (0–100 cm). Soil bulk density was decreased significantly (p < .05) independent of soil depths. Annual harvest did not reduce total nitrogen and phosphorus, available nitrogen, and potassium, but total the potassium content of soil (0–100 cm). Cultivation of M. sacchariflorus increased available phosphorus contents in 40–100 cm soil and reduced that value in 20–40 cm soil. Biological nitrogen fixation provided ~218.74 kg ha^?1 year^?1 (1 m depth) nitrogen for the system offsetting nitrogen export by biomass harvest and stabilizing nitrogen levels of soil. In conclusion, M. sacchriflorus exhibited sustainable biomass yields and ameliorated soil properties but the decrease of total potassium contents after 12 years’ cultivation without any input. These conclusions could provide important information timely for the government and encourage farmers to promote large‐scale utilization of M. sacchriflorus on the abandoned farmland in China.     

Sonication assisted <Emphasis Type="Italic">Agrobacterium</Emphasis>-mediated transformation enhances the transformation efficiency in flax (<Emphasis Type="Italic">Linum usitatissimum</Emphasis> L<Emphasis Type="Italic">.</Emphasis>)

A sonication-assisted, Agrobacterium-mediated, co-cultivation technique was used in an attempt to increase the transformation efficiency of flax. Hypocotyls and cotyledons excised from about 10-day-old flax seedlings grown in vitro were placed into a 10 mM MgSO₄ solution, and inoculated with an A. tumefaciens vector bearing the mgfp5-ER gene driven by the CaMV 35S promoter. The explants were subjected to pulses of ultrasound delivered by a sonicator apparatus (35 kHz) for 0–150 s and co-cultivated for 2 h at 27°C. The dried hypocotyls and cotyledons were grown on a selective MS medium to promote shoot regeneration. An electron microscopic study showed that the sonication treatment resulted in thousands of microwounds on and below the surface of the explants. A stereo microscope Leica MZ 12 equipped with a GFP adaptor was used to assess the infection and transformation of plant tissues in real time. After only 48 h and for at least 30 days after bacteria elimination, signs of transgene expression could be seen as a bright fluorescence. Our results show that treatment with ultrasound facilitates an enhanced uptake of plasmid DNA into the cells of flax hypocotyls and cotyledons and that its efficiency depends on the duration of the treatment and the frequency used. SAAT could be a promising tool for enhancing transformation efficiency in flax.     

Flax in Sweden: the archaeobotanical, archaeological and historical evidence

The earliest recorded evidence of flax being cultivated in Sweden is from the end of the Bronze Age/beginning of the Iron Age. Later, from ca. a.d. 1100 and onwards, flax became an economically important plant in the country, and during the 12th to 16th centuries there was a substantial increase in the Swedish export of linen to other parts of Europe. Alongside its extensive cultivation, a set of cultural traditions and rituals was eventually built up around flax. The objective of this article is to draw an outline of the history of flax cultivation in Sweden and to present the relevant prehistoric and historic source material. A point of discussion will be the different roles that fibre flax and oil flax played over a long period of time and the problem of seed corn import for the development of domestic fibre flax in the country. The study is based on the prehistoric archaeobotanical record, mainly charred seeds from the Swedish Iron Age (ca. 500 b.c.–a.d. 1050), the archaeological record, documentary evidence and folklore.     

Impact of meteorological and geographical factors on the distribution of Phlebotomus chinensis in northwestern mainland China

