油茶插穗生根过程的解剖学观察

采用常规石蜡切片法,观察油茶插穗不定根发育的解剖学特征。结果表明：油茶当年生插穗茎内无潜伏根原基, 插条的皮部存在连续排列成环状的厚壁细胞,这些结构特征可能与油茶插条生根时间较长有关。不定根由诱生根原基发育形成, 诱生根源于形成层、韧皮部及愈伤组织等部位,不定根属于诱导根原始体型、混合生根型。只有极少数插条的不定根由愈伤组织长出,不定根的发生与愈伤组织没有直接关系。     

杂种鹅掌楸插穗不定根发生与发育的解剖学观察

从解剖学角度着手,对杂种鹅掌楸〔Liriodendronchinense(Hemsl.)Sarg.×L.tulipiferaL.〕扦插过程中不定根的发生发育进行了研究。结果表明:杂种鹅掌楸插穗内未发现潜伏根原基。扦插后,不定根原基起源于维管形成层区,属于诱导生根类型。维管形成层恢复活动后,在不定根发生的部位附近形成1个明显的多薄壁细胞区域,在此区域不定根较容易发生。愈伤组织内没有发现根原基,愈伤组织在发育的过程中,内部细胞部分分化,并形成不规则的输导组织。大量的愈伤组织对不定根的发生有较强的抑制作用。杂种鹅掌楸插穗上不定根的发生可分为4个阶段:(1)维管形成层恢复活动,分裂出多层薄壁细胞;(2)维管形成层及附近的薄壁细胞脱分化,形成不定根原基发端细胞;(3)根原基发端细胞不断分裂成具有方向性的根原基,根原基穿过韧皮射线和皮层,向皮孔或下切口方向发展;(4)不定根从皮孔或下切口伸出,其内部的维管系统开始发育。     

侧柏扦插不定根发生模式研究

该研究以侧柏一年生硬枝插穗为实验材料,利用连续组织切片技术观察插穗不定根发生发育过程中的组织结构变化,分析插穗外部形态变化、不定根原基起源和不定根的形成过程,探讨侧柏插穗不定根发生模式和不定根的组织学起源。结果显示:侧柏扦插后可由愈伤组织、皮部诱导产生不定根,出现皮部生根、愈伤组织生根、愈伤组织兼具皮部生根3种类型;侧柏插穗中存在少量潜伏根原基,但插穗生根类型以诱导生根为主;不定根原基诱导产生于愈伤组织、木质部、形成层及次生韧皮部等部位。研究认为侧柏扦插生根属于多位点发生模式,不定根原基的组织学起源是愈伤组织、髓射线、射线原始细胞、尚未分化成熟的木质部细胞,通过人工诱导同时激活这些不定根起源位点能够显著提高生根率和生根质量。     

四合木茎插穗生根的解剖学研究

采用石蜡制片法对四合木茎插穗不定根的形成进行了解剖学研究,探讨四合木生根类型、生根部位、愈伤组织与生根的关系以及不定根的形成过程。结果显示:(1)四合木具有典型的木本植物茎结构,茎皮层内未发现厚壁组织。(2)四合木茎薄壁组织含有丰富的淀粉粒和蛋白质。(3)四合木茎插穗内无潜伏根原基,不定根由诱生根原基发育形成,诱生根原基是由愈伤组织自身的薄壁细胞反分化形成。研究表明,愈伤组织是孕育不定根的前提,四合木扦插生根属于愈伤组织生根类型。     

黑果腺肋花楸扦插生根特性及不定根发生模式研究

【目的】为了解黑果腺肋花楸扦插不定根起源及发育过程,揭示其扦插生根机理。【方法】以‘福康源1号’当年生半木质化插穗为研究材料,利用水培扦插技术和石蜡切片法对不定根形成过程中插穗内部组织结构及外部形态的变化规律进行观察。【结果】在水培条件下,IBA处理扦插生根期为30~40 d,扦插过程中皮孔处10~15 d出现不定根,插穗切口处15~20 d出现不定根,生根速度、不定根数量及根长均优于对照,外源诱导可显著提高生根率和生根质量。扦插前的插穗内无潜伏根原基存在,不定根原基在插后形成;不定根形成为愈伤组织生根型和内部分生组织生根型。皮部产生的不定根起源于维管形成层、韧皮薄壁细胞或皮层;愈伤组织产生的不定根是由愈伤组织内的薄壁细胞团特化而成;叶隙或枝隙是形成不定根原基和产生愈伤组织的主要区域。【结论】扦插生根属于多位点发生模式,属于诱导生根型。     

