七叶树繁育系统的研究

对七叶树的开花物候期、花部特征、单花开放动态、花粉活力、柱头可授性、花粉-胚珠比(P/O)和杂交指数(OCI)等有关生殖生物学特性进行了研究。结果表明:(1)在西安地区七叶树4月22日进入初花期,5月5日至13日为盛花期,5月14日进入终花期,整个群花期持续30d左右,单花花期持续5～8d。(2)七叶树的花有雄花和两性花两种形态,其在形态大小和生理上有显著差异,雄花小于两性花,其子房退化,雄花的花粉活力远远大于两性花的花粉活力,雄花开花当天花粉活力最强,达到75.69%,是七叶树授粉的最佳时间;两性花雌雄蕊发育正常,其柱头可授期持续8～9d,开花后3d柱头可授性达到最强。(3)P/O和OCI检测结果均表明,七叶树繁育系统为异交,需要传粉者,属于雄全同株植物。     

光果甘草生殖生物学特性的初步研究

对光果甘草的花部特征、花粉活力、柱头可授性和花粉-胚珠比(P/O)进行了初步研究.结果表明:(1)光果甘草雄蕊异型,雌雄蕊异位,有利于避免自花授粉;(2)开花当天花粉活力在上午12:00最高,为91.8%,14:00迅速下降,16:00到达最低,16:00以后逐渐上升;(3)柱头可授性可持续4 d,以开花当天可授性最强;(4)花粉-胚珠比(P/O)为1 751.1±217.002,表明其繁育系统类型为兼性异交.     

野生烟草花粉活力与柱头可授性及繁育特性研究

采用TTC法测定2个野生烟草材料(花烟草、哥西氏烟草)和1个栽培品种(K326)的花粉活力及其日变化情况,通过联苯胺-过氧化氢法测定3个烟草材料的柱头可授性、利用直接授粉法测定不同开花天数柱头可授性变化,并通过估算花粉胚珠比(P/O)、杂交指数(OCI)及授粉试验分析3个烟草材料的繁育特性。结果表明:(1)哥西氏烟草的花粉活性(74.9%)显著高于K326(52.2%)和花烟草(45.3%),且K326与花烟草间差异不显著;3个烟草材料花粉活力日变化均呈双峰曲线,峰值分别在13:00与15:00左右,且3个烟草材料的花粉活力日最低值与气温日最高值同时出现在14:00。(2)K326柱头可授性显著高于花烟草和哥西氏烟草,且2个野生烟草间可授性无显著差异;不同烟草的最佳授粉时期不同,哥西氏烟草自开花前1d至花后4d,一直保持较高的柱头可授性;花烟草的最佳授粉时期为花后2~3d;K326的柱头在开花前1d至开花后1d授粉最佳。(3)K326以自交为主,存在异交现象;哥西氏烟草繁育类型为兼性异交,自交亲和;花烟草繁育以异交为主,自交亲和性差。研究认为,野生烟草柱头可授性显著低于栽培品种从而影响其结实性,花烟草结实率低主要是由自交不亲和性造成的,而缺乏有效的传粉机制是造成哥西氏烟草结实性差的主要原因。     

簇枝补血草花的二态性及繁育系统研究

白花丹科被列为异型花柱较多的科,该文以补血草属簇枝补血草为材料,通过对野外居群的花部特征、花期物候和繁育系统等研究,探讨花部形态多态性及其对生殖的影响。簇枝补血草具有两种类型植株,具玉米状柱头和A型花粉的植株称为C型植株;具乳头状柱头和B型花粉的植株称为P型植株,且A/B型花粉的大小、外壁纹饰不同。单花发育过程中两型植株的花萼、雌蕊大小差异明显,随着花的成熟差异逐渐消失。两型植株都为雌蕊高于雄蕊,柱头探出式雌雄异位;C型植株的花期较P型植株长约2 d。一天当中,A型花粉活力高峰期为13:00,B型花粉在11:00和15:00都表现为高峰期;玉米状柱头可授性最强时期在13:00～15:00,乳头状柱头则在15:00。两型花粉可育性在盛花期最高,终花期时B型花粉可育性明显高于A型。荧光染色观察发现花粉萌发和花粉管的生长速度都为:异型授粉＞同型授粉,B型花粉在乳头状柱头上不能完成受精。此外,人工授粉实验也表明异型授粉结实率显著高于同型,P型植株经同型授粉结实现象并不明显,存在少量无融合生殖。研究表明簇枝补血草花部具二态性,繁育系统为兼性异交,其中乳头状柱头对A型花粉亲和,对B型花粉不亲和,但玉米状柱头却对A/B型花粉都亲和,这打破了该科的异型自交不亲和的例证。     