Phlebotomine sandflies (Diptera: Phlebotomidae) are vectors of the zoonotic disease leishmaniasis. To better understand the distribution of phlebotomine sandflies in order to facilitate control of leishmaniasis transmission, the present study explored the impacts of climate and landscape on local abundances of Phlebotomus chinensis in northwestern mainland China. Identification records were used to create a geodatabase for the locations at which P. chinensis had been collected in the region, and a regional‐scale map was developed to show the distribution of P. chinensis. Location data and data on environmental factors during the years in which the samples were collected were incorporated, and a presence‐only modelling method was used to evaluate the species' habitat preferences and to predict its potential distribution in northwestern mainland China. Jackknife analysis revealed that several meteorological variables, including maximum temperature in the warmest quarter, precipitation in the driest month, daily average temperature and daily precipitation, significantly affected the presence of this species. Moreover, the presence of P. chinensis was significantly associated with grassland and shrubland. Probability distributions using maximum entropy were used to map the distribution ranges of P. chinensis based on suitable habitats in northwestern mainland China. The models generated can be used to develop detailed strategies for the prevention and control of leishmaniasis.     

Flax and weld: archaeobotanical records from Mutina (Emilia Romagna, Northern Italy), dated to the Imperial Age, first half 1st century a.d.

In the city centre of Modena (Emilia Romagna, Northern Italy) a noteworthy amount of carpological remains attributable to flax and weld came to light dated to the Imperial Age (first half 1st century a.d.). Flax remains, i.e. capsules and extremely small seeds, suggest the presence of either immature seeds and fruits of cultivated flax (Linum usitatissimum L.) or of a wild flax species (Linum bienne Mill.). The quantity of these remains along with the co-presence of seeds of Reseda luteola, an important dye plant, leads to the hypothesis of the cultivation of both flax and weld for textile manufacturing purposes, which are attested as important in the economy of the Roman period.     

Flax for oil or fibre? Morphometric analysis of flax seeds and new aspects of flax cultivation in Late Neolithic wetland settlements in southwest Germany

The transition from the early to the middle phase of the Late Neolithic (fourth–third millennium b.c.) is closely connected with the term “secondary products revolution”, which involves the adoption of animal traction and an increased production of rendered animal commodities such as wool and dairy products. Based on measurements of Linum usitatissimum L. (flax) seeds and their abundance in 32 wetland settlements in southwest Germany, we presume that the introduction of a new flax variety, maybe a better flax for fibre, and the intensification of flax cultivation were also a part of this process. The morphometric analysis shows that flax seed sizes in the early phase of the Late Neolithic (4000–3400 cal. b.c.) differ significantly from those of the middle and latest phase (3400–2400 cal. b.c.).     

Cultivation and processing of Linum usitatissimum and Camelina sativa in southern Scandinavia during the Roman Iron Age

Charred seed conglomerates of Linum usitatissimum (flax) and Camelina sativa (gold of pleasure) were found at Uppåkra 2:25, a Roman Iron Age site in Skåne, southern Sweden. The conglomerates showed no mixing with each other, as they were almost pure flax and gold of pleasure respectively. Together with other archaeobotanical data from the site, they provide new evidence on the use, processing and cultivation of these two plants in early Iron Age in Scandinavia. Metric analyses were applied to flax seeds from both conglomerates and other contexts at this site, and compared to seed assemblages from other Roman Iron Age sites in Europe. The comparison showed that the flax cultivation at Uppåkra 2:25 was intended for the production of oil-rich seeds. The contextual relationship indicates that both flax and gold of pleasure seeds were processed in a similar way and used for oil. Furthermore, the pure seed conglomerate of gold of pleasure suggests that this plant was not a weed, but rather an intentionally grown crop which was cultivated separately from flax.     

Artificial cultivation of true morels: current state,issues and perspectives

Morels (Morchella, Ascomycota), which are some of the most highly prized edible and medicinal mushrooms, are of great economic and scientific value. Morel cultivation has been a research focus worldwide for more than 100 years, and the outdoor cultivation of morels has succeeded and expanded to a large scale in China in recent years. In this study, we review the progress in recent research regarding the life cycle and reproductive systems in the genus Morchella and the current state of outdoor cultivation. Sclerotia formation and conidia production are two important phases during the life cycle. The morel species cultivated commercially in America is M. rufobrunnea based on molecular phylogenetic analysis. The species currently cultivated in China are black morels, including M. importuna, M. sextalata and M. eximia. The field cultivation of morels expanded in the majority of the provinces in China with a yield of fresh morels of 0–7620?kg per ha. The key techniques include spawn production, land preparation and spawning, the addition of exogenous nutrition, fruiting management and harvesting. The application of exogenous nutrition is the most important breakthrough in the field of morel cultivation, but the mechanism remains unclear. It was estimated that the total amount of field cultivated fresh morels was ～500 t in 2015–2016. We also discuss the potential issues remaining in the current literature and suggest directions for future studies.     

