[Objectives]To evaluate the cold resistance and semi-lethal temperature of pear cultivars,and provide a theoretical basis for the regional extension and breeding of cold-resistant pear cultivars.[Methods]Nine pear cul...[Objectives]To evaluate the cold resistance and semi-lethal temperature of pear cultivars,and provide a theoretical basis for the regional extension and breeding of cold-resistant pear cultivars.[Methods]Nine pear cultivars were used to study the changes in relative conductivity and cell injury rate of pear branches under low temperature stress,and the semi-lethal temperature(LT_(50))of pear branches was analyzed by fitting Logistic equation.[Results]The relative conductivity and cell injury rate of pear branches took on the trend of slow increase,rapid increase,and slow increase the decrease of treatment temperature.The LC_(50) of the nine pear cultivars were as follows:Nanguo pear-33.9℃,Wanyu-32.3℃,Red D Anjou-31.8℃,Jinfeng-31.3℃,Wujiuxiang-29.2℃,20 th Century Pear-29.1℃,Hanxiang-35.1℃,Yuluxiang-27.9℃ and Korla Fragrant Pear-29.2℃.[Conclusions]The semi-lethal temperature could reflect the cold resistance of pear trees,and Wanxiang had better cold resistance.The evaluation of cold resistance and semi-lethal temperature of pear cultivars can provide theoretical basis for regional extension and breeding of cold-resistant pear cultivars.展开更多
为了明确绣球〔Hydrangea macrophylla(Thunb.)Ser.〕品种的耐寒性及筛选耐寒性评价主要指标,对40个绣球品种的低温半致死温度(LT_(50))进行比较和耐寒性分级,在此基础上,对5℃、0℃、-5℃、-10℃、-15℃、-20℃下耐寒品种‘小町’(‘Ko...为了明确绣球〔Hydrangea macrophylla(Thunb.)Ser.〕品种的耐寒性及筛选耐寒性评价主要指标,对40个绣球品种的低温半致死温度(LT_(50))进行比较和耐寒性分级,在此基础上,对5℃、0℃、-5℃、-10℃、-15℃、-20℃下耐寒品种‘小町’(‘Komachi’)、‘佳澄’(‘Kasumi’)、‘无尽夏’(‘Endless Summer’)和不耐寒品种‘甜蜜幻想’(‘Sweet Fantasy’)、‘灵感’(‘Inspiration’)、‘你我的情感’(‘You and Me Feelings’)叶的抗氧化酶活性及丙二醛(MDA)和渗透调节物质含量进行比较,并对这些耐寒指标进行相关性分析和主成分分析。结果表明:供试绣球品种LT 50的波动较大,变化范围为-36.68℃~-1.87℃,其中,‘小町’的LT_(50)最低,‘佳澄’、‘平瓣’(‘Flat’)、‘蒂亚娜’(‘Tijana’)、‘塞尔玛’(‘Selma’)、‘含羞叶’(‘Elbtal’)、‘花手鞠’(‘Stockings’)、‘蓝色多瑙河’(‘Blue Danube’)和‘无尽夏’的LT_(50)均低于-20℃。40个绣球品种的耐寒性被分成不耐寒、较耐寒、耐寒和强耐寒4个等级,分别包含13、18、8和1个品种。6个代表品种的过氧化氢酶(CAT)、多酚氧化酶(PPO)和超氧化物歧化酶活性及MDA、脯氨酸(Pro)、可溶性蛋白质(SP)和可溶性糖含量随温度降低基本呈先升高后降低的变化趋势。相关性分析结果表明PPO活性和Pro含量与LT_(50)呈极显著(P<0.01)负相关。主成分分析结果表明:前4个主成分的累计贡献率为81.212%,说明这4个主成分基本能够反映绣球品种的耐寒性;PPO活性、CAT活性、Pro含量和SP含量的负荷量绝对值分别在第1、第2、第3和第4主成分中最高。研究结果显示:供试绣球品种间的耐寒性差异较大,‘小町’等9个品种的耐寒性较强,能够在冬季温度偏低地区露天栽培,并可作为绣球耐寒品种选育的亲本。PPO活性、CAT活性、Pro含量和SP含量为绣球耐寒性评价的主要指标,尤其是PPO活性和Pro含量。展开更多
The differences of glucose-6P dehydrogenase (G6PDH) activity and freezing resistance induced by freezing acclimation between cuttings of freezing-sensitive P. tomentosa and freezing-resistant P. suaveolens were compar...The differences of glucose-6P dehydrogenase (G6PDH) activity and freezing resistance induced by freezing acclimation between cuttings of freezing-sensitive P. tomentosa and freezing-resistant P. suaveolens were compared for exploring the role of G6PDH on the enhancement of freezing resistance induced by freezing acclimation. After 5 d of freezing acclimation at -3 ℃, the LT50 of P. tomentosa has decreased from -6.2 ℃ in control cuttings to -14.3 ℃ in freezing acclimated ones, and the increase of G6PDH activity was observed in freezing acclimated cuttings as compared with control ones. Whereas, when P. suaveolens was freezing acclimated at -20℃ for 5 d, the LT50 has decreased from -27.1℃ in control cuttings to -43.5 ℃ in freezing acclimated ones, and the activity of G6PDH increased considerably. In addition, the