锦带花的花粉活力、柱头可授性及传粉者的观察

在野外实地观测锦带花(Weigela florida(Bunge)A．DC．)的开花动态和访花者,在显微镜下观测柱头和花粉的形态及花粉-胚珠比,用TTC法测定锦带花花粉的活力,用联苯胺-过氧化氢法测定柱头可授性。结果表明,锦带花的花粉活力在开花时达70％以上,且能维持3d,之后明显下降。锦带花的柱头在开花3h后多数呈白色、二裂、具可授性,柱头的可授期持续2～3d。柱头与花药之间有5．3士0．9mm的空间距离,自然条件下难于自花授粉．开花当天7．00～10．00之间访花者最丰富,开花第2天访花者减少,开花第3天时访花者更少。在锦带花上记录到的访花者隶属于膜翅目、鳞翅目和双翅目,其中,熊蜂和蜜蜂是主要传粉者。     

平贝母传粉生物学及繁育系统的研究

用TTC法测定花粉的活力,用联苯胺-过氧化氢法测定柱头的可授性,通过实地观测访花者、套袋实验、花粉-胚珠比(P/O比)的估算及花粉粒形态的观察研究了平贝母的传粉特性及繁育系统类型.结果表明,平贝母的花粉活力在开花后2～5 d可达90%以上,6 d后有所减弱,10 d后仍有71.3%的花粉保持活力.柱头的可授期约持续8 d,在开花后3～4 d柱头的可授性最强,5 d以后可授性逐渐减弱.平贝母的繁育系统是以自花传粉为主,虫媒异花传粉为辅的兼性自交.研究结果为平贝母的品种选育、杂交育种、引种栽培及物种保育提供了理论和技术依据,为深入研究贝母属植物的演化提供了生殖生态学依据.     

珍稀濒危植物蒙古扁桃花生物学特性

蒙古扁桃的植株可分为长花丝植株、短花丝植株和中花丝植株。群落花期约50d,单花花期约8d,分为露粉、微开、盛开、凋谢4个时期。过氧化物法测定4个时期花粉均具活力,可保持30d左右,联苯胺-过氧化氢测定柱头可授性,花粉活力与柱头可授性重叠,长花丝植株为8d左右,而中花丝约为5d。蒙古扁桃花一般在9:00开始泌蜜,11:00分泌量达到高峰,之后产蜜量减少直至停止,日泌蜜和散粉集中在10:00～14:00。蒙古扁桃开花受环境的影响。     

