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1.
对海南吊罗山国家级自然保护区枝毛野牡丹(Melastoma dendrisetosum)的开花进程,访花昆虫、访花行为、访花频率以及气候条件等进行观察记录,同时检测了花粉活力、柱头可授性、花粉胚珠比、繁育系统,并分析其致濒机制。结果表明:枝毛野牡丹是典型的异型雄蕊植物,5:30—8:30逐步开放,8:30—9:00完全开放,19:00花朵闭合,单花开放时间为12—14 h,群体花期36±2 d,无花蜜。访花昆虫主要有木蜂科、条蜂科、蚁科、食蚜蝇科的昆虫,最有效传粉昆虫为木蜂科昆虫。自然与人工授粉、套袋等试验结果表明,枝毛野牡丹不存在主动自花授粉、无融合生殖的生殖保障现象,为自交亲和的异交种,需要昆虫传粉,枝毛野牡丹繁育系统是兼性自交。枝毛野牡丹相对生殖成功率低仅为0.035,主要限制因子为花粉限制和传粉者限制。 相似文献
2.
对海南吊罗山国家级自然保护区枝毛野牡丹（Melastoma dendrisetosum）的开花进程,访花昆虫、访花行为、访花频率以及气候条件等进行观察记录,同时检测了花粉活力、柱头可授性、花粉胚珠比、繁育系统,并分析其致濒机制。结果表明：枝毛野牡丹是典型的异型雄蕊植物,5：30—8：30逐步开放,8：30—9：00完全开放,19：00花朵闭合,单花开放时间为12—14 h,群体花期36±2 d,无花蜜。访花昆虫主要有木蜂科、条蜂科、蚁科、食蚜蝇科的昆虫,最有效传粉昆虫为木蜂科昆虫。自然与人工授粉、套袋等试验结果表明,枝毛野牡丹不存在主动自花授粉、无融合生殖的生殖保障现象,为自交亲和的异交种,需要昆虫传粉,枝毛野牡丹繁育系统是兼性自交。枝毛野牡丹相对生殖成功率低仅为0.035,主要限制因子为花粉限制和传粉者限制。 相似文献
3.
绵枣儿是一种极具应用潜力的野生植物种类,研究其花部综合特征与繁育系统有助于加快绵枣儿在园林上的应用。通过野外定点观察并记录其花部综合特征和开花动态,运用花粉/胚珠比、杂交指数以及套袋试验等方法对其繁育系统进行测定。结果显示:绵枣儿为顶生总状花序,开放次序为由下至上,花淡紫红色,每个花序具有小花40~300朵不等。通过扫描电镜和石蜡切片观察可以发现,绵枣儿每朵小花具有6枚花药,花药四室,花粉较大且外壁光滑,柱头相对表面积较大且具有许多球状凸起。绵枣儿单花花期为4~5 d,其单花期依据散粉特征和形态可以分为散粉期、柱头发育期、凋谢期。单株花期在9~28 d之间波动,花朵开放百分比和开花式样大小均呈现单峰变化的趋势。绵枣儿花粉/胚珠比结果为3 111,杂交指数结果为4,结合套袋试验结果可以确定绵枣儿的繁育系统为异交,部分可以自交亲和,需要传粉者的参与。 相似文献
4.
