油松无性系开花物候特点的研究

在河南卢氏油松种子园对46个无性系结实初期和结实盛期开花物候作了观测，结果表明，一般雌球花可授期比授期比雄球花散粉期来得早，持续时间长，散粉期含在可授期内，散粉期和可授期同步性较好；在不同年份开花始期前后相差2-3d，开花始期早晚与当年≥10℃的活动积温有关，由于受花期温度和降雨等因素的影响，不同年份花期长短可相差10d左右，但不存在花期不遇，不同无性系在开花物候上存在很大差异，但在不同年份各无性系在始花时间上序次则相对稳定，无性系内分株间开花物候仅有1-2d的差异，位于树冠北向的雌雄球花各日期在开花频率上与其它3个方位有较大差异。始花期推后1d左右，此外，还研究了开花物候对同步指数的影响，以及不同物候类型授粉效率的差异。     

Flowering and Airborne Pollen Occurrence in a Pinus sylvestris Seed Orchard Consisting of Northern Clones

To explain the high background pollination rate detected in earlier studies, this study investigated the flowering phenology of a Scots pine seed orchard with respect to airborne pollen occurrence during 1992 and 1993. The receptive period of the female strobili and the shedding period of the male strobili were observed visually. Airborne pollen was monitored with Rotorod traps located inside and outside the seed orchard. There was no time gap in the onset of flowering between the earliest female and male strobili in 1992. Female flowering began 3 days earlier than male flowering in 1993, and the earliest strobili were probably pollinated by pollen transported long distance from more southerly areas. The almost simultaneous peak in pollen occurrence inside the seed orchard and in surrounding pine stands indicates that the seed orchard clones are not temporally isolated from sources of contamination. However, pollen concentrations inside the seed orchard were higher than those in the surrounding stands. Therefore, flowering phenology cannot sufficiently explain the observed pollen contamination rates in this seed orchard.     

Intrapopulation variation in flowering phenology and fecundity of silver birch, implications for adaptability to changing climate

Earlier modeling has suggested that long distance gene flow is of importance in increasing the adaptability of tree populations in a changing climate. In times of warming temperatures, early flowering phenotypes may be favored, because early flowering may be connected to early onset of growth. Long term direct measurements of flowering, pollen cloud and intrapopulation fecundity variations are needed to test this hypothesis. Having one of the furthest transported types of pollen grains, birch may have good potential for long distance gene flow. Our daily observations over eight years, of 30 silver birches (Betula pendula Roth), showed that the onset and duration of flowering phenology was determined by the accumulation of spring temperature sums, but the window for potential long distance gene flow was narrow. The interannual phenology variations were large, the order of timing of female and male catkins in various trees of this monoecious species tended to differ, and the timing of generative and vegetative spring phenologies were not correlated at tree level. Early flowering trees tended to have a higher variation in germinability than later flowering trees. No other connection between timing of phenology of flowering and seed quantity or quality was found. Although stochastic climatic conditions produce interannually variable phenological windows, probability for long distance gene flow from areas differing in timing of spring temperature accumulations may be low in silver birch. Intertree variations in fecundity were high, and the majority of seeds and pollen were produced by only a few trees. Moreover, the amount of seeds produced was positively related to seed germinability, thus large phenotypic fecundity variations may decrease interannual genetic variations in seed sets.     

银杏雄株开花生物学特性的研究

对从泰安和郯城共５０５０株银杏雄株中筛选出的２６个优良单株的开花生物学特性进行了研究。这些单株具有花期长、花粉量大及花粉生活力强等特点。相关分析和方差分析结果表明,随海拔高度的增加,花期逐渐延长,但小孢子叶球数／短枝下降。每米长枝上的短枝数最高达４５个。短枝长与小孢子叶球数／短枝呈极呈著的正相关。３年生枝段短枝开花率最高,达９６％。每个短枝上小孢子叶球数最高达６４５个,每个小孢子叶球最多含花药５８个,每个花药含有花粉粒最高达２３×１０４个,平均每个小孢子叶球含花粉粒达６５×１０４个。１４＃单株出粉率达６８３％。一株４５年生雄株可产花粉１６５ｇ。花粉生活力平均为９２％。授粉后座果率９０％,有胚率９１％。     

