Abstract:m⁶A modification is one of the most abundant modifications on mRNAs and regulates the fate decisions of mRNAs. YT521B homology (YTH) domaincontaining proteins are typical m⁶A “readers” that recognize and bind m⁶A for posttranscriptional regulation of genes. To investigate the functions of Arabidopsis YTH domaincontaining proteins ECT6 and ECT7 and their molecular mechanisms, we conducted genotyping, semiquantitative PCR identification and flowering phenotype observation of ECT6, ECT7 and ECT6 ECT7 double mutants. Meanwhile, we also analyzed the subcellular localization of ECT6 and ECT7 by cytological observation and detected the expression of key flowering genes by qRTPCR. The results showed that: (1) ECT6 contains five exons and four introns, and the ECT6 mutants is inserted in exons 3 and 5 of the ECT6, respectively; the ECT7 contains six exons and five introns, and the ECT7 mutants is inserted in exons 4 and 6 of the ECT7, respectively. (2) Mutants ECT6 and ECT7 were both lossoffunction mutants, and they both exhibited earlier flowering and reduced leaf number under longday condition. (3) The ECT6 ECT7 double mutant showed earlier flowering and reduced leaf number under both longday and shortday conditions. (4) FLC and FTLC are key flowering regulators. qRTPCR results showed that the expression levels of the flowering repressor gene FLC were reduced and the expression levels of the florigenin gene FTLC were increased in the ECT6 ECT7 double mutants. In addition, the expression levels of the vernalization pathway genes VIN3, VRN2, VRN5 and the autonomous pathway gene FVE were also significantly increased. (5) Both ECT6 and ECT7 were localized in the nucleus and cytoplasm.

Abstract:MiRNA (microRNA) plays an important role in plant growth, development and stress resistance by regulating its target genes. In this study, we used molecular biology and biochemistry methods to study the mechanism of cotton miR397LAC4 module involved in plant lignin biosynthesis and resistance to cotton bollworm. The results showed that: (1) cotton miR397 (ghrmiR397) regulated laccase gene (GhLAC4) expression after transcription, and GhLAC4 belongs to the blue copper oxidase family. It controls the synthesis of lignin and prevents cotton bollworm from invading cotton. (2) GUS reporter gene fusion expression and enzyme activity assay showed that ghrmiR397 directedly cleaved the target gene GhLAC4 after transcription and inhibited its expression. (3) Using VIGS (virus induced gene silencing) technology, miR397 was silenced and overexpressed in cotton. Cotton bollworm analysis showed that silencing ghrmiR397 expression would increase cotton resistance to cotton bollworm, but overexpression of ghrmiR397 would reduce cotton resistance. (4) The experimental analysis, histochemical staining and lignin content determination of selective and non selective cotton bollworm showed that silencing GhLAC4 would reduce the accumulation of lignin and increase the sensitivity of cotton to bollworm. These results show that ghrmiR397GhLAC4 module can fine tune cotton lignin synthesis to participate in the regulation of cotton insect resistance. At the same time, it also provides a new idea for cotton insect resistance breeding.

