橄榄种质资源花序表型性状遗传多样性研究

为了解橄榄[Canarium album(Loureiro)Raeuschel]花序表型性状的遗传多样性,对90份橄榄种质资源的花序性状进行观测分析。结果表明,橄榄花序的类型、支轴紧密度、着生位置和花性等表现出较丰富的多样性;从数量性状看,花序花朵数的变异系数最大,其次为支轴花朵数,变异系数最小的是花蕾直径,此外橄榄雄花花序的多样性较雌花丰富。花蕾直径与花瓣长度呈极显著正相关关系,与花序长度、花序支轴数、花序花朵数和支轴花朵数呈极显著负相关。聚类分析结果表明,橄榄种质资源的花序类型可分为3类,大部分雄花和雌花类群间差异较明显。因此,橄榄花序表型性状存在多样性和复杂性,且花序重要单一性状可能影响整体表型。     

我国山毛榉科植物中一个新分布的属——三棱栎属

乔木。三叶轮生具成对合生的叶柄间托叶,或叶互生具离生的托叶。花序穗状,自正常和退化两者叶的腋中生出,单性,雄花序位于下方而雌花序位于上方,或仅有雄花序,簇状,或为雌雄同序下方具雄花而上方具雌花。雄花序挺直或曲折。雄花:(1—)3—7朵簇生,每簇具1基生和2侧生苞片;花被具6个复瓦状裂片,裂片下部合生;雄蕊6,与花被裂片对生,花药大(如栎属Quercus),宽卵圆形,基部心形,近背着但不为丁字着;退化雄蕊缺失。雌花:单生或3(—7)朵簇生,两种情况下承以3枚     

小叶桦花序生长物候及其生态适应意义

小叶桦(Betula microphylla)是一种典型的荒漠和山地乔木植物,在中国仅分布于新疆。为了明确小叶桦花序生长物候规律及发育特征,该研究对小叶桦进行了花序物候观测,分析其生长规律及果实结籽情况。结果显示:小叶桦雄花序为越年生殖器官,物候周期为345d,其中营养生长期154d、休眠期158d、开花生长期33d;雌花序与果序为当年生殖器官,物候期为105d,其中雌花序生长期24d、果序生长期90d。虽然雄花序比雌花序的生长周期明显较长,但开花授粉均在4月中下旬,雄花序散粉期和雌花序可授粉期之间具有较高的同步性和协调性,表现出集中开花授粉模式,同时这种开花模式在自然条件下,果序的结籽数和结籽率分别为220和76.7%,种子库中具有活力的种子约每平米4万粒,表明小叶桦在荒漠极端环境中能顺利完成有性生殖过程。     

常绿阔叶树种栲树开花物候动态及花的空间配置

 基于定株观测和随机枝取样法,对浙江天童常绿阔叶林内栲树（Castanopsis fargesii）的开花物候动态及其雌花、雄花的空间配置进行了研究。结果表明：在栲树的生殖枝上,并非所有的芽都分化、萌发生成花序,栲树花芽的分化和发育集中在一级生殖枝上。生殖枝上花芽的分化与该枝的空间位置密切相关。栲树花期明显晚于春季的展叶期,与叶片生长时间重叠。盛花期集中于5月下旬,约持续8 d左右,属于同步发生的花期。栲树雄花序的数量明显高于雌花序,雄花序约占花序总数的77.88%,雌花序仅占22.12%。大量雄花和花粉的存在是保证雌花接受花粉和完成受精的基础。花序在植冠层中的空间配置明显不同：在同一植冠内,向阳面和背阴面生殖枝上芽萌发成花序的比率存在明显差异(p<0.01),阳面生殖枝上顶芽萌发成花序的比率高于阴面生殖枝的比率,并且,阳面的每个生殖枝上平均花序数和雄花数量均高于阴面生殖枝,花序的分化和发育与枝系的生长发育状况有密切关系。     

