Study On Storage And Physiological Characteristics Of Apple Seedlings

In order to meet the planting needs of apple seedlings in different regions and time and maintain the quality of the seedlings and prolong the supply period of the seedlings,it is necessary to store the seedlings from the nursery.However,during the Seedling storage period,It often happens that the quality of apple seedling roots is poor,the water loss and germination of seedlings,and the occurrence of diseases seriously affect the quality and survival rate of seedlings.In this experiment,the annual dwarfing self-rooted seedlings and M9-T337 rootstocks planted by Haisheng were used as experimental materials,and four groups of treatments were set up,including Refrigerated high humidity(temperature 1 °C,humidity 99%),and Refrigerated high-humidity seedlings spray high-fat membrane,Refrigerated high-humidity seedlings spray anti-transpiration agent and Only refrigerated wet sawdust covered seedlings,storage time is 105 d,the physiological indicators of seedlings are measured every 15 days,including root activity,root conductivity,relative water content of seedlings,bud mitotic index and pathogen infection status.In order to obtain the best storage method of seedlings,as well as to evaluate the physiological indicators of seedling vigor,and provide a theoretical basis for seedling storage.The main findings are as follows:On the 15 day of storage,the relative water content of the four treated seedlings increased slightly.The water content of the seedlings changed smoothly within 105 storage days,and the water content of the seedlings treated with the high-fat membrane changed the least.At the same time,the relative water content of the seedlings treated by the refrigerated wet sawdust was also very stable in storage,the relative water content was close to that of the refrigerated high-humidity storage,at the 90 th day of storage the descending speed began to increase,This indicates that compared with the high refrigerated high-humidity storage,only the refrigerated wet sawdust cover seedlings are more economical to store and more suitable for small farmers.The physiological changes of seedlings during storage were complicated,and the root vitality of refrigerated seedlings increased first and then decreased.This indicates that in the early stage of storage,in order to adapt to the cold stress environment,it showed some resistance to maintain its normal metabolism.The increase of storage time,the bare root storage of apple grafted seedlings will cause certain damage to the roots of the seedlings,so the root activity gradually decreases.The use of wet sawdust storage has little change in root activity,indicating that wet sawdust can give a suitable environment for roots and reduce damage to the roots caused by the environment.The relative conductivity of roots increased slowly during storage,which corresponds to the trend of Pathogen infection rate during storage,the correlation between the two is up to 0.9,therefore,the relative conductivity of roots can be used as a physiological index to evaluate the vigor of seedlings.During the storage period,the mitotic index of refrigerated seedlings began to increase slowly around the 90 th day,and the mitotic index of buds was 0 or close to 0 in the past two months,but it still did not reach the degree of releasing dormancy,indicating that apple seedlings could be prolonged under refrigeration.During the storage period,the mitotic index of seedlings treated with refrigerated wet sawdust reached the highest at 75 d,and increased slowly,close to the first measurement.There is a bud mitotic index of 0 or close to 0 in one month,indicating that only the wet sawdust is refrigerated.The seedling buds in the covered seedlings are very unstable and are only suitable for short-term storage.The infection rate of seedlings during storage was 0 in the half month after storage,and then increased continuously.After 30 days of storage,it began to increase.It is recommended to spray the fungicide every other month during storage to reduce the infection rate of the bacteria,and pay attention to clean up the water in the cold storage.