Impact of agroforestry practices on the flowering phenology of <Emphasis Type="Italic">Vitellaria paradoxa</Emphasis> in parklands in southern Mali

The impact of human practices on the phenology of flowering was assessed for an important agroforestry tree species of the Sudano-Sahelian zone: Vitellaria paradoxa. Flowering was monitored at two sites in southern Mali over 2 years. At each site, the impact of agricultural practices on flowering phenology was assessed by comparing field, fallow and forest. The site effect and agricultural practices were significant for all the monitored variables. The proportion of individuals that flowered was 89% at Koumantou and 40% at MPeresso. About 98, 95 and 75% of individuals at Koumantou and 88, 12 and 20% at MPeresso flowered in the field, fallow and forest, respectively. The mean length of flowering ranged from 69 to 81 days at Koumantou and from 45 to 108 days at MPeresso. The mean number of days for the active phase ranged from 36 to 49 days at Koumantou and from 27 to 64 days at MPeresso. Koumantou’s favourable climatic conditions resulted in better flowering ability and a higher probability of abundant flowering. Field appeared to provide better conditions than fallow and forest regarding flowering ability and probability of abundant flowering. However, tree diameter did not affect flowering phenology. Agricultural practices appear to have a noticeable impact on the phenology of flowering of V. paradoxa. Trees flowered abundantly in the parkland and therefore increased gene flow via pollen and/or seeds and the dynamics of genetic diversity.     

马尾松母树林营建技术及结实特性研究

通过对马尾松母树林７ａ的观测资料分析表明：（１）马尾松花期为１０￣１５ｄ,雌雄球花的散粉期与受粉期大致同步。（２）球果及种子产量与雌球花数正相关,与雄球花数相关性不显著;（３）建立母树林可从幼林期开始疏伐,７年生时密度每公顷保留３３０株左右为宜;（４）７年生时开花结实株率达８０％以上,母树结果较多的部位为中下冠层的东南方向,占６０％以上,１０年生母树林每公顷可产种６．７ｋｇ。     

Seed-cone receptivity and seed production potential in white spruce

Three to five ramets were selected from each of five white spruce clones for the study. Seed cones (megastrobili) were pollinated once and some were sampled at the different stages of development to study the pollination mechanism, seed-cone receptivity, and seed production potential.The proximal end of a seed cone emerged from the bud scales and was the area to be receptive first. As the seed cones continued to develop, the margins of the cone scales became reflexed to increase the surface area and to funnel pollen along the margins of two adjacent scales onto the micropylar arms. Pollen was transferred to a deep depression in the nucellus and it germinated in the depression a weel after pollination. Another week later the micropyle was sealed by the ingrowth and divisions of the cells in the micropylar canal. Receptivity of a seed cone lasted for about 10 days and the end of receptivity was signalled by the closure of cone scales.The optimal receptivity appeared to occur when seed cones approached the end of receptivity and this coincided with the peak of pollen shedding. It was evident that seed cones pollinated at this stage produced the most filled seeds, an average of 41.6 from a seed production potential of 88 seeds per cone. Total cone scales averaged 67.7 per cone of which 43.6 scales were fertile and located at the mid-portion of a cone.     

