Canopy temperature strongly influences crop yield formation and is closely related to plant physiological traits.However, the effects of nitrogen treatment on canopy temperature and rice growth have yet to be comprehe...Canopy temperature strongly influences crop yield formation and is closely related to plant physiological traits.However, the effects of nitrogen treatment on canopy temperature and rice growth have yet to be comprehensively examined. We conducted a two-year field experiment with three rice varieties(HD-5, NJ-9108, and YJ-805) and three nitrogen treatments(zero-N control(CK), 200 kg ha~(–1)(MN), and 300 kg ha~(–1)(HN)). We measured canopy temperature using a drone equipped with a high-precision camera at the six stages of the growth period. Generally,canopy temperature was significantly higher for CK than for MN and HN during the tillering, jointing, booting, and heading stages. The temperature was not significantly different among the nitrogen treatments between the milky and waxy stages. The canopy temperature of different rice varieties was found to follow the order: HD-5>NJ-9108>YJ-805, but the difference was not significant. The canopy temperature of rice was mainly related to plant traits, such as shoot fresh weight(correlation coefficient r=–0.895), plant water content(–0.912), net photosynthesis(–0.84), stomatal conductance(–0.91), transpiration rate(–0.90), and leaf stomatal area(–0.83). A structural equation model(SEM) showed that nitrogen fertilizer was an important factor affecting the rice canopy temperature.Our study revealed:(1) A suite of plant traits was associated with the nitrogen effects on canopy temperature,(2) the heading stage was the best time to observe rice canopy temperature, and(3) at that stage, canopy temperature was negatively correlated with rice yield, panicle number, and grain number per panicle. This study suggests that canopy temperature can be a convenient and accurate indicator of rice growth and yield prediction.展开更多
The canopy temperature of rice is an important index that directly reflects the growth and physiological state of rice,and affects the yield of rice plants to a great extent.The correlation between the temperatures of...The canopy temperature of rice is an important index that directly reflects the growth and physiological state of rice,and affects the yield of rice plants to a great extent.The correlation between the temperatures of different rice organs and canopy in different growth stages and the grain yield is complex.The stability and universality of these correlations must be verified.We conducted a pot experiment using two rice varieties and two temperature treatments(high temperature treatment was carried out at the beginning of heading stage for 10 days).We measured rice organ temperature during seven stages of growth using a high-precision infrared thermal imager.Results showed that the optimal observation period for the rice canopy temperature was 13:00.Although the rice variety did not significantly impact the canopy or organ temperature(p>0.05),the different organs and canopy exhibited significantly different temperatures(p<0.05).The correlations between the leaf,stem,panicle,canopy–air temperature differences and seed setting rate,theoretical and actual yields were the strongest during the milk stage.Among them,the correlation coefficient betweenΔT_(s) and theoretical and actual yields was the highest,the relationship between theoretical yield(Y)andΔT_(s)(X)was Y=−5.6965X+27.778,R^(2)=0.9155.Compared withΔT_(l),ΔT_(p) andΔTc,ΔT_(s) was closely related to the main traits of plants.ΔT_(s) could better reflect the growth characteristics of rice thanΔT_(c),such as dry matter accumulation(r=−0.931),SPAD(r=0.699),N concentration(r=0.714),transpiration rate(r=−0.722).In conclusion,stem temperature was more important indicator than canopy temperature.Stem temperature is a better screening index for rice breeding and cultivation management in the future.展开更多
Abstract On May 24–29,2019,a harmful algal bloom occurred in Pingtan coastal areas,Fujian,southeast China,and caused mass mortality of cage-cultured fi sh.Two clonal cultures of an unknown naked dinofl agellate were ...Abstract On May 24–29,2019,a harmful algal bloom occurred in Pingtan coastal areas,Fujian,southeast China,and caused mass mortality of cage-cultured fi sh.Two clonal cultures of an unknown naked dinofl agellate were set up from seawater samples taken during the bloom.The cultures were examined for morphological features,ultrastructure characters,photosynthetic pigments,the large subunit(LSU)of the rRNA gene,and the internal transcribed spacer(ITS)sequences,as well as acute toxicity analysis.The cell was unarmored,small-sized,and ovoid,and was characterized by elaborate striations on the epicone and hypocone.The nucleus was large,ellipsoid to oval or kidney-shaped,and centrally located in the cell.A long linear apical groove originated above the sulcus in the ventral epicone and extended to the dorsal side.An elongate,slit-like“ventral pore”was located on the left of the epicone,well away from the apical groove.The chloroplasts were yellowish brown,numerous,band like,and irregularly distributed in the cell periphery.Fucoxanthin was the main accessory pigment composition.Phylogeny topology reconstructed on partial LSU rDNA showed that the unknown dinofl agellate branched as a sister species to Karlodinium sp.