新小竹花形态结构及雌、雄配子体的发育研究

新小竹(Neomicrocalamus prainii)是一种小型攀援竹类,笋秆两用型竹种。该研究通过形态观察和石蜡切片的方法对新小竹花器官形态及解剖结构特征进行观察与描述,为研究竹类植物的生殖生物学提供新的理论信息。结果显示:(1)新小竹的花序为无限花序,没有小穗柄,成熟小穗平均长度为2.98 cm;每个小穗约有4～6朵小花,其中3～5朵为可育小花,顶端均有1朵不育小花;小穗基部有2～4个苞片;小穗轴每节长约0.52 cm。(2)新小竹的可育小花包括1片内稃、1片外稃、3枚浆片(浆片2大1小,边缘光滑)、6枚雄蕊和1枚雌蕊;雄蕊呈梭型,雌蕊羽毛状柱头三裂。(3)新小竹成熟花粉粒多为二核,具1个萌发孔;花药具有4个药室,花药壁由表皮、药室内壁、中层和绒毡层4层结构组成,绒毡层为腺质型;花药发育过程还存在多种异常情况。(4)新小竹子房一室,侧膜胎座,倒生胚珠,双珠被;大孢子母细胞由1个孢原细胞直接发育而成,合点端1个大孢子分化成为功能大孢子,由功能大孢子经过有丝分裂形成多核胚囊,直至发育成熟。研究表明,新小竹雄配子体存在发育异常现象,但大部分发育正常,其结实率低不仅与内在因素有关,外部环境也可能是导致其结实率低的重要因素。     

棉花竹花形态与结构研究

棉花竹（Fargesia fungosa）是箭竹属重要经济竹种,有关其花器官的形态与解剖结构研究至今尚无报道。本文通过对棉花竹花器官的形态与解剖结构进行观察和分析,结果显示棉花竹花序为“混合花序”,小穗基部具潜伏芽,由单个叶片形成的“佛焰苞”包裹多枚小穗。小穗单次发生,均长3.05±0.390 cm,每枚小穗具有3~7朵小花,小花均长1.85±0.167 cm,颖片2枚。每朵小花皆具有内、外稃各1片,3枚浆片,雄蕊3枚,雌蕊1枚组成。未成熟花药具有4药室,花药壁由外到内依次为表皮、药室内壁、中层和绒毡层。花药成熟后纵裂散粉。成熟花粉粒为2或3细胞型,且具有1个萌发孔。子房1室,上位,侧膜胎座,倒生胚珠,雌蕊具2分叉羽毛状柱头。花药发育异常,导致出现大量败育现象。     

巨龙竹生殖器官形态结构及雌、雄配子体的发育

通过石蜡切片的方法对巨龙竹生殖器官结构、大小孢子的发生和雌、雄配子体的发育过程进行了观察研究。 巨龙竹为一心皮组成的单室单子房,子房内具有一个胚珠,倒生、双珠被、厚珠心。大孢子母细胞减数分裂形成线形排列的4个大孢子;合点端大孢子具功能。胚囊的发育为蓼型;具多个反足细胞。巨龙竹的花药壁由4层结构组成,包括表皮、药室内壁、中层、绒毡层;花药壁发育为单子叶型,绒毡层为腺质型。小孢子母细胞减数分裂中的胞质分裂为连续型,四分孢子为四面体型;成熟花粉粒为2细胞型,具1个萌发孔。小穗发育雌雄异熟,雌蕊的发育早于雄蕊的发育。     

香港木兰小孢子发生及雄配子体发育的研究

采用常规胚胎学方法,对香港木兰（Magnolia championii Benth．）小孢子形成及雄配子体发育过程进行了研究。结果显示,香港木兰花药具4个小孢子囊,小孢子囊壁5—6层,其中腺质绒毡层1—2层;小孢子减数分裂时胞质分裂方式为修饰性同时型,四分体排列方式为四面体型或左右对称型,偶为交叉型,成熟花粉粒为二细胞型。在次生造孢细胞、小孢子母细胞、四分体时期都会出现败育,且在很多成熟花药中全部是败育的单核花粉。PAS染色后发现,相对正常发育的小孢子囊,在这种小孢子囊壁中仍有大量淀粉粒残留,可能是药隔中的营养物质不能及时从药隔组织转移到小孢子囊壁以供给小孢子发育所需的营养,使整个药室内的小孢子发育都停滞在单核期。通过不同生境植株花粉萌发率的对比,推断空气湿度是影响香港木兰小孢子正常发育的一个重要因素。     