[目的]紫薇具有红色、紫色和白色等显著不同的花色以及形态、大小和颜色明显不同的2种雄蕊,使其成为花色多态型和异型雄蕊研究的良好材料.对紫薇花部综合特征和繁育系统进行系统研究,探究紫薇不同花色植株的繁殖策略以及2种雄蕊在传粉过程中的功能作用.[方法]通过野外定点观测,采用传粉昆虫调查、人工授粉以及人工控制套袋试验等方法对紫薇3种花色植株的花部形态特征、开花进程、传粉式样以及花朵的功能形态特征进行检测.[结果]1)3种花色植株的花期和单花开放进程基本相同(单花花期为4～5天).2)3种花色植株的花在形态特征上存在差异.3)3种花色植株的短雄蕊数表现为白色花植株＞紫色花植株＞红色花植株,花色间存在显著差异(P＜0.05);红色花植株的单花花粉量和P/O值显著低于其他2种花色植株(P＜0.05).4)3种花色植株的花粉活性和柱头可授性动态变化趋势相似;花粉寿命与柱头可授期有部分重叠,长雄蕊花粉活性最高时期早于柱头最佳可授期,短雄蕊的与柱头最佳可授期同步;白色和紫色花植株的柱头最佳可授期比红色花植株的长(约2h).5)2种雄蕊在形态、颜色、花粉量、人工控制试验条件下的结实率和结籽数以及传粉昆虫访花行为等方面都存在显著差异,说明2种雄蕊在传粉过程中存在功能分化,即黄色短雄蕊主要起招引昆虫作用,暗黄色长雄蕊主要起传粉作用;但2种雄蕊在花粉活性、花粉组织化学成分以及人工控制授粉后的结实率等方面均无显著差异,表明二者在生理上尚未分化;去除雄蕊试验表明,雄蕊的排列方式是影响2种雄蕊功能分化程度的重要因素.6)P/O值、套袋试验以及传粉昆虫观察结果表明,紫薇不存在无融合生殖、主动自交和自交不亲和现象,其交配方式是以异交为主、自交亲和的兼性异交繁育系统.7)传粉昆虫对红色花植株有明显偏好,访问该花色植株的频率显著高于其他2种花色植株(P＜0.01);人工授粉后,白色和紫色花植株的结实率显著提高.[结论]在自然条件下,紫薇的白色和紫色花植株存在一定的花粉限制.此时,增加对雄性功能的投入、延长柱头最佳可授期是其维持繁殖成效的适应策略;在传粉过程中,2种雄蕊既有分工,又有协作.2种雄蕊花药开裂时间不同步,花粉活力维持时间也不同,花粉的这种装配机制是紫薇提高花粉输出效率的繁殖策略. 相似文献
5.
从花部形态、花粉活力、柱头可授性、花粉与胚珠比、杂交指数、套袋实验、传粉观察等方面,对花柱二型植物滇丁香的繁育系统进行了研究.结果表明:针型花植株的单株花序数明显较多,而花冠管和柱头裂片长却明显较短;散粉8 h后,滇丁香的花粉活力达到最高值70%左右,从花药始散粉期至末花期其柱头均具过氧化物酶活性;针型花和线型花的花粉与胚珠比分别为1641.7±365.84和947.3±194.84,杂交指数均为3.结合套袋实验和传粉观察结果认为:在自然条件下,滇丁香为虫媒花植物,其中针型花和线型花所接受的亲和性花粉分别为异株同型花和异型花提供.滇丁香不仅是形态意义而且是功能意义上的花柱二型植物. 相似文献
6.
濒危植物扇脉杓兰的花部特征与繁育系统 总被引：2，自引：0，他引：2
通过野外观测,运用杂交指数(OCI),花粉萌发试验,去雄、套袋、人工授粉等方法对扇脉杓兰开花特性、花粉活力、柱头可授性、繁育系统进行研究,并对其柱头表面和花粉进行扫描电镜观察.结果表明:扇脉杓兰4-6月份开花,群体花期23天,单花花期12 ～ 16天.开花当天柱头即具有可授性,柱头可授性持续期为14天左右.花粉活力在花朵刚开放时最高(95％),至花朵凋谢之前仍保持较高的活力(70％).雌雄生殖单位在持续时间上有较长的相遇期.开花时柱头略高出花药,在花朵开放的整个过程中雌、雄蕊的相对位置始终不变.扇脉杓兰杂交指数OCI =4.自然条件下,扇脉杓兰的结实率仅为5％.人工自花授粉、异花授粉的结实率分别为90％和95％,表明扇脉杓兰是高度自交亲和的.而套袋后不采取措施和去雄的花均小结实,表明扇脉杓兰不存在自动的自花授粉、无融合生殖,因而扇脉杓兰必须通过一定的媒介传粉才能繁衍后代. 相似文献
7.