欧美杂种山杨微扦插不定根发生过程的解剖学研究

采用石蜡切片技术,以欧美杂种山杨插穗基部茎段为实验材料,连续解剖观察插穗不定根发生发育过程,分析根原基发生部位与扦插生根的关系。结果显示:欧美杂种山杨插穗不定根的发生过程分为4个时期,为根原基诱导期,不定根起始期、表达期和伸长生长期。根原基诱导期维管形成层产生具有分生组织特点的薄壁细胞;不定根起始期,维管形成层及附近的薄壁细胞脱分化,形成不定根原基发端细胞;不定根表达期,根原基发端细胞不断分裂成具有方向性的根原基,根原基穿过韧皮射线和皮层,向皮孔方向发展;不定根伸长生长期,根原基从皮孔伸出,其内部的维管系统开始发育,形成不定根。研究认为,欧美杂种山杨为皮部诱导生根类型,不定根原基起源于维管形成层区,起源部位单一,扦插难生根。     

油茶组培苗器官发生的形态学与解剖学研究

以油茶岑软3号组培苗为研究材料,对其器官发生过程进行形态学和解剖学观察。结果表明:在选定的培养基上,外植体不经过愈伤组织,直接由器官诱导形成增殖芽,从而有效地保持了其遗传的稳定性。油茶增殖芽不定根由诱导的根原基发生,它起源于形成层薄壁细胞定向分化,不断向外进行伸长生长,并穿透愈伤组织而形成。这种不定根发生形式属皮部生根类型。油茶增殖芽单芽生根培养25 d后在不定根内形成次生维管形成层和木栓形成层,培养40 d以上根内的输导分子与茎内的输导分子相连。     

翅果油树茎段愈伤组织和芽发生的组织学研究

本文对翅果油树大宫灯型茎段培养在ＭＳ附加６－ＢＡ较高、ＮＡＡ较低浓度的培养基上培养０～３０ｄ的组织学变化进行了研究。创伤对其愈伤组织的形成有明显的刺激作用,培养３～４ｄ切口处的皮层细胞、形成层细胞、韧皮部薄壁细胞以及髓组织细胞,甚至表皮细胞均脱分化开始分裂;培养８～１１ｄ,切口明显膨大,起源于髓及维管组织周围薄壁细胞的愈伤组织突起大;培养１２～２０ｄ愈伤组织块中出现了分生组织和维管组织结节;培养２１～３０ｄ,愈伤组织表层和近表层细胞分化出芽原基,但与维管组织结节无直接联系。     

柃木插条生根的解剖学研究

采用石蜡切片法对柃木（Eurya japonica Thunb．）插条不定根的形成进行了解剖学研究。观察结果表明,柃木插条不定根原始体为诱生根原始体;不定根原基起源于维管形成层与髓射线的交叉区域。插条的韧皮部存在较连续的排列成环状的厚壁纤维细胞,茎内无生根原基。柃木插条的这些结构特征可能与柃木插条生根率低有关。     

亚麻植株的再生及诱导因素的研究

亚麻根、下胚轴、茎和叶外植体在适宜培养基上可产生愈伤组织和不定芽。愈伤组织在分化培养基上产生幼芽。在生根培养基上小苗生根长大。组织细胞学观察表明,下胚轴表皮、皮层和韧皮部细胞都能产生小分生细胞团,后者形成不定芽和愈伤组织。愈伤组织边缘区域分化芽原基,内部产生大量的分生组织结节和维管组织结节。根原基起源于维管组织结节的形成层状细胞。不同器官外植体再生植株的潜力不同,对诱导条件的反应有差别,其中茎和下胚轴切段易兼生不定芽和愈伤组织,再生植株频率高。外源激素、基本培养基和损伤刺激明显影响植株再生。     

The integration of growth activity in vegetatively propagated poplar during the establishment year

On rooting the poplar stem cutting, the growth processes are coordinated so as to ensure optimum development of the new, vegetatively acquired individual. At first, adventitious roots develop on the cutting from latent root primordia. A part of them is short-lived, but in the meantime other, the so-called wound adventitious roots initiate from the callus on the lower cut surface of the cutting, which complement the permanent root system. In this way, conditions are prepared for a rapid growth and development of the stem, which forms from the upper bud on the cutting. The action of apical meristems providing the elongation of the stem and root, is followed by the action of vascular cambium. By the radial growth of organs controlled by cambium, the capacity of substance transport increases relatively to progressing development of the new plant. In the buried stem cutting cambium is the first to start functioning. Its reactivation is slow, discontinuous, and at the beginning it depends on local stimulating sources of the cutting itself. It was observed for the first time that, in addition to expanding buds, activated root primordia are also such sources of stimuli. The overall induction of cambial activity in the cutting occurs only in the period of rapid growth and development of the new stem, which thus becomes the main source of factors controlling the cambial activity of the cutting. In comparison with the growth of stem and cutting, the radial growth of adventitious roots is limited and there are considerable differences in the thickness of radial increments between individual roots.     

Histological study of callus formation and root regeneration from mung bean (Vigna radiata W.)