Abstract:In order to speed up the creation of cytoplasmic male sterility (CMS) restorer line with phytophthora blight resistance in processing type pepper, a hybrid combination was prepared with long fruit inbred line 481410 as female parent and disease resistant restorer lines 9391 and 1021 (1) 1 as male parent. Rf gene and disease resistant gene were introduced into long fruit inbred lines by anther culture technology, molecular marker assisted selection (MAS) was used to preliminarily determine whether DH lines contain Rf gene and disease resistance. The disease resistance of DH lines was verified by seedling resistance identification. The results showed that: (1) twentytwo embryoids were induced by donor parent (481410×9391) F₁, and eleven DH lines were obtained. 9 DH lines were obtained from donor ［481410×1021(1)1］ F₁. (2) The PCR results of molecular marker CRFSCAR showed that seven DH lines obtained from donor (481410×9391) F₁ could amplify 870 bp specific bands, accounting for 63.6%. However, eight DH lines from donor ［481410×1021(1)1］ F₁ could also amplify 870 bp specific bands, accounting for 88.9%. (3) PCR results of FQ01/RQ01 molecular marker showed that five DH lines from donor (481410×9391) F₁ could amplify 717 bp specific bands, accounting for 45.5%. Four DH lines from donor ［481410×1021(1)1］ F₁ could amplify specific bands of 717 bp, accounting for 44.4%. (4) Seven phytophthora blight resistance DH lines carrying Rf gene were preliminarily screened by MAS technology. The identification results of seedling resistance showed that five DH lines were disease resistant and two were moderately disease resistant among the seven DH lines. The investigation of agronomic characters and the test crossing experiment showed that ‘Yulaxuan 32’ and ‘Yulaxuan 71’were single pepper with longer fruit and spicy taste, and both were cytoplasmic male sterility (CMS) restorers. The two DH lines created in this study will lay a foundation for breeding new disease resistant processing pepper varieties with CMS three lines.

Abstract:In order to reveal the roles of asparagus lettuce WRKYⅢ subfamily transcription factors in different biological processes, we cloned two WRKYⅢ subfamily transcription factor genes LsWRKY08 and LsWRKY37 from asparagus lettuce cultivar ‘Yonganhong’ in the study. The sequence alignment, evolutionary tree construction, qRTPCR, interaction network and promoter analysis were carried out. The results will provide a basis for further studying the function of WRKYⅢ transcription factor of asparagus lettuce and improving the yield and quality of asparagus lettuce. The results showed that: (1) LsWRKY08 and LsWRKY37 transcription factors contained 945 bp and 930 bp open reading frames, encoding 314 and 309 amino acid residues, respectively. (2) qRTPCR analysis showed that the expression of LsWRKY08 in leaves was higher than that in roots and stems; in the process of stem expansion, its expression decreased gradually; but compared with control, the expression patterns of LsWRKY08 increased in drought, high/low temperature and salt; the expression of LsWRKY08 increased significantly in SA treatment compared with control. LsWRKY37 showed a higher level of expression in roots than in leaf and stem. Its expression pattern during stem expansion was different to that of LsWRKY08. There were differences in the expression pattern of LsWRKY37 under different abiotic stresses. (3) Interaction network analysis showed that LsWRKY08 and LsWRKY37 could interact with plant defense related proteins and other transcription factors. Promoter analysis showed the promoter regions of LsWRKY08 and LsWRKY37 genes contained multiple cis elements. Wbox element was identified in the promoter region of LsWRKY37, which indicating the selfregulation and crossregulation existed between LsWRKY37 and other WRKY transcription factors. These results showed that LsWRKY08 and LsWRKY37 genes could respond to different abiotic stresses and hormone treatments, but the expression patterns of these two genes were different, which indicating that the function of transcription factor genes belonged to the same subfamily may be different. LsWRKY08 and LsWRKY37 transcription factors could participate in different biological processes through interaction with other proteins or regulation by other genes.

Abstract:Medicago archiducisnicolai was endemic to China, distributed in the eastern margin of the QinghaiTibet Plateau, and has developed spreading rhizome. In order to explore the relationship between the abnormal development of M. archiducisnicolai rhizome and plateau climate adaptation, we anatomized the primary and secondary structure of the plant rhizomes by paraffin section. The results showed that: (1) compared with the primary structure, the secondary structure of M. archiducisnicolai rhizome was unbalanced, only a few vascular bundles developed normally, with developed xylem. (2) The secondary growth of rhizome produced two kinds of periderm: inner periderm and outer periderm. The outer periderm was formed by endodermis cells near phloem, and the inner periderm was formed by medulla cells near xylem. After the formation of inner and outer periderm, they replaced the epidermis and the main parenchyma in primary structure, formed a complex new protective system. (3) The inward constriction of the outer periderm or outward extension of the inner periderm could cause the split of the rhizome, but the two types of splits had not been observed at the same time. It was concluded that the formation of inner and outer periderm and abnormal split of the rhizome of M. archiducisnicolai could enhance the resistance to drought and cold stress, which was the adaptive strategy of M. archiducisnicolai to the cold and drought environment of QinghaiTibet Plateau.