(strain IFR981&IFR797,from France)and Karlodinium corrugatum(strain KDGSO08,from Australia),with genetic divergences of 0.6%and 3.3%,respectively.Based on the morphological and molecular phylogenetic analysis,we describe the novel dinofl agellate as Karlodinium elegans sp.nov.A toxicity assay revealed that the clonal culture of K.elegans(strain PTB601)had no adverse eff ect on brine shrimp(Artemia salina)and marine medaka(Oryzias melastigma),indicating it may not be a toxic species.展开更多
Some benthic Prorocentrum can produce okadaic acid(OA)and dinophysistoxins(DTXs)that cause diarrheic shellfish poisoning(DSP)in humans.The diversity and toxin profi les(OA and DTXs)of benthic Prorocentrum were investi...Some benthic Prorocentrum can produce okadaic acid(OA)and dinophysistoxins(DTXs)that cause diarrheic shellfish poisoning(DSP)in humans.The diversity and toxin profi les(OA and DTXs)of benthic Prorocentrum were investigated in the Xisha Islands,South China Sea.The benthic Prorocentrum was identified by both morphological features and molecular phylogenies.Morphologies were examined by light,fluorescence,and scanning electron microscopy,and phylogenetic analyses were based on partial large subunit(LSU)rDNA and ITS1-5.8S-ITS2(ITS)region.Seven Prorocentrum species including P.borbonicum,P.caipirignum,P.concavum,P.elegans,P.cf.emarginatum,P.lima complex,and P.rhathymum were identified in Xisha Islands.Among them,P.borbonicum and P.elegans were recorded in Chinese waters for the first time.OA and DTXs contents of seven benthic Prorocentrum species were evaluated based on liquid chromatography-tandem mass spectrometry(LC-MS/MS).All Xisha Islands strains of P.lima complex produced OA at contents ranging from 1663 to 3816 fg/cell.P.caipirignum also generated OA at 407 fg/cell,but other five species had no detectable toxins.Besides,interestingly,two strains of P.lima complex produced DTX-1 only(74 and 183 fg/cell)and another two strains generated an isomer of OA and DTX-2.Our findings provided insight into the biodiversity of benthic Prorocentrum in the Xisha Islands and pointed out the potential risk of DSP in this area.展开更多
基金supported by the National Key Research and Development Program of China(2022YFD1500404)the National Natural Science Foundation of China(31801310)+1 种基金the Natural Science Projects of Universities in Jiangsu Province,China(21KJA210001)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),China。
文摘Canopy temperature strongly influences crop yield formation and is closely related to plant physiological traits.However, the effects of nitrogen treatment on canopy temperature and rice growth have yet to be comprehensively examined. We conducted a two-year field experiment with three rice varieties(HD-5, NJ-9108, and YJ-805) and three nitrogen treatments(zero-N control(CK), 200 kg ha~(–1)(MN), and 300 kg ha~(–1)(HN)). We measured canopy temperature using a drone equipped with a high-precision camera at the six stages of the growth period. Generally,canopy temperature was significantly higher for CK than for MN and HN during the tillering, jointing, booting, and heading stages. The temperature was not significantly different among the nitrogen treatments between the milky and waxy stages. The canopy temperature of different rice varieties was found to follow the order: HD-5>NJ-9108>YJ-805, but the difference was not significant. The canopy temperature of rice was mainly related to plant traits, such as shoot fresh weight(correlation coefficient r=–0.895), plant water content(–0.912), net photosynthesis(–0.84), stomatal conductance(–0.91), transpiration rate(–0.90), and leaf stomatal area(–0.83). A structural equation model(SEM) showed that nitrogen fertilizer was an important factor affecting the rice canopy temperature.Our study revealed:(1) A suite of plant traits was associated with the nitrogen effects on canopy temperature,(2) the heading stage was the best time to observe rice canopy temperature, and(3) at that stage, canopy temperature was negatively correlated with rice yield, panicle number, and grain number per panicle. This study suggests that canopy temperature can be a convenient and accurate indicator of rice growth and yield prediction.
