In plants,the genome structure of hybrids changes compared with their parents,but the effects of these changes in hybrids remain elusive.Comparing reciprocal crosses between Col × C24 and C24 × Col in Arabidopsis using high-throughput chromosome conformation capture assay（Hi-C）analysis,we found that hybrid three-dimensional（3D） chromatin organization had more long-distance interactions relative to parents,and this was mainly located in promoter regions and enriched in genes with heterosis-related pathways.The interactions between euchromatin and heterochromatin were increased,and the compartment strength decreased in hybrids.In compartment domain（CD） boundaries,the distal interactions were more in hybrids than their parents.In the hybrids of CURLY LEAF（clf） mutants clf Col ×clf C24 and clf C24 ×clf Col ,the heterosis phenotype was damaged,and the long-distance interactions in hybrids were fewer than in their parents with lower H3K27me3.ChIP-seq data revealed higher levels of H3K27me3 in the region adjacent to the CD boundary and the same interactional homo-trans sites in the wild-type（WT） hybrids,which may have led to more long-distance interactions.In addition,the differentially expressed genes（DEGs） located in the boundaries of CDs and loop regions changed obviously in WT,and the functional enrichment for DEGs was different between WT and clf in the longdistance interactions and loop regions.Our findings may therefore propose a new epigenetic explanation of heterosis in the Arabidopsis hybrids and provide new insights into crop breeding and yield increase.

Morella rubra, red bayberry, is an economically important fruit tree in south China. Here, we assembled the first high-quality genome for both a female and a male individual of red bayberry. The genome size was 313-Mb, and 90% sequences were assembled into eight pseudo chromosome molecules, with 32 493 predicted genes. By whole-genome comparison between the female and male and association analysis with sequences of bulked and individual DNA samples from female and male, a 59-Kb region determining female was identified and located on distal end of pseudochromosome 8, which contains abundant transposable element and seven putative genes, four of them are related to sex floral development. This 59-Kb female-specific region was likely to be derived from duplication and rearrangement of paralogous genes and retained non-recombinant in the female-specific region. Sex-specific molecular markers developed from candidate genes co-segregated with sex in a genetically diverse female and male germplasm. We propose sex determination follow the ZW model of female heterogamety. The genome sequence of red bayberry provides a valuable resource for plant sex chromosome evolution and also provides important insights for molecular biology, genetics and modern breeding in Myricaceae family.

This book introduces readers to nearly 600 common weeds. In addition to essential information, each chapter includes photos for a specific type of weed to

One-year-old bulblets of Lycoris aurea were obtained by propagation of cuttings. Different concentrations of N-(2-chloro-4-pyridyl)-N1-phenylurea (CPPU; 0, 1.0, 2.0, 5.0, 7.5, or 10.0 mg l(-1)) were sprayed on all the leaves on each plant at the green-leaf stage. Morphological indices including bulblet fresh weights (FW) and diameters, carbohydrate concentrations, the activities of enzymes related to starch metabolism, and the concentrations of endogenous hormones were determined in bulblets during dormancy. Bivariate correlation analysis was used to analyse the relationships of all parameters. The results showed that spray treatment with an appropriate concentration of CPPU was beneficial for the enlargement of L. aurea bulblets. The optimum concentration was 1.0 mg Bivariate correlation analysis showed that bulblet FW and diameter had a significant (P <= 0.05) positive correlation with starch concentration. The concentration of zeatin riboside (ZR) showed a significant (P <= 0.01) positive correlation with soluble starch synthase (SSS) and granule-bound starch synthase (GBSS) activities. Our study indicated that 1.0 mg l(-1) CPPU promoted the activity of starch synthase and accelerated the accumulation of starch in bulblets, and that the observed increase in endogenous ZR may also have an important role.