为探索四合木的濒危机制，对四合木种群的传粉生态学进行了初步研究。研究地点设在内蒙古杭锦旗地区，时间为1998年3～10月。研究结果表明：四合木花部形态有以下变异：萼片4～5。花瓣4～5，雄蕊8～10，心皮4～5。四合木的花期为5月上旬至6月初，单朵花的花期约为4～5d，整株开花可持续8～15d。花在上午盛开，下午花的多数萼片、花瓣呈半合拢状。在花开之前。花丝和花柱就已伸长，而且柱头高出花药2～3mm。花盛开时，花丝进一步伸长，与柱头近相等，内轮4～5个雄蕊花药先开裂，开裂方式为背向纵裂；花药紧围靠着雌蕊柱头，柱头有分泌物，可与花药粘在一起；外轮4～5个雄蕊花药至少晚一天开裂。花将谢时，花药全部开裂；花粉散毕之后。萼片、花瓣又闭上，并在几天后脱落。四合木种群传粉媒介是昆虫(主要是蜂类和蚁类)。四合木的传粉效率较低：50％的柱头上无花粉，20％的柱头上有1～2个花粉，30％的柱头上有多个花粉；只有25％的花柱中有多个花粉管。四合木的座果率为57．36％～68．76％，结籽率为1．26％～2．8％。在生境条件较差的群落中，座果率较高，这是其适应恶劣环境所采取的生殖对策。结实率低的主要原因是传粉过程受到障碍，即传粉媒介(昆虫)的访花频率极低，使得柱头上的花粉量受到限制。 相似文献
8.
白花野牡丹兼具观赏性和药用价值,极具开发潜力。为更好地保护和利用该物种,对白花野牡丹的开花进程、花部形态特征及访花昆虫进行观察,运用花粉萌发、杂交指数、花粉-胚珠比及人工授粉试验等方法测定其繁育系统。结果显示:白花野牡丹的单花花期约为12 h;白花野牡丹为雌雄异熟,柱头先花药成熟;雄蕊异型,2类雄蕊产生的花粉粒极轴长有差别,萌发率也不同;领木蜂、东亚无垫蜂、蓝彩带蜂、彩带蜂是白花野牡丹的主要传粉者;杂交指数(OCI)为4,花粉-胚珠比(P/O)约为417.6~1035.2;在自然条件下白花野牡丹不能自花授粉,繁殖需要传粉者参与,没有无融合生殖,自交亲和与异交亲和;白花野牡丹的繁育系统为自交亲和的异花授粉植物,需要传粉者。繁育系统为兼性异交。 相似文献
9.
2012年对锈叶杜鹃自然居群进行了开花物候及访花昆虫的调查,分析了其开花特性;并运用杂交指数、花粉-胚珠比和人工控制授粉方法,对其繁育系统进行了研究。结果表明,锈叶杜鹃开花时间为2月初至7月,其单花花期、单花序花期及单株花期分别为7.06±2.74 d,12.33±2.37 d和16.17±4.24 d。锈叶杜鹃的雌、雄性器官具有同熟性,但两者的最佳活性时间不同,花粉活力在开花第1天的活力最高,而柱头可授性在开花第4～6天最好。锈叶杜鹃的繁育系统为异交型,自交亲和,需要传粉者;同株异花授粉是其主要的授粉方式。锈叶杜鹃的有效传粉昆虫主要为蜂类,而象甲类、蚁类、叶蜂类昆虫是侵害性昆虫,严重影响其传粉;传粉昆虫访花频率低,可能是导致锈叶杜鹃自然杂交结实率低的主要原因。 相似文献
10.
在野外定位观测小桐子花朵的功能形态特征、开花动态、传粉方式,用杂交指数(OCI)、花粉/胚珠比(P/O)、去雄、套袋、人工授粉等方法分别测定小桐子的繁育系统.结果显示:(1)小桐子是单性花,雌雄同株同序.雄花单花期2 d,雌花单花期5～8 d,雌花直径略大于雄花.(2)雄花开花后9 h内花粉活力较高,24 h后花粉活力明显降低,48 h后花粉基本散失活力;雌花柱头可授性在开花后4 d内最强,5～8 d可授性开始降低,第9天基本失去可授性.(3)传粉方式以虫媒传粉为主,为虫媒植物.(4)繁育系统检测结果为部分自交亲和异交,需要传粉者活动才能完成授粉过程. 相似文献
11.