Abstract:Abies fanjingshanensis is a critically endangered plant. In order to reveal the traits of the cone development and maturation process of A. fanjingshanensis, so as to confirm the appropriate harvesting time of mature cones, we regularly observed and collected the cones on mature fruiting trees of A. fanjingshanensis in their natural growth area, then comparatively analyzed the traits of cones, seed scales and seeds at different collecting stages by physical anatomy and morphological parameters determination. The results showed that: (1) the cones of A. fanjingshanensis begun to form in the middle of July and mature in the middle of October every year. The length and width of cone increased significantly from early development to late development, but their morphology and color did not change notably from late development to maturity. (2) The average length, width, fresh weight, dry weight and water content of the mature cone was 7.18 cm, 3.84 cm, 36.98 g, 20.33 g, 45.06%, respectively. (3) The average seed scale layer, total seed scales, seed quantity, and full seed rate per mature cone was 30.76, 250.67, 436.67 g, 82.49%, respectively. (4) The traits of the seeds in the basal, middle and top part of the mature cones were different, the parameters of the seeds in the middle part of the mature cones were the largest and which with the highest full seed rate. The average length, width and thickness of the seeds in the middle part of the mature cones was 9.14, 2.30, 2.37 mm, and the 1000seeds weight was 11.44 g. All the results indicated that the cone ripening process of A. fanjingshanensis took about 3 months from formation to maturity, and the best collection time of mature cone would be in later October. There was no obvious difference in cone shape and color between mature and late development of the cone, so color and shape should not be used as the indicator of cone ripening. Seed scales develop and mature synchronously with their cones, the seed scales in the middle of cone could be fully developed, of which had the largest shape parameters and highest plump seeds. The mature cones of A. fanjingshanensis had large seed quantity and high plump rate, but their seeds were small and light in weight.

Abstract:The molecular mechanism of fruit suture premature of Jinghong mutant peach was explored in this study. Peach fruits of ‘Jinghong’ mutant (JHM) and its wild type (JHW) were used as experimental materials. The hardness, anthocyanin, and the differential expression genes between the suture pulps and the other pulps were compared and analyzed. The results showed that: (1) the fruits of JHM ripened about two weeks later than its wild type fruits, and the suture of JHM matured earlier than the other parts of fruit, and turned red two weeks in advance. (2) The fruit hardness of JHW and JHM gradually decreased during fruit maturation, and the anthocyanin content gradually increased, and all of them changed significantly at 66 days after blooming, also the hardness of the suture was lower, but the anthocyanin content of the suture was higher than that of the other parts of fruit. (3) At 66 days after blooming, the number of differentially expressed genes reached 1 889 between the suture of JHM (MSP) and the fruit surface of JHM (MP). These genes were significantly enriched in the pathway of metabolic pathways, biosynthesis of secondary metabolites, plant hormone signal transduction, phenylpropanoid biosynthesis, etc. Among them, 24 differential candidate genes were screened, including 5 cell wall degradation related genes, 9 pigment synthesis and regulation related genes, 5 ethylene synthesis and conduction related genes, 3 auxin response genes, and 2 NAC transcription factors. (4) To confirm the accuracy and reproducibility of the transcriptome analysis results, 12 genes were selected for qRTPCR validation. The expression profiles of the 12 genes have been assessed using qRTPCR, which were consistent with the RNAseq results, thus confirming our transcriptome analysis. The study found that ethylene diffused from the seed kernel into pulps through suture, which accelerated the expression of ASC1 and ACO1 genes, therefore more ethylene was synthesized. The synthesis of massive amount of ethylene in pulps around the suture site induced the expression of genes related to cell wall degradation and pigment synthesis such as PG, XTH33, CHS, DFR, etc; which finally led to early ripe, softening and changing red.

