千金榆花序及花器官发育

在扫描电镜下首次观察了桦木科鹅耳枥属千金榆花序和花的形态发生过程。千金榆雌花序由多个小聚伞花序螺旋状排列组成;每个小花序原基分化出1枚初级苞片和一团小花序原基分生组织,由小花序原基分生组织分化形成2个花原基和2个次级苞片;每个花原基分化出2个心皮原基,形成1个二心皮雌蕊;次级苞片远轴面发育快于近轴面,呈不均等的联合状;雌蕊基部有1层环状花被原基。雄花序为柔荑状,由多个小聚伞花序螺旋状排列组成;每个小花序原基分化出1枚初级苞片和一团小花序原基分生组织,由小花序原基分生组织分化出3个花原基分区,并分化形成3朵小花,小花无花被,位于两侧的小花分别有2枚雄蕊,位于中央的小花有4枚雄蕊,雄蕊共8枚,稀为10枚,该3朵小花为二歧聚伞状排列,其花基数应为2基数。     

铁破锣花序的开花特性与昆虫传粉的相互关系研究

为了揭示植物花的空间布局与开花动态的调节机制以及避免同株异花传粉的生态学策略,该研究对铁破锣［Beesia calthifolia (Maxim.) Ulbr.］花序形态结构、开花动态和传粉生物学进行了观察分析。结果表明：（1）铁破锣花序结构设计巧妙,由3朵花组成一个聚伞花序单元并依次排列在主花序轴上,且花序轴上聚伞花序之间距离较远。（2）铁破锣通过单个聚伞花序顶花先开,通常只有6～8朵聚伞花序的顶花同时开放,而且总状花序从基部到顶部逐次开放,从而使得大量聚集单花的花序达到尽量少开花。（3）铁破锣花白色,花粉是访花昆虫的仅有诱物,纤细巴蚜蝇（Baccha maculata）是铁破锣的主要传粉昆虫,这种昆虫能够以花丝为着力点取食花粉,通常在一个花序上取食一朵单花后很快飞向另外一个花序的花。研究认为,铁破锣花序的空间设计和开花的时间序列动态减少了昆虫访问同株异花的可能性。     

赤霉素诱导小桐子产生两性花

小桐子（Jatropha curcas）种子含油率高,油脂组成适合于生产生物燃油,是制备航空生物燃油和生物柴油的理想原料。小桐子是一种雌雄同株植物,雌雄花着生于同一花序,其花序中雌花比例很低,可能是其种子产量低的主要原因之一。本文研究用不同浓度的赤霉素外源喷施处理小桐子花序芽对其花和种子发育的影响。结果表明：外源赤霉素处理能够诱导小桐子产生两性花,且处理浓度越高,两性花数量越多;随着两性花数量的增加,雌花数量相应越少,但雌花与两性花数量之和在各处理和对照之间差异不显著,这表明赤霉素诱导出的两性花可能来源于雌花。另外,高浓度(500~1500mg·L-1)的赤霉素处理会导致小桐子的种子不能正常发育, 表现为每个果实中的种子数量、大小、单粒种子重量、每个果序的种子重量以及种子的含油量都显著减少。这些结果有助于深入理解赤霉素在小桐子花器官形成及种子发育过程中所发挥的生理作用,为从分子水平上对小桐子进行遗传改良、提高其种子产量奠定基础。     

