Introduction:Quince A (Cydonia oblonga Mill.), a typical dwarfing rootstock in pear cultivation, is susceptible to iron (Fe) deficiency in calcareous soils. The aim of this study was to compare the strategies in Fe uptake and utilization in dwarfing rootstock quince A (low Fe efficiency) versus a typical vigorous rootstock Pyrus betulifolia (PB) with high Fe efficiency. Methods:Quince A and PB were grown in nutrient solution (pH 6.3) for 4 weeks followed by three pH treatments: pH6.3, pH8.3a (adjusted with hydroxide) and pH8.3b (adjusted with bicarbonate). The Fe uptake and utilization indicators of the rootstocks were assessed at the onset of chlorosis symptoms (after 58 days of treatments). Results and discussion:In contrast to PB, quince A exhibited Fe deficiency chlorosis under bicarbonate (pH8.3b). Bicarbonate stimulated the root proton secretion, inhibited root growth and ferric chelate reductase (FCR) activity in both PB and quince A, whereas high pH without bicarbonate (pH8.3a) stimulated only root proton release. Both species accumulated more Fe in roots under high pH treatments than under pH6.3, resulting in Fe sufficiency in leaves. Both high pH treatments increased the activity of leaf FCR in PB and quince A. However, extractable Fe(II) concentration in leaves was increased by high pH treatments in PB only. This study demonstrated that depressed Fe(III) reduction in leaves caused by bicarbonate rather than high pH explained Fe deficiency in quince A grown in bicarbonate-containing medium.

DNA methylation and transcription factors play roles in gene expression and animal development. In insects, DNA methylation modifies gene bodies, but how DNA methylation and transcription factors regulate gene expression is unclear. In this study, we investigated the mechanism that regulates the expression of Bombyx mori Zinc finger protein 615 (ZnF 615), which is a downstream gene of DNA methyltransferase 1 (Dnmt1), and its effects on the regulation of embryonic development. By progressively truncating the ZnF 615 promoter, it was found that the -223 and -190 nt region, which contains homeobox (Hox) protein cis-regulatory elements (CREs), had the greatest impact on the transcription of ZnF 615. RNA interference (RNAi)-mediated knockdown and overexpression of Hox family genes showed that Hox A1-like can enhance the messenger RNA level of ZnF 615. Further studies showed that Hox A1-like regulates ZnF 615 expression by directly binding to the -223 and -190 nt region of its promoter. Simultaneous RNAi-mediated knockdown or overexpression of Hox A1-like and Dnmt1 significantly inhibited or enhanced the regulatory effect of either gene alone on ZnF 615 expression, suggesting that both DNA methylation of gene bodies and binding of transcription factors to promoters are essential for gene expression. RNAi-mediated knockdown of Hox A1-like and Dnmt1 showed that the embryonic development was retarded and the hatching rate was decreased. Taken together, these data suggest that Hox A1-like and DNA methylation enhance the expression of ZnF 615, thereby affecting the development of B. mori embryos.

Quince (Cydonia oblonga Mill.) is a dwarfing rootstock often used in pear cultivation. However, the pear cultivar 'Huangguan' (Pyrus bretschneideri Rehd. cv) grafted onto quince A (HG-QA) suffered iron (Fe) deficiency chlorosis in the calcareous soils of North China, while 'Huangguan' grafted onto Pyrus betulifolia (HG-PB) did not. We hypothesized that the higher leaf apoplastic pH of HG-QA than HG-PB causes Fe deficiency chlorosis by restricting Fe transportation within leaves. Three-year-old rootstocks quince A and Pyrus betulifolia and the combinations HG-QA and HG-PB were grown in the same orchard in a calcareous soil. Newly expanded leaves were analysed for Fe related properties. Micro X-ray fluorescence analysis was used for Fe mapping within the individual leaves. The extractable Fe(II) concentrations in quince A and HG-QA leaves were much lower than those in Pyrus betulifolia and HG-PB, even though the total leaf Fe concentrations were similar. More Fe was located near the leaf midrib in quince A and HG-QA than in Pyrus betulifolia and HG-PB. These were correlated with the lower ferric chelate reductase (FCR) activity in the chlorotic leaves of the quince A rootstock than Pyrus betulifolia and the lower FCR activity and higher apoplastic pH in the chlorotic leaves of the HG-QA rootstock-scion combination than HG-PB. In conclusion, the reduced Fe availability within the leaves caused by the lower FCR activity and higher apoplastic pH compared with those of HG-PB led to HG-QA leaf chlorosis in calcareous soils. This result implies that rootstocks are involved in the regulation of leaf Fe utilization by scions.