濒危植物凹叶厚朴的花部综合特征和繁育系统

为了解凹叶厚朴(Magnolia officinalis subsp.biloba)濒危的生殖生物学原因,通过野外观测,运用杂交指数、花粉-胚珠比、花粉活力和柱头可授性观测、人工授粉和套袋实验等方法,对凹叶厚朴种群的开花生物学、繁育系统进行了研究。结果表明:凹叶厚朴单花花期一般为4～5d,单花花期根据形态和散粉时间可分为4个时期:蕾期、初开期、盛开期和凋零期;种群于4—5月开花,一般开花历时30d左右,但不同地点、年份间有所差异;种群无开花高峰,单株平均开花数量为171.4～188.8朵,平均开花振幅为5～6朵·株-1·d-1;凹叶厚朴杂交指数为4,花粉胚珠比为5728.86,结合人工套袋和授粉实验结果可确定,繁育系统为异交,传粉过程需要传粉者;花粉活力较高(94%),且花粉活力可维持至散粉后的第6天。散粉后,柱头可授性显著下降,花粉高活力期与柱头可授期有5～6h的重叠;自然状况下结果率和单果出种百分率低,异株异花授粉可明显提高结果率和单果出种百分率,二者相对自然状况分别提高14.25%和43.66%。表明自然状态下传粉效率低、柱头最佳可授期短、同株自花授粉败育严重是其濒危的主要生殖生物学原因。     

观赏海棠品种间的杂交亲和性研究和亲本选择

为筛选出优质亲本及杂交组合,确定最佳授粉时期,探究观赏海棠品种间的杂交亲和性,为观赏海棠的新品种培育提供参考,该研究以15个性状互补的海棠品种为供试材料,用离体培养法测定花粉活力、悬液法测定花粉含量并对其雄性育性进行评价;联苯胺-过氧化氢法测定其不同开花时期的柱头可授性;荧光显微观察法观察授粉后花粉管的生长及受精情况;人工控制授粉法研究5个杂交组合的坐果动态变化情况。结果显示,(1)根据花粉活力可将15个海棠品种的雄性育性分为不育型、较低型、中等型、优质型4类,其中‘印第安之夏’、‘冬红’等6个品种为优质父本。(2)海棠从开花前1 d至第6天的柱头可授性呈现“弱—强—弱”的变化规律,开花第3天时的柱头可授性最强。(3)授粉后4～8 h花粉开始萌发,48～96 h完成受精。(4)花粉育性和柱头可授性与杂交坐果率、种子饱满率间均存在显著的正相关性。授粉后2个月内是落果集中期,此后至果实成熟坐果率基本趋于稳定。‘冬红’ב印第安之夏’、‘草莓果冻’ב印第安之夏’为高坐果率杂交组合。研究表明,海棠雌雄蕊存在发育不同步现象,选择育性优质的亲本是杂交取得成功的关键,而受精后障碍是本研究中海棠杂交...     

‘川早枇杷’头花柱头可授性及花粉活力与花粉管生长的研究

为揭示特早熟枇杷新品系‘川早枇杷’头花坐果率低的原因,该试验采用田间调查方法观察了‘川早枇杷’头花的开花期,并用联苯胺-过氧化氢法检验了柱头可授性、TTC法测定了花粉活力、苯胺蓝染色法观察了花粉管生长情况。结果显示:(1)‘川早枇杷’头花7月中旬进入初花期,7月下旬至8月上旬为盛花期,8月中旬至下旬为终花期,头花花期的果园气温最高、最低和平均分别为34.9℃、18.9℃和26.03℃。(2)开花当天及花后1~4d柱头具有可授性,且花后1d柱头可授性最强、花粉活力最高,以后花粉活力逐渐迅速降低。(3)自花授粉的花粉管在授粉后48h抵达花柱基部、96h到达胚珠,但数量极少。研究表明,‘川早枇杷’头花具有最佳可授性的时间较短,花粉活力降低迅速,花粉管能够抵达花柱基部和进入胚珠的数量极少,花期高温等诸多因素的综合作用可能是造成其头花坐果不良的重要原因。     

