DNA methylation plays important roles in regulating gene expression during development.However,little is known about the influence of DNA methylation on secondary metabolism during leaf development in the tea plant(Ca...DNA methylation plays important roles in regulating gene expression during development.However,little is known about the influence of DNA methylation on secondary metabolism during leaf development in the tea plant(Camellia sinensis).In this study,we combined the methylome,transcriptome,and metabolome to investigate the dynamic changes in DNA methylation and its potential regulatory roles in secondary metabolite biosynthesis.In this study,the level of genomic DNA methylation increased as leaf development progressed from tender to old leaf.It additionally exhibited a similar distribution across the genomic background at the two distinct developmental stages studied.Notably,integrated analysis of transcriptomic and methylomic data showed that DNA hypermethylation primarily occurred in genes of the phenylpropanoid,flavonoid,and terpenoid biosynthesis pathways.The effect of methylation on transcription of these secondary metabolite biosynthesis genes was dependent on the location of methylation(i.e.,in the promoter,gene or intergenic regions)and the sequence context(i.e.,CpG,CHG,or CHH).Changes in the content of catechins and terpenoids were consistent with the changes in gene transcription and the methylation state of structural genes,such as serine carboxypeptidase-like acyltransferases 1A(SCPL1A),leucoanthocyanidin reductase(LAR),and nerolidol synthase(NES).Our study provides valuable information for dissecting the effects of DNA methylation on regulation of genes involved in secondary metabolism during tea leaf development.展开更多
Carotenoids are the largest group of natural pigments responsible for the yellow,orange,and red colors in plant kernels,fruits,and leaves(Gupta and Hirschberg,2021).In plants,carotenoids are involved in manybiological...Carotenoids are the largest group of natural pigments responsible for the yellow,orange,and red colors in plant kernels,fruits,and leaves(Gupta and Hirschberg,2021).In plants,carotenoids are involved in manybiological processes,such as acting as accessory light-harvesting pigments in photosynthesis,participating in photoprotection,and serving as precursors for the hormones abscisic acid(ABA)and strigolactones(Ruiz-Sola and Rodriguez-Concepcion,2012).展开更多
Ecological water supplement projects have been implemented in many coastal wetlands,influencing saltmarsh vegetation restoration by altering tidal creek development.To clarify the effectiveness of ecological water sup...Ecological water supplement projects have been implemented in many coastal wetlands,influencing saltmarsh vegetation restoration by altering tidal creek development.To clarify the effectiveness of ecological water supplement on tidal creek development and saltmarsh vegetation restoration,time series of high-resolution remote sensing images from2000 to 2021 were used to extract and analyze tidal creeks and saltmarsh vegetation in the Diaokou Estuary Reserve.The results are summarized as follows:(1)All tidal creek indices,except curvature,exhibited a significant linear increase with time,while curvature initially decreased and increased afterwards.The 5-year cumulative ecological water supplement volume was significantly positively correlated(R^(2)>0.7)with all tidal creek indices.(2)During the same period,most landscape pattern metrics of Phragmites australis increased,while those of Tamarix chinensis initially increased and then declined.Although the class area(CA)of Suaeda salsa increased with time,its perimeter-area fractal dimension(PAFRAC)and aggregation index(AI)fluctuated.(3)The CA of P.australis and S.salsa was significantly positively correlated with most tidal creek indices except curvature,while that of T.chinensis showed no significant correlation with any tidal creek index.Moreover,the AI and PAFRAC of P.australis were significantly positively correlated with fractal dimension,frequency/curvature of tidal creeks,respectively,while those of S.salsa and T.chinensis exhibited no significant correlation.In summary,the ecological water supplement project enhanced tidal creek development in coastal wetlands,promoting the restoration of P.australis and S.salsa,while having little impact on the restoration of T.chinensis.展开更多
The leaf development of Podocarpus macrophyllus var.maki Endl.started from the leaf primordium formed by the cell division in shoot apical meristem.During the leaf development,three resin canals from the inferior part...The leaf development of Podocarpus macrophyllus var.maki Endl.started from the leaf primordium formed by the cell division in shoot apical meristem.During the leaf development,three resin canals from the inferior part of vascular bundles firstly began to differentiate,then protoxylem in vascular bundles differentiated from adaxial side to abaxial side.Meanwhile,a layer of parenchyma cells from the inferior part of protoderm developed into the sclerenchyma,which played an important role in supporting young leaves.When xylem became mature basically,transfusion tissue,phloem and accessory transfusion tissue began to differentiate,so mesophyll tissue finally differentiated into developmental palisade cells and sponge cells.The thicker cuticle was formed in the lateral side of epidermal cells at the same time of differentiation and development for the inner structure of leaves.Therefore,the developmental palisade cells and the cuticle in the leaf structure of Podocarpus macrophyllus var.maki Endl.is greatly significant for photosynthesis and transpiration when it grows in arid and cold regions.展开更多
Molecular and genetic characterizations of mutants have led to a better understanding of many developmental processes in the model system Arabidopsis thaliana. However, the leaf development that is specific to plants ...Molecular and genetic characterizations of mutants have led to a better understanding of many developmental processes in the model system Arabidopsis thaliana. However, the leaf development that is specific to plants has been little studied. With the aim of contributing to the genetic dissection of leaf development, we have performed a large-scare screening for mutants with abnormal leaves. Among a great number of leaf mutants we have generated by T-DNA and transposon tagging and ethylmethae sulfonate (EMS) mutagenesis, four independent mutant lines have been identified and studied genetically. Phenotypes of these mutant lines represent the defects of four novel nuclear genes designated LL1 (LOTUS LEAF 1), LL2 (LOTUS LEAF 2), URO (UPRIGHT ROSETTE), and EIL (ENVIRONT CONDITION INDUCED LESION). The phenotypic analysis indicates that these genes play important roles during leaf development. FOr the further genetic analysis of these genes and the map-based cloning of LL1 and LL2, we have mapped these genes to chromosome regions with an efficient and rapid mapping method.展开更多
