【作者】 王婷婷；

【导师】 张文明； 姚大年；

【作者基本信息】 安徽农业大学 ， 草业科学， 2015， 硕士

【摘要】 超低温保存是指在超低温度低于-80℃保存生物材料的保藏技术,应用于育种材料和种质保存技术,通常在液氮(-196℃)作为超低温冷源。本研究选用PH6WC、郑58、昌7-2、9801和齐319 5个玉米品种种子为材料,各品种通过硅胶干燥或喷水吸湿处理,分别获6%、8%、10%、12%和14%左右的5种水分档次种子,取适量的种子于液氮中密封贮藏7d,进行液氮超低温保存试验,以常温条件下保存的起始水分种子为对照,采用幼苗生长测定、模拟田间出苗率测定、抗冷测定和电导率测定,以及ADH、POD、CAT、SOD和LOX等5种酶活性测定,来综合评价种子的活力;选用PH6WC起始水分种子为试验材料,进行不同时间和不同处理方式的液氮超低温贮藏试验,选择幼苗生长测定、模拟田间出苗率测定、电导率测定及ADH活性测定等方法来测定种子活力。旨在探讨液氮超低温贮藏对玉米种子活力的影响,以及玉米种子超低温贮藏的适宜含水量。主要结果如下:1.对常用的种子活力指标进行测定,结果表明:5个玉米品种,不同水分档次种子,在液氮超低温条件下贮藏7d,与对照相比,其主要的常用活力指标均有所下降,水分为8%和10%的处理,下降幅度较小,其余水分处理的种子,下降幅度偏大。2.酶活性的测定结果表明:5个玉米品种,不同水分档次种子,在液氮超低温条件下贮藏7d,种子的ADH、POD、CAT、SOD以及LOX等5种酶活性,与对照相比各品种大多数处理均表现不同程度的下降,少数处理有所上升。水分档次为8%或10%的处理,5种酶活性与对照差异较小。3.液氮超低温贮藏7d、14d和21d的PH6WC种子活力均明显低于对照,但不同处理时间的种子之间活力差异不显著。缓速冷冻和缓速解冻两种处理方式的种子活力均明显高于对照,且缓速冷冻处理种子活力高于缓速解冻处理。4.各品种种子含水量为6%~10%的两个较适宜处理的各项活力指标其平均下降幅度表明:不同玉米品种的耐超低温能力大小存在差异,耐超低温能力大小依次为昌7-2﹥齐319﹥郑58﹥9801﹥PH6WC。5.根据玉米种子超低温贮藏主要活力指标及5种酶活性的变化,5个玉米品种种子均可寻找出超低温贮藏的适宜含水量,PH6WC为8.07%;郑58为7.91%;昌7-2为8.06%;9801为7.81%;齐319为7.94%。初步认为,玉米品种适合超低温贮藏,超低温贮藏的适宜含水量一般为8%左右。更多还原

【Abstract】 Cryopreservation is a storage technology that germplasm resources were preserved below the temperature of-80 ℃,which commonly was used to preserve breeding materials and germplasm resources.Generally,the cold source of cryopreservation are liquid nitrogen(-196 ℃).In this study,5 maize variety seeds of PH6 WC,zheng58,chang7-2,9801 and qi319 were chosen as materials.Each maize variety seeds respectively got 5 water levels(6% 、8%、10% 、12%and14%)by silicone drying and spraying water.Before liquid nitrogen cryopreservation tests were carried out,adequate above-mentioned seeds were taken and stored 7 days at-196 ℃,setting the starting moisture seeds preserved under room temperature as CK.Seedling growth test,simulated field germination test,cold water test,electrical conductivity test,and ADH,POD,CAT,SOD,LOX activities test were used to determine the vitality indexes of maize seeds.PH6 WC seeds were used as the materials to carry out seedling growth test 、 electrical conductivity test 、 simulated field germination test and ADH test after liquid nitrogen cryopreservation in different times and different treatment methods,which were used to test influence of cryopreservation on seed vigor and optimum moisture content of maize seeds stored at-196 ℃.The results are as follows:1.The results of commonly seed vigor indicator testing showed:maize seeds of 5kinds of moisture grades after stored in liquid nitrogen for 7d,the treatment which moisture content exceed 10% or below8% declined greatly,while the treatment which moisture content is 8% or 10% had no significant difference compared with control.2.The results of enzyme activities testing showed:maize seeds of 5 kinds of moisture grades after stored in liquid nitrogen for 7d,most seeds’ activities of ADH,POD,CAT,SOD and LOX were declined different degree,while a few was got up compared with control.The enzyme activities of treatment 10% and 8% descended smaller and had no significant difference compared with control.3.There were no significant differences of seed vigor indexes between maize seeds after liquid nitrogen cryopreservation in different times,eventhough which were lower than the check.Most major seed vigor indexes of the maize seeds were higher than the check after liquid nitrogen cryopreservation in different treatment methods,and the vigor indexes of muted freeze treatment were higher than the muted thaw treatment.4.In every maize varieties,the average decline of each vigor indicator of two better treatment of 6%~10% indicated: maize varieties’ ability of ultra-low temperatureresistance is different,which is from big to small:chang7-2﹥qi319﹥zheng58﹥9801﹥PH6WC.5.According to the changes of indicators or activities,five maize variety seeds can find an optimum moisture content at ultra–low temperature storage,PH6 WC is 8.07%,zheng58 is 7.91%,chang7-2 is 8.06%,9801 is 7.81%,qi319 is 7.94%.Preliminary view is that maize variety seeds are suitable for ultralow temperature storage,of which the optimum moisture content is about 8%.更多还原