桃儿七种子休眠解除过程中细胞壁代谢及种皮超微结构的变化  

Changes in Seed Cell Wall Metabolism and Seed Coat Ultrastructure of Sinopodophyllum hexandrum(Royle)Ying during Dormancy Release

作　　者：久西加 陈红刚[1,2] 王惠珍 曾翠云[1,2] 杜弢 JIU Xijia;CHEN Honggang;WANG Huizhen;ZENG Cuiyun;DU Tao(Hezheng Botanical Garden of Medicinal Plants,Gansu University of Chinese Medicine,Hezheng,Gansu 731200,China;Northwest Collaborative Innovation Center for Traditional Chinese Medicine,Lanzhou 730000,China)

机构地区：[1]甘肃中医药大学和政药用植物园,甘肃和政731200 [2]西北中藏药协同创新中心,兰州730000

出　　处：《西北植物学报》2023年第10期1704-1715,共12页Acta Botanica Boreali-Occidentalia Sinica

基　　金：国家中药材产业技术建设专项资金资助(CARS-21);甘肃省科技创新基地和人才计划项目(18JR2TA017)。

摘　　要：为探究低温层积过程中桃儿七种子细胞壁代谢及种皮超微结构与休眠解除的内在联系,该研究通过低温层积解除桃儿七种子休眠,分析休眠解除过程中种子不同部位细胞壁组分及相关代谢酶的变化,同时利用扫描电镜对种皮的超微结构进行观察。结果表明,(1)桃儿七种皮主要由角质层、栅状石细胞层及海绵组织层3层构成,在层积过程中,种皮内部的海绵组织逐步疏松膨胀,种皮表面破损加剧;(2)种子不同部位的细胞壁组分具有明显差异,整个层积过程中,种胚、种皮和胚乳中的纤维素含量均在层积中期(45 d和60 d)降至最低,3个部位的纤维素酶活性在层积中期对应升高;种胚和种皮内的半纤维素含量均在层积中期显著下降,种皮中甘露聚糖酶活性和木糖苷酶活性在层积中期时相应达到最大;3个部位的果胶含量均在层积后期(75 d和90 d)时显著下降,而种皮和胚乳中多聚半乳糖醛缩酶活性也在层积后期相应升高;(3)种胚和胚乳内过氧化物酶活性在层积75 d和90 d时明显下降,而SOD活性在此时显著上升。(4)种子不同部位3种木质素单体的组成比例具有明显区别,同时3种木质素单体含量均随层积时间的延长而显著降低,且胚乳和种皮中的S-木质素含量对种子萌发存在显著的负向影响关系。研究认为,在低温层积过程中,桃儿七种子内细胞壁组分纤维素、半纤维素及木质素的逐步酶解,活性氧作用下的细胞壁松弛以及海绵组织层的疏松膨胀和种皮的破裂,破坏了细胞壁的刚性结构,促使种子机械束缚力降低,吸水性能提高、胚根生长能力增强,最终导致其休眠解除。In order to investigate the intrinsic relationship between cell wall metabolism and seed coat ultrastructure and dormancy lifting during low-temperature stratification,this study released the dormancy of Sinopodophyllum hexandrum seeds by low-temperature stratification,analyzed the changes of cell wall components and related metabolism enzymes in different parts of the seeds during the process of dormancy releasing,and at the same time,used the scanning electron microscope to observe the seed coat ultrastructure.The results showed that,(1)the seed coat of S.hexandrum seed was mainly composed of three layers:Cuticle,fenestrated stone cells and spongy tissue,and the spongy tissue inside the seed coat gradually loosened and swelled,and the surface damage of the seed coat intensified in the process of stratification.(2)There were obvious differences in the cell wall components of different parts of the seeds,and the cellulose contents of seed embryo,seed coat and endosperm decreased to a minimum in the middle of the stratification process(45 d and 60 d);hemicellulose contents of seed embryo and seed coat decreased significantly in the middle of stratification,and cellulase activity and xyloside activity of the seed coat increased correspondingly in the middle of stratification.The cellulose content of seed embryo,seed coat and endosperm decreased to the lowest in the middle of stratification(45 d and 60 d),and the cellulase activities of the three parts increased in the middle of stratification;the hemicellulose content of seed embryo and seed coat decreased significantly in the middle of stratification,and the mannanase activity and xylosidase activity of seed coat reached the maximum in the middle of stratification;the pectin content of the three parts decreased in the late stage of stratification(75 d and 90 d),and the activity of polygalacturonase of seed coat and endosperm increased in the late stage of stratification;the cell wall components of different parts of the cell wall differed significantly.(3)Peroxida

关 键 词：桃儿七 休眠解除 细胞壁代谢 种皮超微结构 

分 类 号：S567.239[农业科学—中草药栽培]