Low light stress is one of the main limiting factors which influence the production of sweet pepper under protected cultivation in China. In this experiment, two genotypes of sweet pepper, ShY （low light-tolerant gen...Low light stress is one of the main limiting factors which influence the production of sweet pepper under protected cultivation in China. In this experiment, two genotypes of sweet pepper, ShY （low light-tolerant genotype） and 20078 （low light-sensitive genotype）, were used to study the effects of low light （photosynthetic photon flux density, PPFD was 75- 100 umol m-2 s-1, control 450-500 umol m-2 s-1） on photosynthesis during leaf development. The result indicated that under low light chlorophyll content, net photosynthetic rate （PN）, photosynthetic apparent quantum efficiency （Фi） and carboxylation efficiency （CE） of sweet pepper leaves increased gradually and decreased after reaching the maximum levels. The time to reach the peak values for all the above parameters was delayed, whereas the light compensation point （LCP） decreased gradually along with leaf expansion. The decrease in maximum quantum yield of PS II （Fv/Fm） was not observed at any stages of the leaf development under low light condition, but the actual PS II efficiency under irradiance （ФPS II） was lower accompanied by an increased non-photochemical quenching （NPQ） in young and/or old leaves compared with mature leaves. The antenna thermal dissipation （D） was a main way of heat dissipation when young leaves received excessive light energy, while the decline in photosynthetic function in senescence leaf was mostly owing to the decrease in carbon assimilation capacity, followed by a significantly increased allocation of excessive energy （Ex）. Compared with 20078, ShY could maintain higher PN, ФPS II and lower QA reduction state for a longer time during leaf development. Thus, in ShY photosynthetic efficiency and the activity of electron transport of PS II were not significantly affected due to low light stress.展开更多
Leaf development involves many complex genetic interactions,signals between adjacent cells or between more distant tissues and consequent changes in cell fate.This review describes three stages in leaf development whe...Leaf development involves many complex genetic interactions,signals between adjacent cells or between more distant tissues and consequent changes in cell fate.This review describes three stages in leaf development where regulation by small RNAs have been used to modulate gene expression patterns.展开更多
Forest fires in mountainous areas can cause severe defores-tation which can potentially trigger secondary natural hazards like debris falls and avalanches. We documented an extreme case study for the range of possible...Forest fires in mountainous areas can cause severe defores-tation which can potentially trigger secondary natural hazards like debris falls and avalanches. We documented an extreme case study for the range of possible post-fire land cover （LC） dynamics. We investigated a 15-ha, steep （10°-65°） burnt slope in Styria （Austria） at elevation of 760-1130 m, which burned in 1946 and has not fully recovered to date. Seven 8-class legend LC maps were produced （1954, 1966, 1973, 1982, 1998, 2004, 2009） and integrated in a vector-based GIS, mainly by on-screen interpretation of aerial photos. Our aim was to clarify how post-wildfire LC dynamics take place on a severely damaged, steep slope and to give a basic projection of the future vegetation recovery process. The pre-fire Pinus sylvestrisstands have been mainly replaced by Picea abies and Larix decidua. Regeneration proceeded mainly from the base of the slope upwards. All tree species together still cover no more than 40% of the slope after more than 60 years of recovery, while grassland communities and rock/debris areas have expanded. Multitemporal analysis showed a slow but steady increase in woodland cover. Degraded rock/debris areas, however, expanded as well because soil erosion and related debris flows remained active. Slope angle （with a threshold value of approx. 35-40°） seemed to control whether erosion or regeneration prevailed. According to a simple extrapolation, the slope will not reach its former condition before 2070. This extreme disturbance window of more than 120 years is owed to the steepness of the slope and to the shallow soils on dolomitic bedrock that were severely damaged by the fire. The neglect of any game fencing is a further factor slowing regeneration.展开更多
Located in the intertidal zone of the tropical and subtropical coasts, mangrove forests are an important ecosystem in the global carbon cycle and serve as a protector of local seashores. Under the double impacts of cl...Located in the intertidal zone of the tropical and subtropical coasts, mangrove forests are an important ecosystem in the global carbon cycle and serve as a protector of local seashores. Under the double impacts of climate change,especially sea-level rise, and human activity, mangrove forests around the world have faced degradation, against which the reconstruction of the historical development of mangrove forests using an effective indicator has been regarded as a necessary strategy for designing a predictable model. As the primary product of mangrove forest, it is reasonable that the content of leaf fragments of mangrove(CLFM) buried in sediments in the form of sub-fossils potentially has the same indicative function for the development of mangrove forests as that of widely-used mangrove pollen. In this study, the leaf fragments of mangrove in two sediment cores(YLW02 and YLW03) drilled in the Yingluo Bay in Guangxi, Southwest China were picked out and weighted for calculation of CLFM, which was used as an indicator of mangrove development after examination of parallelism and a statistical correlation of the CLFM with the concentration of mangrove pollen. The results clearly show that the vertical distribution of the CLFM for the core taken from the landward margin of mangrove forests(YLW03) only parallels that of the local mangrove species(Rhizophora. stylosa) with a significantly positive correlation(R=0.56, P=0.05), while the vertical distribution of the CLFM for the core taken from the interface between seaward margin of mangrove forest and the trunk of tidal creeks of the bay(YLW02) parallels the summed concentration of mangrove pollen(SCMP) with a more positive correlation than that of YLW03(R=0.85, P=0.01), indicating that the trunk outlet of tidal creeks must have been the site where mangrove production gathered from the overall forest rather than from local production. The variations in the CLFM of both cores indicate that overall the mangrove forests in the Yingluo Bay have increasingly flourished over the last 130 years except for the interval of 1940–1950 AD in response to an increase in air temperature and decrease in rainfall, which would have resulted in an increase in seawater salinity;while the coupled extreme increases in air temperature and in rainfall in summer, which would have resulted in extreme decreases in seawater salinity, would be responsible for the relative degradation of mangrove forests in the interval of 1940–1950 AD.展开更多