Methyl-CpG (mCpG) binding domain (MBD) proteins especially bind with methylated DNA, and are involved in many important biological processes; however, the binding mechanism between insect MBD2/3 and mCpG remains unclear. In this study, we identified 2 isoforms of the MBD2/3 gene in Bombyx mori, MBD2/3-S and MBD2/3-L. Binding analysis of MBD2/3-L, MBD2/3-S, and 7 mutant MBD2/3-L proteins deficient in β1-β6 or α1 in the MBD showed that β2-β3-turns in the β-sheet of the MBD are necessary for the formation of the MBD2/3-mCpG complex; furthermore, other secondary structures, namely, β4-β6 and an α-helix, play a role in stabilizing the β-sheet structure to ensure that the MBD is able to bind mCpG. In addition, sequence alignment and binding analyses of different insect MBD2/3s indicated that insect MBD2/3s have an intact and conserved MBD that binds to the mCpG of target genes. Furthermore, MBD2/3 RNA interference results showed that MBD2/3-L plays a role in regulating B. mori embryonic development, similar to that of DNA methylation; however, MBD2/3-S without β4-β6 and α-helix does not alter embryonic development. These results suggest that MBD2/3-L recognizes and binds to mCpG through the intact β-sheet structure in its MBD, thus ensuring silkworm embryonic development.

化学杀虫剂是农业害虫防治的主要手段,然而农业害虫已对化学杀虫剂产生了抗药性.RNA农药的应用将是减少使用化学杀虫剂的一种途径.RNA农药具有专一、高效、易降解和对环境友好等优点而受到了关注,但在靶标分子、靶标分子的双链 RNA(dsRNA)生产工艺和应用制剂等方面仍需进一步研究.本研究以褐飞虱Nilaparvata lugens蛋白激酶B基因的dsRNA(dsNlAKT)为例,对利用细菌体系生产dsRNA的方法进行了探究.将NlAKT构建进L4440 载体后,将其转化到缺乏核酸酶(RNase Ⅲ)的大肠杆菌Escherichia coli HT115(DE3)中,进行了dsRNA生产条件的测试.结果表明:(1)当异丙基-β-D-硫代半乳糖苷(IPTG)工作浓度为0.1 mM或0.5 mM时dsRNA的产量没有明显变化,而当其工作浓度增加至1mM时dsRNA产量明显减少;(2)在IPTG诱导时间为2～8h范围内,添加IPTG后诱导6h获得的dsRNA产量最多;(3)在实验室常规提取RNA方法中,增加低剂量溶菌酶预处理这一步骤可增加提取产物中dsRNA的含量.试验结果证明了采用工作浓度为 0.1 mM的IPTG诱导6h的生产条件,并在提取过程中增加溶菌酶的预处理步骤有助于获得较高的dsRNA含量.研究结果为RNA农药的生产条件提供了实验依据.