喜树花序内性别表达及性别分配

 花序内性别表达和性别分配的差异在被子植物中非常普遍。常见的变化模式是: 在顺次开放的花序内, 从早开的花到晚开的花, 生殖结构大小和数量依次减少, 晚开的花偏向雄性。通常认为资源竞争和位置效应是形成这种差异的主要原因。在喜树(Camptotheca acuminata)的聚伞花序内, 早开的头状花序在花序直径、小花直径、短雄蕊长度、坐果率、果序重量等方面与晚开的头状花序差异显著。通过去除喜树聚伞花序一级或一级和二级头状花序来控制花序内的资源分配, 从而分析影
响喜树花序内花性状、性别分配及生殖能力的主要因子。结果显示, 去除部分头状花序后, 剩余头状花序的花序直径、小花直径明显增加, 短雄蕊长度明显缩短, 位置间差异消失; 而坐果率、果序重量的位置间差异依然显著。表明资源限制对花序直径、小花直径和短雄蕊长度等影响显著, 而坐果率和果序重量受位置效应影响明显。喜树雄全同株的性别分配可能是对特定生殖状况和资源状况适应的结果。     

与小桐子雌花形成、雌雄花比例提高相关影响因素的研究进展

小桐子是重要的能源植物,由于它是雌雄同株植物,雌花少,雄花多,雌雄花比例低,因而导致其种子产量很低,严重制约了其产业化进程。因此,了解与小桐子雌花形成、雌雄花比例提高相关影响因素的研究进展,不但对种植者进行小桐子大田种植采取必要的栽培措施具有指导意义,而且也为下一步开展相关的研究工作指明了方向。为此,综述了与小桐子单性花性别分化相关影响因素的研究进展,并对该领域未来的研究重点作了展望。与小桐子雌花形成、雌雄花比例提高相关的影响因素既有内因,也有外因,内因有开花习性、植物激素、遗传基因和结果枝的年龄与大小;外因包括植物生长调节剂、立地环境、CO2浓度、光照、水份、土壤厚度、所施肥料等环境因素。其中,最重要的影响因素是植物激素和遗传基因,二者协同作用共同调控小桐子的性别分化。     

外来物种黄顶菊花器官分化的初步研究

利用扫描电镜(SEM)观察了黄顶菊(Flaveria bidentis(L.)Kuntz)花序发育过程中蝎尾状聚伞花序、头状花序和小花的形成.黄顶菊的花序由主轴及一至三级分枝组成,各级分枝交互对生,形成方式相同.植株主轴和侧枝顶端的每个花序由3～6个蝎尾状聚伞花序密集而成;每一蝎尾状聚伞花序由5～15个头状花序组成;每一头状花序中有4～11枚小花.小花分化顺序为5个花冠原基、5个雄蕊原基和2个心皮原基.2007年,天津地区黄顶菊的花期是7月下旬到9月下旬.7月中旬,花序和花器官原基不断形成并分化,至花器官成熟经历的时间约15 d.     

土施多效唑对小桐子营养生长与生殖生长的影响

小桐子(Jatropha curcas)是一种具有多种用途的植物,其种子含油量高达40％,是一种很有应用前景的能源植物.小桐子在温度、湿度较高的地区,特别是其修剪后新萌发的枝条经常出现营养生长旺盛,成花量较少的现象,导致其种子产量较低.本研究采用多效唑(paclobutrazol,PAC)对小桐子进行土施处理,结果表明:多效唑的使用剂量为0.8g·m-1树冠直径时,可有效抑制小桐子的营养生长,降低株高;同时促进小桐子的生殖生长,增加开花和结果枝条数量,增加花序和果序数量,增加单个花序的总花数和雌花的比例,可将小桐子单株种子产量提高2.4倍.此外,多效唑处理使小桐子的开花期和结果期更加集中,便于田间管理和采收.多效唑作为赤霉素合成的抑制剂,可以有效地促进小桐子由营养生长向生殖生长的转变,对于了解赤霉素在调控小桐子花发育方面的作用具有重要意义;同时也有助于克隆有关功能基因,进一步采用转基因技术对小桐子进行遗传改良.     

