Studies were conducted over the effects of 1-methylcycolpropene （1-MCP） treatment on postharvest life of Suli pears （Pyrus bretschneideri Rehd.） stored at room and cold temperatures on nitric oxide （NO）,nitric o...Studies were conducted over the effects of 1-methylcycolpropene （1-MCP） treatment on postharvest life of Suli pears （Pyrus bretschneideri Rehd.） stored at room and cold temperatures on nitric oxide （NO）,nitric oxide synthase （NOS） activity,and hydrogen dioxide （H2O2）.Results showed that the 1-MCP treatment had little effect on total soluble solids （TSS） at both room and cold temperatures.1-MCP delayed softening of Suli pear fruits,decreased respiratory rate and H2O2 accumulation,and increased NO and NOS activity at room temperature storage,while the effect of cold temperature storage was relatively inferior.There was a significant positive correlation between NOS activity and NO content.It is concluded that 1-MCP had effects on endogenous NO content and accumulation of H2O2.Similarly,H2O2 acting as a signaling molecule via regulating NO level affects the ripening and senescence of Suli pears.展开更多
Drought stress is a devastating natural disaster driven by the continuing intensification of global warming,which seriously threatens the productivity and quality of several horticultural crops,including pear.Gibberel...Drought stress is a devastating natural disaster driven by the continuing intensification of global warming,which seriously threatens the productivity and quality of several horticultural crops,including pear.Gibberellins(GAs)play crucial roles in plant growth,development,and responses to drought stress.Previous studies have shown significant reductions of GA levels in plants under drought stress;however,our understanding of the intrinsic regulation mechanisms of GA-mediated drought stress in pear remains very limited.Here,we show that drought stress can impair the accumulation of bioactive GAs(BGAs),and subsequently identified PbrGA2ox1 as a chloroplast-localized GA deactivation gene.This gene was significantly induced by drought stress and abscisic acid(ABA)treatment,but was suppressed by GA_(3)treatment.PbrGA2ox1-overexpressing transgenic tobacco plants(Nicotiana benthamiana)exhibited enhanced tolerance to dehydration and drought stresses,whereas knock-down of PbrGA2ox1 in pear(Pyrus betulaefolia)by virus-induced gene silencing led to elevated drought sensitivity.Transgenic plants were hypersensitive to ABA,and had a lower BGAs content,enhanced reactive oxygen species(ROS)scavenging ability,and augmented ABA accumulation and signaling under drought stress compared to wild-type plants.However,the opposite effects were observed with PbrGA2ox1 silencing in pear.Moreover,exogenous GA_(3)treatment aggravated the ROS toxic effect and restrained ABA synthesis and signaling,resulting in the compromised drought tolerance of pear.In summary,our results shed light on the mechanism by which BGAs are eliminated in pear leaves under drought stress,providing further insights into the mechanism regulating the effects of GA on the drought tolerance of plants.展开更多
Water permeability can be used as a parameter to evaluate the effects of chitosan / nano-TiO2 composite film on the preservation of fruits and vegetables. In this study, using water permeability as the objective funct...Water permeability can be used as a parameter to evaluate the effects of chitosan / nano-TiO2 composite film on the preservation of fruits and vegetables. In this study, using water permeability as the objective function, an L9 （3）3 orthogonal experiment was conducted with addition amounts of chitosan, nano-TiO2 and glycerin as three factors at three levels. According to the experimental results, when the percentages of chitosan, nano-TiO2 and glycerin in chitosan / nano-TiO2 composite film was 2%, 0.03% and 2.5%, respectively （ i. e. , there were 2.0 g of chitosan, 0.03 g of nano-TiO2 and 2.5 g of glycerin per 1130 g composite film solution）, the water permeability of chitesan / nano-TiO2 composite fdm reached the minimum. Chitosan / nano-TiO2 composite film prepared with the optimal composition was used for preservation of Jinqiu pear. The water loss rate, respiratory intensity and good fruit rate of preserved Jinqiu pear were determined, which indicated that the prepared chitosan / nano-TiO2 composite film exhibited good preservative effects.展开更多