The data described in this paper were collected from the Circum-Bohai Bay and Loess Plateau regions of northern China. Soil, leaf and fruit nutrients from 225 typical pear orchards in these regions were measured. Soil data included pH, organic matter, total N, alkaline hydrolysable N, available P and available K concentrations of 3 different soil layers, 0–20 cm, 20–40 cm and 40–60 cm, from different orchards. Leaf and fruit data included N, P, K, Ca, Fe, Mn, Cu, Zn and B concentrations of pear trees from different orchards. These data can be used to assess the soil nutrient supply and leaf and fruit nutrient status of pear orchards in two major producing areas, Circum-Bohai Bay and Loess Plateau. Additionally, this dataset provides data to support the development of regionalized and standardized soil nutrient management programs for pear orchards, as well as regionalized layouts of the main varieties in the two producing areas.

Iron (Fe) is a mineral micronutrient for plants, and Fe deficiency is a major abiotic stress in crop production because of its low solubility under aerobic and alkaline conditions. In this study, 18 maize inbred lines were used to preliminarily illustrate the physiological mechanism underlying Fe deficiency tolerance. Then biparental linkage analysis was performed to identify the quantitative trait loci (QTLs) and candidate genes associated with Fe deficiency tolerance using the recombinant inbred line (RIL) population derived from the most Fe-efficient (Ye478) and Fe-inefficient (Wu312) inbred lines. A total of 24 QTLs was identified under different Fe nutritional status in the Ye478 × Wu312 RIL population, explaining 6.1–26.6% of phenotypic variation, and ten candidate genes were identified. Plants have evolved two distinct mechanisms to solubilize and transport Fe to acclimate to Fe deficiency, including reduction-based strategy (strategy I) and chelation-based strategy (strategy II), and maize uses strategy II. However, not only genes involved in Fe homeostasis verified in strategy II plants (strategy II genes), which included ZmYS1, ZmYS3, and ZmTOM2, but also several genes associated with Fe homeostasis in strategy I plants (strategy I genes) were identified, including ZmFIT, ZmPYE, ZmILR3, ZmBTS, and ZmEIN2. Furthermore, strategy II gene ZmYS1 and strategy I gene ZmBTS were significantly upregulated in the Fe-deficient roots and shoots of maize inbred lines, and responded to Fe deficiency more in shoots than in roots. Under Fe deficiency, greater upregulations of ZmYS1 and ZmBTS were observed in Fe-efficient parent Ye478, not in Fe-inefficient parent Wu312. Beyond that, ZmEIN2 and ZmILR3, were found to be Fe deficiency-inducible in the shoots. These findings indicate that these candidate genes may be associated with Fe deficiency tolerance in maize. This study demonstrates the use of natural variation to identify important Fe deficiency-regulated genes and provides further insights for understanding the response to Fe deficiency stress in maize.

Zinc (Zn) deficiency is the most widespread micronutrient deficiency, affecting yield and quality of crops worldwide. Identifying genes associated with Zn-deficiency tolerance in maize is a basis for elucidating its genetic mechanism. A K22 × CI7 recombinant inbred population consisting of 210 lines and an association panel of 508 lines were used to identify genetic loci influencing Zn-deficiency tolerance. Under –Zn and –Zn/CK conditions, 15 quantitative trait loci (QTL) were detected, each explaining 5.7%–12.6% of phenotypic variation. Sixty-one significant single-nucleotide polymorphisms (SNPs) were identified at P < 10−5 by genome-wide association study (GWAS), accounting for 5%–14% of phenotypic variation. Among respectively 198 and 183 candidate genes identified within the QTL regions and the 100-kb regions flanking these significant SNPs, 12 were associated with Zn-deficiency tolerance. Among these candidate genes, four genes associated with hormone signaling in response to Zn-deficiency stress were co-localized with QTL or SNPs, including the genes involved in the auxin (ZmARF7), and ethylene (ZmETR5, ZmESR14, and ZmEIN2) signaling pathways. Three candidate genes were identified as being responsible for Zn transport, including ZmNAS3 detected by GWAS, ZmVIT and ZmYSL11 detected by QTL mapping. Expression of ZmYSL11 was up-regulated in Zn-deficient shoots. Four candidate genes that displayed different expression patterns in response to Zn deficiency were detected in the regions overlapping peak GWAS signals, and the haplotypes for each candidate gene were further analyzed.