Abstract:We analyzed the morphology, growth and stress resistance traits of rice seedlings under PEG6000 treatment to explore the effect of BCAT4 on the response to drought stress, using the wildtype ‘Nipponbare’ (NIP) and mutant bcat41 as materials. The results showed that: (1) after 20% PEG treatment, the expression level of BCAT4 in wildtype NIP seedling leaves was significantly higher than that of the control, and the survival rate after rehydration was significantly higher than that of mutant bcat41. (2) After 20% PEG treatment, the relative contents of chlorophyll were decreased, the contents of proline and soluble sugar were increased, while the activities of antioxidant enzymes were increased first and then decreased in the leaves of both rice seedlings and the values of above traits in mutant bcat41 were significantly lower than those in NIP. (3) The contents of malondialdehyde and hydrogen peroxide, and relative conductance increased with the increase of treatment days in the leaves of both rice seedlings and were significantly higher in bcat41 than in NIP. (4) The differences of the morphological, growth and physiological traits between the two rices in roots were less than those in leaves. It was found that BCAT4 mutation aggravated the decrease of chlorophyll content in rice seedling leaves, inhibited the accumulation of osmotic substances and the increase of antioxidant enzyme activities in the shoots, and promoted the accumulation of malondialdehyde and hydrogen peroxide and the increase of relative conductivity under drought stress, which resulting in reduced tolerance of rice seedlings to drought.

Abstract:The oat variety ‘Baiyan No.2’ was used as the material. Setting the salt solution (NaCl∶Na₂SO₄=5∶1) and the alkali solution (NaHCO₃∶Na₂CO₃=5∶1) with 0, 50, 100, 150, 200 mmol/L, respectively, we carried out the potting experiments in the greenhouse. The growth rate, plant water content, leaf ion content and leaf organic acid content of oat were detected. We analyzed the effects of the salt stress and alkali stress on oat ion balance and compared the adaptability of oat to the two types of stress. The results showed that: (1) the plant growth rate and plant water content increased under lower salt stress (50 and 100 mmol/L), and decreased under higher salt stress (150 and 200 mmol/L). However, it depressed with the alkali stress concentration increasing. At the same saline concentration, the influence of alkali stress on plant is greater than salt stress. (2) The contents of K⁺, Ca²⁺, Mg²⁺, SO^2-₄, H₃PO^-₄ and NO^-₃ decreased with the concentration increasing of both salt stress and alkali stress. The contents of Na⁺, Cl^- and SO^2-₄ increased significantly under salt and alkali stress. For example, comparing with CK, at the 200 mmol/L of salt stress and alkali stress, Na⁺ increased 367.15% and 518.41%, respectively; Cl^- increased 785.07% and 52.59%, respectively; SO^2-₄ increased 142.01% and 52.86%, respectively. (3) At 200 mmol/L of the salt stress and alkali stress, the organic acids increased 74.52% and 1 232.34%, respectively. The contents of citrate, aconite, succinate and malic acid were higher in oat leaves under alkali stress and higher concentration of salt stress, and the aconic acid is the main component of total organic acids under both salt stress and alkali stress, citric acid and succinate acid were changed significantly, there were less formic acid, acetic acid, lactic acid, malate acid and oxalic acid. It is concluded that the effect of the alkali stress is more harmful on oat plant growth rate, plant water content, leaf ion content and organic acids than salt stress. Both salt stress and alkali stress caused the accumulation of cation (Na⁺) in oat leaves. Futher, it blocked the absorption of K⁺, Ca²⁺, Mg²⁺, H₃PO^-₄, and NO^-₃. The oat leaves accumulate Cl^- to adjust the leaf ion balance under salt stress, while, it accumulate organic acids under alkali stress to adjust the ion balance. Organic acid is the specific metabolites in response to alkali stress, and aconic acid is the main component of organic acids.

