Exogenous Selenium Application To Grape And Peach Leaves Physiological Characteristics And The Influence Of Fruit Quality

Selenium is an indispensable trace element for the human body,selenium enriched treatment of grapes and peaches can effectively improve the quality of fruits.increase the nutritional value of fruits,achieve the goal of supplementing human trace elements by eating grapes and peach fruits,and is beneficial to human health.In this paper,two grape varieties,’Summer Black’ and ’Jumeigui’(with four treatment concentrations of 0、25、50 and 75 mg·L-1)and three peach varieties,Tezaohong’,’Chunyan’,and’Meishuo’(with four treatment concentrations of 0、10、20 and 30 mg·L-1),were used as experimental materials to spray different concentrations of sodium selenite on the leaves during fruit development,and analyze the physiological characteristics of the leaves and related indicators of fruit quality after selenium treatment,The most suitable treatment concentration for grape and peach was selected.The relevant results are as follows:1.By measuring the chlorophyll content in the leaves of’Xiahei’、’Jumeigui’,’Tezaohong’、’Chunyan’ and’Meishuo’.it was found that exogenous selenium application can effectively increase the chlorophyll content in the leaves.The leaves of’Xiahei’ and’Jumeigui’ have the best effect at 50 mg·L-1,while the leaves of’Tezaohong’、’Chunyan’ and ’Meishuo’,have the best effect at 20 mg·L-1,Furthermore,the antioxidant level and photosynthetic characteristics of ’summer black’ leaves treated with 50 mg·L-1 selenium and ’Chunyan’ leaves treated with 20 mg·L-1 selenium were measured.The results showed that selenium treatment could effectively improve superoxide dismutase(SOD)、peroxidase(POD)、catalase(CAT)、reduced glutathione(GSH)、Oxidized glutathione(oxidized)GSSG and other antioxidant enzyme activities reduce the level of reactive oxygen species(ROS)in leaves and effectively improve Photosynthetic efficiency of leaves.2.By measuring the appearance quality and content of the fruits of ’Xiahei’、’Jumeigui’、’Tezaohong’、’Chunyan’ and ’Meishuo’,it was found that external selenium application increased the single grain(fruit)weight,single ear weight,fruit hardness,soluble solids,and Vc content of the fruits,reduced the ethylene release of the fruits.promoted uniform fruit coloring,and effectively improved the overall quality of the fruits.Within the set concentration range,the fruit quality indicators continuously improve with the increase of exogenous selenium spraying concentration.The selenium treatment concentration of ’Summer Black’ and ’Jumeigui’ grape fruit quality reaches the optimal value when it rises to 50 mg·L-1,and then shows a downward trend at 75 mg·L-1.Based on comprehensive analysis,the optimal concentration of exogenous selenium treatment is 50 mg·L-1 The optimal concentration of selenium in peach fruit fruits of’Tezaohong’、’Chunyan’ and’Meishuo’ was reached when the concentration increased to 20 mg·L-1,and then showed a downward trend at 30 mg·L-1.Based on comprehensive analysis,the best effect was achieved when the concentration of exogenous selenium was 20 mg·L-1.3.By measuring the antioxidant enzyme activity in the fruits of ’Xiahei’、’Jumeigui’、’Tezaohong’、’Chunyan’ and’Meishuo’,the antioxidant enzyme activity,SOD、POD、CAT、GSH、GSSG,and other antioxidant enzyme activities in the fruits of ’Xiahei’ and ’Jumeigui’ grapes were continuously increased within the set concentration range with the increase of exogenous selenium spraying concentration.The fruit of ’Xiahei’ and ’Jumeigui’ grapes reached its maximum value at a selenium treatment concentration of 50 mg·L-1,and then decreased The peach fruits of’Tezaohong’、’Chunyan’ and ’Meishuo’ reached their maximum value at a selenium concentration of 20 mg·L-1,and then decreased,indicating that appropriate selenium concentration can effectively improve the antioxidant level of the fruit and enhance its antioxidant capacity.However,if the concentration is too high,it will have the opposite effect.4.Comprehensively analyze the fruit quality indicators of ’Tezaohong’、’Chunyan’and ’Meishuo’ peach.and send the fruit samples without selenium treatment and 20 mg·L-1 selenium treatment to transcriptome for testing.The results are as follows:the number of differentially expressed genes in ’Tezaohong’ peach fruits without treatment and after treatment is 1721,and the number of differentially expressed genes in’Chunyan’ peach fruits without treatment and after treatment is 248,The number of differentially expressed genes between untreated and treated fruits of the ’Meishuo’peach variety is 546;And 10 genes related to selenium metabolism were screened by combining selenium metabolism related pathways,namely ACS1、ACS3、ACO2、SULTR,GST23、GSTU10、GSTU9、6PGD-1、6PGD-2、GPX,qRT PCR analysis was performed on the obtained genes,and the results showed that the expression levels of SULTR、GST23、GSTU9、GSTU10、GPX,and ACO2 genes were significantly higher than those of fruits without selenium treatment,it shows that exogenous selenium can effectively respond genes involved in selenium in fruit.