In the monocot rice species Oryza sativa L., one of the most striking morphological processes during reproductive development is the concurrence of panicle development with the sequential elongation of upper internod...In the monocot rice species Oryza sativa L., one of the most striking morphological processes during reproductive development is the concurrence of panicle development with the sequential elongation of upper internodes （UPIs）. To elucidate the underlying molecular mechanisms, we cloned the rice gene NECK LEAF 1 （NL1）, which when mutated results in delays in flowering time, smaller panicles with overgrown bracts and abnormal UPI elongation patterns. The NL1 gene encodes a GATA-type transcription factor with a single zinc finger domain, and its transcripts are de- tected predominantly in the bract primordia, which normally degenerate in the wild-type plants. Overexpression of NL1 in transgenic plants often gives rise to severe growth retardation, less vegetative phytomers and smaller leaves, suggesting that NL1 plays an important role in organ differentiation. A novel mutant allele of PLASTOCHRON1 （PLAD, a gene known to play a key role in regulating leaf initiation, was identified in this study. Genetic analysis demonstrated an interaction between nil and plal, with NL1 acting upstream of PLA1. The expression level and spatial pattern of PLA1 were found to be altered in the nil mutant. Furthermore, the expression of two regulators of flowering, Hd3a and OsMADS1, was also affected in the nil mutant. On the basis of these findings, we propose that NL1 is an intrinsic factor that modulates and coordinates organogenesis through regulating the expression of PLA1 and other regulatory genes during reproductive development in rice.展开更多
Leaf cells undergo two main developmental events;i.e., cell proliferation and cell differentiation, before maturation. These events occur sequentially at specific positions and with specific timing during leaf develop...Leaf cells undergo two main developmental events;i.e., cell proliferation and cell differentiation, before maturation. These events occur sequentially at specific positions and with specific timing during leaf development. To understand the transition from cell proliferation to cell differentiation of rice leaves, we analyzed rice leaves from both morphological and molecular viewpoints. The results of anatomical, morphological, and histochemical analyses indicated that P4 leaf primordium is the stage when dynamic transition of the cellular state from immature to mature along the proximal-distal axis of the leaf occurs. We screened for marker genes showing a dynamic expression pattern along the proximal-distal axis of the P4 leaf, and applied them to expression analysis in wild-type and various morphogenetic mutants. The changes in expression pattern of the marker genes varied between developmental stages and between mutants. Our analysis reinforced previous data regarding the developmental transition of wild-type rice leaves and indicated that the transition can be monitored using our molecular markers. The results of this study indicate that expression analysis using these molecular markers would be valuable for understanding the genetic effects on leaf development in various leaf morphogenetic mutants.展开更多
The leafing rates of fourteen rice varieties were measured in a sowing-time experiment, and a rapid leafing genotype at the vegetative growth stage was discovered in an indica variety Yanhui 559. The leaf number on th...The leafing rates of fourteen rice varieties were measured in a sowing-time experiment, and a rapid leafing genotype at the vegetative growth stage was discovered in an indica variety Yanhui 559. The leaf number on the main culm of Yanhui 559 was always 4-5 leaves more than that of Lemont, and the leafing rate of Yanhui 559 was significantly higher than that of Lemont based on similar growth durations from sowing to heading. Furthermore, the difference of the leafing rate was significant at the vegetative growth stage, but not distinctive at the panicle initiation stage. Genetic analysis of the leafing rates in the two backcross populations of Yanhui 559 and Lemont showed that major and quantitative genes controlled the expression of rapid leafing character. Based on results of investigation for some plants with similar growth durations in the backcrossing populations, the rapid leafing genotypes exhibited earlier tillering and more tiller numbers per plant, and its yield components including the number of panicles per plant and number of grains per panicle were superior to those of the slow leafing genotypes. Further research and application feasibility of the rapid leafing genotype in breeding were discussed.展开更多
Carotenoids are essential components in tea quality, contributing to leaf color and aroma. However, little information about carotenoids in different tea cultivars and their biosynthesis regulation mechanism during le...Carotenoids are essential components in tea quality, contributing to leaf color and aroma. However, little information about carotenoids in different tea cultivars and their biosynthesis regulation mechanism during leaf development is known. Here we analyzed carotenoids by HPLC in the buds and leaves of 113 tea cultivars harvested on the same day. By profile clustering, carotenoids were divided into five groups. Same group cultivars displayed divergence in the total content of carotenoids but a similar molar ratio. To figure out the molecular mechanisms of this phenomenon, we further characterized all functional lycopene cyclases, which are the branch point of the carotenoid biosynthesis pathway. Two β-lycopene cyclases(CsLCYB1 and CsLCYB2) and one ε-lycopene cyclase(CsLCYE1) were cloned. Subcellular localization analysis showed that all cloned CsLCYs were localized in plastids. Enzyme activity assays in E. coli indicated both CsLCYBs catalyzed lycopene into β-carotene, and CsLCYE1 produced δ-carotene and ε-carotene. We found CsLCYB1 and CsLCYE1 predominantly expressed in leaf, while CsLCYB2was mainly expressed during flowering stages. Suppression by antisense oligonucleotides reduced CsLCYB1 and CsLCYE1 transcripts and led to reduction of both β,β-branch and β,ε-branch carotenoids in leaf. The expression levels of CsLCYB1 showed a significant positive correlation withβ,β-branch carotenoids in leaf. Our study provides carotenoid profiles of different tea cultivars, which can assist tea producers in selecting cultivars of interest. Meanwhile, we proposed the molecular mechanism of carotenoids reflecting the tenderness of tea plant leaf from a metabolic flux perspective, and suggested lycopene cyclase that could be applied to the breeding of tea varieties with different branch carotenoids.展开更多
Rhizosheath development benefits drought resistance in many upland crops.Although water-saving irrigation techniques induce rice rhizosheath formation,how and whether root hairs and different root types influence rice...Rhizosheath development benefits drought resistance in many upland crops.Although water-saving irrigation techniques induce rice rhizosheath formation,how and whether root hairs and different root types influence rice rhizosheath development and shoot water relations at seedling stage in drying soil are unclear.Wild-type(WT)seedlings with root hairs and its root hairless mutant rth2 were watered every 2 or 4 d,with root hair,whole root and shoot traits determined.Less frequent irrigation significantly increased rhizosheath of both genotypes by 14%during the seedling stage.Although root exudates from rth2 adhered 54%more soil than WT,facilitating rhizosheath development,root hairs and 25%greater lateral root proliferation of WT seedlings allowed 48%more rhizosheath especially in older seedlings.Greater root hair length,root hair length density and root hair number/root surface area on lateral than axial roots especially enhanced WT rhizosheath development.Soil water deficit increased root and leaf ABA concentrations especially in WT seedlings,causing stomatal closure that contributed to increased leaf water potential.In 36-d-old seedlings,10%greater shoot biomass of WT plants than rth2 accompanied 15%higher root and 36%higher foliar ABA concentrations and ultimately lower stomatal conductance.Higher ABA concentrations of WT plants at the same soil moisture suggested root hairs may be important in mediating shoot water status of rice seedlings.展开更多