乌拉尔甘草花部特征和开花结荚特性的研究

通过田间观测和室内数据分析,对内蒙古杭锦旗乌拉尔甘草的花部特征和开花结荚特性进行了研究.结果表明,在甘草群体中,花颜色性状存在变异.对甘草的开花习性研究发现,一日内,以10:00-16:00开花最多,占开花总量的38.9%;20:00至第2天早晨6:00次之,占开花总量的35.3%.小花数和单荚应结种子数服从近似正态分布.供试花序中单个花序的平均结荚率为30.8%,一个花序表现的种子生产能力约为196粒,实际一个花序的种子生产能力约为41粒.本研究表明,甘草小花具备闭花授粉的自交条件,花序小花数和单荚应结种子数都属于数量性状遗传,可以通过多种措施提高种子产量,为揭示甘草的有性生育规律和甘草杂交育种提供科学依据.     

鹅耳枥和虎榛子（桦木科）雌性生殖器官的形态发生

为了进一步理解类群之间的系统发育关系,在扫描电镜下,对桦木科植物鹅耳枥（Carpinus turczaninowii Hance)和虎榛子（Ostryopsis davidiana Decne.)的雌花序、小花序和雌花的原基形成和发育过程进行了观察。两种植物均具单性花、雌雄同株。其雌花序为复合的穗状花序,每两朵小花构成一个小聚伞花序,多个这样的小花序螺旋排列在一个总花序轴上。小花序由5枚苞片组成,1枚初级苞片,4枚次级苞片。后分别由两个半环状的共同原基发育而来。鹅耳枥的近轴面次级苞片生物缓慢,远轴面的生长较快,成熟时呈扩展的叶片状;虎榛子的近轴面和远轴面次给苞片均生长较快,成熟时靠全呈囊状。花被原基为环状,花被随着子房的发育而而逐渐长大包围子房并与之愈合。研究对前人有关小花序的苞片数目和两个二心皮子房的定位方式等方面的认识作了澄清或纠正。每个小花序的苞片数目不像Abbe观察的那么多;二心皮子房定位方式在鹅耳枥属是互成直角,而非相互平行。     

桤木属花序和花的形态发生

在扫描电镜下首次观察了桦木科Betulaceae桤木属Alnus花序和花的形态发生过程,为桦木科属级鉴定提供了微形态学依据.实验材料为东北桤木A.mandshurica和辽东桤木A.sibirica,其雌花序均为柔荑状,由多个小聚伞花序螺旋状排列组成:每个小花序外具1枚初级苞片、2枚次级苞片、2枚三级苞片,内有2朵花.每个花具1个二心皮合生雌蕊,雌蕊具二叉分枝的长柱状花柱.每个小花序的2个二心皮合生雌蕊的定位方式为相互垂直.东北桤木的雌花序由芽鳞包被越冬,而辽东桤木的雌花序裸露越冬.东北桤木和辽东桤木的雄花序亦为柔荑状,由多个小聚伞花序螺旋状排列组成.每个小花序外被1枚初级苞片、2枚次级苞片、2枚三级苞片,内有3朵花.先形成的2枚次级苞片和后形成的2枚三级苞片均来源于小花序原基.3个花原基中.位于中间的比两侧的分化要早.每个花具4枚被片和4枚雄蕊,每个雄蕊具4个药囊.花的被片比雄蕊发育得早,均由花原基发育而成.东北桤木和辽东桤木的雄花序均裸露越冬.     

A Top-Down Hierarchy in Fruit Set on Inflorescences in Iris fulva (Iridaceae)

Abstract: In Iris fulva, the apical flower on an inflorescence opens first, and the flowering sequence then proceeds from the most basal flower upward to the apex (acropetally). Flowering order and flower position are thus partially decoupled, and this provides an opportunity to separately investigate the effects of these two factors upon fruit formation. We recorded natural patterns of fruit set and seed production, and found that fruit set patterns were determined by what appears to be a form of apical dominance. The first, apical flower had the highest fruit set and seed production. Fruit set decreased towards the base of the inflorescence, with later-opening flowers having a higher fruit set. This is contrary to the pattern usually observed in other acropetally flowering plants, which is a higher fruit set for basal, early flowers. By performing additional hand pollinations and counting pollen grains on naturally pollinated flowers, we found that pollen deposition was not a major factor limiting fruit set, and that it could not explain the large difference in fruit set between the apical and basal flowers. Removing the first flower after it had wilted increased fruit set in the remaining flowers, but mainly in the more apical flowers. Only by removing the two topmost flowers could we obtain an increase in fruit set for the basal flower. The fact that the basal flower rarely sets fruit, despite being closer to resources, suggests that the apical meristem is either a strong sink for resources or produces hormones that form a gradient along the inflorescence, which is comparable with apical dominance.     