Iron (Fe) is an essential trace element for almost all organisms and is often the major limiting nutrient for normal growth. Fe deficiency is a worldwide agricultural problem, which affects crop productivity and product quality. Understanding the Fe-deficiency response in plants is necessary for improving both plant health and the human diet. In this study, Fe-efficient (Ye478) and Fe-inefficient maize inbred lines (Wu312) were used to identify the genotypic difference in response to low Fe stress during different developmental stages and to further determine the optimal Fe-deficient Fe(II) supply level which leads to the largest phenotypic difference between Ye478 and Wu312. Then, genome-wide association analysis was performed to further identify candidate genes associated with the molecular mechanisms under different Fe nutritional statuses. Three candidate genes involved in Fe homeostasis of strategy II plants (strategy II genes) were identified, including ZmDMAS1, ZmNAAT1, and ZmYSL11. Furthermore, candidate genes ZmNAAT1, ZmDMAS1, and ZmYSL11 were induced in Fe-deficient roots and shoots, and the expression of ZmNAAT1 and ZmDMAS1 responded to Fe deficiency more in shoots than in roots. Beyond that, several genes that may participate in Fe homeostasis of strategy I plants (strategy I genes) were identified, which were either encoding Fe transporters (ZmIRT1 and ZmZIP4), or acting as essential ethylene signal transducers (ZmEBF1). Interestingly, ZmIRT1, ZmZIP4, and ZmEBF1 were significantly upregulated under low Fe stress, suggesting that these genes may be involved in Fe-deficiency tolerance in maize which is considered as strategy II plant. This study demonstrates the use of natural variation in the association population to identify important genes associated with Fe-deficiency tolerance and may further provide insights for understanding the molecular mechanism underlying the tolerance to Fe-deficiency stress in maize.

Iron (Fe) is a limiting factor in crop growth and nutritional quality because of its low solubility. However, the current understanding of how major crops respond to Fe deficiency and the genetic basis remains limited. In the present study, Fe-efficient inbred line Ye478 and Fe-inefficient inbred line Wu312 and their recombinant inbred line (RIL) population were utilized to reveal the physiological and genetic responses of maize to low Fe stress. Compared with the Fe-sufficient conditions (+Fe: 200 μM), Fe-deficient supply (−Fe: 30 μM) significantly reduced shoot and root dry weights, leaf SPAD of Fe-efficient inbred line Ye478 by 31.4, 31.8, and 46.0%, respectively; decreased Fe-inefficient inbred line Wu312 by 72.0, 45.1, and 84.1%, respectively. Under Fe deficiency, compared with the supply of calcium nitrate (N1), supplying ammonium nitrate (N2) significantly increased the shoot and root dry weights of Wu312 by 37.5 and 51.6%, respectively; and enhanced Ye478 by 23.9 and 45.1%, respectively. Compared with N1, N2 resulted in a 70.0% decrease of the root Fe concentration for Wu312 in the −Fe treatment, N2 treatment reduced the root Fe concentration of Ye478 by 55.8% in the −Fe treatment. These findings indicated that, compared with only supplying nitrate nitrogen, combined supply of ammonium nitrogen and nitrate nitrogen not only contributed to better growth in maize but also significantly reduced Fe concentration in roots. In linkage analysis, ten quantitative trait loci (QTLs) associated with Fe deficiency tolerance were detected, explaining 6.2–12.0% of phenotypic variation. Candidate genes considered to be associated with the mechanisms underlying Fe deficiency tolerance were identified within a single locus or QTL co-localization, including ZmYS3, ZmPYE, ZmEIL3, ZmMYB153, ZmILR3 and ZmNAS4, which may form a sophisticated network to regulate the uptake, transport and redistribution of Fe. Furthermore, ZmYS3 was highly induced by Fe deficiency in the roots; ZmPYE and ZmEIL3, which may be involved in Fe homeostasis in strategy I plants, were significantly upregulated in the shoots and roots under low Fe stress; ZmMYB153 was Fe-deficiency inducible in the shoots. Our findings will provide a comprehensive insight into the physiological and genetic basis of Fe deficiency tolerance.