一品红雄配子体发育研究

一品红花药来源于雄蕊原基,花药由表皮(1层)、药室内壁(1层)、中层(1层)、绒毡层(1层)及造胞细胞组成,花药四室,药壁发育为双子叶型。小孢子发生和雄配子体发育是经由小孢子母细胞减数分裂形成四分体,该四分体胞质分裂为同时型,四分体排列为四面体型,小孢子再经有丝分裂形成2-核花粉。花药壁层的变化是表皮在花药成熟期消失,中层在四分体时消失,药室内壁在花药成熟期形成柱状纤维层。绒毡层在单核小孢子期径向伸长,有双核或多核,另外有的绒毡层细胞形成横隔或类胎座;进入2-核花粉期,绒毡层细胞分泌颗粒物进入药室,为非典型腺质绒毡层;进入成熟期绒毡层消失。同时观察到花药发育异常现象。     

秤锤树雌、雄配子体发育的研究

秤锤树(Sinojakia rylocarpa Hu)为我国特产的稀有观赏树木。迄今,国内外对其胚胎发育缺乏系统报道,本文报告这方面的研究结果。 其花药为4个花粉囊组成,小孢子四分体呈四面体形排列,小孢子母细胞减数分裂时,胞质分裂属于同时型。2胞花粉,具 3 孔沟,有不规则穴状纹饰。 花药壁的分化过程为双子叶植物型,在其成熟时,药室内壁和部分表皮细胞的细胞壁上出现微弱的条状纤维加厚。腺质绒毡层。雌蕊为3心皮构成,开放型花柱,子房内含多枚倒生胚珠。单珠被,薄珠心,未发现珠孔塞结构。大孢子四分体多呈线形,个别的为T形。蓼型胚囊。受精前,2个极核相互靠拢,但未见融合。反足细胞较小,寿命似较长。成熟胚囊中充满淀粉粒。从有关胚胎发生的资料分析,野茉莉科与柿树科、山榄科、山矾科关系密切,这支持了将它们共同列入柿树目的植物分类系统的观点。     

七叶树小孢子发生及雄配子体发育研究

用石蜡切片法观察了七叶树花药的发育过程.结果表明:(1)雄蕊花药四室,花药壁完全分化时,从外到内依次是表皮、药室内壁、中层和绒毡层,花药壁发育为基本型.表皮细胞1层,发育过程中始终存在;药室内壁在花药成熟时形成带状纤维层加厚;幼小花药壁的中层3~4层细胞,在花药发育成熟时退化消失;绒毡层1层细胞,发育类型为分泌型,小孢子母细胞减数分裂时绒毡层开始退化解体,花药成熟完全消失,仅剩1层绒毡层膜.每一花药中有多列雄性孢原细胞,发生于幼小花药表皮下方;(2)小孢子母细胞减数分裂为同时型,四分体多呈正四面体排列;减数分裂过程中,小孢子母细胞外方被胼胝质壁所包被,小孢子形成后胼胝质壁逐渐消失.成熟花粉二细胞型,外形呈圆三角状,具三孔沟.     

穗花杉的胚珠结构与雌、雄配子体的发育

穗花杉胚珠结构最显著的特点之一是,珠心顶部有一比较发达的贮粉室。珠孔道的闭塞主要是由珠被中层区细胞形成的;珠被维管束8—14个。假种皮中具14—17个粘液分泌道。小孢子囊远轴着生,起源于皮下细胞。在小孢子母细胞分裂前后,绒毡层出现局部异常膨大现象。成熟花粉由两个细胞组成。雌配子体游离核经8次分裂产生256个核后形成胞壁。颈卵器单个,顶生。从胚珠结构和雌雄配子体发育来看,穗花杉属在红豆杉科中可能居于最原始的位置;而且它与三尖杉属有许多共同之处。     

西瓜小孢子囊发育及雄配子体发生的观察

西瓜(Citrullus lanatus)小孢子囊的孢原细胞出现在雄花原基出现后4—6天,孢原细胞数目推测只有一列;初生造孢细胞经过2—3次分裂,形成次生造孢细胞。开花前7—8天,小孢子囊发育健全,小孢子母细胞进入减数分裂期。同一花药不同花粉囊相同一药室,花粉母细胞减数分裂和小孢子的发育,并不是高度同步的。绒毡层为异型细胞,腺质绒毡层。雄配子体的发育开始于开花前6—7天,充分成熟的西瓜花粉已分裂为三细胞花粉。     