优质荔枝新品种'草莓荔'开花与落果特性观察

从植株群体和单穗调查分析‘草莓荔’雌雄花开花特性,结果表明,‘草莓荔’雌雄花交替开放的顺序主要是雌→雄,即前期开雌花,后期开雄花;但也有少量交替开放顺序是雄→雌→雄,即先开雄花,中期开雌花后再开雄花。植株群体的花期和雌雄花开放相遇时间比单穗长,更有利于传粉受精。落果从花后15d开始出现,并在花后18～25d出现第一次落果高峰,落果最多,开花后51～58d为第二次落果高峰。     

优质荔枝新品种‘草莓荔’开花与落果特性观察

从植株群体和单穗调查分析‘草莓荔’雌雄花开花特性,结果表明,‘草莓荔’雌雄花交替开放的顺序主要是雌→雄,即前期开雌花,后期开雄花;但也有少量交替开放顺序是雄→雌→雄,即先开雄花,中期开雌花后再开雄花。植株群体的花期和雌雄花开放相遇时间比单穗长,更有利于传粉受精。落果从花后15d开始出现,并在花后18～25d出现第一次落果高峰,落果最多,开花后51～58d为第二次落果高峰。     

Patterns and implications of floral nectar secretion, chemical composition, removal effects and standing crop in Mandevilla pentlandiana (Apocynaceae)

Flower morphology, nectar features (chemical composition, production pattern, removal effects, and standing crop) and floral visitors are analysed in an Argentine population of Mandevilla pentlandiana. Nectar variability was examined during the lifetime of a single flower, over the course of the flowering season, and at different times of the day. Nectar is sucrose dominant. There were some variations in the proportions of sugar throughout both the flower lifespan and the flowering season. Flowers produced most nectar during bud-stage. Nectar secretion ceased near the end of the first day after flower opening. Nectar quantity varied as a function of flower age due to a combination of nectar secretion, cessation, and resorption periods. Overall sugar production was increased by nectar removal. Standing crop data showed that each open flower and inflorescence offers c. 2 and 11 mg of sugar respectively at any time of the flowering season. There was higher nectar availability at the beginning of the flowering season compared with the rest of the period. Flowers were visited by bumblebees, honeybees and hummingbirds. The greater the number of open flowers and the nectar variance, the more the mean reward quantity per flower available in the inflorescence. The sources of nectar variability in M. pentlandiana seem to be linked with both the female function (nectar resorption, nectar cessation) and the male one (early and comparatively large nectar availability, variation in nectar production as the flower ages, nectar secretion stimulation by nectar removals).     

The adaptive significance of monoecism in Cnidoscolus urens (L.) Arthur (Euphorbiaceae)

Cnidoscolus urens is a monoecious, selfcompatible herb. Male and female flowers differ structurally, but appear superficially similar and the principal dry season pollinator, a butterfly (Eurema daira) did not discriminate between them. Female flowers offered little or no nectar reward and may mimic males in order to receive pollen. Male flowers last only 1 day; female flowers usually last 1 day but may remain receptive for 7 days if unpollinated. Flowers opened between 00.00 hours and 01.00 hours, opening earlier as the wet season approached. This shift is probably correlated with a change to nocturnal moth pollination in the wet season.
Within an inflorescence there are c. 16 times more male than female flowers. Female flowers occur in the lowermost positions and open first. Female flowering is followed by a brief period when no flowers open and then by an extended period of male flowering.
Although there is no overlap between male and female phases within an inflorescence, nonsynchronous development of several inflorescences on one individual means that selfing is possible for nearly all female flowers. However, observations of pollinator behaviour indicate that butterflies frequently move to another plant after visiting one inflorescence. Thus there is a large degree of outcrossing in practice.     