Zinc (Zn) deficiency is one of the most common micronutrient disorders in cereal plants, greatly impairing crop productivity and nutritional quality. Identifying the genes associated with Zn deficiency tolerance is the basis for understanding the genetic mechanism conferring tolerance. In this study, the K22×BY815 and DAN340×K22 recombination inbred line (RIL) populations, which were derived from Zn-inefficient and Zn-efficient inbred lines, were utilized to detect the quantitative trait loci (QTLs) associated with Zn deficiency tolerance and to further identify candidate genes within these loci. The BLUP (Best Linear Unbiased Prediction) values under Zn-deficient condition (-Zn) and the ratios of the BLUP values under Zn deficient condition to the BLUP values under Zn-sufficient condition (-Zn/CK) were used to perform linkage mapping. In QTL analysis, 21 QTLs and 33 QTLs controlling the Zn score, plant height, shoot and root dry weight, and root-to-shoot ratio were detected in the K22×BY815 population and the DAN340×K22 population, explaining 5.5–16.6% and 4.2–23.3% of phenotypic variation, respectively. In addition, seventeen candidate genes associated with the mechanisms underlying Zn deficiency tolerance were identified in QTL colocalizations or the single loci, including the genes involved in the uptake, transport, and redistribution of Zn (ZmIRT1, ZmHMAs, ZmNRAMP6, ZmVIT, ZmNAS3, ZmDMAS1, ZmTOM3), and the genes participating in the auxin and ethylene signal pathways (ZmAFBs, ZmIAA17, ZmETR, ZmEIN2, ZmEIN3, ZmCTR3, ZmEBF1). Our findings will broaden the understanding of the genetic structure of the tolerance to Zn deficiency in maize.

Cell division and differentiation after egg fertilization are critical steps in the development of embryos from single cells to multicellular individuals and are regulated by DNA methylation via its effects on gene expression. However, the mechanisms by which DNA methylation regulates these processes in insects remain unclear. Here, we studied the impacts of DNA methylation on early embryonic development in Bombyx mori. Genome methylation and transcriptome analysis of early embryos showed that DNA methylation events mainly occurred in the 5' region of protein metabolism-related genes. The transcription factor gene zinc finger protein 615 (ZnF615) was methylated by DNA methyltransferase 1 (Dnmt1) to be up-regulated and bind to protein metabolism-related genes. Dnmt1 RNA interference (RNAi) revealed that DNA methylation mainly regulated the expression of nonmethylated nutrient metabolism-related genes through ZnF615. The same sites in the ZnF615 gene were methylated in ovaries and embryos. Knockout of ZnF615 using CRISPR/Cas9 gene editing decreased the hatching rate and egg number to levels similar to that of Dnmt1 knockout. Analysis of the ZnF615 methylation rate revealed that the DNA methylation pattern in the parent ovary was maintained and doubled in the offspring embryo. Thus, Dnmt1-mediated intragenic DNA methylation of the transcription factor ZnF615 enhances its expression to ensure ovarian and embryonic development.