基金supported by the National Natural Science Foundation of China(31801310)Category A of the Major Projects of Natural Science Research in Universities of Jiangsu Province(21KJA210001)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘The canopy temperature of rice is an important index that directly reflects the growth and physiological state of rice,and affects the yield of rice plants to a great extent.The correlation between the temperatures of different rice organs and canopy in different growth stages and the grain yield is complex.The stability and universality of these correlations must be verified.We conducted a pot experiment using two rice varieties and two temperature treatments(high temperature treatment was carried out at the beginning of heading stage for 10 days).We measured rice organ temperature during seven stages of growth using a high-precision infrared thermal imager.Results showed that the optimal observation period for the rice canopy temperature was 13:00.Although the rice variety did not significantly impact the canopy or organ temperature(p>0.05),the different organs and canopy exhibited significantly different temperatures(p<0.05).The correlations between the leaf,stem,panicle,canopy–air temperature differences and seed setting rate,theoretical and actual yields were the strongest during the milk stage.Among them,the correlation coefficient betweenΔT_(s) and theoretical and actual yields was the highest,the relationship between theoretical yield(Y)andΔT_(s)(X)was Y=−5.6965X+27.778,R^(2)=0.9155.Compared withΔT_(l),ΔT_(p) andΔTc,ΔT_(s) was closely related to the main traits of plants.ΔT_(s) could better reflect the growth characteristics of rice thanΔT_(c),such as dry matter accumulation(r=−0.931),SPAD(r=0.699),N concentration(r=0.714),transpiration rate(r=−0.722).In conclusion,stem temperature was more important indicator than canopy temperature.Stem temperature is a better screening index for rice breeding and cultivation management in the future.
基金Supported by the National Key R&D Program of China(No.2017YFC1404301)the National Natural Science Foundation of China(Nos.41906112,41606175)+1 种基金the Science&Technology Basic Resources Investigation Program of China(No.2018FY100200)the Beijing Natural Science Foundation(No.8194059)。
文摘Abstract On May 24–29,2019,a harmful algal bloom occurred in Pingtan coastal areas,Fujian,southeast China,and caused mass mortality of cage-cultured fi sh.Two clonal cultures of an unknown naked dinofl agellate were set up from seawater samples taken during the bloom.The cultures were examined for morphological features,ultrastructure characters,photosynthetic pigments,the large subunit(LSU)of the rRNA gene,and the internal transcribed spacer(ITS)sequences,as well as acute toxicity analysis.The cell was unarmored,small-sized,and ovoid,and was characterized by elaborate striations on the epicone and hypocone.The nucleus was large,ellipsoid to oval or kidney-shaped,and centrally located in the cell.A long linear apical groove originated above the sulcus in the ventral epicone and extended to the dorsal side.An elongate,slit-like“ventral pore”was located on the left of the epicone,well away from the apical groove.The chloroplasts were yellowish brown,numerous,band like,and irregularly distributed in the cell periphery.Fucoxanthin was the main accessory pigment composition.Phylogeny topology reconstructed on partial LSU rDNA showed that the unknown dinofl agellate branched as a sister species to Karlodinium sp.(strain IFR981&IFR797,from France)and Karlodinium corrugatum(strain KDGSO08,from Australia),with genetic divergences of 0.6%and 3.3%,respectively.Based on the morphological and molecular phylogenetic analysis,we describe the novel dinofl agellate as Karlodinium elegans sp.nov.A toxicity assay revealed that the clonal culture of K.elegans(strain PTB601)had no adverse eff ect on brine shrimp(Artemia salina)and marine medaka(Oryzias melastigma),indicating it may not be a toxic species.
基金Supported by the National Natural Science Foundation of China(Nos.41876173,41606176,41576162,41606175)the Special Foundation for National Science and Technology Basic Research Program of China(Nos.2018FY100200,2018FY100100)。
文摘Some benthic Prorocentrum can produce okadaic acid(OA)and dinophysistoxins(DTXs)that cause diarrheic shellfish poisoning(DSP)in humans.The diversity and toxin profi les(OA and DTXs)of benthic Prorocentrum were investigated in the Xisha Islands,South China Sea.The benthic Prorocentrum was identified by both morphological features and molecular phylogenies.Morphologies were examined by light,fluorescence,and scanning electron microscopy,and phylogenetic analyses were based on partial large subunit(LSU)rDNA and ITS1-5.8S-ITS2(ITS)region.Seven Prorocentrum species including P.borbonicum,P.caipirignum,P.concavum,P.elegans,P.cf.emarginatum,P.lima complex,and P.rhathymum were identified in Xisha Islands.Among them,P.borbonicum and P.elegans were recorded in Chinese waters for the first time.OA and DTXs contents of seven benthic Prorocentrum species were evaluated based on liquid chromatography-tandem mass spectrometry(LC-MS/MS).All Xisha Islands strains of P.lima complex produced OA at contents ranging from 1663 to 3816 fg/cell.P.caipirignum also generated OA at 407 fg/cell,but other five species had no detectable toxins.Besides,interestingly,two strains of P.lima complex produced DTX-1 only(74 and 183 fg/cell)and another two strains generated an isomer of OA and DTX-2.Our findings provided insight into the biodiversity of benthic Prorocentrum in the Xisha Islands and pointed out the potential risk of DSP in this area.