Effects of repeated cultivation of transgenic Bt cotton on functional bacterial populations in rhizosphere soil

The impact of multiple-year (0–5 years) cultivation of transgenic Bacillus thuringiensis (Bt) cotton on the functional bacterial populations in rhizosphere soil was investigated. The transgenic Bt + CpTI cotton line SGK321 and a non-Bt cotton line Shiyuan321 were planted in four fields in which Bt cotton had been continuously cultivated for 0, 1, 3, and 5 years. Rhizosphere soil samples were collected at the seedling, squaring, flower and boll, and boll-opening stages of cotton. Numbers of bacteria involved in nitrogen-fixing, organic phosphate-dissolving, inorganic phosphate-dissolving, and potassium-dissolving were measured with cultivation-dependent approaches. The data presented here showed no consistent statistically significant differences in the numbers of different groups of functional bacteria between rhizosphere soil of Bt and non-Bt cotton in the same field, and no obvious trends in the numbers of the various group of functional bacteria with the increasing duration of Bt cotton cultivation. These studies suggest that multiple-year cultivation of transgenic Bt cotton may not affect the functional bacterial populations in rhizosphere soil.     

Crop water availability in early agriculture: evidence from carbon isotope discrimination of seeds from a tenth millennium BP site on the Euphrates

The analysis of carbon isotope discrimination (Δ) in crop plant remains from archaeological sites may help to assess water availability for early agriculture. This study presents the analysis of Δ in seeds of naked wheat (Triticum aestivum/durum), lentil (Lens orientalis/culinaris), and flax (Linum sp.) found at the archaeological site of Tell Halula in the valley of the Middle Euphrates (Syria). This Neolithic site is the oldest in this region of the Fertile Crescent where the cultivation of domesticated plants has been reported, with seed remains ranging from 9550 to 8465 BP. Most of the seeds analysed showed Δ values greater than 16 ‰, reaching 20 ‰ for some samples of flax. For wheat, Δ values were much higher than those reported in present-day (1996) durum wheat crops cultivated under rainfed conditions in north-west Syria under environments with somewhat higher rainfall than Tell Halula. Similarly, grains of present-day (1997) barley cultivated in the archaeological site also showed lower values than those found in archaeological kernels. An empirical relationship between Δ of mature kernels and total precipitation (plus irrigation where applicable) from heading to maturity (r² = 0.82, n = 11) was established for durum wheat, currently cultivated in different environments of the Mediterranean basin. The resulting relationship was applied to the data on Δ of wheat fossil kernels from Tell Halula to estimate the accumulated water inputs during the time (about 6 weeks) the kernels were produced. Calculated water inputs for wheat during early agriculture were (over 110 mm) at least 5 times higher than current-day rainfall accumulated in Tell Halula during the same phenological period. These results strongly suggest that early agriculture wheat was cultivated at Tell Halula under much wetter conditions than are currently to be found in the area. The presence of flax and its very high Δ values also support this conclusion. Whether such humid conditions during cultivation were due to moister conditions prevailing at this time, by planting in alluvial areas or by irrigation works is discussed.     