Abstract:We analyzed 7 cultivars of Cymbidium hybrid to explore on components basis of flower coloration. The pigment type was determined by chromogenic reaction and UVvisible spectra, and pigment components and content differences between yellow ‘Yufeng’ and red ‘Fuyunhongxia’ were conducted by ulterperformance liquid chromatography tandem mass spectrometry (UPLCMS/MS). This will provide theoretical references for further revealing mechanism of color formation and breeding in Cymbidium hybrid. The results showed that: (1) 7 cultivars all contained flavonoids, but did not contain carotenoids. Except for ‘Yufeng’ and ‘Shuangyiyafeng’, the rest contained anthocyanins. (2) A total of 160 differential metabolites were identified between the two cultivars and they exhibited more significant enrichment in anthocyanin biosynthesis and flavone and flavonol biosynthesis. (3) In ‘Fuyunhongxia’, the main flavonoids metabolotes are cyandin derivatives and peonidin derivatives, while flavonoids metabolites in ‘Yufeng’ are quercetin derivatives. The results indicated that the diversion of anthocyanin and flavonol is a major reason for the color change in Cymbidium hybrid.

Abstract:Weih 4yearold ‘Mengyuan’ Cerasus humilis was used as the test material, this experiment conducted to explore the phenolic contents (total phenol, total flavonoids, proanthocyanidins, anthocyanin and flavonol) and antioxidant activities (total antioxidant, iron ion reduce power, DPPH·clearance rate and ·OHclearance rate) of leaves in different growing stages of C. humilis, so as to provide theoretical basis for the further development and application of C. humilis leaves resources. The results show that: (1) the contents of phenolic substances in leaves of C. humilis increased firstly and then decreased, and reached the maximum at the pigmentation expansion stage. (2) The antioxidant activities of phenolic compounds were similar to that of phenolic compounds, and reached the maximum at the pigmentation expansion stage, except for individual differences. (3) During the pigmentation expansion stage, the contents of phenolic substances and their antioxidant activities in leaves of C. humilis were the highest, followed by total flavonoids and procyanidins, and flavonols and anthocyanins. In conclusion, the contents of phenolic compounds in leaves of C. humilis had obvious synergistic change relationship with its antioxidant activity, and the antioxidant activity increased or decreased with the increase or decrease of the contents of phenolic compounds. Apart from proanthocyanidin and anthocyanins, the accumulation peak of phenolic substances and total antioxidant capacity of C. humilis leaves reached the highest in the pigmentation expansion stage.

Abstract:To explore the calcium contents, components and distribution characteristics in organs of Vitis quinquangularis Rehd. in Karst area, and to reveal its calcium requirement characteristics and its adaptation mechanism to high calcium soil, we used V. quinquangularis in Karst area of Guizhou as the material in the experiment. The pH valve and exchangeable Ca content in soil, Ca, Mg and calcium component contents in root, stem and leaf of V. quinquangularis in 40 samples were tested. The correlation between exchangeable Ca content in soil and different calcium component contents were analyzed. The calcium crystals on the leaf surface and in root, stem and leaf of V. quinquangularis were observed. The results showed that: (1) the distribution of calcium content in organs of V. quinquangularis was leaf > root > stem, and its distribution characteristic is similar to that of calcicole. (2) The contents of main calcium components in root, stem and leaf of V. quinquangularis from high to low were HClCa, NaClCa, H₂OCa, HACCa, ALCCa, ResCa, but slightly different in stem. The proportion of HClCa in all calcium components and calcium content was the highest in root, stem and leaf, followed by NaClCa. (3) The content of Ca+Mg in leaf of V. quinquangularis ranged from 1.30% to 4.07%, and the majority content ranged from 3.0% to 4.0%, which showed that the characteristic of high Ca+Mg content in leaf of calcicole. (4) There were significant or extremely significant correlations between the contents of various calcium components in V. quinquangularis in Karst area and the exchangeable Ca content in soil. (5) A large number of calcium oxalate crystals were found in leaf and root of V. quinquangularis by scanning electronic microscope, which can be excreted through the stomata in leaf. The studies showed that V. quinquangularis in Karst area was calcicole, which had strong adaptability to high calcium environment. A large number of calcium enriched in leaf, and a large amount of HClCa and NaClCa stored in plants. It played an important role in adapting to high calcium environment that calcium storage characteristic and stomatal calcium excretion behavior.