In order to study the effect of different explant and different hormone concentrations on callus induct,in this study,floral organs of Lycoris aurea and L. sprengeri were cultured on MS medium supplemented with different hormones and the induced calluses were observed by SEM and TEM. The results showed that five kinds of the floral organs of L.aurea and L. sprengeri were able to generate callus. Among these,the ovary of L. aurea gave the highest calluses induction rate of 88. 2%. While after cultured on the MS medium supplemented with 1mg·L-1BA and 1mg·L-12,4-D,all the floral organs of L. sprengeri could generate calluses and the highest calluses induction rate could reach64. 7%. The induced callus could be divided into three types according to the color and texture of callus. Ultrostructure observation found that the light yellow granular callus was embryonic callus. Thus,our research results will provide theoretical basis and technology for further research on efficient regeneration system and transgenic breeding of Lycoris.

Differentially expressed genes related to starch metabolism in mature and juvenile bulbs of Lycoris sprengeri were screened via tag-based digital gene expression profiling. The relative expression levels of these genes were further verified by quantitative real-time polymerase chain reaction. Related enzyme activities and carbohydrate concentrations were determined to study the molecular mechanism of starch accumulation during bulb development. Four starch metabolic genes (LsBAM1, L5AMY1, LsAMY3 and LsSS1) were differentially expressed between the mature and juvenile bulbs. LsSS1 is utilised during starch synthesis and the three other genes are utilised for starch degradation. The expressions of the four genes were significantly higher in juvenile bulbs than in mature bulbs. Along with bulb development (seven sizes, from bulblets to mature bulbs), beta-amylase (BAM) activity significantly increased whereas alpha-amylase (AMY) activity slightly fluctuated. The expression levels of LsBAM1, LsAMY1 and LsAMY3 were either negatively correlated or not correlated with BAM and AMY activities. Soluble starch synthase (SSS) activity increased with decreased LsSS1 expression whereas granule-bound starch synthase (GBSS) activity decreased, indicating a positive correlation with the decreased expression level of LsSS1. During bulb development, the carbohydrate concentrations increased. In the largest mature bulbs, the highest concentration of total soluble sugar coincided with the highest beta-amylase activity However, no evidence was found to confirm the relationship between this phenomenon and related gene expression. The results revealed preliminary characteristics related to starch metabolism during the bulb development of L. sprengeri. (C) 2013 Elsevier B.V. All rights reserved.

The plants of the Lycoris genus are precious flower bulb resources of China. However, they are restricted by the long life cycle and low proliferation, and cannot meet the needs of commercial production. For effective asexual propagation methods, scales cutting, spray cultivation and tissue culture were conducted in L. radiata. For the scales cutting in substrate, the highest budding rate and propagation coefficient reached 80.5% and 7.2, respectively. Spray cultivation of bulb pieces was proved to be an effective method for bulblet reproduction of Lycoris, which generated more buds and higher propagation coefficient as 9.8. 5 g/L activated carbon effectively prevented the browning of explants during tissue culture. Medium component with 10 mg/L BA and 0.5 mg/L NAA was proved best for buds inducing and proliferating. Furthermore, we carried out the enrichment analysis of pathways during bulb development, and got some genes related to starch and sucrose metabolism, which will beneficially support the further molecular breeding of Lycoris.

Carbohydrate contents and α-amylases activity were determined to investigate the physiological mechanism of dormancy release with low temperature storage in tubers of Z.hybrida ' Flamigo ',which 4,8,12,and 16 weeks at 6℃ storage before planting.The results showed that the longer in low temperature storage could accelerate the vegetative growth and early bloom.Cultivated 50 days,the starch contents were the highest at 4 weeks while the total soluble sugar reached the highest at 12 weeks.After 12 weeks storage,the contents of total soluble sugar and α-amylases activity decreased significantly,which indicated that the tuber dormancy had been fully released.