increase of LT50 and the decrease of G6PDH activity resulting from 2 d of deacclimation at 25 ℃ were found in two kinds of freezing acclimated cuttings. It is concluded that the increase in the activity of G6PDH may associate with the inherited freezing resistance of species and the enhancement of freezing resistance of cuttings, and may play an important role in the antifreeze process under freezing temperature, which would provide the basis for the study on the molecular mechanism of freezing resistance in P. suaveolens and the cloning of gene associated with freezing resistance.展开更多
The conditions of heating and cooling of piercing mandrels made of 4X5MFS steel of a three-roll screw mill 30-80 in the production of a closed cavity of steel vessels of small volume are determined.It is established t...The conditions of heating and cooling of piercing mandrels made of 4X5MFS steel of a three-roll screw mill 30-80 in the production of a closed cavity of steel vessels of small volume are determined.It is established that multiple cycles of heating up to 600℃ and cooling with water up to 80℃ for about 7 seconds/1 cycle lead to the formation of ridges,shells and cracks on the surface and in the volume of the tool.The loss of structural strength of the material leads to the breakdown of the mandrel during the stitching process.The technique and equipment of magnetic powder control have been developed to establish the dynamics of the growth of internal and external defects of mandrels.An equation is obtained that allows determining the increase in the number of defects in the sewing tool of a screw rolling mill.The technology of non-destructive testing made it possible to develop a rational plan for replacing the sewing mandrels,which allows for predicting the appearance of defects leading to a complex breakdown of the deforming tool at the NPO Pribor machine-building enterprise.展开更多
基金Supported by Basic Research Fund of Hebei Academy of Agriculture and Forestry Sciences(2024020202)"Three-Three-Three"Talent Project of Hebei Province(C20231157)+2 种基金Science and Technology Innovation Project of Hebei Academy of Agriculture and Forestry Sciences(2022KJCXZX-CGS-7)Hebei Agricultural Industry Research System(HBCT2024170406)Key Research and Development Program of Hebei Province(21326308D-1-2).
文摘[Objectives]To evaluate the cold resistance and semi-lethal temperature of pear cultivars,and provide a theoretical basis for the regional extension and breeding of cold-resistant pear cultivars.[Methods]Nine pear cultivars were used to study the changes in relative conductivity and cell injury rate of pear branches under low temperature stress,and the semi-lethal temperature(LT_(50))of pear branches was analyzed by fitting Logistic equation.[Results]The relative conductivity and cell injury rate of pear branches took on the trend of slow increase,rapid increase,and slow increase the decrease of treatment temperature.The LC_(50) of the nine pear cultivars were as follows:Nanguo pear-33.9℃,Wanyu-32.3℃,Red D Anjou-31.8℃,Jinfeng-31.3℃,Wujiuxiang-29.2℃,20 th Century Pear-29.1℃,Hanxiang-35.1℃,Yuluxiang-27.9℃ and Korla Fragrant Pear-29.2℃.[Conclusions]The semi-lethal temperature could reflect the cold resistance of pear trees,and Wanxiang had better cold resistance.The evaluation of cold resistance and semi-lethal temperature of pear cultivars can provide theoretical basis for regional extension and breeding of cold-resistant pear cultivars.