Abstract:Selecting Threeyearold Phellodendron amurense seedlings in field, we conducted the artificially controlled twofactor randomized block experiment. We analyzed the relative chlorophyll content, gas exchange parameters and carbon and nitrogen stoichiometric characteristics under different light ［full light (S₀), 21.4% light shading (S₁) and 8.7% severe shading (S₂)］ and nitrogen ［no addition control (F₀), light nitrogen addition (F₁) and severe nitrogen addition(F₂)］ stresses, to explore the response mechanism of P. amurense seedlings to shading and nitrogen addition. The results showed that: (1) with the increase of shading, the SPAD value, T_r, G_s, C∶N and PNUE of seedling leaves increased at first and then decreased, and the SPAD value under the two shading conditions were significantly higher than that in full light. P_n, WUE and L_s decreased gradually, while the N and C contents decreased at first and then increased; (2) With the increase of nitrogen addition, P_n, WUE, L_s, N and C contents increased at first and then decreased, while T_r, G_s and PNUE decreased and C∶N increased gradually; (3) There was no significant difference in P_n among different light and nitrogen treatments; SPAD value in the combination of S₁F₀, S₂F₀ and S₁F₂ was significantly higher, while that of full light (S₀) was the lowest. T_r, G_s of light shading (S₁) were significantly higher, while those of S₂F₁, S₀F₂ and S₂F₂ were significantly lower. WUE and L_s were significantly the highest in S₀F₂ and the lowest in S₂F₂ treatment. The N and C contents were higher under heavy shading/light nitrogen addition (S₂F₁), while C∶N and PNUE were higher under light shading/nitrogen zero addition (S₁F₀). (4) According to the comprehensive evaluation of membership function menthod, P. amurense seedlings belonged to moderately resistant type to the light and nitrogen interaction effect. The combination of light and nitrogen suitable for seedling growth was no nitrogen in light shading(S₁F₀) , light nitrogen addition in light shading(S₁F₁) and light nitrogen addition in full light(S₀F₁). The research founded that the light factor is the dominant factor affecting the photosynthesis and regeneration of P. amurense seedlings, but P. amurense could tolerate certain shade stress at the seedling stage. When the light is not limited, the moderate nitrogen addition is beneficial to the growth of P. amurense seedlings; when the light intensity is heavily limited, nitrogen addition inhibits the synthesis of chlorophyll and reduces the light energy utilization efficiency in seedlings, which is not conducive to seedling growth.

Abstract:On the basis of field vegetation investigation, specimen collection and data query, the list of seed plants in Zayü River Basin was summarized, and the composition, dominant families and genera, floristic geographical components and properties of plant species in the basin were analyzed. The flora of 16 regions was clustered and analyzed by Rlanguage at the genus level, and the relationship between floristic components and property characteristics with other flora was discussed. The results show that: (1) there are 138 families, 689 genera and 2 771 species (including varieties) of seed plants in Zayü River Basin, including 56 species in 12 genera and 4 families of gymnosperms, 2 715 species in 677 genera and 134 families of angiosperms, and 2 270 species in 531 genera and 112 families of dicotyledons in angiosperms. (2) The geographical elements in the area are widely connected. In addition to the world distribution type, the floristic division of families includes 53 families (55.21%) of tropical distribution type and 43 families (44.79%) of temperate distribution type; In the floristic division of genera, all types are distributed, including 396 genera (62.07%) of arealtype and 230 genera (36.05%) of tropical distribution type; The richness of plant species is high, but the endemic components are low. There are no endemic families and only 12 endemic genera. (3) The vertical zonal distribution of vegetation in the basin is obvious, and many ancient relic plants are retained, such as Taxus wallichiana, Abies chayuensis and Pinus yunnanensis, etc; due to the ascending movement of the QinghaiTibet Plateau, it has become the cradle of differentiation and reproduction of new alpine flora components such as Rhododendron, Saxifraga, Gentiana and Primula. (4) The flora of Zayü River belongs to the floristic nature of the transition from tropical component to temperate component in the south of Himalayas, which is more similar to the flora of Mount Everest Nature Reserve.