We have established a reproducible culture system for callus formation and root development from juvenile stem segments of mung bean(Vigna radiata). In particular, we have studied the influence of plant growth regulators. Induction of calli from young stem explants was very effective on MS inorganic salts supplemented with 0.5 mg/L 2,4-D and 1.0 mg/L kinetin. In regenerating adventitious roots from callus tissues, we found that a combination of 0.75 mg/L NAA, 1.5 mg/L kinetin, and MS salts resulted in 20% efficiency. Histological examination showed that callus tissues originated from out-growths of the cambium rings through de-novo meristematic activity. Those rings were localized outside the vascular cambium. Adventitious roots that developed from root primordia originated from the center of the Callus masses. These primordia produced tracheid-like cells, which then became meristemoid cells for the cambium. Newly formed adventitious roots had the typical tetrarche actinostele type.     

灰叶胡杨根蘖繁殖的形态解剖学特征

利用常规石蜡切片法对灰叶胡杨(Populus pruinosa)根蘖繁殖特性进行形态解剖学研究。结果表明: 灰叶胡杨横走侧根由周皮、次生维管组织和四原型的初生木质部构成, 具有次生维管组织中维管射线、次生韧皮薄壁组织发达的结构特征。灰叶胡杨的根蘖繁殖源于横走侧根上不定芽的发生及生长发育。不定芽起源于横走侧根的木栓形成层, 木栓形成层经细胞分裂活动形成不定芽原基, 不定芽原基细胞分裂和生长分化形成在横走侧根表面可观察到的不定芽, 进而生长发育为根蘖苗。不定芽的发生具有同步或非同步的时间特征和单点或多点聚集的空间分布特点, 在生长发育过程中其基部可以产生新的不定芽。不定芽发生、分布和生长特点是根蘖苗大小不一、密集丛生的内在原因, 表明灰叶胡杨具有较强的根蘖繁殖能力。     

Histological study of initiation and development in vitro of adventitious roots in minicuttings of apple rootstocks of M 26 and EMLA 9

Apple rootstocks M 26 and EMLA 9 'COST' shoots propagated in vitro were used for the histological study of initiation and development of adventitious roots after a brief induction pretreatment. The results show that there are differences in mode and timing of initiation and development of adventitious roots between the two varieties. In M 26, adventitious roots were directly initiated from the derivatives of the cambium, some of which were immediately transformed into meristemoids in situ 36 h after pretreatment. Subsequently, meristemoids differentiated into root primordia. Development of adventitious roots were completed when they emerged at the surface of stem bases 10 days after pretreatment. In EMLA 9, before the meristemoids formed, internal cell files were formed by continuous divisions of cambial cells. The cells were regularly arranged in files external to the cambium. On the fourth day after pretreatment, some cells in the outermost layers of these files became meristematic, started to divide and turned into meristemoids, which differentiated into root primordia. The cells of the files between the root primordium and the cambium were transformed into vascular tissues which connected the vascular systems of the adventitious roots and stems.     

核桃试管不定根的组织学研究

以核桃品种‘新早丰’试管嫩茎为试材,采用二步生根法诱导生根,对其试管苗不定根发生发育过程进行了解剖学研究。结果表明:核桃试管嫩茎内未发现潜伏根原基;诱导生根后,不定根原基起源于形成层,特别是髓射线正对的形成层部分,属于诱生根原基型;不定根上的侧根起源于中柱鞘细胞。核桃试管嫩茎不定根的发育过程可分为4个阶段:(1)形成层细胞分裂;(2)转变为分生组织细胞群(即根原始细胞);(3)细胞群发育成可见的根原基; (4)根原基内细胞继续分裂分化形成根尖的外形,其内发育出维管束,并向外生长,穿过皮层,突破茎表皮。在组织培养条件下长出的不定根内部解剖构造为典型的初生构造,移栽后68 d出现次生构造。另外,试管苗根毛出现与否及其发育状况受基质理化性质的影响,即生态条件可以改变组织发生及其形状。     

田旋花营养器官及不定芽发生的解剖学研究

对田旋花营养器官的解剖学研究结果表明,叶为两面叶,栅栏组织和海绵组织发达。主脉为周韧型维管束,在其主脉的远轴面,紧领下表皮的为1－2层同化组织细胞。地上茎表皮内具由2层细胞组成的同化组织,维管组织呈连续的环状排列,木质部内外侧都为韧皮部。地下根状茎的结构类似地上茎的结构,维的维管组织发达,在次生生长中,中央初生木质部导管周围薄壁细胞分化产生大量薄壁细胞和韧皮部分子。根状芭茎上的不定芽及不定根由维管形成层活动产生,根上的不定芽也是由根的维管形成层产生。     

桤木插穗不定根发生与发育的解剖学观察

采用常规石蜡切片法对桤木插穗进行解剖观察,研究茎的次生结构及不定根的起源和发生发育过程,探讨影响不定根发生的因素。结果表明:桤木茎的次生构造从外至内由周皮、皮层和次生维管组织3部分组成。皮孔有2种类型。不定根的发育过程可分为4个阶段:(1)维管形成层与髓射线交叉处的细胞活动,产生具有典型分生组织特点的薄壁细胞团;(2)薄壁细胞不断分裂,形成不定根原基发端细胞;(3)分裂分化形成的不定根沿着韧皮射线向皮层延伸;(4)随着不定根内部的维管系统的发育,不定根从皮孔或下切口伸出。