Leaf color mutants (LCMs) provide crucial insights into the regulatory mechanisms underlying chloroplast development,photo synthesis,and stre ss adaptation.In this study,we identified a temperature-sensitive albino mu...Leaf color mutants (LCMs) provide crucial insights into the regulatory mechanisms underlying chloroplast development,photo synthesis,and stre ss adaptation.In this study,we identified a temperature-sensitive albino mutant,tsa4,characterized by an albino phenotype at the seedling stage and abnormal chloroplast development at temperatures below 25℃.展开更多
Chloroplasts are essential for normal plant growth and development.In plants,pentatricopeptide repeat(PPR)proteins mediate RNA processing in chloroplasts.Here,we characterized a rice albino leaf 5(al5)mutant which exh...Chloroplasts are essential for normal plant growth and development.In plants,pentatricopeptide repeat(PPR)proteins mediate RNA processing in chloroplasts.Here,we characterized a rice albino leaf 5(al5)mutant which exhibits albinism during early leaf development.The MutMap+analysis and transformation experiments revealed that AL5 encodes a chloroplast-localized P-type PPR protein.The AL5 mutation resulted in the defective splicing of ribosomal protein L2(rpl2)and ribosomal protein S12(rps12),which are involved in the synthesis of chloroplast 50S and 30S ribosomal subunits,respectively.The RNA-electrophoretic mobility shift assay(REMSA)further demonstrated that AL5 directly binds to rpl2 transcripts.Finally,disruption of AL5 led to reduced expression of plastid-encoded polymerase(PEP)-dependent plastid genes and nuclear-encoded photosynthetic genes.Notably,the albino al5 mutant phenotype was regulated by low temperature.These results suggest that AL5 participates in plastid RNA splicing and plays an important role in chloroplast development in rice.展开更多
The rapid growth and early development period of the dual-scale surface topography was studied on the adaxial leaf surfaces of two aspen tree species with non-wetting leaves: the columnar European aspen (Populus tremu...The rapid growth and early development period of the dual-scale surface topography was studied on the adaxial leaf surfaces of two aspen tree species with non-wetting leaves: the columnar European aspen (Populus tremula “Erecta”) and quaking aspen (Populus tremuloides). Particular attention was focused on the formation of micro- and nano-scale asperities on their cuticles, which was correlated with the development of superhydrophobic wetting behaviour. Measurements of the wetting properties (contact angle and tilt-angle) provided an indication of the degree of hydrophobicity of their cuticles. Scanning electron microscopy and optical profilometry micrographs were used to follow the growth and major morphological changes of micro-scale papillae and nano-scale epicuticular wax (ECW) crystals, which led to a significant improvement in non-wetting behaviour. Both species exhibited syntopism in the form of small and larger nano-scale ECW platelet morphologies. These findings provide additional support for earlier suggestions that due to fluctuations in leaf hydrophobicity throughout the growing season, canopy storage capacity may also vary considerably throughout this time period.展开更多
Based on the survey on wild plants in 21 counties( cities) in Yichun Area,89 species of 32 families of wild vegetables were collected. The species,parts,edible parts,distribution and current development and use of wil...Based on the survey on wild plants in 21 counties( cities) in Yichun Area,89 species of 32 families of wild vegetables were collected. The species,parts,edible parts,distribution and current development and use of wild vegetables in Yichun Area were expounded. Then,existing problems of wild vegetables in Yichun Area were discussed. Finally,pertinent recommendations were put forward.展开更多
As an important rice disease, rice bacterial leaf blight (RBLB, caused by the bacterium Xanthomonas oryzae pv.oryzae), has become widespread in east China in recent years. Significant losses in rice yield occurred as ...As an important rice disease, rice bacterial leaf blight (RBLB, caused by the bacterium Xanthomonas oryzae pv.oryzae), has become widespread in east China in recent years. Significant losses in rice yield occurred as a result ofthe disease’s epidemic, making it imperative to monitor RBLB at a large scale. With the development of remotesensing technology, the broad-band sensors equipped with red-edge channels over multiple spatial resolutionsoffer numerous available data for large-scale monitoring of rice diseases. However, RBLB is characterized by rapiddispersal under suitable conditions, making it difficult to track the disease at a regional scale with a single sensorin practice. Therefore, it is necessary to identify or construct features that are effective across different sensors formonitoring RBLB. To achieve this goal, the spectral response of RBLB was first analyzed based on the canopyhyperspectral data. Using the relative spectral response (RSR) functions of four representative satellite or UAVsensors (i.e., Sentinel-2, GF-6, Planet, and Rededge-M) and the hyperspectral data, the corresponding broad-bandspectral data was simulated. According to a thorough band combination and sensitivity analysis, two novel spectralindices for monitoring RBLB that can be effective across multiple sensors (i.e., RBBRI and RBBDI) weredeveloped. An optimal feature set that includes the two novel indices and a classical vegetation index was formed.The capability of such a feature set in monitoring RBLB was assessed via FLDA and SVM algorithms. The resultdemonstrated that both constructed novel indices exhibited high sensitivity to the disease across multiple sensors.Meanwhile, the feature set yielded an overall accuracy above 90% for all sensors, which indicates its cross-sensorgenerality in monitoring RBLB. The outcome of this research permits disease monitoring with different remotesensing data over a large scale.展开更多
The logistics transportation and distribution of fruits and vegetables has become one of the important links for people to obtain food,and it is also an important direction and emerging challenge in the logistics indu...The logistics transportation and distribution of fruits and vegetables has become one of the important links for people to obtain food,and it is also an important direction and emerging challenge in the logistics industry.As the social economy and transportation develop,the consumption ability of residents has been improved,and the high demand for fruits and vegetables has promoted the transportation of fruits and vegetables to meet the development conditions of the future fruit and vegetable industry.The study of fruit and vegetable logistics distribution can improve the efficiency of fruit and vegetable distribution,improve the construction of fruit and vegetable distribution system,and also meet the needs of people for different kinds of fruits and vegetables.Taking Guangxi fruit and vegetable distribution as an example,through empirical investigation,this paper studies the existing problems in the development of logistics distribution in the fruit and vegetable distribution industry,and puts forward corresponding measures and countermeasures according to the problems,so as to innovate the fruit and vegetable distribution mode in Guangxi Zhuang Autonomous Region.展开更多