[Objective] This study was conducted to evaluate three training systems for Korla fragrant pear trees by comparing the characteristic parameters of light response curve and CO2 response curve, and to provide some theo...[Objective] This study was conducted to evaluate three training systems for Korla fragrant pear trees by comparing the characteristic parameters of light response curve and CO2 response curve, and to provide some theoretical basis for improving the pruning techniques of Korla fragrant pear trees. [Method] The light response curve and CO2 response curve of the trees trained to three systems were measured by LI-6400 portable photosynthesis system. The SPAD value was measured using SPAD-502 chlorophyll meter, and specific leaf weight was calculated, to evaluate the effects of the three training systems. [Result] The CO2 response curves of the three training systems were basically in agreement with their light response curves, but there were some differences in their characteristic parameters. Among the three training systems, the maximum net photosynthetic rate, apparent quantum yield and light compensation point of espalier trained trees were the highest, while their light saturation point was the lowest. The CO2 saturation point of delayed-open central leader trained trees and open center trained trees were 1 752 and 1 665 μmol/mol, both of which were much higher than that of espalier trained trees. In addition, the carboxylation efficiency and photorespiration rate of espalier trained trees were both higher than those of delayed-open central leader trained trees and open center trained trees, while the CO2 compensation point of espalier trained trees was the lowest. The leaf SPAD value of espalier trained trees was the largest, followed by that of open center trained trees, and the leaf SPAD value of delayed-open central leader trained trees was the smallest. In addition, the leaf area and specific leaf weight of espalier trained trees were both the highest, followed by those of open center trained trees. [Conclusion] Among the training systems for Korla fragrant pear trees, the espalier training system had better ability to capture light, higher photosynthetic productivity and strongest adaptability to light environment, and open center training system takes the second place. On the contrary, delayed-open central leader training system has the weakest adaptability to light environment, but it can adapt to a higher CO2 concentration. In summary, for the training of Korla fragrant pear trees, espalier training system, which has the highest theoretical yield, is the best among the three training systems, and delayed-open central leader training system is the worst.展开更多
基金supported by the Earmarked Fund for Modern Pear-Industry Technology Research System of China (nycytx-29-19)
文摘Studies were conducted over the effects of 1-methylcycolpropene （1-MCP） treatment on postharvest life of Suli pears （Pyrus bretschneideri Rehd.） stored at room and cold temperatures on nitric oxide （NO）,nitric oxide synthase （NOS） activity,and hydrogen dioxide （H2O2）.Results showed that the 1-MCP treatment had little effect on total soluble solids （TSS） at both room and cold temperatures.1-MCP delayed softening of Suli pear fruits,decreased respiratory rate and H2O2 accumulation,and increased NO and NOS activity at room temperature storage,while the effect of cold temperature storage was relatively inferior.There was a significant positive correlation between NOS activity and NO content.It is concluded that 1-MCP had effects on endogenous NO content and accumulation of H2O2.Similarly,H2O2 acting as a signaling molecule via regulating NO level affects the ripening and senescence of Suli pears.
基金supported by grants from the China Agriculture Research System(CARS-28-14)the Technical System of Fruit Industry in Anhui Province,China(AHCYTX-10)the Scientific Research Projects for Postgraduates of Anhui Universities,China(YJS20210207).