Zinc (Zn) deficiency, a globally predominant micronutrient disorder in crops and humans, reduces crop yields and adversely impacts human health. Despite numerous studies on the physiological mechanisms underlying Zn deficiency tolerance, its genetic basis of molecular mechanism is still poorly understood. Thus, the Zn efficiency of 20 maize inbred lines was evaluated, and a quantitative trait locus (QTL) analysis was performed in the recombination inbred line population derived from the most Zn-efficient (Ye478) and Zn-inefficient inbred line (Wu312) to identify the candidate genes associated with Zn deficiency tolerance. On this basis, we analyzed the expression of ZmZIP1-ZmZIP8. Thirteen QTLs for the traits associated with Zn deficiency tolerance were detected, explaining 7.6-63.5% of the phenotypic variation. The genes responsible for Zn uptake and transport across membranes (ZmZIP3, ZmHMA3, ZmHMA4) were identified, which probably form a sophisticated network to regulate the uptake, translocation, and redistribution of Zn. Additionally, we identified the genes involved in the indole-3-acetic acid (IAA) biosynthesis (ZmIGPS) and auxin-dependent gene regulation (ZmIAA). Notably, a high upregulation of ZmZIP3 was found in the Zn-deficient root of Ye478, but not in that of Wu312. Additionally, ZmZIP4, ZmZIP5, and ZmZIP7 were up-regulated in the Zn-deficient roots of Ye478 and Wu312. Our findings provide a new insight into the genetic basis of Zn deficiency tolerance.

In North China, the high-quality pear cultivar “Huangguan” (Pyrus bretschneideri Rehd. cv), which is grafted onto dwarf quince A (Cydonia oblonga Mill. cv) rootstock and grown in calcareous soil, experiences severe iron (Fe) deficiency; this deficiency greatly constrains tree growth as well as fruit yield and quality. Therefore, we evaluated the effects of six practices for alleviating chlorosis caused by Fe deficiency in “Huangguan” grafted onto quince A (HG-QA). The practices included ridging with landscape fabric mulching as a control, flattening with landscape fabric mulching (FM), ridging without landscape fabric mulching (R), flattening without landscape fabric mulching (F), Fe fertilizer application in soil (SFe), foliar Fe application (FFe), and manure application (M). The results showed that the leaf Fe concentration increased by 356% under FFe, compared to that under the control, but the practice failed to alleviate Fe deficiency chlorosis. In contrast, an increase in leaf Fe concentration and chlorosis alleviation were observed under F. F alleviated chlorosis mainly by increasing the root ferric-chelate reductase activity. These results indicate that Fe uptake and utilization in leaves are independent biochemical processes and soil aeration improvement have positive effect on increasing Fe uptake. M improved both the soil active Fe concentration and leaf Fe utilization. Thus, manure application should be the first choice for alleviating Fe deficiency chlorosis in HG-QA grown in calcareous soils. Combining manure application with other practices that increase Fe uptake would likely be an effective way to address the problem of Fe deficiency chlorosis.

All over the world, a common problem in the soil is the low content of available zinc (Zn), which is unevenly distributed and difficult to move. However, information on the foraging strategies of roots in response to heterogeneous Zn supply is still very limited. Few studies have analyzed the adaptability of maize inbred lines with different Zn efficiencies to different low Zn stress time lengths in maize. This study analyzed the effects of different time lengths of low Zn stress on various related traits in different inbred lines. In addition, morphological plasticity of roots and the response of Zn-related important gene iron-regulated transporter-like proteins (ZIPs) were studied via simulating the heterogeneity of Zn nutrition in the soil. In this report, when Zn deficiency stress duration was extended (from 14 to 21 days), under Zn-deficient supply (0.5 μM), Zn efficiency (ZE) based on shoot dry weight of Wu312 displayed no significant difference, and ZE for Ye478 was increased by 92.9%. Under longer-term Zn deficiency, shoot, and root dry weights of Ye478 were 6.5 and 2.1-fold higher than those of Wu312, respectively. Uneven Zn supply strongly inhibited the development of some root traits in the -Zn region. Difference in shoot dry weights between Wu312 and Ye478 was larger in T1 (1.97 times) than in T2 (1.53 times). Under heterogeneous condition of Zn supply, both the –Zn region and the +Zn region upregulated the expressions of ZmZIP3, ZmZIP4, ZmZIP5, ZmZIP7, and ZmZIP8 in the roots of two inbred lines. These results indicate that extended time length of low-Zn stress will enlarge the difference of multiple physiological traits, especially biomass, between Zn-sensitive and Zn-tolerant inbred lines. There were significant genotypic differences of root morphology in response to heterogeneous Zn supply. Compared with split-supply with +Zn/+Zn, the difference of above-ground biomass between Zn-sensitive and Zn-tolerant inbred lines under split-supply with –Zn/+Zn was higher. Under the condition of heterogeneous Zn supply, several ZmZIP genes may play important roles in tolerance to low Zn stress, which can provide a basis for further functional characterization.