基金supported by the Natural Science Foundation of Guangdong Province(Grant Nos.2022A1515111141 and 2023A1515010786)。
文摘DNA methylation plays important roles in regulating gene expression during development.However,little is known about the influence of DNA methylation on secondary metabolism during leaf development in the tea plant(Camellia sinensis).In this study,we combined the methylome,transcriptome,and metabolome to investigate the dynamic changes in DNA methylation and its potential regulatory roles in secondary metabolite biosynthesis.In this study,the level of genomic DNA methylation increased as leaf development progressed from tender to old leaf.It additionally exhibited a similar distribution across the genomic background at the two distinct developmental stages studied.Notably,integrated analysis of transcriptomic and methylomic data showed that DNA hypermethylation primarily occurred in genes of the phenylpropanoid,flavonoid,and terpenoid biosynthesis pathways.The effect of methylation on transcription of these secondary metabolite biosynthesis genes was dependent on the location of methylation(i.e.,in the promoter,gene or intergenic regions)and the sequence context(i.e.,CpG,CHG,or CHH).Changes in the content of catechins and terpenoids were consistent with the changes in gene transcription and the methylation state of structural genes,such as serine carboxypeptidase-like acyltransferases 1A(SCPL1A),leucoanthocyanidin reductase(LAR),and nerolidol synthase(NES).Our study provides valuable information for dissecting the effects of DNA methylation on regulation of genes involved in secondary metabolism during tea leaf development.
基金supported by the National Key Research and Development Program of China(2022YFD1200704-3)Crop Varietal Improvement and Insect Pests Control by Nuclear Radiation,the Sichuan Province Science and Technology Program(2022NSFSC0018,2021YFYZ0011,2020YJ0249,MZGC20230108)the Biological Breeding Program of State Key of Sichuan Agricultural University(SKL-ZY202234).
文摘Carotenoids are the largest group of natural pigments responsible for the yellow,orange,and red colors in plant kernels,fruits,and leaves(Gupta and Hirschberg,2021).In plants,carotenoids are involved in manybiological processes,such as acting as accessory light-harvesting pigments in photosynthesis,participating in photoprotection,and serving as precursors for the hormones abscisic acid(ABA)and strigolactones(Ruiz-Sola and Rodriguez-Concepcion,2012).
基金National Key Research and Development Program of China,No.2022YFC3204302China National Admin-istration of Coal Geology,No.ZMKJ-2021-ZX04。
文摘Ecological water supplement projects have been implemented in many coastal wetlands,influencing saltmarsh vegetation restoration by altering tidal creek development.To clarify the effectiveness of ecological water supplement on tidal creek development and saltmarsh vegetation restoration,time series of high-resolution remote sensing images from2000 to 2021 were used to extract and analyze tidal creeks and saltmarsh vegetation in the Diaokou Estuary Reserve.The results are summarized as follows:(1)All tidal creek indices,except curvature,exhibited a significant linear increase with time,while curvature initially decreased and increased afterwards.The 5-year cumulative ecological water supplement volume was significantly positively correlated(R^(2)>0.7)with all tidal creek indices.(2)During the same period,most landscape pattern metrics of Phragmites australis increased,while those of Tamarix chinensis initially increased and then declined.Although the class area(CA)of Suaeda salsa increased with time,its perimeter-area fractal dimension(PAFRAC)and aggregation index(AI)fluctuated.(3)The CA of P.australis and S.salsa was significantly positively correlated with most tidal creek indices except curvature,while that of T.chinensis showed no significant correlation with any tidal creek index.Moreover,the AI and PAFRAC of P.australis were significantly positively correlated with fractal dimension,frequency/curvature of tidal creeks,respectively,while those of S.salsa and T.chinensis exhibited no significant correlation.In summary,the ecological water supplement project enhanced tidal creek development in coastal wetlands,promoting the restoration of P.australis and S.salsa,while having little impact on the restoration of T.chinensis.
基金Supported by Natural Basic Research Program of Universities in Jiangsu(06KJD180201)~~
文摘The leaf development of Podocarpus macrophyllus var.maki Endl.started from the leaf primordium formed by the cell division in shoot apical meristem.During the leaf development,three resin canals from the inferior part of vascular bundles firstly began to differentiate,then protoxylem in vascular bundles differentiated from adaxial side to abaxial side.Meanwhile,a layer of parenchyma cells from the inferior part of protoderm developed into the sclerenchyma,which played an important role in supporting young leaves.When xylem became mature basically,transfusion tissue,phloem and accessory transfusion tissue began to differentiate,so mesophyll tissue finally differentiated into developmental palisade cells and sponge cells.The thicker cuticle was formed in the lateral side of epidermal cells at the same time of differentiation and development for the inner structure of leaves.Therefore,the developmental palisade cells and the cuticle in the leaf structure of Podocarpus macrophyllus var.maki Endl.is greatly significant for photosynthesis and transpiration when it grows in arid and cold regions.
基金supported by a grant from the Chinese Academy of Sciences,KJ951-B1-604 and a National Distinguished Young Scholar Award to Hai HUANG.
文摘Molecular and genetic characterizations of mutants have led to a better understanding of many developmental processes in the model system Arabidopsis thaliana. However, the leaf development that is specific to plants has been little studied. With the aim of contributing to the genetic dissection of leaf development, we have performed a large-scare screening for mutants with abnormal leaves. Among a great number of leaf mutants we have generated by T-DNA and transposon tagging and ethylmethae sulfonate (EMS) mutagenesis, four independent mutant lines have been identified and studied genetically. Phenotypes of these mutant lines represent the defects of four novel nuclear genes designated LL1 (LOTUS LEAF 1), LL2 (LOTUS LEAF 2), URO (UPRIGHT ROSETTE), and EIL (ENVIRONT CONDITION INDUCED LESION). The phenotypic analysis indicates that these genes play important roles during leaf development. FOr the further genetic analysis of these genes and the map-based cloning of LL1 and LL2, we have mapped these genes to chromosome regions with an efficient and rapid mapping method.