Studies on reproductive biology are difficult but useful in species like Aegle marmelos (Linn.) Correa which is of considerable socio-economic importance and possess morphogenetic variation and qualities of wider
adaptability to different soils. Cytology, phenology, pollination, breeding system and natural regeneration of wild and cultivated
trees from India revealed the existence of diploid (2n = 18) and tetraploid trees (2n = 36) in Pachmarhi hills and only diploid
trees in Punjab plains and Shiwalik hills. The diploid and tetraploid trees showed normal meiosis and high pollen fertility.
Phenological events which included leaf fall, leaf emergence, floral bud break, flowering and fruiting are nearly the same
in wild and cultivated trees. Natural pollen transfer in the species was highly efficient. Levels of fruit set following open
pollination was quite high and is reduced considerably following hand pollination probably due to some injury caused to stigma
during experiments. Inspite of synchronous nature of anther dehiscence and stigmatic receptivity, selfing in a flower was
avoided due to herkogamy. Some selfing, however, occurred through geitonogamous mode as bagging of panicles yielded 12.21 ± 0.99
to 14.12 ± 0.91% fruit set. High pollen ovule ratio (9,250–10,600) indicated toward the obligate outbreeding nature. The species
suited to insect and wind mode of pollination. High amount of air borne pollen grains deposited on glycerine smeared glass
microscopic slides suggested towards the wind mode of pollination. Though flowers are dull coloured a variety of insects visited
the flowers due to sweet fragrance and stamen/pollen as food reward. Among insect pollinators, honey bee (Apis dorsata) was the major and legitimate pollinator while the rest were either minor pollinators or mere visitors. Inspite of high fruit/seed
set, natural regeneration through seeds was poor as fallen fruits were destroyed by fungal pathogens and white ants. The species
also propagated vegetatively through coppices and root suckers. It lacks agamospermy as bagging of emasculated flowers yielded
no fruit. It is inferred that ‘bael’ which lacks agamospermy reproduced successfully through gamospermy (xenogamy and geitonogamy)
and vegetative mode (coppices and root suckers). We also concluded that tetraploid trees growing in the Pachmarhi hills with
large sized fruits possessed better potentialities in horticulture if planted through root suckers or coppices. 相似文献
12.
Density-dependent selfing and its effects on seed performance in a tropical canopy tree species, Shorea acuminata (Dipterocarpaceae) 总被引：1，自引：0，他引：1
Yoko Naito Mamoru Kanzaki Hiroyoshi Iwata Kyoko Obayashi Soon Leong Lee Norwati Muhammad Toshinori Okuda Yoshihiko Tsumura 《Forest Ecology and Management》2008,256(3):375-383
In the conservation and management practices of natural forests, sound reproduction and regeneration form the basis of the maintenance and viability of the tree populations. To obtain and serve biological information for sustainable forest management, we investigated reproductive biology and inbreeding depression in seeds of an important dipterocarp tree species, Shorea acuminata (Dipterocarpaceae), by both field and laboratory experiments. Results of parental analysis of immature and mature seeds showed that selfing rates varied greatly, from 7.6 to 88.4% among eight mother trees, and the mean overall selfing rate was 38.3%. Observed outcrossing events within a 40-ha study plot were predominantly (76.5%) short-distance events with a mating distance (md) ≤ 100 m. Since the selfing rate sharply decreased with increase in the number of flowering conspecifics (i.e., individuals of the same species) within a 100-m radius from the mother trees, the local density of flowering conspecifics appears to be the key factor determining the outcrossing rate in S. acuminata. However, the extremely high selfing rate (88.4%) observed for one tree could not be simply explained by the low local density of flowering conspecifics. Instead, differences in its flowering phenology (its flowering peaked ca. a week earlier than most of the other examined individuals) may have severely limited its receipt of pollen from other conspecifics, and thus promoted selfing. Since there were no significant differences in the proportion of selfed progeny between immature and mature seed stages, there was no evidence of selective abortion of selfed seeds during seed development. However, the seed mass of outcrossed progeny was heavier than that of selfed progeny, and heavier seeds showed higher success rates at germination and seedling establishment. These results suggest that inbreeding depression resulted in reductions in seed mass and may reduce the fitness of selfed seeds in S. acuminata. In addition, the outcrossing rate of S. acuminata was more sensitive to low local conspecific flowering-tree densities than that of a sympatric bee-pollinated dipterocarp species with greater pollination distances. These results suggest that the management of local adult-tree densities is important for avoiding selfing and inbreeding depression in future generations, especially in a species like S. acuminata with predominantly short-distance pollination. 相似文献
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提高球果出籽率是油松种子园种子产量的关键因素之一。在卢氏种子园结实初期胚珠败育率达到了70%,进入盛果期下降到45%。不同无性系间胚珠败育有很大差异,无性系间异交可配性、花期同步和自交是引起胚珠败育的主要因素。在结实初期辅助授粉可以显著提高种子产量,进入盛期后无效,但可以改善种子的遗传组成,增加种子的遗传多样性。 相似文献
15.