银杏雄性优良单株选择的初步研究

通过对11个与银杏良种桂G86-1花期接近或相遇的雄株2年生长枝上的短枝间距、花芽率、每短枝上雄花数及雄花穗长、粗,出粉率等各项性状的分析,发现B号雄性单株的散粉期与桂G86-1花期基本相遇,且散粉期长,花芽率高,出粉量大,每单位长枝上雄花数多,是桂G86-1的最适宜授粉树。     

马占相思开花生物学特征研究

利用光学显微镜和扫描电子显微镜（SEM）,对马占相思开花物候、花部形态和传粉效率等进行了研究。结果表明：马占相思于9-11月开花,整个群体花期有6 7个小花期;单株开花同步性强,呈现“集中开花”模式;穗状花序由172.7±27.1朵花组成,每个花序平均有（10.35±7.78）%的雄花,两性花具有雌蕊１枚,含14.11±1.05粒胚珠;柱头凹陷,大小可容纳1 2粒直径为29 35 μm的16合花粉粒,P/O’为1.13/1;马占相思开花时,雌蕊先于雄蕊伸展并成熟,为雌蕊先熟;SEM结果显示：花药在开花第2、3阶段仅有开裂线,在第4阶段之后才开裂,即7：00－9：00开裂,9：00－12：00大量散粉;柱头在开花第1天上午可观察到分泌物,预示柱头可授。此研究结果将为今后加强相思种子园的管理及开展相思杂交育种奠定重要基础。     

林木种子园生殖系统研究进展

本文对种子园生殖系统中亲本开花物候、配子产量、球果和种子败育、授粉机制、球花分布对种子园遗传效率的影响及其研究进展作了综述。论述了开花物候、球花产量与配子贡献以及种子园生殖系统遗传效率的关系。不同亲本开花物候及授粉机制的差异限制了亲本之间的基因交流 ,雌雄球花产量、球果败育及其雌雄球花空间分布的差异都会引起亲本配子贡献的变化 ,并最终影响种子园生殖系统的遗传效率。为提高种子园种子的遗传品质和遗传多样性 ,更系统深入地研究种子园生殖系统是必要的     

Revisiting the relationship between common weather variables and loblolly–shortleaf pine seed crops in natural stands

Seed production was monitored during24 years using seed-collection traps inloblolly–shortleaf pine (Pinus taeda L.–P.echinata Mill.) stands located in southeast Arkansas,north-central Louisiana, and southwest Mississippi onthe southeastern Coastal Plain, USA. Sound seedproduction was correlated with mean monthlyprecipitation and temperature from National Oceanicand Atmospheric Administration weather stationslocated near the seed-collection areas to determinethe potential of weather factors in forecasting pineseed crops. Correlations were restricted to threecritical periods in the pine reproductive cycle –strobili primordia differentiation, pollination, andfertilization. The most important (P 0.05)variables correlated with pine seed production for combined locations were cumulative precipitation (r = +0.60) during July, August, and September at 27 to 25 months before seed dispersal and mean temperature (r = –0.45) in August at 26 months before seed dispersal. Because multiple environmental factors can negatively impact pine seed development during the two yearsfollowing strobili primordia differentiation,seed-production forecasts based on weather variablesshould be verified by on-site cone counts during thesummer preceding autumn seed dispersal.     

Success rate of supplemental mass pollination in a seed orchard of Pinus sylvestris L.

Two experiments (Expt 1, Expt 2) with supplemental mass pollination (SMP) were carried out in a seed orchard of Pinus sylvestris L. in order to assess the biological and operational prospects for SMP. The success of the SMP was studied by means of allozyme markers. In Expt 1 the pollen mix was applied very close to each female strobilus. The estimated success rates for treatments varied between 66% and 84%. When supplemental pollination was done at peak receptivity, one single pollination was enough to obtain high success rates. In Expt 2 the pollen mix was dusted over clusters of receptive strobili on whole‐trees. The estimated success rates for treatments varied between 10% and 23%. The success rates improved when the trees were pollinated on more than one occasion per day during the receptive period. The overall conclusion is that SMP is practical for P. sylvestris seed orchards.     

