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Background and Aims: The mutualistic interaction between insects and flowers is considered to be a major factor in the early evolution of flowering plants. The Schisandraceae were, until now, the only family in the ANITA group lacking information on pollination biology in natural ecosystems. Thus, the objective of this research was to document the pollination biology and breeding system of Schisandra henryi., Methods: Field observations were conducted in three populations of S. henryi and the floral phenology, floral characters and insect activities were recorded. Floral fragrances were sampled in the field and analysed using TCT-GC-MS. Floral thermogenesis was measured with a TR-71U Thermo Recorder. Pollen loads and location of pollen grains on insect bodies (including the gut) were checked with a scanning electron microscope and under a light microscope., Key Results: Schisandra henryi is strictly dioecious. Male flowers are similar to female flowers in colour, shape, and size, but more abundant than female flowers. The distance between tepals and the androecium or gynoecium is narrow. Neither male nor female flowers are fragrant or thermogenic. Schisandra henryi is pollinated only by adult female Megommata sp. (Cecidomyiidae, Diptera) that eat the pollen grains as extra nutrition for ovary maturation and ovipositing. Both male and female flowers attract the pollinators using similar visual cues and thus the female flowers use deceit as they offer no food., Conclusions: Schisandra henryi exhibits a specialized pollination system, which differs from the generalized pollination system documented in other ANITA members. Pollen is the sole food resource for Megommata sp. and the female flowers of S. henryi attract pollinators by deceit. This is the first report of predacious gall midges utilizing pollen grains as a food source. The lack of floral thermogenesis and floral odours further enforces the visual cues by reducing attractants for other potential pollinators.

The eIF6 proteins are distributed extensively in eukaryotes and play diverse and essential roles. The bona fide eIF6 protein in Arabidopsis, At-eIF6;1, is essential for embryogenesis. However, the role of eIF6 proteins in rice growth and development remains elusive and requires further investigation. Here, we characterized the functions of OseIF6.1, which is homologous to At-eIF6;1. OseIF6.1 encodes an eukaryotic translation initiation factor with a conserved eIF6 domain. The knockdown of OseIF6.1 resulted in a decrease in grain length and pollen sterility, whereas the overexpression of OseIF6.1 displayed opposite phenotypes. Further studies revealed that OseIF6.1 regulates grain shape by influencing cell expansion and proliferation. In addition, OseIF6.1 interacts with OsNMD3, which is a nuclear export adaptor for the 60S ribosomal subunit. The knockdown of OsNMD3 in plants exhibited reduced fertility and seed setting. Therefore, our findings have significantly enriched the current understanding of the role of OseIF6.1 in rice growth and development. [ABSTRACT FROM AUTHOR]

A representative modern calibration dataset is an essential prerequisite for a reliable quantitative reconstruction of paleoclimate. However, there has been a notable lack of systematic research on the optimal filtering of calibration sets. Four representative high-resolution pollen records were selected to repeatedly reconstruct paleoclimate using multiple approaches such as geographical distance, analogues and climate gradient. Comparisons of pollen-based reconstructions indicate that these varied approaches exhibit significant discrepancy in model performance and reconstruction accuracy under different geographical circumstances and time scales. Generally, in terms of calibration-set selection, the geographical distance method demonstrates greater efficiency for the plain region, but exhibit limitations in areas characterized by significant topographic changes. Analogue-calibration has been found to be more suitable for the edge of the database and also has been proven superior to other two methods for reconstructions exceed Holocene. Selecting calibration sets based only on climate gradients is inappropriate for independent applications, but may act as a limitation for other methods. This preliminary research can contribute to a more precise projection of potential future climate changes by providing essential data input or validating hindcasts for Earth system models. • The approach of the calibration-set selection does matter much to the accuracy of quantitative climate reconstruction. • The distance-calibration is suitable for plain areas, but not for areas with significant topographic changes or atthe edge of the database. • Analog-calibration is aneffective method for the area with complex terrain, as well as for long-time series. • Gradient-calibration could not be used alone, but shouldbetaken into the other two methodsin the meantime. [ABSTRACT FROM AUTHOR]