肋果沙棘(Hippophae neurocarpa S.W.Liu et T.N.He)自然种群的风媒传粉特征

野外调查了青藏高原特有植物肋果沙棘的花期物候、开花式样以及风媒传粉特征,对其花粉生活力、柱头可授性及单花花粉量进行了检测.结果表明,肋果沙棘有许多适应风媒传粉的特征:雌雄异株,花小,无花冠,先叶开放,雄花萼片纵裂形成对流的"风洞",花粉近球形,单花花粉量大;雌花柱头细长捻状,伸出萼筒,授粉面大,密布乳突.花粉生活力可以持续16.5 d,柱头可授性为10～20d.肋果沙棘传粉多发生在昼夜温差大的5月中下旬,在多变的气候条件下,种群花期可持续约12～25d,但在晴朗的天气条件下具有爆发性的集中开花机制,是对恶劣条件的适应.重力玻片法检测表明,离花粉源15m左右远的地点花粉密度最大,135m仍能接收到花粉,夜间接收到的花粉数量也很可观,这些研究结果表明,该植物集中在有利的晴朗天气昼夜进行长距离的风媒散粉,能较好地适应青藏高原的复杂环境.     

Stigma development and receptivity in almond (Prunus dulcis)

BACKGROUND AND AIMS: Fertilization is essential in almond production, and pollination can be limiting in production areas. This study investigated stigma receptivity under defined developmental stages to clarify the relationship between stigma morphology, pollen germination, tube growth and fruit set. METHODS: Light and scanning electron microscopy were employed to examine stigma development at seven stages of flower development ranging from buds that were swollen to flowers in which petals were abscising. Flowers at different stages were hand pollinated and pollen germination and tube growth assessed. Artificial pollinations in the field were conducted to determine the effect of flower age on fruit set. KEY RESULTS: Later stages of flower development exhibited greater stigma receptivity, i.e. higher percentages of pollen germination and more extensive tube growth occurred in older (those opened to the flat petal stage or exhibiting petal fall) than younger flowers. Enhanced stigma receptivity was associated with elongation of stigmatic papillae and increased amounts of stigmatic exudate that inundated papillae at later developmental stages. Field pollinations indicated that the stigma was still receptive and nut set was maintained in older flowers. CONCLUSIONS: Stigma receptivity in almond does not become optimal until flowers are past the fully open stage. The stigma is still receptive and fruit set is maintained in flowers even at the stage when petals are abscising. Strategies to enhance pollination and crop yield, including the timing and placement of honey bees, should consider the effectiveness of developmentally advanced flowers.     

Changes in Florets’ Vertical Direction within Inflorescence Affects Pollinator Behavior,and Fitness in <i>Trifolium repens</i>

Ecological interactions between flowers and pollinators greatly affect the reproductive success. To facilitate these interactions, many flowers are known to display their attractive qualities, such as scent emission, flower rewards and floral vertical direction, in a rhythmic fashion. However, less is known about how plants regulate the relationship between these flower traits to adapt to pollinator visiting behavior and increase reproduction success. Here we investigated the adaptive significance of the flower bending from erect to downward in Trifolium repens. We observed the flowering dynamic characteristics (changes of vertical direction of florets, flowering number, pollen grain numbers, pollen viability and stigma receptivity over time after blossom) and the factors affecting the rate of flower bending in T. repens. Then we altered the vertical direction of florets in inflorescence of different types (upright and downward), and compared the pollinator behaviors and female reproductive success. Our results showed that florets opened sequentially in inflorescence, and then bend downwards slowly after flowering. The bending speed of florets was mainly influenced by pollination, and bending angle increased with the prolongation of flowering time, while the pollen germination rate, stigma receptivity and nectar secretion has a rhythm of “low-high-low” during the whole period with the time going. The visiting frequency of all the four species of pollinators on upward flowers was significantly higher than that of downward flowers, and they especially prefer to visit flowers with a bending angle of 30°–60°, when the flowers was exactly of the highest flower rewards (nectar secretion and number of pollen grains), stigma receptivity and pollen germination rate. The seed set ratio and fruit set ratio of upward flowers were significantly higher than downward flowers, but significantly lower than unmanipulated flowers. Our results indicated that the T. repens could increase female and male fitness by accurate pollination. The most suitable flower angle saves pollinators’ visiting energy and enables them to obtain the highest nectar rewards. This coordination between plants and pollinators maximizes the interests of them, which is a crucial factor in initiating specialized plant-pollinator relationships.     