薄壳山核桃不同无性系开花物候特性观测和比较

对薄壳山核桃32个无性系的雌、雄花开花物候期和花量进行了观测和比较。结果表明:2011——2014年薄壳山核桃无性系开花物候期有所差异,但开花物候类型一致。2013年,供试的32个薄壳山核桃无性系整个花期持续时间为4月24日——5月21日。雄花花期持续时间为11 18 d,雌花花期持续时间为9 17 d;雌花最佳授粉期与雄花散粉盛期持续天数均为3 8 d。依据雌花与雄花开放的先后次序可以确定其中的16个无性系为雌先型,10个无性系为雄先型,6个无性系为同时型;并根据观测结果确定了其中86个可行的授粉组合。最佳的授粉配置方案为:将1号、5号、27号、29号、35号无性系作为马汉、28号、65号无性系的授粉配置无性系。32个薄壳山核桃无性系之间,雄花序长度无显著性差异,单枝雄花簇数、单个雄花序花粉囊数、单株雄花序总数、单枝雌花数、每簇雄花序数、单株雌花总数的差异均达到显著水平,总体变异幅度最大的是单株雄花序总数(变异系数为75.51%)。     

Pollen dispersal in a hinoki (Chamaecyparis obtusa) seed orchard detected using a chloroplast DNA marker

Pollen dispersal was estimated in two test plots in a hinoki (Chamaecyparis obtusa) seed orchard using a chloroplast DNA marker, the spacer region between thetrnD andtrnY genes, and SSCP (single strand conformation polymorphism). In Plot 1, 2,020 seeds from 40 trees within 30 m of the marker tree were analyzed using the PCR-SSCP method. In Plot 2, 1,850 seeds from 37 trees were analyzed in the same manner. The results revealed that the maximum pollen dispersal distance in the two plots exceeded 25 m. Pollen dispersal appeared to be inversely proportional to the distance from the marker tree. The effective pollen dispersal was suggested to be less than about 20 m in a mature hinoki seed orchard. Adjacent trees had an excessive influence when the pollen density was increased by artificial flower stimulation. Therefore, it was suggested that seed production better resembles ideal random mating when carried out as naturally as possible. In conclusion, the SSCP chloroplast DNA marker was a useful tool for amassing basic information on pollen management in seed orchards of coniferous species.     

Lateral female strobili production in a Japanese red pine (Pinus densiflora Sieb. et Zucc.) clone by exogenous cytokinin application

Application ofN ⁶-benzylaminopurine (BAP) and gibberellin (GA₃) to a grafted Japanese red pine (Pinus densiflora Sieb. et Zucc.) clone promoted flowering. BAP (250 mg/l) was sprayed five times to the top of branches in July or September 1992. GA₃ (100 or 500 mg/l) was applied five times to the whole plants by spray treatment during the above period, or GA₃ solution of the same concentration was injected once into a small incision made in the main stem of clone trees at the beginning of July or the middle of September 1992. In May 1993, no apical female strobili were observed at the top of the new shoots in any treatment. However, lateral female and bisexual strobili were produced in the lower part of new shoots by BAP application in September, regardless of GA₃ application. BAP applied in September without GA₃ application was sufficient to produce lateral female and bisexual strobili. In such treatment, production of female and bisexual strobili was 47 and 25, and they occurred in 16 out of 68 new shoots, 11 out of 15 treated branches and 5 out of 5 treated trees. The average number of female and bisexual strobili per new shoot was 1.06. BAP treatment either in July or in September significantly decreased (p<0.05) the production of male strobili. These results indicate that BAP application induces the development of lateral female strobili in Japanese red pine when applied during the period of floral differentiation. A part of this paper was presented at the 105th annual meeting of the Japanese Forestry Society.     