罗汉松雄球花及其雄配子体发育的形态结构

该研究采用光学显微镜和扫描电镜,观察罗汉松雄球花、小孢子及其配子体发育过程的形态结构特征,以揭示罗汉松小孢子的发生和雄配子体的发育规律,为罗汉松的生殖和杂交组合提供胚胎学证据。结果发现：(1)罗汉松花芽于每年的7月开始分化,至次年5月花粉成熟散粉,雄球花由单生的卵圆形转为2～3个葇荑花序并生,小孢子叶螺旋状着生于圆柱状的花序轴上,每一小孢子叶远轴面基部并列着生2个小孢子囊。(2)小孢子囊壁发育过程中由外及里出现各由1层薄壁细胞组成的表皮、药室内壁、中层和绒毡层,至散粉前,后两者基本被分解吸收。(3)同一小孢子囊内的造孢细胞发育在时间上存在差异,小孢子母细胞减数分裂后形成的四分体有四面体型和十字交叉型两种排列方式,成熟的雄配子体包括生殖细胞和粉管细胞,发育过程中出现的第一和第二原叶细胞大部分被分解消失。(4)电镜下罗汉松花粉粒为典型的松花型花粉,两侧各具1个气囊,远极面具一萌发沟,花粉粒表面具纹理或皱褶。     

黄连木雌花芽形态分化研究

采用石蜡切片法观察了黄连木雌花芽的分化过程,以揭示黄连木雌花芽分化规律,为合理调控雌花芽分化质量和数量提供依据.结果表明:黄连木雌花芽的分化时期为当年4月中旬至10月底和翌年3月中下旬至4月上旬,历时345 d左右.具有分化时间早、分化速度快但整个花序分化持续时间长的特点.黄连木雌花芽分化包括花序分化和小花分化2个过程,可划分为未分化期、花芽分化始期、苞片分化期、花序形成期、小花原基分化期、被片分化期、雌蕊原基分化期、雌蕊分化期等8个时期.     

Photoperiodically independent flowering of Pharbitis nil plants regenerated from flower buds

Summary Flower buds and anthers of the short-day plant Pharbitis nil were treated either with thermic shock (7 or 35°C) or osmotic/trophic shock (12% sucrose) for 24 h. Explants were transferred either to Murashige and Skoog medium (MS) with addition of 6-benzylaminopurine (BA; 4.4μM) and 6% sucrose or to the same growth medium containing 22 μM BA and 3% sucrose. Both media were supplemented with α-naphthaleneacetic acid (NAA; 0.55 μM). Osmotic/trophic shock stimulated the occurrence of shoots on flower buds grown on medium containing 22 μM BA. Thermic shock (7 and 35°C) inhibited this process on both types of explants. Regenerated plantlets were transferred to MS medium supplemented with 6% sucrose, gibberellic acid (GA₃; 1.44μM), NAA (0.55 μM) and Ca²⁺ (0.66 mgl⁻¹). After 3–4 wk they were able to produce flowers without photoperiodic induction.     

长白落叶松生殖生物学特性研究——Ⅰ.球花芽分化与早期发育

本文研究了长白落叶松(Larix olgensis Henry)大小孢子叶球的分化及其分布规律。获得如下结果:(1)6月下旬芽鳞形成期终止,7月初进入小孢子叶分化期,7月未至8月上旬小孢子叶分化期结束。8月上旬进入小孢子囊分化期,8月下旬出现造孢细胞,9月中旬形成小孢子母细胞。10月底小孢子母细胞保持在细线期阶段,小孢子叶球进入冬季休眠期。(2)9月初苞片原基开始形成,9月中旬珠鳞原基形成;10月上旬出现胚珠原始体,10月下旬大孢子母细胞形成,10月底大孢子叶球芽进入冬季休眠。(3)小孢子叶球芽主要分布在树冠的中、下部。数量上远远大于大孢子叶球芽的数量,约为大孢子叶球芽的19倍。大孢子叶球芽主要集中分布在树冠中部,而且树冠下部多于树冠上部。     

巨峰葡萄花芽分化的研究

以巨峰葡萄(Vitis vinifera L.×V.Labrusca L.cv.Kyoho)为材料,用摘叶、去穗法判定花芽的生理分化期,并用GMA半薄切片法观察花芽分化进程。结果表明:从新梢顶端到第9个展开叶之间的芽处于生理分化期,花芽生理分化期分为成花诱导期和花芽孕育期。葡萄的花序分化阶段可分为未分化期、花序原基分化期和花序第二穗轴分化期3个时期。第1年只进行花序分化,次年进行花器官分化。原分生组织衍生的组织中淀粉粒分布较多,蛋白质则在分裂旺盛的原基组织中含量高。     