高山植物扁蕾的延迟自交机制

扁蕾(Gentianopsis barbata)具有鲜艳的花和显著的腺体,并且花开放的前5 d柱头和花药始终处于不同的位置(雌雄异位),这些花综合征表明该植物应为异花传粉。为检验这一假设,我们对青藏高原植物扁蕾的海北站种群进行了3年的传粉生物学研究实验。与花综合征所表明的繁育系统相反,两年的野外观察发现昆虫的访花频率十分低,不去雄并隔离昆虫处理也能产生大量种子,说明这一种群的繁殖主要是依赖于自花传粉。尽管利用种子结实评价的柱头可授性从花开放4 d后开始下降,但随着花的发育进程,雄蕊的伸长能使得花药与柱头完全接触。实验也证明,柱头可授性和花粉活力都超过5 d,说明花药和柱头的接触能够发生自花授粉。扁蕾的这种自花传粉机制应属于典型的延迟自交类型。自花授粉发生在单花花期快要结束前,自交之前仍然保持异交传粉机制,这种延迟自交避免了自交与异交竞争造成的花粉或者种子折损,并为扁蕾在青藏高原极端环境下由于访花昆虫缺乏造成的异交失败提供了繁殖保障。     

黑河中游和烟台海滨中国柽柳的传粉生态学研究

中国柽柳(Tamarix chinensis)是干旱及半干旱地区的重要建群物种.为便于其有效利用和引种栽培,对黑河中游和烟台海滨的中国柽柳的开花动态、花粉活力、柱头可授性、访花者种类、花粉-胚珠比(P/O)、杂交指数(OCI)及座果率进行观测,结果表明:黑河中游和烟台海滨柽柳的花期和柱头可授性相似,花序花期为2-5天,开花当天柱头可授活性最大,之后逐渐下降,第4天柱头无可授性;花粉活力和访花者种类差别较大,黑河柽柳开花第1天花粉活力为(62±4.31)％,最高为(82.12±7.23)％,4天后花粉完全失活.烟台柽柳的花粉活力在开花后第1天最高为(89.13±7.23)％,第4天花粉活力下降为(11±1.12)％.黑河中游和烟台海滨柽柳的访花者均以膜翅目昆虫为主,黑河柽柳以黑带斑沙蜂(Bembix melanura)、卡切叶蜂[Megechile (Amegachile) kagiana]和黑带食蚜蝇(Episyrphus balteatus)等为主要访花者;烟台柽柳以姬蜂(Ichneumon sp.)、大灰食蚜蝇(Metasyrphus corollae)和灰地种蝇(Delia platura)等为主要访花者.二者P/O值、OCI及座果率差异不显著,黑河和烟台柽柳的P/O值分别为373.6±71.9和382.1±86.2;最高座果率分别为(89.72±7.76)％和(93.17±8.21)％;OCI均为3.上述研究结果显示,黑河中游和烟台海滨柽柳均为兼性异交的繁育系统.     

浅裂剪秋萝和丝瓣剪秋萝传粉特性的初步研究

为了探究浅裂剪秋萝(Lychnis cognata)和丝瓣剪秋萝(L. wilfordii)的传粉生物学特征, 从花部特征、花粉呈现规律及传粉者访花行为等方面对其开展研究。结果表明, 2种剪秋萝的花期持续时间相近, 但浅裂剪秋萝始花日期较早; 二者花部特征虽有显著差异, 但主要传粉者均为碧翠凤蝶(Papilio bianor)。在开花过程中, 2种剪秋萝的雄蕊均分2批呈现花粉, 第1批雄蕊的花粉生活力在开花后第1天达到最大值, 而第2批雄蕊在第2天达到最大值。浅裂剪秋萝的柱头可授性在开花后第5天最强, 而丝瓣剪秋萝在开花后第4天最强, 花粉生活力和柱头活性的时间差异表明两物种均为雌雄异熟。两物种共同的传粉者碧翠凤蝶对浅裂剪秋萝的访花高峰出现在上午8:00-11:00, 而对丝瓣剪秋萝的访花高峰出现在上午11:00-12:00, 导致访花高峰出现差异的主要影响因素可能是生境和花药开裂时间。     

