| Peach originated in China,has a long history of cultivation and a wide distribution area.Peach gummosis is an infectious disease,which has a wide incidence and serious harm.As a new type of fertilizer,silicon fertilizer contains a large amount of sil icon elements needed by plants,which can improve soil environment,promote plant growth and improve plant disease resistance.In recent years,the research of silicon fertilizer on the growth and development of Gramineae plants,disease control and its mechanism has been increasing,but the application of silicon fertilizer on peach trees has not been reported.Therefore,the experiment was conducted to study the effects of silicon fertilizer combined with potassium fulvic acid on soil enzyme activity,soil nutrient content,root structure and plant growth of potted peach saplings,using one-year-old’Amygdaluspersica Linn’.The effects of silicon fertilizer on convective gum disease of three-year-old peach trees and its preliminary mechanism were further explored.In order to provide theoretical basis for rational use of silicon fertilizer and prevention of peach gummosis.The main results of research were as follows:1、Silicon fertilizer can improve the activities of acid phosphatase,soil urease and soil catalase during the growth period of young peach trees(June-October),and significantly increase the contents of alkali-hydrolyzed nitrogen,available phosphorus,available potassium and available silicon in the soil.In different periods,soil enzyme activities were T2(silicon fertilizer + potassium fulvic acid)> T1(silicon fertilizer)> CK(blank).In July,the acid phosphatase,urease,catalase and catalase increased by 26.5% and 37.8%,8.0% and 18.6% respectively,and 48.2% and 57.5% respectively in T1 and T2 treatments.The contents of alkali-hydrolyzed nitrogen,available potassium and available silicon in all treatments from June to October were T2 > T1 > CK.In mid-July,soil available phosphorus content T1 > T2 > CK,but in late growth stage,T1 was significantly less than T2,which also showed T2 > T1 > CK.2、Silicon fertilizer could significantly reduce the browning degree of peach roots,and the browning degree was CK > T1 > T2.Compared with the control,silicon fertilizer treatments had developed roots and evenly distributed fine roots.Compared with the control,the proportion of fine roots in T1 and T2 treatments increased by 11.2% and 26.2% respectively,and the root activity increased by 12.2% and 18.1% respectively.After applying silicon fertilizer,the total length of roots increased,the average length of primary lateral roots decreased significantly,and the number of primary lateral roots and secondary lateral roots increased significantly.Therefore,silicon fertilizer can promote the root growth of young peach trees,and potassium fulvic acid has a more significant effect.3、Compared with the control,the total dry weight of T1 and T2 treatments increased by 1.2 and 2.0 times,the dry stem increased by 23.2% and 42.6% respectively,a nd the root-shoot ratio increased by 9.4% and 17.0% respectively.The contents of total nitrogen,total phosphorus and total potassium in different organs of different treatments were T2 > T1 > CK,and the difference was significant.Compared with CK,the silicon content in shoot and underground parts of young peach trees treated with T1 and T2 increased 61.3% and 91.9% respectively,and 63.4% and 99.4% respectively.Therefore,the application of silicon fertilizer can significantly increase the content of nitrogen,phosphorus,potassium and silicon in young peach trees,and the combination of potassium fulvic acid is more conducive to the accumulation of these elements in young peach trees.In mid-June,the net photosynthetic rate of T2 treatment combined with potassium fulvic acid was slightly lower than that of single application of silicon fertilizer.After that,the net photosynthetic rate of T2 treatment was higher than that of T1,and higher than that of control.The SPAD value of leaves of all treatments increased first and then decreased,and the difference between treatments was the same as the net photosynthetic rate.It can be seen that the application of silicon fertilizer alone and potassium fulvic acid combined with silicon fertilizer can improve the SPAD value of chlorophyll and photosynthesis,and the effect of the latter is more significant.4、Compared with the control,the silicon content of peach branches increased after soaking with different concentrations of silicon fertilizer.The silico n content of T1,T2 and T3 treatments increased by 38.7%,53.5% and 91.4% respectively,compared with the control.In the concentration range of 0-2%,the higher the concentration of silicon fertilizer soaked,the higher the silicon content of the treated peach branches.Only CK produced gum flow when cultured in light incubator for 1 day.After incubation for 3 days,all treatments had branch gum flow.CK gum flow rate was 82.2%,T1 and T2 gum flow rates were 67.8% and 64.4%,respectively.T3 treatment had the lowest gum flow rate,and only about half of the branches appeared gum flow.After 7 days of incubation,all the peach branches treated with CK showed gum flow,and the gum flow rate reached 100%.However,a few of the branches treated with silicon foam still did not produce gum flow.It can be seen that silicon can alleviate the occurrence time and severity of gummosis,but can not completely inhibit gummosis.5、Compared with CK,PME activity in T1,T2 and T3 treatments were 64%,45% and 34% of CK,respectively.Compared with CK,PGE activity in T1,T2 and T3 treatments decreased by 20.8%,27.1% and 31.3% respectively,while the activity of beta-galactosidase decreased by 45.6%,51.3% and 62.5% respectively.There is a similar trend in the expression of enzyme-related genes.At the beginning of the treatment,ethylene produced by the branches foamed with silicon was significantly more than CK,and the higher the silicon concentration,the higher the ethylene release rate.After 24 hours,the ethylene re lease of foamed silicon decreased rapidly,which was significantly lower than that of untreated CK.After that,the ethylene release was CK > T1 > T2 > T3.ACS activity and ACO activity had the same trend as ethylene release rate.Therefore,silicon can inhibit the activity of cell wall degrading enzymes by inhibiting the expression of cell wall degrading enzymes genes,and also inhibit the release of ethylene by inhibiting the activity of enzymes related to ethylene synthesis.It is speculated that silicon may aleviate the gummosis through these two ways. |
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