Bioremediation efficiencies of <Emphasis Type="Italic">Gracilaria verrucosa</Emphasis> cultivated in an enclosed sea area of Hangzhou Bay,China

Due to the discharge of nutrients into the East China Sea, severe eutrophication has appeared in Hangzhou Bay. Therefore, we cultivated Gracilaria verrucosa on a large scale in the Jinshan enclosed sea with an area of 1.72 km² in the northern part of Hangzhou Bay to perform bioremediation. The Fengxian enclosed sea with an area of 2.3 km² and 50 km far from Jinshan was used as the control. The results showed that the Hangzhou Bay was severely eutrophicated before G. verrucosa cultivation. During the period of cultivation between August 2006 and July 2007, the annual growth rate of G. verrucosa was 9.42% day⁻¹, and the sea water quality was improved from worse than grade IV to grades II–III, with the concentration of dissolved inorganic nitrogen (DIN) and PO₄-P significantly lower than that in the Fengxian enclosed sea (p < 0.01). The concentration of NH₄-N, NO₃-N, NO₂-N, and PO₄-P after G. verrucosa cultivation was decreased by 54.12%, 75.54%, 49.81%, and 49.00%, respectively. The density of phytoplankton in the Jinshan enclosed sea with cultivation of G. verrucosa was 6.90 –126.53 × 10⁴ cells m⁻³, which was significantly lower than that in the Fengxian enclosed sea. In addition, species diversity, richness, and evenness was significantly increased after cultivation of G. verrucosa in the Jinshan enclosed sea compared with that in the Fengxian enclosed sea. The density of Skeletonema costatum, Prorocentrum micans, and Prorocentrum donghaiense, which were the usual species of red tides at the coastal sea of China, in the Jinshan enclosed sea with cultivation of G. verrucosa was significantly lower. Based on these results, if the water quality in the Jinshan enclosed sea were to be maintained at grade I (DIN ≤0.20 mg  L⁻¹) or II (DIN ≤0.30 mg  L⁻¹), 21.8 t or 18.0 t fresh weight of G. verrucosa need to be cultivated, respectively. These results indicated that large-scale cultivation of G. verrucosa could play a significant role in the bioremediation of Hangzhou Bay.     

Morphological variability and allometric relationships of the herb Panax notoginseng in Yunnan,China

A plant's morphology changes throughout its ontogeny. Investigating the allometric relationships between different morphological traits could provide useful information for cultivation of medicinal plants. Here we collected 698 individuals of Panax notoginseng for allometric analysis from seven populations cultivated in Yunnan, Southwest China. The slopes and intercepts of the allometric relationships were estimated by Standardized Major Axis regression. Significant differences (p < 0.05) were found in each morphological variable considered among populations. Allometric analysis showed that all of the log-log relationships had different slopes or shared a common slope but differed in intercept (p < 0.001). The morphological traits showed flexible allometric relationships. However, the root biomass that considered as a target trait showed the least allometric variability (slope = 1.068–1.378) when compared to other variables. This could be because of the hundreds of years of cultivation and artificial selection.     

A comparative study of the population genetics of wild and cultivated populations of Paris polyphylla var. yunnanensis based on amplified fragment length polymorphism markers

Paris polyphylla var. yunnanensis is one of the original plants used to make the traditional medicine Paridis Rhizoma. Wild individuals have been excessively collected in recent decades, and thus, it has become increasingly endangered. Cultivation is a major method for the conservation and sustainable utilization of its wild resources. In this study, amplified fragment length polymorphism markers were used in the genetic analysis of 15 wild and 17 cultivated populations of P. polyphylla var. yunnanensis. This study revealed that cultivated populations possessed higher genetic diversity than wild ones at the species level (H = 0.2636 vs. 0.2616, respectively). However, most of the genetic variation was found within populations for both of these groups (Φ_ST = 18.83% vs. 19.39%). In the dendrogram produced using UPGMA, the 32 populations were divided into three groups (I, II, and III). In group II, both wild and cultivated populations were included, but remained in distinct clusters within this group, which showed the significant separation between the cultivated and wild populations. Furthermore, wild populations were also clustered into three subgroups (W‐I, W‐II, and W‐III), with an obvious geographic structure. In contrast, although cultivated populations were similarly placed in three subgroups (C‐I, C‐II, and C‐III), the latter two of these were not separated based on geography. Finally, the wild populations in Guizhou, China (W‐I), possessed higher genetic diversity than those in Yunnan (W‐II and W‐III). As P. polyphylla var. yunnanensis is an endangered medicinal plant, the fact that it showed richer genetic diversity in its wild populations in Guizhou means that these should be regarded as priority areas for protection and used for provenance selection. Moreover, cultivated populations also showed high genetic variation, which might be attributed to them having originated from mixed provenances, indicating that screening for superior provenances should be carried out as soon as possible.     