Tomatoes are essential for human health, and there is an urgent need to increase tomato yield and quality worldwide. Arginine is beneficial to crop storage quality and stress resistance in plants; however, its effects on nitrogen nutrition, tomato production, and quality have not been thoroughly investigated. Thus, this study investigated the influences on tomato growth, yield, and quality by spray arginine. Arginine significantly increased the nitrogen concentration in tomato shoots and fruits, induced by three pathways: assimilate arginine as nitrogen resource; up-regulate SlNRT1.1 expression; increase root development and activity. The photosynthesis was then significantly improved via increased nitrogen levels, further led to enhancement in plant growth, fruit size and yield of tomato. Moreover, arginine treatment positively affected tomato qualities, especially lycopene and vitamin C, by improving nitrogen accumulation. Present results revealed that arginine displayed tremendous potential for increasing tomato production and quality.

目的 研究稳定同位素技术鉴别天麻真伪的可行性.方法 利用稳定同位素质谱仪测定天麻及其伪品碳、氮同位素比率,比较不同样品中稳定性碳、氮同位素含量的差异,对结果进行方差分析和聚类分析.结果 天麻及其伪品马铃薯、洋姜、紫茉莉、大丽菊的δ13C平均值分别为-24.2、-26.3、-30.4、-29.3、-26.2,方差分析结果为天麻δ13C值显著性高于马铃薯、洋姜、紫茉莉、大丽菊(P ＜0.000 1);聚类分析显示天麻样品属于一类,伪品属于其他类,证明δ13C值可以将天麻与伪品完全分开.天麻、马铃薯、洋姜、紫茉莉、大丽菊的δ15N平均值分别为-1.28、-0.53、-0.86、2.76、-0.73,方差分析结果为天麻δ15N值显著性低于马铃薯、紫茉莉、大丽菊(P＜0.000 1),而天麻与洋姜无显著性差异;聚类分析表明天麻样品与部分伪品聚在一起,没有单独归类,δ15N值不能将天麻与伪品完全分开.结论 利用稳定碳同位素δ13C值可明显将天麻与其他伪品分开;稳定氮同位素δ15N值可将天麻与部分伪品区分开,有一定的鉴别潜力,可作为一种参考.

Quince (Cydonia oblonga Mill.) represents an examplar rootstock in modern training programmes to escalate pear production worldwide because of its dwarfing characteristic and precocity. However, iron deficiency often poses a hard hurdle to overcome for developing quince grafted pears in calcareous and alkaline soils. In North China, we observed that the high-quality pear cultivar Huangguan (Pynus bretschneideri Rehd.) grafted onto quince A (Hardy as interstock, defined as HG-QA) suffered iron deficiency chlorosis in calcareous soils in early spring, even more severe during late spring to early summer. In contrast, Huangguan grafted onto Pyrus betulifolia (Hardy as interstock, defined as HG-PB) did not suffer it. We were inspired to design this field experiment to figure out iron mobilization/uptake in the two rootstocks and the two scion-rootstock combinations. Our results showed that the soil plant analysis development (SPAD) values of quince A (24.7) and HG-QA (13.7) were much lower than that of Pyrus betulifolia (41.6) and HG-PB (36.1). The root length density and surface area density of quince A and HG-QA were more than 2-fold higher than those of Pyrus betulifolia and HG-PB. The rhizosphere pH of quince A and HG-QA was more than 0.20 units lower than that of Pyrus betulifolia and HG-PB respectively, whereas we didn't detect any obvious differences in the root ferric-chelate reductase activity, iron concentrations in leaves and roots, and iron transport ratio. These results strongly suggest that the iron efficiency of HG-PB is attributed to an iron activation mechanism in leaves. The deciphering of the mechanisms that how rootstock influences the iron acquisition system inside the leaf of the scion and changes the efficiency of iron utilization will facilitate making effective solutions for iron deficiency induced chlorosis, popularizing and planting Huangguan grafted onto quince A in pear production.