爱玉子花的变异类型及其相关统计分析

该文报道了爱玉子(Ficus awkeotsang)花序中存在变异花的现象, 并通过花序解剖观测及数据统计分析方法, 研究比较雌、雄花序中变异花的类型、不同品系的花序变异率以及单花序中变异花的数量, 了解变异花发育过程、变异花与传粉小蜂之间的相互关系, 以及变异花对爱玉子产量造成的影响。结果表明: 爱玉子变异花在形态上有单生与伞形花序状2种类型, 雌花序中的变异花分布在雌花区和退化花区; 雄花序中的变异花均生长在瘿花区。雌花序中伞形花序状的A型变异花影响传粉小蜂对正常雌花的授粉, 与正常雌花争夺养分和生长空间从而影响正常雌花的生长发育, 大量A型变异花的存在使未授粉的雌花序延迟凋落或挂树不落, 造成养分流失。雌性品系太和6、太7、W13、乐野8、日野20和大洋Z106的花序中A型变异花数量较多, 对产量有一定的影响。除A型外的其它类型的变异花, 由于数量少且结构简单, 或发育后熟, 对传粉小蜂的传粉、产卵以及花序的发育、成熟没有显著影响。无论是雌性品系还是雄性品系, 以扦插苗繁殖方式形成的植株, 其花序变异率高于以实生苗繁殖方式形成的植株。以上研究结果为高产优质爱玉子品系的选育提供了一定的依据, 且对于爱玉子的栽培和推广有着重要的指导意义。     

爱玉子花的变异类型及其相关统计分析

该文报道了爱玉子（Ficusawkeotsang）花序中存在变异花的现象,并通过花序解剖观测及数据统计分析方法,研究比较雌、雄花序中变异花的类型、不同品系的花序变异率以及单花序中变异花的数量,了解变异花发育过程、变异花与传粉小蜂之间的相互关系,以及变异花对爱玉子产量造成的影响。结果表明：爱玉子变异花在形态上有单生与伞形花序状2种类型,雌花序中的变异花分布在雌花区和退化花区：雄花序中的变异花均生长在瘿花区。雌花序中伞形花序状的A型变异花影响传粉小蜂对正常雌花的授粉,与正常雌花争夺养分和生长空间从而影响正常雌花的生长发育,大量A型变异花的存在使未授粉的雌花序延迟凋落或挂树不落,造成养分流失。雌性品系太和6、太7、W13、乐野8、日野20和大洋Z106的花序中A型变异花数量较多,对产量有一定的影响。除A型外的其它类型的变异花,由于数量少且结构简单,或发育后熟,对传粉小蜂的传粉、产卵以及花序的发育、成熟没有显著影响。无论是雌性品系还是雄性品系,以扦插苗繁殖方式形成的植株,其花序变异率高于以实生苗繁殖方式形成的植株。以上研究结果为高产优质爱玉子品系的选育提供了一定的依据,且对于爱玉子的栽培和推广有着重要的指导意义。     

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.     

两种生境条件下西南桦的生殖构件及其空间格局

在广西靖西土石山生态交错区调查了西南桦(Betula alnoides)生殖植株的生长状况,并研究土山和石山两种生境条件下西南桦的生殖构件及其在冠层的分布格局.结果表明:石山西南桦开始开花结实的林木胸径明显小于土山;两种立地上西南桦植株的花芽、花序数以及雄花序比率与其胸径、树高均不显著相关(P>0.05);土山和石山的西南桦雄花序数随着总花序数的增加均呈对数曲线增长趋势,在生殖投资较小的情况下植株趋向于优先发育雄花序,而在生殖投资较大时主要增加雌花序的数量;西南桦生殖构件在两种生境间存在显著差异,石山植株的雄花芽数、每个雄发芽发育出的雄花序数均显著低于土山(P<0.05),雄花序少于雌花序的植株比例远高于土山,生殖枝比率亦显著低于土山(P<0.05);尽管石山雄花序、雌花序和总花序数量以及雄花序比率低于土山,其雌花序比率高于土山,但是由于两种立地上单株间变异幅度大,独立t检验表明其差异均未达到显著水平;两种立地上西南桦花序大多着生于树冠上、中层,且90%以上的生殖枝居于树冠外层.     