雌全同株植物三脉紫菀花期偏雄的个体大小依赖的性别分配

经典的虫媒传粉植物个体大小依赖的性别分配模型通常预期:分配给雌性功能的资源比例将随着个体大小的增大而增加;但一些研究表明,花期个体大小依赖的性别分配模式表现出随个体大小增大而偏雄的趋势.我们以植株高度衡量个体大小,从花和花序两个水平上研究了雌花、两性花同株植物三脉紫菀(Aster ageratoides)花期个体大小依赖的性别分配策略.随着植株高度的增大,植株产生的头状花序数量增加,表明三脉紫菀投入到繁殖的资源不是固定不变的,而是随个体大小增大而增加的.在花和花序水平上,繁殖资源在雌雄性别功能之间的分配均表现为随个体大小的增大而更偏雄的模式,即花粉/胚珠比增加,产生花粉的两性花占两性花和雌花总花数的比例升高.这些结果与花期个体越大、性别分配越偏雄的预期一致.花期更偏雄的性别分配可能有助于植物在花期通过输出花粉提高雄性适合度,从而实现个体适合度的最大化.     

不同生境对蝴蝶花花部与果实特征的影响

通过对毛竹林(Bamboo forest,BF)与林缘旷地(Open area of forest edge,OAFE)两类生境蝴蝶花自然种群花部与果实(种子)特征及降雨干扰影响的研究,探讨不同生境中蝴蝶花花部特征适应性及有性各组分的差异。结果表明:(1)竹林生境相对于林缘旷地生境,蝴蝶花单花花冠的长、宽较大,子房、花部(除花柄)及单花总生物量较小,比花柄长较大;两类生境蝴蝶花花柄生物量与子房生物量呈正相关(P0.05),协方差分析表明,两类生境该直线回归的总体斜率间(F=18.420,P0.001)及总体截距间(F=3791.7,P0.001)均具有显著差异,竹林生境花柄生物量随子房生物量增大而增大的程度更强。竹林生境的蝴蝶花侧花花冠长与宽最高,竹林生境顶花次之,林缘旷地顶花与林缘旷地侧花最低;花部(除花柄)与全花重都表现为林缘旷地侧花最高,林缘旷地顶花次之,竹林侧花与竹林顶花最低。比花柄长随竹林侧花与竹林顶花-林缘旷地侧花-林缘旷地顶花依次降低;竹林顶花的花柄比率最高,竹林侧花与林缘旷地侧花最低。(2)林缘旷地生境中蝴蝶花的每花序花数、花序结果百分率、单花结果百分率、每结果花序果实数、每结果花序果实重与种子重及花期内每花序掉落花数都高于竹林生境。(3)林缘旷地生境大雨干扰的4个时段花朵掉落数显著高于竹林环境(P0.01)。不同生境花部形态结构特征表明其自身的生境适应性,林缘旷地生境蝴蝶花为抵御干扰及为获得有性繁殖成功,有性组分的投入更高。     

Gender modification in a monoecious species <Emphasis Type="Italic">Sagittaria potamogetifolia</Emphasis> (Alismataceae)