Observation of Flowering Process of Grape (<i>Vitis vinifera</i> L.)—Insight into the Starting of Pollination of Flower Hiding in Calyptras (Cap)

It is generally agreed that many Vitis vinifera L. cultivars are self-fertile, where self-pollination often occurs before capfall in a process called cleistogamy. Therefore, it is difficult to identify the right time to remove stamens before self-pollination during the cross-breeding of grape. For this paper, we observed the process of grape flowering and measured the pollen viability and stigma receptivity of grape flowers of ‘Shine Muscat’ in order to identify the starting time of self-pollination before capfall and to provide useful information for improving the efficiency of cross-breeding. The results demonstrate that the anther is not cracked during the visible clusters and separated clusters stages. Meanwhile, in the separated floral buds, flowering begins, and full bloom stages, the pollen viability is 60.7%, 73.2% and 80.3%, respectively; however, at the berry set stage, pollen viability drops to zero. The top of the mature stigma is composed of a layer of nearly cylindrical papillary cells, and the stigma receptivity for pollen changes with the development of flowers: in particular, no reaction was observed in the visible clusters stage; weak positive reaction at the separated clusters stage; strong positive reaction at the separated floral buds, flowering begins, and full bloom stages; and no reaction at the berry set stage. In the separated floral buds stage, pollen tubes were seen germinating in the style. In the flowering begins stage, more pollen tubes were observed at the entry of the ovary. During the full bloom stage, most pollen tubes elongated into the ovary base and some entered the pearl hole. At the berry set stage, newborn endosperm nucleus could be seen in the ovule. From the above, we can conclude that the initiation time of closed fertilization for ‘Shine Muscat’ grape can be judged as the separated floral buds stage, and it is best to discard the stamen before the separated floral buds stage when conducting cross-breeding.     

The effects of stigma age on receptivity in Silene alba (Caryophyllaceae)

Silene alba, a perennial, dioecious plant, produces flowers that open in the evening and can remain open and receptive to pollination for up to 5 d, though in hot and dry conditions the flowers will wilt during the day only to reopen night after night. In the field, it is visited by two different kinds of pollinators with differential success: moths visit the flowers at night, and their movements result in broad pollen dispersal and large seed production, whereas bees, wasps, and flies visit the flowers in the mornings and have decreased pollination effectiveness. However, this differential success may be due to a decrease in stigmatic receptivity soon after the flowers open. We performed controlled pollinations to determine the effect of stigma age on pollen germination and seed set. We pollinated flowers at 12-h intervals up to 120 h and divided these into two sets: from one set, we removed stigmas 24 h after pollination to examine percentage of pollen germination. The second set of flowers was allowed to produce fruits, and the seeds were counted and weighed. Pollen germination declined significantly with stigma age, but there was no significant effect of stigma age at pollination on the number or mass of resulting seeds. Thus, the decreased pollination success of bees is not due to a decrease in stigmatic receptivity but is most likely a result of pollinator inefficiency.     

多伞阿魏的繁育系统及其生态适应性

多伞阿魏（Ferula ferulaeoides）是新疆特有的类短命植物,具有巨大的生态作用和潜在的经济价值。实验通过研究多伞阿魏的花部形态特征、繁殖系统及传粉昆虫,来阐明其对生态环境的响应。结果表明：（1）多伞阿魏花序花期一般持续10~15 d,单花花期为7~10 d,两性花呈现雌雄异位和雌雄异熟的现象;（2）其繁育系统类型为兼性异交,存在自交部分亲和,自然结果率较高,为72.24%;（3）传粉昆虫多种多样,其中以双翅目和膜翅目昆虫居多;（4）开花当天的花粉活力呈单峰曲线,在12：00时活力最高,柱头可授性在花药完全散粉后第2天最强。