封面植物介绍--印度蛇菰

印度蛇菰[Balanophora indica(Arn.)Griff.]隶属于蛇菰科蛇菰属,是一种寄生植物。根状茎黄橙色到棕色,表面粗糙并具有星状疣;分枝近球形,直径0.5~5.6 cm,很少圆筒状。雄花序红色,卵球形椭圆形,(5~10)cm×(2~6)cm。雄花:略带红色,辐射对称,每朵被一个粗壮的截形苞片包围。花被裂片4~6,椭圆形披针形,(3~7)mm×(1~2.5)mm,聚药雄蕊椭圆形卵形,长2.5~5 mm,具柄;花药4或5,U形,纵向开裂。雌花序球状,直径3~5 cm。附属体棍棒状,长约2 mm,顶端1/2~1/3椭圆状倒卵球形。雌花生于花序基部和主轴上。花期10~12月。     

基部被子植物雪香兰（金粟兰科）单性花的形态发生和发育

基部被子植物金粟兰科（Chloranthaceae）的单性花或两性花结构十分简单,雪香兰（Hedyosmum orientale）花单性、雌雄异株,花的形态及结构与其它属物种具有显著的差异,对于研究被子植物花特别是花被的起源和系统进化具有重要意义。该研究采用电子显微镜和光学显微镜观察了雪香兰单性花的器官发生及发育过程。结果表明,雌、雄花均为顶生和腋生,多个小花呈聚伞圆锥状排列。雄花外侧是苞片,每朵雄花上着生150–200个雄蕊,花轴基部着生少数退化的叶原体。苞片原基及其腋生的花原基最初呈圆丘状,随后伸长。在雄花发育过程中,苞片原基比雄蕊原基生长快,雄花原基纵向伸长,叶原体原基在基部发生,雄蕊原基自下而上发生。每2朵雌花底部合生形成小聚伞花序,每朵雌花被一苞叶包裹,由单心皮和三棱型子房构成,外覆三裂叶状花被。在雌花发育过程中,雌花原基比苞片原基生长快,花被原基首先于花顶端发生,随后花顶端中心凹陷,进一步发育成具有单心皮的子房原基。雪香兰的单性花发育不经过两性同体阶段,花分生组织只起始雄蕊器官或雌蕊器官的发育。研究结果支持雪香兰单性花是原始性状的观点,雄花叶原体与雌花三裂叶状花被同源,可能是花被（萼片与花瓣）的起源。     

Male-biased sex allocation in late-blooming flowers driven by resource limitation in the clonal perennial Aconitum kusnezoffii (Ranunculaceae)

Flowering phenology and clonal growth are known to affect resource and pollen availability, and therefore select for adaptive or constrained sex allocation strategies to some degree. However, the consequences of temporal sex allocation patterns for reproductive fitness across the flower, inflorescence, and genet levels have rarely been examined. Moreover, experimental tests of the underlying regulatory mechanisms are scarce. We examined the association of flowering phenology and inflorescence position with temporal sex allocation and reproductive success in the protandrous perennial clonal herb, Aconitum kusnezoffii, over four consecutive growing seasons by examining more than 39 000 flowers. We also conducted controlled experiments to test the effects of resource and pollen limitation on the female reproductive success of lateral inflorescences. We found that some male functions were positively correlated with flowering phenology, whereas female reproductive success was negatively correlated with flowering phenology and inflorescence position. Lateral inflorescences invested more in male function than terminal inflorescences and therefore yielded fewer and smaller seeds. Resource limitation may serve as the key mechanism underlying this differentiated pattern. Decreased female reproductive success was consistently observed at the flower and inflorescence levels as flowering occurred later in the growth season. Late-blooming lateral inflorescences specialized in the male function, and their female reproductive success was constrained by early-blooming terminal inflorescences. This might be the first attempt to systematically demonstrate sex allocation strategy differentiation in a protandrous plant species at the inflorescence level. In addition, our study provides empirical evidence of dichogamy selecting for specialized sex allocation strategies among inflorescences.     