文摘Drought stress is a devastating natural disaster driven by the continuing intensification of global warming,which seriously threatens the productivity and quality of several horticultural crops,including pear.Gibberellins(GAs)play crucial roles in plant growth,development,and responses to drought stress.Previous studies have shown significant reductions of GA levels in plants under drought stress;however,our understanding of the intrinsic regulation mechanisms of GA-mediated drought stress in pear remains very limited.Here,we show that drought stress can impair the accumulation of bioactive GAs(BGAs),and subsequently identified PbrGA2ox1 as a chloroplast-localized GA deactivation gene.This gene was significantly induced by drought stress and abscisic acid(ABA)treatment,but was suppressed by GA_(3)treatment.PbrGA2ox1-overexpressing transgenic tobacco plants(Nicotiana benthamiana)exhibited enhanced tolerance to dehydration and drought stresses,whereas knock-down of PbrGA2ox1 in pear(Pyrus betulaefolia)by virus-induced gene silencing led to elevated drought sensitivity.Transgenic plants were hypersensitive to ABA,and had a lower BGAs content,enhanced reactive oxygen species(ROS)scavenging ability,and augmented ABA accumulation and signaling under drought stress compared to wild-type plants.However,the opposite effects were observed with PbrGA2ox1 silencing in pear.Moreover,exogenous GA_(3)treatment aggravated the ROS toxic effect and restrained ABA synthesis and signaling,resulting in the compromised drought tolerance of pear.In summary,our results shed light on the mechanism by which BGAs are eliminated in pear leaves under drought stress,providing further insights into the mechanism regulating the effects of GA on the drought tolerance of plants.
基金Supported by Science and Technology Fund of Guizhou Province[QKHJZ(2012)2179]
文摘Water permeability can be used as a parameter to evaluate the effects of chitosan / nano-TiO2 composite film on the preservation of fruits and vegetables. In this study, using water permeability as the objective function, an L9 （3）3 orthogonal experiment was conducted with addition amounts of chitosan, nano-TiO2 and glycerin as three factors at three levels. According to the experimental results, when the percentages of chitosan, nano-TiO2 and glycerin in chitosan / nano-TiO2 composite film was 2%, 0.03% and 2.5%, respectively （ i. e. , there were 2.0 g of chitosan, 0.03 g of nano-TiO2 and 2.5 g of glycerin per 1130 g composite film solution）, the water permeability of chitesan / nano-TiO2 composite fdm reached the minimum. Chitosan / nano-TiO2 composite film prepared with the optimal composition was used for preservation of Jinqiu pear. The water loss rate, respiratory intensity and good fruit rate of preserved Jinqiu pear were determined, which indicated that the prepared chitosan / nano-TiO2 composite film exhibited good preservative effects.
文摘[Objective] This study was conducted to evaluate three training systems for Korla fragrant pear trees by comparing the characteristic parameters of light response curve and CO2 response curve, and to provide some theoretical basis for improving the pruning techniques of Korla fragrant pear trees. [Method] The light response curve and CO2 response curve of the trees trained to three systems were measured by LI-6400 portable photosynthesis system. The SPAD value was measured using SPAD-502 chlorophyll meter, and specific leaf weight was calculated, to evaluate the effects of the three training systems. [Result] The CO2 response curves of the three training systems were basically in agreement with their light response curves, but there were some differences in their characteristic parameters. Among the three training systems, the maximum net photosynthetic rate, apparent quantum yield and light compensation point of espalier trained trees were the highest, while their light saturation point was the lowest. The CO2 saturation point of delayed-open central leader trained trees and open center trained trees were 1 752 and 1 665 μmol/mol, both of which were much higher than that of espalier trained trees. In addition, the carboxylation efficiency and photorespiration rate of espalier trained trees were both higher than those of delayed-open central leader trained trees and open center trained trees, while the CO2 compensation point of espalier trained trees was the lowest. The leaf SPAD value of espalier trained trees was the largest, followed by that of open center trained trees, and the leaf SPAD value of delayed-open central leader trained trees was the smallest. In addition, the leaf area and specific leaf weight of espalier trained trees were both the highest, followed by those of open center trained trees. [Conclusion] Among the training systems for Korla fragrant pear trees, the espalier training system had better ability to capture light, higher photosynthetic productivity and strongest adaptability to light environment, and open center training system takes the second place. On the contrary, delayed-open central leader training system has the weakest adaptability to light environment, but it can adapt to a higher CO2 concentration. In summary, for the training of Korla fragrant pear trees, espalier training system, which has the highest theoretical yield, is the best among the three training systems, and delayed-open central leader training system is the worst.
