On May 21,2021,a local case of coronavirus disease 2019(COVID-19)was confirmed in a 75-year-old woman(experienced onset of symptoms on May 18)in Liwan District,Guangzhou City,Guangdong Province,China.The number of inf...On May 21,2021,a local case of coronavirus disease 2019(COVID-19)was confirmed in a 75-year-old woman(experienced onset of symptoms on May 18)in Liwan District,Guangzhou City,Guangdong Province,China.The number of infections has increased in the following 10 days and led to 5 generations of transmission.展开更多
Changes in soil carbon pools under Chinese fir (Cunninghamia lanceolata) andbamboo (Phyllostachys pubescens) plantations substituted for a native forest (Quercus acutissima,Cyclobalanopsis glauca, Cas-tanopsis sclerop...Changes in soil carbon pools under Chinese fir (Cunninghamia lanceolata) andbamboo (Phyllostachys pubescens) plantations substituted for a native forest (Quercus acutissima,Cyclobalanopsis glauca, Cas-tanopsis sclerophylla, Platycarya strobilacea, Lithocarpus glaber) werestudied on the hills with acid parent rock and soils classified as red soils (Ferrisols) in Huzhou,Zhejiang Province of east China. It was found that total soil organic carbon (TSOC), easilyoxidisable carbon (EOC) and water-soluble organic carbon (WSOC) under bamboo plantation wereincreased, but microbial biomass carbon (MBC) was decreased. On the contrary, Chinese fir induceddeclines of all fractions of C including TSOC, EOC, WSOC and MBC. The percentages of the activefractions of soil C (EOC and WSOC) were increased in the plantations as compared to the nativebroad-leaved forest, but proportions of soil organic C as MBC were decreased. It could be concludedthat bamboo plantation had a great ability of not only fixing C but also accelerating soil C poolcycle, improving nutrient and microorganism activity; therefore, it is a good ecosystem and could berecommended for wide development. Chinese fir would shrink the soil C pool and deteriorate soilbiological fertility, so it did not benefit CO2 fixing and land sustainable utilization.展开更多
Ginkgo biloba is grown worldwide as an ornamental plant for its golden leaf color.However,the regulatory mechanism of leaf coloration in G.biloba remains unclear.Here,we compared G.biloba gold-colored mutant leaves an...Ginkgo biloba is grown worldwide as an ornamental plant for its golden leaf color.However,the regulatory mechanism of leaf coloration in G.biloba remains unclear.Here,we compared G.biloba gold-colored mutant leaves and normal green leaves in cytological,physiological and transcriptomic terms.We found that chloroplasts of the mutant were fewer and smaller,and exhibited ruptured thylakoid membranes,indistinct stromal lamellae and irregularly arranged vesicles.Physiological experiments also showed that the mutant had a lower chlorophyll,lower flavonoid and higher carotenoid contents(especially lutein).We further used transcriptomic sequencing to identify 116 differentially expressed genes(DEGs)and 46 transcription factors(TFs)involved in chloroplast development,chlorophyll metabolism,pigment biosynthesis and photosynthesis.Among these,the chlorophyll biosynthesis-related PPO showed down-regulation,while chlorophyll degradation-related NYC/NOL had up-regulated expression in mutant leaves.Z-ISO,ZDS,and LCYE,which are involved in carotenoid biosynthesis were up-regulated.Quantitative real-time PCR(RT-qPCR)further confirmed the altered expression levels of these genes at three stages.The alteration of PPO and NYC/NOL gene expression might affect chlorophyll biosynthesis and promote degradation of chlorophyll b to chlorophyll a,while the up-regulated genes Z-ISO,ZDS and LCYE enhanced carotenoid accumulation.Consequently,changes in the ratio of carotenoids to chlorophylls were the main factors driving the golden leaf coloration in the mutant G.biloba.展开更多
树高和胸径是森林调查中重要的测量因子,常用来计算材积、立地指数和其他与森林生长和收获、演替和碳汇相关的重要变量（Dorado et al.,2006）。树木胸径可以快速、方便且准确的测量，而树高的测量费时费力。在森林调查时，常常只测量...树高和胸径是森林调查中重要的测量因子,常用来计算材积、立地指数和其他与森林生长和收获、演替和碳汇相关的重要变量（Dorado et al.,2006）。树木胸径可以快速、方便且准确的测量，而树高的测量费时费力。在森林调查时，常常只测量部分树木的树高，缺失的树高则通过不同树种的树高曲线来预测（S6nehez—Gonzalez et al．，2007）。展开更多