目的 研究稳定同位素技术用于鉴别酸枣仁的可行性.方法 以酸枣仁、理枣仁和枳椇子为试材,采用稳定同位素技术,测定酸枣仁、理枣仁和枳椇子的碳、氮同位素比率,对结果进行方差分析和聚类分析.结果 酸枣仁、理枣仁和枳椇子中稳定同位素δ13C平均值分别为-26.60、-27.50、-27.84,方差结果表明酸枣仁碳同位素比率平均值显著高于理枣仁和枳椇子(P ＜0.0028);聚类分析结果表明,利用碳同位素δ13C值聚类可以完全的将酸枣仁与理枣仁和枳椇子进行区分.酸枣仁、理枣仁和枳椇子中稳定同位素δ15N平均值分别为-1.38、2.31、1.98,方差结果表明为酸枣仁氮同位素比率平均值显著低于理枣仁和枳椇子(P＜0.0071);聚类分析结果表明,利用氮同位素δ15N值聚类可以区分出部分酸枣仁.理枣仁与枳椇子的碳同位素比率值、氮同位素比率值相近,碳方差分析、氮方差分析无显著性差异,碳聚类分析和氮聚类分析结果均为同一类.结论 稳定同位素技术可望为酸枣仁的真伪鉴别提供新的方法.

Background Zn is essential for plants and Zn deficiency leads to great reduction in quality and quantity of crops. Maize, as one of the most important main staple crops worldwide, is more susceptible to Zn deficiency than any other cereal crops. Therefore, understanding the functional mechanisms in tolerance to Zn deficiency in maize is urgent but is still lacking. In this study, quantitative trait loci (QTL) analysis in K22 and By815 RIL population with high-density bin map was conducted to investigate genetic basis of the mechanisms in maize to tolerate Zn deficiency, subsequently some candidate genes were identified and considered as being associated with Zn metabolisms in plants. Results 21 QTLs were detected and accounted for 5.9% - 16.6% of phenotypic variations. Based on the co-localization in this study and the comparisons with previous studies in different RIL and GWAS populations, 223 candidate genes were identified inside the reduced QTL peak intervals on chromosome 1, 2, 6, 7 and 9. Furthermore, 9 genes detected within the peak bins of valuable genomic regions are suggested to be associated with ions transportation and some redox processes affected by Zn deficiency. Additionally, 5 genes, including ZmIRT1, ZmNRAMP6, ZmEIN2 and ZmHMAs, whose homologous gene have been studied and considered to be responsible for metal cations transportation and ethylene-signaling pathway requiring a transition metal were discovered in 5 loci we mapped. Conclusions 14 target genes identified in 9 loci we mapped in this work were explored to elucidate the potential functions in Zn homeostasis and the direct or indirect effects on mechanisms in Zn deficiency tolerance in maize. It is the first time that ZmIRT1, ZmNRAMP6, ZmHMAs were identified using linkage analysis under Zn deficiency in maize, providing genetic evidence and foundation for further gene functional characterization. Our findings have assisted us untangling the genetic basis of possible mechanisms in response to Zn deficiency in maize.