基金supported by the National Science and Technology Support Program, China (2011BAZ01732-2)the Earmarked Fund for Modern Agro-Industry Technology Research System in China (CARS-25-A-07)
文摘Low light stress is one of the main limiting factors which influence the production of sweet pepper under protected cultivation in China. In this experiment, two genotypes of sweet pepper, ShY （low light-tolerant genotype） and 20078 （low light-sensitive genotype）, were used to study the effects of low light （photosynthetic photon flux density, PPFD was 75- 100 umol m-2 s-1, control 450-500 umol m-2 s-1） on photosynthesis during leaf development. The result indicated that under low light chlorophyll content, net photosynthetic rate （PN）, photosynthetic apparent quantum efficiency （Фi） and carboxylation efficiency （CE） of sweet pepper leaves increased gradually and decreased after reaching the maximum levels. The time to reach the peak values for all the above parameters was delayed, whereas the light compensation point （LCP） decreased gradually along with leaf expansion. The decrease in maximum quantum yield of PS II （Fv/Fm） was not observed at any stages of the leaf development under low light condition, but the actual PS II efficiency under irradiance （ФPS II） was lower accompanied by an increased non-photochemical quenching （NPQ） in young and/or old leaves compared with mature leaves. The antenna thermal dissipation （D） was a main way of heat dissipation when young leaves received excessive light energy, while the decline in photosynthetic function in senescence leaf was mostly owing to the decrease in carbon assimilation capacity, followed by a significantly increased allocation of excessive energy （Ex）. Compared with 20078, ShY could maintain higher PN, ФPS II and lower QA reduction state for a longer time during leaf development. Thus, in ShY photosynthetic efficiency and the activity of electron transport of PS II were not significantly affected due to low light stress.
基金supported by BBRSC (Biotechnology and Biological Sciences Research Council,UK),RERAD (Rural and Environment Research and Analysis Directorate,Scotland) and the McIntyre Begonia Research Trust,UK
文摘Leaf development involves many complex genetic interactions,signals between adjacent cells or between more distant tissues and consequent changes in cell fate.This review describes three stages in leaf development where regulation by small RNAs have been used to modulate gene expression patterns.
文摘Forest fires in mountainous areas can cause severe defores-tation which can potentially trigger secondary natural hazards like debris falls and avalanches. We documented an extreme case study for the range of possible post-fire land cover （LC） dynamics. We investigated a 15-ha, steep （10°-65°） burnt slope in Styria （Austria） at elevation of 760-1130 m, which burned in 1946 and has not fully recovered to date. Seven 8-class legend LC maps were produced （1954, 1966, 1973, 1982, 1998, 2004, 2009） and integrated in a vector-based GIS, mainly by on-screen interpretation of aerial photos. Our aim was to clarify how post-wildfire LC dynamics take place on a severely damaged, steep slope and to give a basic projection of the future vegetation recovery process. The pre-fire Pinus sylvestrisstands have been mainly replaced by Picea abies and Larix decidua. Regeneration proceeded mainly from the base of the slope upwards. All tree species together still cover no more than 40% of the slope after more than 60 years of recovery, while grassland communities and rock/debris areas have expanded. Multitemporal analysis showed a slow but steady increase in woodland cover. Degraded rock/debris areas, however, expanded as well because soil erosion and related debris flows remained active. Slope angle （with a threshold value of approx. 35-40°） seemed to control whether erosion or regeneration prevailed. According to a simple extrapolation, the slope will not reach its former condition before 2070. This extreme disturbance window of more than 120 years is owed to the steepness of the slope and to the shallow soils on dolomitic bedrock that were severely damaged by the fire. The neglect of any game fencing is a further factor slowing regeneration.
基金The National Natural Science Foundation of China under contract Nos 41376075 and 41576061
文摘Located in the intertidal zone of the tropical and subtropical coasts, mangrove forests are an important ecosystem in the global carbon cycle and serve as a protector of local seashores. Under the double impacts of climate change,especially sea-level rise, and human activity, mangrove forests around the world have faced degradation, against which the reconstruction of the historical development of mangrove forests using an effective indicator has been regarded as a necessary strategy for designing a predictable model. As the primary product of mangrove forest, it is reasonable that the content of leaf fragments of mangrove(CLFM) buried in sediments in the form of sub-fossils potentially has the same indicative function for the development of mangrove forests as that of widely-used mangrove pollen. In this study, the leaf fragments of mangrove in two sediment cores(YLW02 and YLW03) drilled in the Yingluo Bay in Guangxi, Southwest China were picked out and weighted for calculation of CLFM, which was used as an indicator of mangrove development after examination of parallelism and a statistical correlation of the CLFM with the concentration of mangrove pollen. The results clearly show that the vertical distribution of the CLFM for the core taken from the landward margin of mangrove forests(YLW03) only parallels that of the local mangrove species(Rhizophora. stylosa) with a significantly positive correlation(R=0.56, P=0.05), while the vertical distribution of the CLFM for the core taken from the interface between seaward margin of mangrove forest and the trunk of tidal creeks of the bay(YLW02) parallels the summed concentration of mangrove pollen(SCMP) with a more positive correlation than that of YLW03(R=0.85, P=0.01), indicating that the trunk outlet of tidal creeks must have been the site where mangrove production gathered from the overall forest rather than from local production. The variations in the CLFM of both cores indicate that overall the mangrove forests in the Yingluo Bay have increasingly flourished over the last 130 years except for the interval of 1940–1950 AD in response to an increase in air temperature and decrease in rainfall, which would have resulted in an increase in seawater salinity;while the coupled extreme increases in air temperature and in rainfall in summer, which would have resulted in extreme decreases in seawater salinity, would be responsible for the relative degradation of mangrove forests in the interval of 1940–1950 AD.