Abstract:Annual branches with a diameter of 0.5-0.7 cm from grape rootstocks and varieties of ‘Zuoshan No. 1’, 10114, 3309C, SO4, 140R, ‘Pinot noir’, etc. were used as the materials. After the treatment of low temperature gradient (0 ℃, -14 ℃, -19 ℃, -24 ℃, -29 ℃ and -34 ℃), the temperature and time of TTC staining were optimized, and the survival of different tissues from grape branches was observed and counted. The relative electrical conductivity of the branches, the contents of soluble protein, free proline, soluble sugar and starch in phloem and xylem, and the ratio of bound water to free water (bundle to body) were measured. The semilethal temperature (LT₅₀) of branches was calculated by Logistic equation fitting the dyeing area of longitudinal section and relative electrical conductivity to evaluate the cold resistance of branches. Meanwhile, the cold resistance of the phloem and xylem of the branches was comprehensively evaluated by the physiological index membership function method. The evaluation results of the three methods were compared to establish an intuitive method for identifying the cold resistance of grape varieties. The results showed that: (1) the optimal conditions for TTC viability staining of grape shoots were pH=7.0, 0.5% TTC0.1 mol/L phosphate buffer at 35 ℃ for 36 h in the dark. With the decrease of stress temperature, the dyeing area of the longitudinal section of each variety decreased gradually. According to the optimized TTC method, the LT₅₀ of branches form ‘Zuoshan No 1’, 10114, 3309C, SO4, 140R, ‘Pinot noir’ were -31.38 ℃, -26.51 ℃, -26.10 ℃, -23.60 ℃, -23.33adually increased, and the relative conductivity of ‘Pinot noir’ basically maintained the highest and the largest increase (51.93%), while the relative electrical conductivity of ‘Zuoshan No.1’ always had the lowest and the smallest increase (44.07%). According to the relative conductivity, LT₅₀ of ‘Zuoshan No.1’, 10114, 3309C, SO4, 140R and ‘Pinot noir’ were -30.02 ℃, -26.40 ℃, -25.75 ℃, -23.16 ℃, -21.13 ℃ and -17.72 ℃, respectively. (3) The comprehensive evaluation results of the membership function of branch cold resistance through five physiological indicators showed that the cold resistance of the phloem in the same variety was stronger than that of the xylem. The cold resistance of different varieties in the same part was as follows: ‘Zuoshan No. 1’ > 10114 > 3309C > SO4 > 140R > ‘Pinot noir’. This study found that the TTC staining method was consistent with conductance method and comprehensive membership function method in evaluating the cold resistance of grape branches. However, compared with the other two methods, TTC staining was more intuitive and effective in evaluating the cold resistance of grape branches.