The dose of 1-naphthaleneacetic acid determines flower-bud regeneration in tobacco explants at a large range of concentrations

Short-term applications of very high concentrations of 1-naphthaleneacetic acid (NAA) to expiants from flower stalks of tobacco (Nicotiana tabacum L. cv. Samsun) induced flower-bud regeneration to the same extent as longer or continuous incubation on lower concentrations. The maximum number of flower buds per explant after 15 d of culture was obtained not only by continuous culturing at 1 mol·l^–1 NAA but also by 12 h of culturing at 22 mol·l^–1 or 0.5 h at 220 mol· l^–1, followed by incubation on medium without auxin for the remaining period. Continuous application of such high concentrations resulted in callus formation or caused the death of the explanted tissue. In all experiments in which auxin concentration and time of application were independently varied, the product of concentration and time determined the number of buds formed. Most, but not all, of the NAA taken up by the tissues was converted into conjugates. In expiants which had received a dose which was optimal for regeneration, the internal concentration of free NAA remaining beyond the pulse period was between 1.7 and 6.2 mol·l^–1. Suboptimal applications led to lower values, supraoptimal treatments to much higher internal concentrations. The physiological effect, which depends on the internal hormone concentration, thus manifested itself as dose-dependent with regard to applied hormone.Abbreviations BAP N⁶-benzylaminopurine - NAA 1-naphthaleneacetic acid     

文心兰花芽分化过程中糖类和蛋白质的组织化学定位

以文心兰‘milliongolds’不同发育阶段的花芽为试材,研究糖类和蛋白质在文心兰花芽分化过程中的变化。经石蜡切片高碘酸席夫反应法（PAS法）和汞溴酚蓝组织化学染色观察发现,糖类和蛋白质主要以颗粒状分布在各器官的原基顶端及其周围。在花序原基分化期,细胞中糖含量较少,而蛋白质含量丰富且整体分布均匀。随着花芽的继续分化,糖和蛋白质含量在花萼原基分化期最为丰富,在花瓣原基时期含量明显减少;进入合蕊柱及花粉块分化期时,糖和蛋白质在合蕊柱及花粉块着生处最为集中。在文心兰花发育过程中,对不同分化时期中花芽的糖和蛋白质含量进行测定,表明糖和蛋白质含量的变化趋势与组织化学定位相一致。     

Bud development in corydalis (Corydalis bracteata) requires low temperature: a study of developmental and carbohydrate changes

Background and Aims

Spring geophytes require a period of low temperature for proper flower development but the mechanism that underlies the relationship between cold treatment and flowering remains unknown. The present study aims to compare the developmental anatomy and carbohydrate content of the tuberous geophyte Corydalis bracteata growing under natural winter conditions from 10 to −10 °C (field-grown) and under a mild temperature regime of 18 °C (indoor-grown plants).

Methods

Samples were studied under light and electron microscopy. A histochemical test (periodic acid – Schiff''s) was employed to identify starch in sectioned material. Sugars were analysed by capillary gas chromatography. Apoplastic wash fluid was prepared.

Key Results

Under natural conditions, shoots were elongated, and buds gained in dry mass and developed normally. For indoor-grown plants, these parameters were lower in value and, from December, a progressive necrosis of flower buds was observed. The tuber consisted of the new developing one, which was connected to the bud, and the old tuber with its starch reserve. Due to the absence of plasmodesmata between new and old tuber cells, sugar transport cannot be through the symplast. Thus, a potential apoplastic route is proposed from old tuber phloem parenchyma cells to the adjacent new tuber cells. Sugar content in buds during the autumn months (September–November) was lower for indoor-grown plants than control plants, whereas the sugar content in tubers during the same period was similar for plants from both temperature treatments. However, the amount of apoplastic sugars in tubers of field-grown plants was almost 15-fold higher than in indoor-grown tubers.

Conclusions

The results suggest that low temperature activates the apoplastic route of sugar transport in C. bracteata tubers and a consequent carbohydrate delivery to the bud. In the absence of cold treatment, the carbohydrate reserve is locked in old tuber cells so the nutrient supply to the buds is suppressed, possibly leading to bud abortion.