Water Deficit and Inflorescence Development in Zea mays L.--The Role of the Developing Tassel

In the normal pattern of development of Zea mays (cv. Iochief)a single mature female inflorescence is produced at node 7.A brief episode of water deficit at the time of terminal maleinflorescence initiation induced the subsequent developmentof two to three mature female inflorescences at nodes 5–7.This growth of the inflorescences at lower nodes was accompaniedby a marked inhibition of the growth of the terminal male inflorescence.Removal of either the developing terminal inflorescence or ofthe axillary inflorescence at node 7 at this time also promotedthe growth of the lower axillary inflorescences. The growthof these inflorescences was further stimulated by a period ofwater deficit when only the inflorescence at node 7 was removed,but removal of the male inflorescence abolished the capacityof these inflorescences to respond to the water deficit Excisionof the male inflorescence immediately before or immediatelyafter the period of water deficit produced the same response.It is concluded that this response of the lower axillary inflorescencesto water deficit is mediated through an effect on the developingterminal male inflorescence. Zea mays, water deficit, inflorescence development, tassel, correlative inhibition     

Diversity,systematics, and evolution of Cynodonteae inflorescences (Chloridoideae – Poaceae)

The species of the Cynodonteae tribe show great morphological diversity in their reproductive structures. Previous studies where inflorescences were comparatively analysed in the context of phylogeny have shown that although grass inflorescences seem to be excessively variable, there are certain aspects of inflorescences that store relevant information on the evolution and systematics in Poaceae. We have analysed and compared the inflorescence structures of species belonging to the Hilariinae, Monanthochloinae, Scleropogoninae, and Muhlenbergiinae subtribes. Considering the most relevant morphological characters, the most recurrent types of inflorescences in the lineage were determined by means of a principal coordinates analysis. To understand the evolution of inflorescence morphology, ancestral reconstructions of inflorescence characters were performed using the Bayesian inference method. The results obtained demonstrate that the processes of homogenization and truncation might account for the diversity observed in adult inflorescences. Five different types of inflorescences were identified out of 36 theoretical possibilities. Amongst these, inflorescence type 1 (panicle of spikelets, with a terminal spikelet, non-homogenized, and bearing third- or higher-order branches) was found to be the most frequent in the studied group. Ancestral reconstructions of morphological characters allowed us to suggest that the ancestor of the group might have had an inflorescence with the form of a raceme of spikelets, non-truncated and bearing first-order branches. More complex inflorescences bearing no terminal spikelets and having branches of higher order might have diverged this lineage.     

A taxonomic reassessment of Blepharocarya F. Muell.

The specialized female and male inflorescences of Blepharocarya are analysed revealing that each is derived from a thyreoid inflorescence. This appears to be a characteristic of the Anacardiaceae. The occurrence of vertical intercellular secretory canals in the primary and secondary phloem is illustrated, whilst the presence of Rhus–type pollen is confirmed. These characters provide further support for the retention of the genus in the Anacardiaceae.     

不同生境入侵植物北美车前繁殖器官性状变异与权衡特征

提高繁殖输出是入侵植物成功入侵的重要机制,但不同生境间繁殖器官性状变异特征尤其是性状权衡关系可能会存在差异。以入侵植物北美车前（Plantago virginica）为研究对象,采集草坪、荒地和林下3个生境的植物花序,探究花穗及花序柄的形态、生物量及其异速生长关系在不同生境间的差异性。结果表明：不同生境北美车前大部分花序形态与生物量指标存在显著差异,草坪和荒地生境花序属细长型,而林下生境则为矮壮型。北美车前繁殖器官不同性状间的异速生长关系既有保守型也有易变型,体现出不同的环境敏感性。不同生境间北美车前繁殖器官资源分配的个体大小依赖关系也存在不一致性。可见,北美车前花序性状及资源分配在不同生境间既存在一定的可塑性也具有相对保守性,这可能是其高入侵能力的重要原因。     

Differential self‐fertilization rates in response to variation in floral traits within inflorescences of Aquilegia buergeriana var. oxysepala (Ranunculaceae)

To assess variation in the proportion of self‐fertilized seeds among flowers within inflorescences and the relationship between floral traits and the rate of self‐fertilization, the proportion of self‐fertilized seeds among individual flowers was estimated using ten microsatellite markers in self‐compatible plants of Aquilegia buergeriana var. oxysepala. Within‐inflorescence variation in floral traits, such as the duration of the male and female phases, flower size, herkogamy and the number of pollen grains and ovules in two natural populations, were investigated. The first flower in an inflorescence produced more seeds and a higher proportion of self‐fertilized seeds than the second flower. The higher proportion of self‐fertilized seeds in the first flowers was accompanied by a higher number of pollen grains and ovules in the bud stage and the female phase. These results indicate that the high proportion of self‐fertilized seeds in the first flowers in an inflorescence may be due to the high number of remaining pollen grains in the female phase. This suggests that variation in floral traits within inflorescences affects seed quality and quantity among flowers within inflorescences.     