<正>每年的12月,荷兰已是白雪皑皑的隆冬时节,而一间间花卉工厂里却温暖如春,全世界80%的郁金香正在这里茁壮成长。笔者有幸在这个季节到荷兰最大的郁金香切花生产公司之一的DeHout进行了为期3个月的实习。DeHout年产郁金香切花3000万～3200

The Illumina GA II high-throughput sequencing technology was used to establish a transcriptome library from the bulbs of Lycoris sprengeri. A total of 24 million short read with an average length of 90 nt were generated, which produced 98,150 unigenes with a mean length of 385 nt. A total of 45.9% of these unigenes (45,052) were annotated using BLAST (E-value <= 1.0E(-5)) against the nr, SwissProt, Kyoto encyclopedia of genes and genomes (KEGG) and Clusters of orthologous groups (COG) databases. The unigenes were annotated with gene ontology (GO) and COG. Of these, 2,173 unigenes were found to be related to carbohydrate metabolism, and 544 were involved in starch and sucrose metabolism.

Gene expression-profiling data are necessary to understand more clearly the differential gene expression that occurs in biological developmental process. This study is aimed to compare the differential gene expression between bulb and bulblet of Lycoris sprengeri, as to reveal the biological and molecular mechanisms in bulb development. Method: Two Digital Gene Expression tag profiling (DGE) libraries of different developmental stages of Lycoris sprengeri were built according to Illumina sequencing and compared using bioinformatics methods. The altered expression levels of these genes, as well as the enrichment of gene ontology terms and pathways in the KEGG database were then analyzed in detail. Result: A total number of 3,476,452 and 3,597,890 of raw tags were generated for the mature and juvenile DGE libraries, and 4,389 significantly differentially expressed genes were obtained. 45,181 (13.95%) and 41,093 (32.25%) distinct tags for the mature and juvenile bulbs were mapped to a unique sequence in the reference database, respectively. For the DGE data quality check, the lowly-expressed tags (the copy number < 10) comprised most of the distinct clean tags, and the number of detected genes kept stable when the tag number larger than 2 million. Most genes expressed in fewer than 10 copies (log 10 < 1). The metabolic process, the catalytic activity, cell and cell part were the most significantly enriched GO term in the three categories, consisting of 74, 67.7, and 98.6% of their differentially expressed gene groups, respectively. Conclusion: DGE is proved to be effective method for differentially expressed gene analysis on bulb development of Lycoris sprengeri.

Sedum lineare,Ophiopogon japonicus var.nana,Trachelospermum jasminoides and Euonymus fortunei var.radicans were used to investigate the plant growth and chlorophyll fluorescence characteristics under trampling stress.The results showed that except for Sedum lineare,all the species behavioured well after trampling and in the next year.Under trampling stress,the color of minimal fluorescence(Fo)image got darker,and indicated a decline of chlorophyll content.The value of Fv/Fm was lower than that of untrampled ones.For Trachelospermum jasminoides and Euonymus fortunei var.radicans,qP and ETR were higher than untrampled ones,and NPQ was lower than them.While Sedum lineare and Ophiopogon japonicus var.nana showed different trend.Combined with the indicators,Trachelospermum jasminoides and Euonymus fortunei var.radicans which belonged to lines exhibited better trampling resistance than tufts like Sedum lineare and Ophiopogon japonicus var.nana.The chlorophyll fluorescence characteristics can be used in the assessing of trampling resistance.

Tolerance of gerbera (Gerbera jamesonii L.) to long-term sodium chloride (NaCl) salt stress was evaluated by subjecting plants to 0, 10, 20, 30 and 40 mM NaCl levels for ten weeks. Increased NaCl led to a significant decrease in leaf and stem biomass. Salt stress significantly affected sodium (Na+), potassium (K+) concentrations in leaves, stems and roots leading to sharp declines in K+/Na+ ratios. Magnesium concentrations in stems and roots also showed significant declines. Adverse effect of salt stress on chlorophyll content was also significant. Proline seemed less effective in osmotic adjustment under long-term high salt stress. Switching from vegetative to reproductive growth phase was crucial for certain physiological functions. Leaf Na+ concentration showed significant correlation with important traits. These data suggest that NaCl threshold level in irrigation water for gerbera is around 10 mM. Leaf fresh weight, chlorophyll content and leaf K+/Na+ ratio are promising indicators of salt-sensitivity of gerbera.