本文应用4对微卫星分子多态引物,对利用优株嫁接建立的蓝桉(E.globulus)树木园中的118个自由授粉子代的DNA微卫星指纹进行了分析.结果表明:选用的引物具有高度多态性,各个位点扩增得到的平均等位基因数为14.25,树木园中母株的异型杂交率为15%(95%,整体异型杂交率为47.9%,外源花粉污染率为17.6%.由于该树木园的异型杂交率低,其自由授粉的种子应用价值不高,因此应采用大规模人工授粉来制种或选用树木园中异型杂交率高的母株采种. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(1-4):41-49
The joint levels of outcrossing and contamination in two young northern Swedish Scots pine (Pinus sylvestris L.) seed orchards were studied with the aid of allozyme markers. High levels of contamination (21–36%) were estimated and were attributed to the observed low within orchard pollen production. Outcrossing rate estimates were high (0.957–0.961), though they departed significantly from complete outcrossing (t= 1.0) in spite of the observed high contamination levels. These results confirmed reported relationships between outcrossing and contamination levels in open‐pollinated seed orchards. It was concluded that a crop management option relying on supplemental mass‐pollination would be effective in reducing both contamination and inbreeding levels. 相似文献
18.
在杉木种子园中对6个无亲缘关系的无性系进行了双列杂交,包括自交。同时取亲本的自由授扮种子作为对照。在他们的子代林中,取一个全同胞家系和一个自由授粉家系,各选4至6株开花植株连同它们的亲本,分别进行自交、回交、同胞内交配和异交测定。结果表明,杉木近交使得种子发芽率和苗木高生长量大幅度下降。近交衰退随着近交系数(F)的增加而加大。同异交相比,自交、回交和全同胞交配、半同胞交配组合的种子发芽率分别平均降低约88％、42％和20％,苗木平均高度分别下降27％、17％和13％左右。结果也显示,在不同个体之间近交衰退程度存在明显差异。 相似文献
19.
20.
Controlled pollination (CP) is a labour-intensive, but useful procedure applied in tree improvement programmes. However, the
high costs involved and relatively low seed yields often obtained has, in most cases, necessitated the use of lower quality,
open pollinated seed. The aim of the present study was to compare control-pollination methods for combinations among small-flowered
eucalypt species. By making crosses within and among Eucalyptus grandis, E. smithii and E. macarthurii, we compared effectiveness, in terms of seed production and level of genetic contamination, of three CP techniques, namely
emasculation of bagged flowers and subsequent pollination of receptive stigmas (Conventional method), emasculation and immediate
pollination of stigmas with induced receptivity followed by bagging (One Stop Pollination), and pollination of cut styles
without emasculation and bagging (Artificially Induced Protogyny). One tree of each species was used as the female in these
crosses. Although Artificially Induced Protogyny using ripe and semi-ripe buds produced the highest seeds/flower pollinated
in the majority of crosses carried out in this study, the technique, when performed on green buds, resulted in the highest
capsule abortion. Molecular analysis using microsatellite markers also revealed that progeny from the Artificially Induced
Protogyny method, when using green and semi-ripe buds, were highly contaminated by self- and external pollen. Of the three
CP-techniques tested, One Stop Pollination had the lowest genetic contamination. However, this technique also had one of the
lowest seed yields, while the Conventional method was intermediate in performance. 相似文献