超低温冷冻对龙眼种子生理生化特性的影响  

Effect of Cryopreservation on the Physiological and Biochemical Characteristics of Longan Seeds

作　　者：李珊珊 孙政 曾琳 LI Shanshan;SUN Zheng;ZENG Lin(Chinese Academy of Medical Sciences/Peking Union Medical College/Hainan Branch,Institute of Medicinal Plant Development/Hainan Provincial Key Laboratory of Resources Conservation and Development of Southern Medicine,Haikou,Hainan 570311,China)

机构地区：[1]中国医学科学院/北京协和医院/药用植物研究所海南分所/海南省南药资源保护与开发重点实验室,海南海口570311

出　　处：《热带作物学报》2024年第12期2599-2606,共8页Chinese Journal of Tropical Crops

基　　金：中国医学科学院医学与健康科技创新工程项目(No.2021-I2M-1-032)。

摘　　要：龙眼(Dimocarpus longan Lour.)原产于我国南方,在南部和东南部地区广泛栽培,是经济价值较高的果树。龙眼种子作为典型的顽拗性种子,对低温和干燥具有高度敏感性,因此在传统的低温种子库中难以保存。本研究在排除冰晶对种子影响后,对新鲜和干燥种子进行玻璃化冷冻和直接冷冻超低温保存,并比较生理生化指标、内含物和淀粉的变化。结果表明:在经过脱水和超低温保存后,龙眼种子活力急剧下降;与新鲜种子相比,脱水导致丙二醛含量大幅度增加,细胞膜受损严重;过氧化氢含量呈下降趋势;抗氧化酶系统表达增加,含水量16%的龙眼种子玻璃化冷冻处理后SOD活性最高,且玻璃化冷冻处理降低了POD和CAT活性。低温和脱水导致种子内可溶性糖和可溶性蛋白质含量增加,脱水导致蛋白质变性,含量降低。观察龙眼种子淀粉发现,经过玻璃化冷冻处理后淀粉颗粒表面有空洞和凹陷生成,直接冷冻处理造成淀粉颗粒破裂。脱水和低温对淀粉分子结构未造成影响,但对内部有序结构造成了一定程度的破坏。Longan(Dimocarpus longan Lour.)is native to southern China and widely cultivated in the southern and southeastern regions.It is a fruit tree with high economic value.Longan seeds,as a typical recalcitrant seed,are highly sensitive to low temperature and drying,making them difficult to preserve in traditional low-temperature seed banks.After excluding the influence of ice crystals on seeds,this study conducted vitrification freezing and direct freezing ultra-low temperature storage on fresh and dry seeds,and compared the changes in physiological and biochemical indicators,contents,and starch.After dehydration and ultra-low temperature storage,longan seeds almost lost the vitality.Compared with healthy seeds,dehydration led to a significant increase in malondialdehyde content and severe damage to cell membranes.The hydrogen peroxide content showed a decreasing trend.The expression of antioxidant enzyme system increased,and the highest SOD activity was observed in longan seeds with a water content of 16%after vitrification and freezing treatment,while vitrification and freezing treatment reduced the activities of POD and CAT.Low temperature and dehydration led to an increase in the content of soluble sugars and proteins in seeds,while dehydration led to protein denaturation and a decrease in content.Observing the starch of longan seeds,it was found that after vitrification and freezing treatment,there were voids and depressions on the surface of starch particles,which were directly frozen and caused starch particle rupture.Dehydration and low temperature did not affect the molecular structure of starch,but caused some degree of damage to the internal ordered structure.

关 键 词：超低温冷冻 生理生化特性 顽拗性种子 龙眼 

分 类 号：S667.2[农业科学—果树学]