Effects Of Different Nano CeO₂ Treatments On Tomato Physiology,Quality And Yield

This research mainly uses tomato as the research plant,adding nano-CeO₂ with low,medium and high dosages（1 mg/kg,10 mg/kg,100 mg/kg）of particle size（10 nm,50 nm,80 nm）to the soil.To study the effects of different particle sizes and different dosages of nano-CeO₂ on tomato physiology,quality and yield.The main findings are as follows:（1）The content of reducing sugar in fruits under nano-CeO₂ treatment increased with the increase of dosage.Compared with the control,the high dosage of 10 nm and 50 nm significantly increased by 24.85%,20.42%,and the medium and high dosage of 80 nm significantly increased by 31.57%,26.94%.Compared with the dosage of 80 nm and 10 nm and 50 nm,the reducing sugar content of fruit increased significantly.There was no significant difference in the vitamin C content of the fruits treated with nano-CeO₂ compared with the control,and the vitamin C content of the fruits decreased with the increase of the particle size under the same dosage.（2）The total N content of the plants under the nano-CeO₂ treatment was reduced to different degrees compared with the control treatment.Among them,the difference between the high dosage of 10 nm and 50 nm and the low dosage of 80 nm was significantly reduced.Compared with the control treatment,the total N content of the fruit was not significantly different in the increase of low dosage,the difference was significantly reduced except for the medium dosage except 80 nm,and the high dosage was reduced and the difference was significant.nano-CeO₂ treatment plants had no significant effect on the total P content of plants.Compared with the control treatment,the fruit total P content was only 80 nm low,the medium dosage increased and the difference was significant.The other nano-CeO₂ treatments had no significant difference with the control treatment.Compared with the control,the total K content of the plant was 50 nm and the three dosages were significantly increased.The increase of 10 nm and 80 nm was not significant,and even the high dosage of 80 nm was lower than the control treatment.The total K content of fruits treated with different nano-CeO₂ showed different trends.With the increase of nano-CeO₂ dosage,the total K content of 10 nm showed an upward trend,50 nm showed a downward trend,and 80 nm showed a trend of first increasing and then decreasing.（3）Compared with the control,the Ca content of plants with low and medium dosage of 50 nm and80 nm and the Mg content of plants with high dosage of 80 nm were significantly reduced by nano-CeO₂ treatment of tomato plants.The high dosage of 10 nm,medium and high dosage of 50 nm significantly increased the Cu content of plants;The dosage and the three dosages of 50 nm significantly increased the Fe content of the plant.Compared with the control,the content of Ca,Mg,Cu,Zn in the fruit and the content of Zn and Mn in the plant did not change significantly.The three dosages of 80 nm significantly increased the Fe content in the fruit,the medium dosage of 50 nm and the low-medium dosage of 80 nm significantly increased the Mn content in the fruit.（4）Under nano-CeO₂ treatment,the Ce content in the shoots and fruits increased with the increase of the applied amount.Compared with the control,the Ce content in the shoots of the plants with the high dosage of 10 nm and the medium and high dosage of 50 nm increased significantly.Compared with the control,the nano-CeO₂ treatments with three particle sizes and different dosages increased the Ce content in the fruit significantly.Only a small part of the soil enters the plant body,and the Ce content in the fruit is even lower.The larger the particle size,the less the nanoparticles enter.（5）Under nano-CeO₂ treatment,compared with the control,the dosage of 50 nm significantly increased the chlorophyll content of tomato leaves.Different 50 nm high dosage significantly increased the intercellular CO2 concentration and transpiration rate of leaves,and the low dosage of 10 nm significantly increased leaf stomatal conductance and significantly reduced leaf net photosynthetic rate.（6）The contents of MDA,proline and CAT in the leaves of the plants increased under the treatment of nano-CeO₂.Compared with the control,the high dosage of 10 nm and the low dosage of 50 nm significantly increased the proline content.The smaller the particle size,the easier it was for nano-CeO₂ to enter the plant to produce stress.The larger the dosage,the stronger the inhibitory effected.The activity of MDA and CAT was not significantly different compared with the control.（7）Nano-CeO₂ treatment inhibited soil urease activity and reduced nitrogen absorption by plants.Enhance soil alkaline phosphatase activity,80 nm high dosages increased significantly compared with the control.Improved the activity of soil invertase,and the high dosage of 50 nm increased significantly compared with the control.Inhibited soil catalase activity,10 nm low and medium dosages were significantly reduced compared with the control.（8）The fresh weight of tomato fruit under nano-CeO₂ treatment increased compared with the control and the difference was not significant.The yields of 10 nm and 50 nm medium dosage were 222.29 g/pot and 226.66 g/pot respectively,and 80 nm medium and high dosage were 237.28 g/pot and 237.68 g/pot respectively.The above experiments show that different nano-CeO₂ treatments can promote tomato fruit quality and nutrient absorption,and can enhance tomato resistance,but reduce leaf photosynthesis and soil enzyme activity,and have no significant effect on tomato fruit yield.