Northeast China is an essential area for studying the strength of East Asian Summer Monsoon (EASM), due to its northernmost location in EASM domain. However, the lack of sufficient modern pollen data in this region hinders an effective interpretation of fossil pollen records and quantitative vegetation/climate reconstructions. Here, 44 surface pollen samples from forest, steppe, and meadow were used to explore pollen-vegetation-climate relationships. Cluster analysis, species indicator analysis, and principal components analysis, were used to identify the discontinuous and continuous trends in pollen dataset. In addition, correlation analysis and boosted regression trees were used to investigate primary explanatory variables, while coinertia analysis and redundancy analysis to examine pollen-vegetation and pollen-climate correlations respectively. Our results show that: (1) vegetation can be well represented by surface pollen assemblages, i.e. forest is characterized by a high proportion of tree pollen (>70%) dominated by Betula (>40%) along with Alnus, Larix, and Pinus, whereas Steppe by herb pollen (>80%), dominated by Artemisia, Chenopodiaceae; (2) significant correlations exist between pollen assemblages and mean annual temperature and then mean annual precipitation; (3) pollen ratios of Artemisia/Chenopodiaceae and arboreal/non-arboreal can respectively be used as good indicators of humidity and temperature in Northeast China. [ABSTRACT FROM AUTHOR]

The plants of Kadsura longipedunculata (Schisandraceae) are monoecious and possess either red or yellow male flowers (the androecium), with yellow tepals, and yellow female flowers. All flower types simultaneously produce heat and floral odours (dominated by methyl butyrate) throughout a 4–5-h nocturnal period. The flowers are pollinated only by female, pollen-eating Megommata sp. (Cecidomyiidae). Pollen is the only reward, and female flowers use the same attractants as male flowers but offer no food (pollination by deceit). Open pollinated flowers in nature varied in fruit set from 8 to 92%. Megommata (subfamily Cecidomyiinae, supertribe Cecidomyiidi), consists of six described species, which feed on Coccoidea (scale insects) and are distributed worldwide. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 93, 523–536. [ABSTRACT FROM AUTHOR]

Terrestrial palaeo-temperature data are of great value in improving our understanding of past climate and they provide a basis for evaluating climate simulations. Such data are, however, poorly constrained for long time-scales. In addition to the scarcity of high-quality continuous time-series, finding proxies with a clear response to past temperature changes and developing appropriate reconstruction methods are major challenges. We present a new and robust method – Locally-weighted Weighted-average partial least squares (LW-WAPLS) to reconstruct quantitative temperature changes based on a high-resolution 1.74-Ma pollen record from the Zoige Basin on the eastern Tibetan Plateau, where the vegetation today is mainly controlled by temperature. The reconstructed mean annual (MAT) and warmest month (MTWM) temperatures reveal a general cooling trend with two major shifts at ~1.54 and 0.62 Ma BP, and regular glacial-interglacial variability ranging from ~ − 4 to 2 °C and from 8 to 16 °C, respectively. They indicate ~4–5 °C (MAT) and ~ 5–6 °C (MTWM) magnitudes of glacial-interglacial temperatures. Both statistical and ecological evaluations validate the reliability of the reconstructions. The reconstructions provide important insights into the spatial aspects of long-term terrestrial temperature change. LW-WAPLS shows advantages over both the traditional modern analogue technique and non-linear transfer-function methodologies such as WAPLS for reconstructing the broad-scale climate changes for the Zoige Basin, by combining the strength of both methods. The LW-WAPLS approach potentially provides a robust tool to develop pollen-based climate reconstructions over long time-scales. • LW-WAPLS approach is a powerful tool for the quantitative reconstructions of climate on glacial-interglacial scales. • Temperature reconstructions of the eastern Tibetan Plateau reveal the stepwise cooling trend with two major shifts at 1.54 and 0.62 Ma BP and with ~4-5oC (MAT) and 5-6oC (MTWM) magnitude. • Our long-term temperature reconstruction fills a data gap in mid-latitude terrestrial regions • The results provide valuable data for model simulations to elucidate the climate mechanisms [ABSTRACT FROM AUTHOR]

