外源细胞分裂素诱导日本菟丝子形成吸器的发育解剖研究

A STUDY ON THE DEVELOPMENTAL ANATOMY OF HAUSTORIA IN CUSUTA JAPONCA CHOISY INDUCED BY EXOGENOUS CYTOKININ APPLICATION

应用外源细胞分裂素(KT和BA)对诱导日本菟丝子(Cuscuta japonica Choisy)形成吸器的研究结果表明:用KT(5000ppm)或BA(1000ppm)处理后48小时,日本菟丝子茎转绿、伸长并增粗;处理后72小时,在茎的处理区段逆时针螺旋状地形成一行乳头状突起,经解剖观察发现其内部皮层已形成吸器原基。6～7天后,吸器原基可伸到茎表面。将KT(5000ppm)与NAA(100ppm)混合后处理日本菟丝子茎,未能诱导出吸器原基。但用浓度低于100ppm的NAA与KT同时处理后,KT又能诱导出吸器,这表明NAA与细胞分裂素之间具有颉颃效应,作者认为,吸器的形成是由菟丝子内源细胞分裂素与生长素等激素共同调控;吸器的特性与功能,是寄生物生存适应的结果。

The haustorial primordia differentiated from the cortex of dodder can be classified into two types, based on the number of redifferentiation of the cortical ceils. The haustoria are developed from the haustorial primordia. The detail structure of the haustoria is described.The tracheid and sieve tube elements are all differentiated from the procambia in the center of the haustoria, and the former occurs prior to the latter. The differentiation of tracheid and sieve elements occur at the same time.The apical ceils of the haustorial primordia are of typical character of meristem. The haustorial hyphae differentiate into tracheids or sieve elements. There are three fashions of connections between the hyphae and the vessel elements of the host. and there are also three fashions of connections between the hyphae and the sieve elements of the host. Three kinds of the wall ingrowth are discussed, one of which is considered as transfer cells.The localizations of the phosphatases and the oxidase are observed in the apical cells of the haustoria. The composition and the function of the haustorial secretion are discussed. The relation hetween the growth and decline of stored starch-grains and the formation of haustorial primordia is investigated.