Flower choice by honey bees (Apis mellifera L.): sex-phase of flowers and preferences among nectar and pollen foragers

Bees foraging for nectar should choose different inflorescences from those foraging for both pollen and nectar, if inflorescences consist of differing proportions of male and female flowers, particularly if the sex phases of the flowers differ in nectar content as well as the occurrence of pollen. This study tested this prediction using worker honey bees (Apis mellifera L.) foraging on inflorescences of Lavandula stoechas. Female flowers contained about twice the volume of nectar of male flowers. As one would predict, bees foraging for nectar only chose inflorescences with disproportionately more female flowers: time spent on the inflorescence was correlated with the number of female flowers, but not with the number of male flowers. Inflorescence size was inversely correlated with the number of female flowers, and could be used as a morphological cue by these bees. Also as predicted, workers foraging for both pollen and nectar chose inflorescences with relatively greater numbers of both male and female flowers: time spent on these inflorescences was correlated with the number of male flowers, but not with the number of females flowers. A morphological cue inversely associated with such inflorescences is the size of the bract display. Choice of flowers within inflorescences was also influenced predictably, but preferences appeared to be based upon corolla size rather than directly on sex phase.     

Influence of inflorescence size on sexual expression and female reproductive success in a monoecious species

Sex allocation theory forecasts that larger plant size may modify the balance in fitness gain in both genders, leading to uneven optimal male and female allocation. This reasoning can be applied to flowers and inflorescences, because the increase in flower or inflorescence size can differentially benefit different gender functions, and thus favour preferential allocation to specific floral structures. We investigated how inflorescence size influenced sexual expression and female reproductive success in the monoecious Tussilago farfara, by measuring patterns of biomass, and N and P allocation. Inflorescences of T.?farfara showed broad variation in sex expression and, according to expectations, allocation to different sexual structures showed an allometric pattern. Unexpectedly, two studied populations had a contrasting pattern of sex allocation with an increase in inflorescence size. In a shaded site, larger inflorescences were female-biased and had disproportionately more allocation to attraction structures; while in an open site, larger inflorescences were male-biased. Female reproductive success was higher in larger, showier inflorescences. Surprisingly, male flowers positively influenced female reproductive success. These allometric patterns were not easily interpretable as a result of pollen limitation when na?vely assuming an unequivocal relationship between structure and function for the inflorescence structures. In this and other Asteraceae, where inflorescences are the pollination unit, both male and female flowers can play a role in pollinator attraction.     

Factors constraining fruit set in Mandevilla pentlandiana (Apocynaceae)

The reproductive success of Mandevilla pentlandiana was studied to disclose its reproductive strategy, and to determine the links between nectar production, breeding system, fruit set and inflorescence size. The plant produces many inflorescences with a large number of flowers but initiates few fruits (9%). This vine is self-compatible but not autogamous. Given that no significant differences could be detected considering many traits (ripe and abortive fruit sets, fruit quality, and seedling survival) between the pollination treatments (self-, cross-and natural-), the low natural fruit set was not related to pollen limitation. Fruits were not distributed at random within inflorescences (earlier fruits had the highest probability of maturation) but there were no significant differences in fruit quality according to different fruit positions. Conversely, the time of fruit initiation influenced most of the fruit-traits. Many developing fruits were aborted (20%). An increase in the probability of abortion was detected when the whole inflorescence was hand pollinated. In addition, a positive correlation was detected between the abortions and the number of ripe fruits which developed before them. Looking at our data from an evolutionary perspective, we argue that a theoretical inflorescence size, corresponding to the intersection point between the mean values of fruit number and fruit set per inflorescence, can be assumed to indicate the optimum inflorescence size that maximizes equally both female and male functions. Comparison between the theoretical and the observed mean inflorescence size suggests, that for M. pentlandiana , pollen donation may be the primary evolutionary factor behind excess flowers.