Fruit cracking is an important problem in horticultural crop production.Polygalacturonase(SlPG)and expansin(SlEXP1)proteins cooperatively disassemble the polysaccharide network of tomato fruit cell walls during ripeni...Fruit cracking is an important problem in horticultural crop production.Polygalacturonase(SlPG)and expansin(SlEXP1)proteins cooperatively disassemble the polysaccharide network of tomato fruit cell walls during ripening and thereby,enable softening.A Golden 2-like(GLK2)transcription factor,SlGLK2 regulates unripe fruit chloroplast development and results in elevated soluble solids and carotenoids in ripe fruit.To determine whether SlPG,SlEXP1,or SlGLK2 influence the rate of tomato fruit cracking,the incidence of fruit epidermal cracking was compared between wild-type,Ailsa Craig(WT)and fruit with suppressed SlPG and SlEXP1 expression(pg/exp)or expressing a truncated nonfunctional Slglk2(glk2).Treating plants with exogenous ABA increases xylemic flow into fruit.Our results showed that ABA treatment of tomato plants greatly increased cracking of fruit from WT and glk2 mutant,but not from pg/exp genotypes.The pg/exp fruit were firmer,had higher total soluble solids,denser cell walls and thicker cuticles than fruit of the other genotypes.Fruit from the ABA treated pg/exp fruit had cell walls with less water-soluble and more ionically and covalently-bound pectins than fruit from the other lines,demonstrating that ripening-related disassembly of the fruit cell wall,but not elimination of SlGLK2,influences cracking.Cracking incidence was significantly correlated with cell wall and wax thickness,and the content of cell wall protopectin and cellulose,but not with Ca^(2+)content.展开更多
An investigation and on 13 year old (1984～1996) Chinese fir and Tsoong's tree mixed forests in Jianou City, Fujian Province, China was carried out to compare the influences of different interplanting types of i...An investigation and on 13 year old (1984～1996) Chinese fir and Tsoong's tree mixed forests in Jianou City, Fujian Province, China was carried out to compare the influences of different interplanting types of individual tree tree, row row, row strip (three rows) and pure Chinese fir stands on soil properties. Compared with the pure stands of Chinese fir, the mixed stands exerted a positive effect on soil fertility, with increases in soil organic matter, total N, available P and available K. Moreover, improvements were also observed in soil enzymatic activities, aggregate structure, structure stability, status of soil porosity, soil aeration and penetrability in mixed stands. The row row interplanted stands had the best effect on tree growth and soil properties among these mixed forests. In the southern subtropical region, the spreading of the row row mixing model of the two tree species would be helpful to preventing the soil from fertility deterioration caused by successive plantation of Chinese fir.展开更多
基金The Key-Area Research and Development Program of Guangdong Province(2019B111103001,2020B111107001)The National Natural Science Foundation of China(No.82041030).
文摘On May 21,2021,a local case of coronavirus disease 2019(COVID-19)was confirmed in a 75-year-old woman(experienced onset of symptoms on May 18)in Liwan District,Guangzhou City,Guangdong Province,China.The number of infections has increased in the following 10 days and led to 5 generations of transmission.
基金Project supported by the National Key Basic Research Support Foundation(NKBRSF)of China (No.G1999011809).
文摘Changes in soil carbon pools under Chinese fir (Cunninghamia lanceolata) andbamboo (Phyllostachys pubescens) plantations substituted for a native forest (Quercus acutissima,Cyclobalanopsis glauca, Cas-tanopsis sclerophylla, Platycarya strobilacea, Lithocarpus glaber) werestudied on the hills with acid parent rock and soils classified as red soils (Ferrisols) in Huzhou,Zhejiang Province of east China. It was found that total soil organic carbon (TSOC), easilyoxidisable carbon (EOC) and water-soluble organic carbon (WSOC) under bamboo plantation wereincreased, but microbial biomass carbon (MBC) was decreased. On the contrary, Chinese fir induceddeclines of all fractions of C including TSOC, EOC, WSOC and MBC. The percentages of the activefractions of soil C (EOC and WSOC) were increased in the plantations as compared to the nativebroad-leaved forest, but proportions of soil organic C as MBC were decreased. It could be concludedthat bamboo plantation had a great ability of not only fixing C but also accelerating soil C poolcycle, improving nutrient and microorganism activity; therefore, it is a good ecosystem and could berecommended for wide development. Chinese fir would shrink the soil C pool and deteriorate soilbiological fertility, so it did not benefit CO2 fixing and land sustainable utilization.
基金This work was financially supported by the Natural Science Foundation of China(No.31670181,31670695)the Three New Forestry Engineering Foundation of Jiangsu Province(No.lysx[2016]55).