Population structure and genetic diversity distribution in wild and cultivated populations of the traditional Chinese medicinal plant Magnolia officinalis subsp. biloba (Magnoliaceae)

Magnolia officinalis subsp. biloba, a traditional Chinese medicinal plant, experienced severe declines in the number of populations and the number of individuals in the late 20th century due to the widespread harvest of the subspecies. A large-scale cultivation program was initiated and cultivated populations rapidly recovered the loss in individual plant numbers, but wild populations remained small as a consequence of cutting. In this study, the levels of genetic variation and genetic structure of seven wild populations and five domestic populations of M. officinalis subsp. biloba were estimated employing an AFLP methodology. The plant exhibited a relatively high level of intra-population genetic diversity (h = 0.208 and H _j = 0.268). The cultivated populations maintained approximately 95% of the variation exhibited in wild populations, indicating a slight genetic bottleneck in the cultivated populations. The analysis of genetic differentiation revealed that most of the AFLP diversity resided within populations both for the wild group (78.22%) and the cultivated group (85.92%). Genetic differentiation among populations in the wild group was significant (F _ST = 0.1092, P < 0.005), suggesting wild population level genetic structure. Principal coordinates analysis (PCO) did not discern among wild and cultivated populations, indicating that alleles from the wild population were maintained in the cultivated gene pool. Results from the present study provide important baseline data for effectively conserving the genetic resources of this medicinal subspecies.     

Cadmium tolerance and accumulation in eight potential energy crops

The production of energy crops that can be used for biodiesel production is a sustainable approach for the removal of metal pollutants by phytoremediation. This study investigated the cadmium (Cd) accumulation and tolerance of eight potential energy crops. After growth for 28 days in substrates containing 0, 50, 100 or 200 mg Cd·kg^− 1, seedlings were evaluated for growth parameters, chlorophyll content, chlorophyll fluorescence parameters and Cd accumulation. All eight crops were moderately tolerant to Cd toxicity, with four [i.e., hemp (Cannabis sativa), flax (Linum usitatissimum), castor (Ricinus communis) and peanut (Arachis hypogaea)] being more tolerant than the others. Three of these crops (hemp, flax and peanut) had higher Cd accumulation capacities. The roots of peanut and hemp had high bioconcentration factors (BCF > 1000), while flax shoots accumulated a higher concentration of Cd (> 100 mg/kg). These results demonstrate that it is possible to grow energy crops on Cd-contaminated soil. Hemp, flax and peanut are excellent candidates for phytoremediation.     

Biomass and lipid production of heterotrophic microalgae <Emphasis Type="Italic">Chlorella protothecoides</Emphasis> by using biodiesel-derived crude glycerol

Microalgal lipids may be a more sustainable biodiesel feedstock than crop oils. We have investigated the potential for using the crude glycerol as a carbon substrate. In batch mode, the biomass and lipid concentration of Chlorella protothecoides cultivated in a crude glycerol medium were, respectively, 23.5 and 14.6 g/l in a 6-day cultivation. In the fed-batch mode, the biomass and lipid concentration improved to 45.2 and 24.6 g/l after 8.2 days of cultivation, respectively. The maximum lipid productivity of 3 g/l day in the fed-batch mode was higher than that produced by batch cultivation. This work demonstrates the feasibility of crude biodiesel glycerol as an alternative carbon substrate to glucose for microalgal cultivation and a cost reduction of carbon substrate feed in microalgal lipid production may be expected.