In order to find out if the inflorescences number variation has influences on the gender modification in plant species, we investigated the gender modification in a cultivated population of the monoecious species Sagittaria potamogetifolia. We also designed two nutrient levels to explore the impact of nutrient on gender modification in S. potamogetifolia. We found that the female and male flowers did not change with increasing plant size for each inflorescence at a low nutrient level. At a high nutrient level, the female flower numbers on each inflorescence did not increase with plant size; however, the male flower numbers had some positive correlation with the plant size. At the ramet level, the total male and female flower numbers increased with the plant size at both nutrient levels. The sex ratio (female to male flower ratio) decreased with the inflorescence numbers and the plant size (Midvein length). Although the nutrient variation had impact on the flower number production, it did not change the gender modification pattern. The high plasticity of inflorescence numbers, which caused the gender variation in S. potamogetifolia, and low plasticity of female and male flowers on a single inflorescence, indicates that the limited modification on gender in a single inflorescence may be compensated by inflorescence number variation at the ramet level.     

心叶凹唇姜的开花格局和雄性先熟机制

心叶凹唇姜 (Boesenbergia longiflora) 是分布于亚洲热带的一种姜科植物, 在我国滇南地区成片生长于石灰山贫瘠的岩石缝隙和路边林下的冲积土壤上。心叶凹唇姜的花寿命为两天, 第1天为严格的雄性阶段, 第2天为严格的雌性阶段, 是典型的花内雄性先熟, 一朵花的雌、雄性阶段没有重叠, 因而完全避免了自花授粉的发生。对这两种生境 (石灰山贫瘠的岩石缝隙和路边林下) 下的心叶凹唇姜的4个野外种群 (在云南省普洱市的翠云乡彩虹洞、南岛河、澜沧县惠民乡和西双版纳州绿石林森林公园) 和栽培植株的开花格局进行调查后发现, 大多数个体在同一时间内只有一个花序开花, 并且每隔一天才开一朵花, 只有10%左右的植株同时具有雄性阶段和雌性阶段的花, 这样的开花格局有效地降低了同株异花授粉发生的可能。心叶凹唇姜的平均花粉-胚珠比 (Pollen-ovuleratio) 为291, 应该是以异交为主的混合交配系统。其自然种群存在着花粉限制, 彩虹洞、南岛河和绿石林3个不同种群的平均结籽率都不到60%, 这可能与其较小的花展示有关。心叶凹唇姜为泛化传粉植物, 不同种群的有效传粉昆虫种类各不相同。在两种不同的生境条件下, 心叶凹唇姜花的大小和开花格局都没有显著的差异, 大多数个体同时只具有一种性阶段的花, 说明心叶凹唇姜这种独特的开花格局是长期进化的结果。心叶凹唇姜通过隔一天开一朵花的开花格局, 配合雄性先熟机制, 有效地降低了自交的发生。     

INFLORESCENCE TYPES AND FRUITING PATTERNS IN HAMLIN AND VALENCIA ORANGES AND MARSH GRAPEFRUIT

The structural, flowering, and fruit-setting patterns of inflorescences of mature Hamlin and Valencia orange and Marsh grapefruit trees were studied for three years. Several development patterns were found, some of which were relatively consistent for the different varieties or years of study. The sequence of anthesis on an inflorescence was: apical flower first, then basal flower, then the subapical flower. Terminals on which the earlier flowers appeared tended to have more inflorescences than those on which flowers appeared later. Inflorescences on which earlier flowers appeared also produced more flowers than those which began flowering later. Inflorescences that began flowering later were more likely to have leaves or have a greater number of leaves than earlier inflorescences. More than half of the inflorescences carried no leaves, and most of these had one flower. No evidence of a relationship between number of flowers and length of the inflorescence was found. Fruit set occurred primarily during the latter part of the flowering period. Many fruit were set on inflorescences without leaves, but on the basis of percent of flowers setting fruit, inflorescences with leaves were more productive. The greatest fruit set occurred in the subapical position on the inflorescence. With growth changes these fruit often appeared to be developing in the apical position. These patterns generally differed little from year to year. Variations may have been due to the differences in the number of flowers produced by the trees. Results were also similar between Hamlin and Valencia oranges. Patterns on Marsh grapefruit resembled those for the oranges but were frequently less consistent.