文摘In the monocot rice species Oryza sativa L., one of the most striking morphological processes during reproductive development is the concurrence of panicle development with the sequential elongation of upper internodes （UPIs）. To elucidate the underlying molecular mechanisms, we cloned the rice gene NECK LEAF 1 （NL1）, which when mutated results in delays in flowering time, smaller panicles with overgrown bracts and abnormal UPI elongation patterns. The NL1 gene encodes a GATA-type transcription factor with a single zinc finger domain, and its transcripts are de- tected predominantly in the bract primordia, which normally degenerate in the wild-type plants. Overexpression of NL1 in transgenic plants often gives rise to severe growth retardation, less vegetative phytomers and smaller leaves, suggesting that NL1 plays an important role in organ differentiation. A novel mutant allele of PLASTOCHRON1 （PLAD, a gene known to play a key role in regulating leaf initiation, was identified in this study. Genetic analysis demonstrated an interaction between nil and plal, with NL1 acting upstream of PLA1. The expression level and spatial pattern of PLA1 were found to be altered in the nil mutant. Furthermore, the expression of two regulators of flowering, Hd3a and OsMADS1, was also affected in the nil mutant. On the basis of these findings, we propose that NL1 is an intrinsic factor that modulates and coordinates organogenesis through regulating the expression of PLA1 and other regulatory genes during reproductive development in rice.
文摘Leaf cells undergo two main developmental events;i.e., cell proliferation and cell differentiation, before maturation. These events occur sequentially at specific positions and with specific timing during leaf development. To understand the transition from cell proliferation to cell differentiation of rice leaves, we analyzed rice leaves from both morphological and molecular viewpoints. The results of anatomical, morphological, and histochemical analyses indicated that P4 leaf primordium is the stage when dynamic transition of the cellular state from immature to mature along the proximal-distal axis of the leaf occurs. We screened for marker genes showing a dynamic expression pattern along the proximal-distal axis of the P4 leaf, and applied them to expression analysis in wild-type and various morphogenetic mutants. The changes in expression pattern of the marker genes varied between developmental stages and between mutants. Our analysis reinforced previous data regarding the developmental transition of wild-type rice leaves and indicated that the transition can be monitored using our molecular markers. The results of this study indicate that expression analysis using these molecular markers would be valuable for understanding the genetic effects on leaf development in various leaf morphogenetic mutants.
文摘The leafing rates of fourteen rice varieties were measured in a sowing-time experiment, and a rapid leafing genotype at the vegetative growth stage was discovered in an indica variety Yanhui 559. The leaf number on the main culm of Yanhui 559 was always 4-5 leaves more than that of Lemont, and the leafing rate of Yanhui 559 was significantly higher than that of Lemont based on similar growth durations from sowing to heading. Furthermore, the difference of the leafing rate was significant at the vegetative growth stage, but not distinctive at the panicle initiation stage. Genetic analysis of the leafing rates in the two backcross populations of Yanhui 559 and Lemont showed that major and quantitative genes controlled the expression of rapid leafing character. Based on results of investigation for some plants with similar growth durations in the backcrossing populations, the rapid leafing genotypes exhibited earlier tillering and more tiller numbers per plant, and its yield components including the number of panicles per plant and number of grains per panicle were superior to those of the slow leafing genotypes. Further research and application feasibility of the rapid leafing genotype in breeding were discussed.
基金supported by grants from the National Natural Science Foundation of China (Grant No.32102433)。
文摘Carotenoids are essential components in tea quality, contributing to leaf color and aroma. However, little information about carotenoids in different tea cultivars and their biosynthesis regulation mechanism during leaf development is known. Here we analyzed carotenoids by HPLC in the buds and leaves of 113 tea cultivars harvested on the same day. By profile clustering, carotenoids were divided into five groups. Same group cultivars displayed divergence in the total content of carotenoids but a similar molar ratio. To figure out the molecular mechanisms of this phenomenon, we further characterized all functional lycopene cyclases, which are the branch point of the carotenoid biosynthesis pathway. Two β-lycopene cyclases(CsLCYB1 and CsLCYB2) and one ε-lycopene cyclase(CsLCYE1) were cloned. Subcellular localization analysis showed that all cloned CsLCYs were localized in plastids. Enzyme activity assays in E. coli indicated both CsLCYBs catalyzed lycopene into β-carotene, and CsLCYE1 produced δ-carotene and ε-carotene. We found CsLCYB1 and CsLCYE1 predominantly expressed in leaf, while CsLCYB2was mainly expressed during flowering stages. Suppression by antisense oligonucleotides reduced CsLCYB1 and CsLCYE1 transcripts and led to reduction of both β,β-branch and β,ε-branch carotenoids in leaf. The expression levels of CsLCYB1 showed a significant positive correlation withβ,β-branch carotenoids in leaf. Our study provides carotenoid profiles of different tea cultivars, which can assist tea producers in selecting cultivars of interest. Meanwhile, we proposed the molecular mechanism of carotenoids reflecting the tenderness of tea plant leaf from a metabolic flux perspective, and suggested lycopene cyclase that could be applied to the breeding of tea varieties with different branch carotenoids.
基金financially supported by the National Natural Science Foundation of China (32071943, 31872853, 31871557)Jiangsu Provincial Department of Education and Yangzhou University (JS-2020-217)+3 种基金Zhejiang A&F University Research Development Fund (2023LFR003)in receipt of a Newton Advanced Fellowship (NA160430)the European Union SHui Project (773903)the GCRF RECIRCULATE (ES/P010857/1) Project
文摘Rhizosheath development benefits drought resistance in many upland crops.Although water-saving irrigation techniques induce rice rhizosheath formation,how and whether root hairs and different root types influence rice rhizosheath development and shoot water relations at seedling stage in drying soil are unclear.Wild-type(WT)seedlings with root hairs and its root hairless mutant rth2 were watered every 2 or 4 d,with root hair,whole root and shoot traits determined.Less frequent irrigation significantly increased rhizosheath of both genotypes by 14%during the seedling stage.Although root exudates from rth2 adhered 54%more soil than WT,facilitating rhizosheath development,root hairs and 25%greater lateral root proliferation of WT seedlings allowed 48%more rhizosheath especially in older seedlings.Greater root hair length,root hair length density and root hair number/root surface area on lateral than axial roots especially enhanced WT rhizosheath development.Soil water deficit increased root and leaf ABA concentrations especially in WT seedlings,causing stomatal closure that contributed to increased leaf water potential.In 36-d-old seedlings,10%greater shoot biomass of WT plants than rth2 accompanied 15%higher root and 36%higher foliar ABA concentrations and ultimately lower stomatal conductance.Higher ABA concentrations of WT plants at the same soil moisture suggested root hairs may be important in mediating shoot water status of rice seedlings.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.32341026 and 32171998)the Hunan Provincial Science and Technology Innovation Program,China(Grant No.2023NK1010)the Changsha Natural Science Foundation,China(Grant No.20209001).