Existing pollen records reveal that a shift from tree-rich to herb-dominated vegetation occurred on the eastern Tibetan Plateau (TP) during the mid-to-late Holocene, which gave rise to the modern vegetation pattern. However, given the complex climatic regulation of vegetation growth, the main climatic controls on arboreal vegetation in the eastern TP still need to be explored. In this study, a 387.5 cm sediment core covering the last 12.6 cal ka was recovered from Emu Co on the eastern TP. Based on pollen analysis in conjunction with the modern analogue technique, the role of various climate factors influencing past vegetation changes was modelled. Our results show that, during 12.6–9.5 cal ka BP, the study area experienced an arid and cold climate, with a sparse vegetation cover, as evidenced by the high abundance of herbaceous pollen and low total pollen concentration. A cold-tolerant deciduous broadleaved arboreal component, dominated by Betula , began to expand at ca. 9.5 cal ka BP, replacing herbaceous vegetation habitat, suggesting a gradual warming and wetting trend. Controlled mainly by rising temperatures, evergreen coniferous tree components develop from 8.7 to 5 cal ka BP, with Picea pollen reaching its maximum abundance. After 5 cal ka BP, the herbaceous vegetation re-expands under the combined pressure of lower temperatures and reduced precipitation. Declining arboreal pollen abundance in the mid-to-late Holocene is prevalent in the available fossil pollen records, but the main drivers have regional peculiarities: in the east-central region of the TP near Emu Co, lower temperatures may have played a more important role in the retreat of trees than reduced precipitation. Conversely, arboreal retreat and vegetation change in the north-east and south-east regions may be related to the weakening of the Asian summer monsoon circulation and seasonal climate changes caused by the East Asian winter monsoon and Indian summer monsoon, respectively. • A Holocene pollen record from the forest/meadow ecotone on the Tibetan Plateau. • Arboreal pollen reduces strongly at ca. 5 cal ka BP on the eastern Tibetan Plateau. • The importance of temperature and precipitation for arboreal decline varies by region. [ABSTRACT FROM AUTHOR]

The Holocene Temperature Conundrum refers to the mismatch between proxy-based temperature records and those based on climate model simulations. A possible reason for this mismatch is a putative proxy-based bias in reconstructed summer temperatures, and therefore, regional reconstructions of seasonal temperature are crucial for resolving the conundrum. In this paper, we reconstruct vegetation and climate changes over the last ∼10,000 years BP based on a high-resolution pollen record from Gushantun peatland, Changbai Mountains, Northeast China. Multiple quantitative reconstruction approaches were used and weighted averaging partial least squares regression (WAPLS) was found to be the most appropriate method for reconstructing Holocene temperature and precipitation. The reconstructed climate record shows that the Holocene Climate Optimum occurred between 8 ka and 6 ka and exhibited a cold month mean temperature that was 3 °C warmer than modern temperatures. Climate gradually cooled during late Holocene with a minimum cold month temperature of −19.6 °C. Four prominent cold events occurred around 8.7 ka BP, 7.8 ka BP, 5.7 ka BP, and 2.5 ka BP with an amplitude variation up to 3 °C. The synthesized seasonal temperature time series and a comparison with other proxies show that the decreasing trend in mean annual temperature is not a seasonal bias caused by summer temperature change. This study provides evidence of a Holocene seasonal temperature change at a regional scale and insights for further understanding of the Holocene Temperature Conundrum. • Reconstructed seasonal temperature changes based on a new high-resolution fossil pollen record in the Changbai Mountains • Synthesized climatic series in Northeast China to investigate the characteristics of regional temperature changes and their driving factors • Reconstructed winter temperature as evidence to address the alleged seasonal bias for the Holocene temperature conundrum [ABSTRACT FROM AUTHOR]

• A mostly undisturbed pollen record from the middle Yangtze River region. • Reconstructed precipitation reveals the pattern of Holocene climate transitions. • Stable humid climate may have favored the development of Neolithic cultures. • Neolithic cultures fell coeval with a rising climate instability ∼ 4000 years ago. Holocene climate transitions have substantially impacted prehistoric civilizations, including those in the Yangtze River Basin (YRB), one of the cradles of human civilizations. The lack of undisturbed sedimentary archives in the YRB poses challenges in understanding the pattern of Holocene climate transitions. We present high-resolution pollen data from a mostly undisturbed wetland in the middle YRB from 11840 cal yr BP to the present. Lithological variations in the sediment core suggest that the wetland transformed into an organic-rich peatland approximately 8000 cal yr BP. Using a tailored pollen-climate training set, our quantitative precipitation reconstruction and a Rate of Change analysis of the reconstructed precipitation indicate that the period 10350–8000 cal yr BP, despite being warm and humid, experienced significant precipitation fluctuations. The increased climate stability during 8000–5500 cal yr BP may have stimulated the development of Neolithic cultures in the YRB. The Late Neolithic cultures rose and fell with an oscillatory precipitation decline due to the weakening monsoon from 5500 cal yr BP. The collapse of YRB Neolithic cultures around 4000 cal yr BP, along with the fall of major civilizations worldwide, suggests a global impact of climate anomalies during mid-late climate transitions. Our study offers insights into the changes in subalpine landscapes in the middle YRB region and the impact of Holocene climate transition on the YRB prehistoric civilizations. [ABSTRACT FROM AUTHOR]