Abstract:In this study, two different sunflower varieties (LD5009 and JK103) were treated with ‘Jinmiao target’ by root irrigation. The root samples were collected at 0, 24, 48 and 72 h after irrigation for histochemical analysis. H₂O₂ content, ROS scavenging enzyme activity and resistance related gene expression in roots were measured. The growth index and tubercle number of sunflower were measured 20 days after irrigation. The aim of this study was to elucidate the mechanism of ‘Jinmiao target’ in inhibiting Orobanche cumana parasitism of sunflower. The results showed that: (1) compared with the control (water application), the number of tubercles in LD5009_{Jinmiao target} decreased by 95.5 and the parasitism rate decreased by 98.20%, the fresh mass and dry mass of tubercles decreased by 94.60% and 81.63%, the height and stem diameter of sunflower increased by 2.09 cm and 0.52 mm respectively, the growth rates were 14.92% and 15.29% respectively. The number of tubercles in the JK103_{Jinmiao target} reduced by 37.5 compared with the control, the parasitism rate decreased by 98.04%, the fresh mass and dry mass of tubercles decreased by 97.06% and 82.69%, the height and stem diameter of sunflower increased by 2.07 cm and 0.39 mm respectively, the growth rates were 12.26% and 9.70% respectively. (2) After irrigating with ‘Jinmiao target’ inducer, the corpus callosum deposition in the roots of both sunflower cultivars increased. However, the JK103 showed the most significant increase after 48 h. The content of H₂O₂ after 24 h reached the maximum in JK103 and LD5009 varieties, which were 3.53 and 2.68 μmol·g^-1, respectively. Compared to the control, the most significant increase of H₂O₂ content was recorded in LD5009, an increase of 208.05%. (3) The activities of four ROS scavenging enzymes in two varieties showed an initial trend of increasing and then decreasing, all of them reached the maximum value after 48 h of treatment. Compared with the control, the activities of SOD, POD, CAT, PPO in JK103_{Jinmiao target} treatment increased by 69.77 U·g^-1, 5.44 U·g^-1·min^-1, 1.88 U·g^-1·min^-1 and 527 U·g^-1·min^-1, respectively. However, the activities of the above four ROS scavenging enzymes were increased by 25.91 U·g^-1, 13.16 U·g^-1·min^-1, 0.50 U·g^-1·min^-1 and 313 U·g^-1·min^-1 in LD5009_{Jinmiao target} treatment. (4) Transcriptional analysis of related resistance genes indicated that the two varieties were induced in different degrees after treatment. However, induction degree of LD5009Jinmiao target was the most obvious, especially CAT, MnSOD and XTH6. The relative expression levels were more than 50 times higher than the control. The results showed that the ‘Jinmiao target’ inducer had significant inhibitory effect on the parasitism of sunflower, the effect was better before parasitizing sunflower (before the formation of tubercles). ‘Jinmiao target’ inducer could promoted callose deposition in sunflower root cells and resisted the infection of sunflower root by O. cumana at the structural level, it also induced the increase of ROS scavenging enzyme activity and the expression of CAT, PAL, MnSOD and XTH6 genes in sunflower roots, so that sunflower increased resistance to O. cumana parasitism. However, the degree of induction varies from cultivar to cultivar.

Abstract:Over the past 40 years, confection sunflower in China has achieved 4 cycles of significant improvements by growing local landraces selected by farmers, largescale cultivating openpollinated varieties (OPV) through conventional breeding, introduced foreign hybrids, and recently proprietary hybrids domestically developed. The area planted to sunflower in China is expected to remain at around 0.59 Mhm², which is mainly concentrated in 10 provinces of the north region with around threefourth of the production in Inner Mongolia, followed by Xinjiang. In term of sunflower production, over 95% is confection sunflower, which enabled China to become a leading producer of the confection sunflower worldwide. Confection sunflower is mostly used for leisue snack, besides seed yield, seed quality of sunflower (e.g. seed size, seed color, tasty flavor) continues to be the top priority of breeding programs. Moreover, in sunflower production areas, due to longterm continuous cultivation of sunflower without crop rotation, coevolution of disease pathogens, broomrape, and other biotic stresses with sunflower crops, plus, the limited genetic background of confection sunflower, varieties of damages caused by diseases, insects and weeds are getting worse. By summarizing of breeding history of Chinese confection sunflower, particularly international progress of diseaseresistant breeding in sunflower crops, this review would provide significant theoretical and technical supports on underlying resistance mechanisms and development of potential resistant varieties, to further enhance the highefficiency development of the confection sunflower industry.