闽楠插条根原基发育机理  

Mechanism underlying root primordium development in Phoebe bournei cuttage

作　　者：龚娜 蔡琦 熊远芳 万露露 陈世品[1] 冯丽贞[1] GONG Na;CAI Qi;XIONG Yuanfang;WAN Lulu;CHEN Shipin;FENG Lizhen(College of Forestry,Fujian Agriculture and Forestry University,Fuzhou,Fujian 350002,China;Youxi Jiufu Mountain Provincial Nature Reserve Service Center,Youxi,Fujian 365100,China)

机构地区：[1]福建农林大学林学院,福建福州350002 [2]尤溪九阜山省级自然保护区服务中心,福建尤溪365100

出　　处：《森林与环境学报》2024年第3期283-288,共6页Journal of Forest and Environment

基　　金：福建省种苗科技攻关项目“闽楠良种选育与繁殖关键技术研究”(ZMGG-0708)。

摘　　要：扦插是闽楠无性繁育的主要技术手段,为探明原发条件下闽楠根原基发育的机理,采用未经植物激素处理的插条进行扦插。在闽楠插条根原基发育扦插起始期(T0期)、根原基初现期(T1期)和根原基分化期(T2期),以插条基部0.5~1.0 cm的茎段为样品进行切片观察,以插条顶芽、插条基部切口处2 cm范围内茎段的维管形成层以外的皮部为样品进行吲哚乙酸(IAA)含量测定及转录组测序,而可溶性糖、可溶性蛋白含量以基部皮为样品进行测定。结果表明:闽楠插条根原基源于维管形成层向外形成的次生韧皮部的薄壁细胞。闽楠根原基在发育过程中皮的可溶性糖、可溶性蛋白含量在T1、T2时期连续下降,IAA含量均显著上升(P<0.05),表明IAA是根原基发育的重要内源信号;芽的IAA含量在T1期先下降,T2期再上升,可能是将芽的IAA运输到皮部。根据系统发育关系,将闽楠基因组的58个PbARF基因分为4个进化枝,分别是进化枝A、进化枝B、进化枝C、进化枝D。在闽楠插条根原基发育过程中PbARF2、PbARF6、PbARF23、PbARF33、PbARF40、PbARF58基因表达量逐渐升高,表明它们在根原基发育过程中起到重要作用,且PbARF33、PbARF40基因表达量较高,是根原基发育的关键基因。The main technique for asexually propagating of Phoebe bournei is through cutting;here,the mechanisms of root primordium development in P.bournei under original conditions were investigated using unprocessed cuttings without plant hormone treatment.At the initial stage of cutting(T0),early stage of root primordium appearance(T1),and differentiation stage of root primordium development(T2)of P.bournei cutting rooting,stem segments measuring 0.5~1.0 cm at the base of the cuttings were sampled for histological observations.Indole-3-acetic acid(IAA)content measurements and transcriptome sequencing were performed on the outer cortex of stem segments within 2 cm of the cutting top bud and base incision.Soluble sugar and soluble protein contents in the basal cortex were measured.Our results indicate that the root primordium of P.bournei cuttings originates from the thin-walled cells of the secondary cork cambium formed exterior to the vascular cambium.During P.bournei root primordium development,soluble sugar and soluble protein contents in the cortex continuously decreased in the T1 and T2 stages,whereas the cortex IAA content increased significantly(P<0.05),indicating that IAA is an important endogenous signal for root primordium development.The IAA content in the buds decreased during the T1 stage and then increased during the T2 stage,possibly indicating IAA transport from the buds to the cortex.On the basis of phylogenetic relationships,the 58 PbARF genes in the P.bournei genome can be classified into four clade:clade A,B,C,and D.During the development of P.bournei cutting roots,the expression levels of genes PbAR F2,PbAR 6,PbAR 23,PbAR 33,PbAR 40,and PbARF58 gradually increased,indicating their significant roles in root primordium development.Moreover,PbAR 33 and PbAR 40 exhibited relatively high expression levels,suggesting that they are key genes involved in root primordium development.

关 键 词：闽楠 扦插 根原基 吲哚乙酸 ARF基因家族 

分 类 号：S792.24[农业科学—林木遗传育种]