Quantitative reconstruction of past climate plays an important role in understanding global and regional climate changes and validating climate models. Although some important progress has been made in quantitative paleoclimate reconstructions based on terrestrial records in the Indian summer monsoon region, high-resolution quantitative studies spanning the last ∼20 ka are still relatively sparse with differing results. This study presents high-resolution quantitative variations in mean temperature of the coldest month (MTCM, the first controlling factor of the regional vegetation), mean annual temperature (MAT, the second controlling factor), and mean annual precipitation (MAP) from Lake Tengchongqinghai in southwestern China, based on an updated modern pollen dataset and the fossil pollen record spanning the last 18.5 ka. The results show that temperature and precipitation increased gradually from 18.5 ka, and peaked from 7.2 to 4.5 ka when MAT was on average 1.0 °C higher than the modern observational value (14.5 °C), corresponding to the mid-Holocene thermal maximum (HTM), and then decreased gradually. The total reconstructed ranges are between −2.2 and 9.2 °C for MTCM, 7.7 and 17.2 °C for MAT, and 840 and 1300 mm for MAP. On top of this overall climate trend, seven abrupt cold and dry events were detected during the periods of 16.2–14.8 ka, 12.8–11.5 ka, ∼11.1 ka, 9.1–8.4 ka, ∼7.7 ka, 4.3–3.7 ka, and 0.68–0.009 ka (1270–1950 CE). The results of this quantitative reconstruction were validated by both statistical and ecological evaluations. We conclude that the trend of climatic change since 18.5 ka in this study area was primarily driven by June, July, August, and September solar insolation and changes in radiative forcing and greenhouse gas concentrations. The abrupt changes may be caused by changes in the Atlantic meridional overturning circulation, solar activity, the position of the Intertropical Convergence Zone, and volcanic activity. • We present high-resolution pollen-based quantitative variations in MTCM, MAT and MAP from southwestern China. • The period 7.2–4.5 ka was the warmest and wettest period since 18.5 ka. • Seven abrupt cold and dry events were detected over the past 18.5 ka. • This study provides quantitative data support for ecological responses and climate mechanisms. [ABSTRACT FROM AUTHOR]

• 'Hongnanguo' pollinizer has a xenia effect on 'Yali' pear fruits aroma quality. • 189 DAMs and 12,032 DEGs were identified. • 'Hongnanguo' pollinizer increased the content of ABA, IAA, and ethylene. • Established a possible regulatory network of the mechanism of xenia effect on pear aroma formation. The flavor of 'Yali' pear fruits has substantially declined recently as a result of poor pollination tree selection. Xenia effect is a powerful mechanism for regulating aroma production. To study the effect of different pollens on aroma quality and the molecular basis of xenia effect in 'Yali' pear fruits, 'Hongnanguo' and 'Xuehuali' were used as pollinizers, and the hybrid fruits were named YH and YX, respectively. Metabolome, transcriptome, volatile compounds, and hormone were jointly analyzed in YH and YX peels with three ripening stages. After pollinating with 'Hongnanguo' pollen, the contents of total aroma, esters and nerolidol, the odor activity value of characteristic volatiles in YH were significantly increased, compared with the aroma character of the pollinizer cultivars, indicating 'Hongnanguo' pollinizer has a xenia effect on 'Yali' pear fruits aroma quality. Further, the content of ABA, IAA, and ethylene reveal the differences during aroma formation between YH and YX. 189 differentially accumulated metabolites (DAMs) and 12,032 differentially expressed genes (DEGs) were identified. Based on co-expression network analysis, network maps of 'Yali' pear aroma-related DEGs were generated. We surmise aroma biosynthesis genes (ADH, ALDH, NES , and FPS), ABA, IAA, ethylene signal transduction, and several transcription factors play important roles in the xenia effect. [ABSTRACT FROM AUTHOR]