文摘为了明确绣球〔Hydrangea macrophylla(Thunb.)Ser.〕品种的耐寒性及筛选耐寒性评价主要指标,对40个绣球品种的低温半致死温度(LT_(50))进行比较和耐寒性分级,在此基础上,对5℃、0℃、-5℃、-10℃、-15℃、-20℃下耐寒品种‘小町’(‘Komachi’)、‘佳澄’(‘Kasumi’)、‘无尽夏’(‘Endless Summer’)和不耐寒品种‘甜蜜幻想’(‘Sweet Fantasy’)、‘灵感’(‘Inspiration’)、‘你我的情感’(‘You and Me Feelings’)叶的抗氧化酶活性及丙二醛(MDA)和渗透调节物质含量进行比较,并对这些耐寒指标进行相关性分析和主成分分析。结果表明:供试绣球品种LT 50的波动较大,变化范围为-36.68℃~-1.87℃,其中,‘小町’的LT_(50)最低,‘佳澄’、‘平瓣’(‘Flat’)、‘蒂亚娜’(‘Tijana’)、‘塞尔玛’(‘Selma’)、‘含羞叶’(‘Elbtal’)、‘花手鞠’(‘Stockings’)、‘蓝色多瑙河’(‘Blue Danube’)和‘无尽夏’的LT_(50)均低于-20℃。40个绣球品种的耐寒性被分成不耐寒、较耐寒、耐寒和强耐寒4个等级,分别包含13、18、8和1个品种。6个代表品种的过氧化氢酶(CAT)、多酚氧化酶(PPO)和超氧化物歧化酶活性及MDA、脯氨酸(Pro)、可溶性蛋白质(SP)和可溶性糖含量随温度降低基本呈先升高后降低的变化趋势。相关性分析结果表明PPO活性和Pro含量与LT_(50)呈极显著(P<0.01)负相关。主成分分析结果表明:前4个主成分的累计贡献率为81.212%,说明这4个主成分基本能够反映绣球品种的耐寒性;PPO活性、CAT活性、Pro含量和SP含量的负荷量绝对值分别在第1、第2、第3和第4主成分中最高。研究结果显示:供试绣球品种间的耐寒性差异较大,‘小町’等9个品种的耐寒性较强,能够在冬季温度偏低地区露天栽培,并可作为绣球耐寒品种选育的亲本。PPO活性、CAT活性、Pro含量和SP含量为绣球耐寒性评价的主要指标,尤其是PPO活性和Pro含量。
基金National Natural Science Foundation of China(Grant No.30271093)
文摘The differences of glucose-6P dehydrogenase (G6PDH) activity and freezing resistance induced by freezing acclimation between cuttings of freezing-sensitive P. tomentosa and freezing-resistant P. suaveolens were compared for exploring the role of G6PDH on the enhancement of freezing resistance induced by freezing acclimation. After 5 d of freezing acclimation at -3 ℃, the LT50 of P. tomentosa has decreased from -6.2 ℃ in control cuttings to -14.3 ℃ in freezing acclimated ones, and the increase of G6PDH activity was observed in freezing acclimated cuttings as compared with control ones. Whereas, when P. suaveolens was freezing acclimated at -20℃ for 5 d, the LT50 has decreased from -27.1℃ in control cuttings to -43.5 ℃ in freezing acclimated ones, and the activity of G6PDH increased considerably. In addition, the increase of LT50 and the decrease of G6PDH activity resulting from 2 d of deacclimation at 25 ℃ were found in two kinds of freezing acclimated cuttings. It is concluded that the increase in the activity of G6PDH may associate with the inherited freezing resistance of species and the enhancement of freezing resistance of cuttings, and may play an important role in the antifreeze process under freezing temperature, which would provide the basis for the study on the molecular mechanism of freezing resistance in P. suaveolens and the cloning of gene associated with freezing resistance.
文摘The conditions of heating and cooling of piercing mandrels made of 4X5MFS steel of a three-roll screw mill 30-80 in the production of a closed cavity of steel vessels of small volume are determined.It is established that multiple cycles of heating up to 600℃ and cooling with water up to 80℃ for about 7 seconds/1 cycle lead to the formation of ridges,shells and cracks on the surface and in the volume of the tool.The loss of structural strength of the material leads to the breakdown of the mandrel during the stitching process.The technique and equipment of magnetic powder control have been developed to establish the dynamics of the growth of internal and external defects of mandrels.An equation is obtained that allows determining the increase in the number of defects in the sewing tool of a screw rolling mill.The technology of non-destructive testing made it possible to develop a rational plan for replacing the sewing mandrels,which allows for predicting the appearance of defects leading to a complex breakdown of the deforming tool at the NPO Pribor machine-building enterprise.