文摘Ginkgo biloba is grown worldwide as an ornamental plant for its golden leaf color.However,the regulatory mechanism of leaf coloration in G.biloba remains unclear.Here,we compared G.biloba gold-colored mutant leaves and normal green leaves in cytological,physiological and transcriptomic terms.We found that chloroplasts of the mutant were fewer and smaller,and exhibited ruptured thylakoid membranes,indistinct stromal lamellae and irregularly arranged vesicles.Physiological experiments also showed that the mutant had a lower chlorophyll,lower flavonoid and higher carotenoid contents(especially lutein).We further used transcriptomic sequencing to identify 116 differentially expressed genes(DEGs)and 46 transcription factors(TFs)involved in chloroplast development,chlorophyll metabolism,pigment biosynthesis and photosynthesis.Among these,the chlorophyll biosynthesis-related PPO showed down-regulation,while chlorophyll degradation-related NYC/NOL had up-regulated expression in mutant leaves.Z-ISO,ZDS,and LCYE,which are involved in carotenoid biosynthesis were up-regulated.Quantitative real-time PCR(RT-qPCR)further confirmed the altered expression levels of these genes at three stages.The alteration of PPO and NYC/NOL gene expression might affect chlorophyll biosynthesis and promote degradation of chlorophyll b to chlorophyll a,while the up-regulated genes Z-ISO,ZDS and LCYE enhanced carotenoid accumulation.Consequently,changes in the ratio of carotenoids to chlorophylls were the main factors driving the golden leaf coloration in the mutant G.biloba.
文摘树高和胸径是森林调查中重要的测量因子,常用来计算材积、立地指数和其他与森林生长和收获、演替和碳汇相关的重要变量（Dorado et al.,2006）。树木胸径可以快速、方便且准确的测量，而树高的测量费时费力。在森林调查时，常常只测量部分树木的树高，缺失的树高则通过不同树种的树高曲线来预测（S6nehez—Gonzalez et al．，2007）。
基金supported by National Natural Science Foundation of China(31701924)the National Science Foundation(US IOS 0957264)+1 种基金Fundamental Research Funds for the Central Universities,China(KYZ201609)the US NSF support to ALTP(IOS 0544504 and 0957264).
文摘Fruit cracking is an important problem in horticultural crop production.Polygalacturonase(SlPG)and expansin(SlEXP1)proteins cooperatively disassemble the polysaccharide network of tomato fruit cell walls during ripening and thereby,enable softening.A Golden 2-like(GLK2)transcription factor,SlGLK2 regulates unripe fruit chloroplast development and results in elevated soluble solids and carotenoids in ripe fruit.To determine whether SlPG,SlEXP1,or SlGLK2 influence the rate of tomato fruit cracking,the incidence of fruit epidermal cracking was compared between wild-type,Ailsa Craig(WT)and fruit with suppressed SlPG and SlEXP1 expression(pg/exp)or expressing a truncated nonfunctional Slglk2(glk2).Treating plants with exogenous ABA increases xylemic flow into fruit.Our results showed that ABA treatment of tomato plants greatly increased cracking of fruit from WT and glk2 mutant,but not from pg/exp genotypes.The pg/exp fruit were firmer,had higher total soluble solids,denser cell walls and thicker cuticles than fruit of the other genotypes.Fruit from the ABA treated pg/exp fruit had cell walls with less water-soluble and more ionically and covalently-bound pectins than fruit from the other lines,demonstrating that ripening-related disassembly of the fruit cell wall,but not elimination of SlGLK2,influences cracking.Cracking incidence was significantly correlated with cell wall and wax thickness,and the content of cell wall protopectin and cellulose,but not with Ca^(2+)content.
文摘An investigation and on 13 year old (1984～1996) Chinese fir and Tsoong's tree mixed forests in Jianou City, Fujian Province, China was carried out to compare the influences of different interplanting types of individual tree tree, row row, row strip (three rows) and pure Chinese fir stands on soil properties. Compared with the pure stands of Chinese fir, the mixed stands exerted a positive effect on soil fertility, with increases in soil organic matter, total N, available P and available K. Moreover, improvements were also observed in soil enzymatic activities, aggregate structure, structure stability, status of soil porosity, soil aeration and penetrability in mixed stands. The row row interplanted stands had the best effect on tree growth and soil properties among these mixed forests. In the southern subtropical region, the spreading of the row row mixing model of the two tree species would be helpful to preventing the soil from fertility deterioration caused by successive plantation of Chinese fir.