文摘Leaf color mutants (LCMs) provide crucial insights into the regulatory mechanisms underlying chloroplast development,photo synthesis,and stre ss adaptation.In this study,we identified a temperature-sensitive albino mutant,tsa4,characterized by an albino phenotype at the seedling stage and abnormal chloroplast development at temperatures below 25℃.
基金supported by the Open Competition Program of Top Ten Critical Priorities of Agricultural Science and Technology Innovation for the 14th Five-Year Plan of Guangdong Province(2022SDZG05)the Guangdong Province Rural Revitalization Strategy Special Fund Seed Industry Revitalization Project(2022-NJS-15-001)the Key-Area Research and Development Program of Guangdong Province(2022B0202060005).
文摘Chloroplasts are essential for normal plant growth and development.In plants,pentatricopeptide repeat(PPR)proteins mediate RNA processing in chloroplasts.Here,we characterized a rice albino leaf 5(al5)mutant which exhibits albinism during early leaf development.The MutMap+analysis and transformation experiments revealed that AL5 encodes a chloroplast-localized P-type PPR protein.The AL5 mutation resulted in the defective splicing of ribosomal protein L2(rpl2)and ribosomal protein S12(rps12),which are involved in the synthesis of chloroplast 50S and 30S ribosomal subunits,respectively.The RNA-electrophoretic mobility shift assay(REMSA)further demonstrated that AL5 directly binds to rpl2 transcripts.Finally,disruption of AL5 led to reduced expression of plastid-encoded polymerase(PEP)-dependent plastid genes and nuclear-encoded photosynthetic genes.Notably,the albino al5 mutant phenotype was regulated by low temperature.These results suggest that AL5 participates in plastid RNA splicing and plays an important role in chloroplast development in rice.
文摘The rapid growth and early development period of the dual-scale surface topography was studied on the adaxial leaf surfaces of two aspen tree species with non-wetting leaves: the columnar European aspen (Populus tremula “Erecta”) and quaking aspen (Populus tremuloides). Particular attention was focused on the formation of micro- and nano-scale asperities on their cuticles, which was correlated with the development of superhydrophobic wetting behaviour. Measurements of the wetting properties (contact angle and tilt-angle) provided an indication of the degree of hydrophobicity of their cuticles. Scanning electron microscopy and optical profilometry micrographs were used to follow the growth and major morphological changes of micro-scale papillae and nano-scale epicuticular wax (ECW) crystals, which led to a significant improvement in non-wetting behaviour. Both species exhibited syntopism in the form of small and larger nano-scale ECW platelet morphologies. These findings provide additional support for earlier suggestions that due to fluctuations in leaf hydrophobicity throughout the growing season, canopy storage capacity may also vary considerably throughout this time period.
文摘Based on the survey on wild plants in 21 counties( cities) in Yichun Area,89 species of 32 families of wild vegetables were collected. The species,parts,edible parts,distribution and current development and use of wild vegetables in Yichun Area were expounded. Then,existing problems of wild vegetables in Yichun Area were discussed. Finally,pertinent recommendations were put forward.
基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA28010500)National Natural Science Foundation of China(Grant Nos.42371385,42071420)Zhejiang Provincial Natural Science Foundation of China(Grant No.LTGN23D010002).
文摘As an important rice disease, rice bacterial leaf blight (RBLB, caused by the bacterium Xanthomonas oryzae pv.oryzae), has become widespread in east China in recent years. Significant losses in rice yield occurred as a result ofthe disease’s epidemic, making it imperative to monitor RBLB at a large scale. With the development of remotesensing technology, the broad-band sensors equipped with red-edge channels over multiple spatial resolutionsoffer numerous available data for large-scale monitoring of rice diseases. However, RBLB is characterized by rapiddispersal under suitable conditions, making it difficult to track the disease at a regional scale with a single sensorin practice. Therefore, it is necessary to identify or construct features that are effective across different sensors formonitoring RBLB. To achieve this goal, the spectral response of RBLB was first analyzed based on the canopyhyperspectral data. Using the relative spectral response (RSR) functions of four representative satellite or UAVsensors (i.e., Sentinel-2, GF-6, Planet, and Rededge-M) and the hyperspectral data, the corresponding broad-bandspectral data was simulated. According to a thorough band combination and sensitivity analysis, two novel spectralindices for monitoring RBLB that can be effective across multiple sensors (i.e., RBBRI and RBBDI) weredeveloped. An optimal feature set that includes the two novel indices and a classical vegetation index was formed.The capability of such a feature set in monitoring RBLB was assessed via FLDA and SVM algorithms. The resultdemonstrated that both constructed novel indices exhibited high sensitivity to the disease across multiple sensors.Meanwhile, the feature set yielded an overall accuracy above 90% for all sensors, which indicates its cross-sensorgenerality in monitoring RBLB. The outcome of this research permits disease monitoring with different remotesensing data over a large scale.
文摘The logistics transportation and distribution of fruits and vegetables has become one of the important links for people to obtain food,and it is also an important direction and emerging challenge in the logistics industry.As the social economy and transportation develop,the consumption ability of residents has been improved,and the high demand for fruits and vegetables has promoted the transportation of fruits and vegetables to meet the development conditions of the future fruit and vegetable industry.The study of fruit and vegetable logistics distribution can improve the efficiency of fruit and vegetable distribution,improve the construction of fruit and vegetable distribution system,and also meet the needs of people for different kinds of fruits and vegetables.Taking Guangxi fruit and vegetable distribution as an example,through empirical investigation,this paper studies the existing problems in the development of logistics distribution in the fruit and vegetable distribution industry,and puts forward corresponding measures and countermeasures according to the problems,so as to innovate the fruit and vegetable distribution mode in Guangxi Zhuang Autonomous Region.