The establishment of Lycoris regeneration and genetic transformation system is significant to solve the breeding problems.Some research institutions have studied on it for long.However,none mature and effective plant regeneration or transformation system was established.This paper summarizes the progresses on tissue culture of Lycoris,including the types and treatments of explants of L.aurea,L.radiate,L.albiflora,and L.squamigera,et al,and the optimal combination of medium as well as culture condition.Moreover,this article also briefs the transgenic status of other flower bulbs,which can be referenced in the future study of Lycoris.

The variegated characters of Hosta is related to the stable inheritance of chimera. Hosta 'So Sweet' and H. ventricosa were selected as the materials to identify the characteristics of variegated-leaf chimera in Hosta plants, which comparing the physiological and morphological differences in various parts of their leaves. The results show that, in the yellow parts of H. 'So Sweet' variegated leaf, the contents of chlorophyll-a and total chlorophyll were significantly lower than those in other parts and in the leaf of H. ventricosa, whereas the content of chlorophyll-b showed obviously higher. An additional esterase isozymogram was found in the Hosta leaf, which probably indicated as the special esterase in variegated Hosta. Concerned different parts from green, intergraded color and yellow in variegated leaves, the aberrance phenomena in ultrastructure of chloroplasts was observed, including the roundness from ellipse, granum-thylakoid swelling, vesicle forming and osmiophilic globule increasing.

Treated with 3 kinds of cultivation mediums:peat,moss and soil,adaptability of Thalia dealbata,Pontederia cordata,Iris sanguinea and Hydrocotyle verticillata were compared.The results showed that:both the above part's and root system's biomass values of Thalia dealbata,Pontederia cordata and Hydrocotyle verticillata which were cultivated with soil are better than those of the other two treatments.The root/shoot ratios of plants which were cultivated in peat or moss are higher than those cultivated in soil.The adaptability of Iris sanguinea presented no obvious difference under 3 different treatments.In the 3 treatments,the variation tendency of root's active absorbing area's percentage of 4 water-plants were similar,bascially fluctuating between 40%～50% without obvious differences.4 kinds of water-plants all had some adaptability cultivated whether in peat or moss mediums.

The new conception of 'Trampling-resistant ground covers' was put forward based on the foreign researches on trampling-resistant vegetation.The characteristics and applied values of trampling-resistant ground covers were introduced in this paper.The extended meaning of ground covers will benefit the native construction of economic and ecological landscape.According to the related researches on trampling stress concerned about the turf grass and ground covers,the indexes of trampling resistance of ground covers were given.At last,several species of trampling-resistant ground covers which available in foreign landscape,as well as some wild plants which can be used as trampling-resistant ground covers among the local plant resources were presented here.

<正>传统的地被植物概念是"贴近地面或匍匐地面生长的草本和木本植物,一般不耐践踏"。因此,尽管地被植物在城市绿地中的应用已十分广泛,而且越来越丰富多彩,但人们的活动却始

An experiment was conducted to study the morphological and physiological changes in three species of ornamental grasses, zebra grass(Miscanthus sinensis), fountain grass(Pennisetum alopecuroides) and pampas grass(Cortaderia selloana)under drought stress. Result shows that the proline content, relative electrical conductivity and malondialdehyde (MDA) content of the three grass species exposed to drought stress for 19 days increase continuously with the prolonging of drought stress, exhibiting an obviously positive correlation with increasing percentage of withered leaves. The SOD activities in zebra grass and fountain grass are remarkably higher than that in pampas grass at the late stage of drought treatment. Fountain grass has the highest drought tolerance, and then followed by zebra grass and pampas grass in order in terms of their morphological and physiological indexes.