Are Phenological Observations Sufficient to Estimate the Quality of Seed Crops from a <Emphasis Type="Italic">Eucalyptus grandis</Emphasis> Open-pollinated Seed Orchard? Consequences for Seed Collections

Reproductive phenology was observed over three years in a Eucalyptus grandis seed orchard in Madagascar to determine the impact of geographic differences of parental selections on the expected genetic composition of seed crops. Pollen flow (observed pollen cloud) was deduced from a paternity assignment based on sampling from one year’s seed production. The two approaches were used to verify whether knowledge of phenology is sufficient to predict the genetic quality of the seeds collected. Despite the high flowering level, with a constant cycle over three years, the results demonstrated wide reproductive phenological differences associated with the parents’ origin, suggesting putative pollination disequilibrium. From both observed and expected pollen clouds, the results showed preferential mating among different provenances, which has consequences for seed crop composition. Phenological observations, which can be made inexpensively, can be used to promote methods of effective seed orchard management in order to improve the genetic quality of seeds.     

Reproductive biology of the critically endangered tropical tree Talbotiella gentii

Talbotiella gentii is a critically endangered caesalpiniaceous legume endemic to Ghana, restricted in distribution to the margins of the forest zone where there has been extensive fire damage in recent decades. It occurs as isolated, near-monospecific populations, some of which show little seedling regeneration. We studied its reproduction to determine limitations that might inform efforts to prevent its extinction. We report on flowering phenology, pollen dispersal and germination, fruit and seed set, seed size and germination, and seedling survival, using controlled and open pollination. Talbotiella gentii flowers profusely in most years. Although the flowers are coloured and scented, no animal pollinators were observed but pollen can be dispersed by wind. In open pollination, the number of pollen grains on stigmas and their germination was sufficient to fertilise the three ovules, despite competition from heavy stigmatic infestation by fungal spores and hyphae. Fruit set and seed set were low due to high flower losses and fruit abortion during development but ripe seeds showed high germination. Controlled pollination experiments (self, supplemented self, and intra- and inter-population crosses) showed that, while the species is self-compatible, selfing was the least successful treatment in all of the above steps of reproduction, whereas cross-pollination enhanced most steps, the more so for inter-population crosses. Seed size was notably greater in inter-population crosses and was positively correlated with genetic distance of the cross. The larger seeds associated with cross-pollination showed higher germination and seedling survival in the nursery. We conclude that limitations to natural reproduction in T. gentii are principally due to processes between pollen germination and fruit and seed set, including pollen quality (low genetic diversity and inbreeding), fertilisation rates, flower and fruit abortion, and resource limitation. Low seed size in open and self pollination may have implications for seedling establishment. Species fitness might be improved by introducing other genotypes to existing populations, but in situ protection of the populations is essential in the medium term.     

Supplemental mass pollination in a seed orchard of Pinus Sylvestris L. investigated by isozyme analyses

Isozyme‐analysis techniques have been applied to test the efficiency of supplemental mass pollination in a seed orchard of Pinus Sylvestris. Mass pollination was done on one single occasion before the general pollen dispersal. The results of isozyme analyses of seed after mass pollination demonstrate that it is possible to introduce desirable genes into the seed orchard crop. Mass pollination without isolation of female strobili gave an average contribution of 4% to the total fertilizations and after isolation of female strobili 26.5%. The main conclusion is that supplemental mass pollination offers very interesting possibilities for breeding, particularly if some kind of isolation of the female flowers is made. It can increase the seed quality as well as improve the breeding value of the seed orchard. More attention should be paid to increasing the efficiency of the controlled pollination. It is suggested that in the future, more effort is invested in improving the technique of mass pollination.     

Reproductive biology of Corymbia citriodora subsp. variegata and effective pollination across its native range in Queensland,Australia

The spotted gum species complex represents a group of four eucalypt hardwood taxa that have a native range that spans the east coast of Australia, with a morphological cline from Victoria to northern Queensland. Of this group, Corymbia citriodora subsp. variegata (CCV) is widespread in south-eastern Queensland and northern New South Wales. It is currently the most commonly harvested native hardwood in Queensland. However, little basic knowledge of the reproductive biology of the species is available to inform genetic improvement and resource management programmes. Here we take an integrative approach, using both field and molecular data, to identify ecological factors important to mating patterns in native populations of CCV. Field observation of pollinator visitation and flowering phenology of 20 trees showed that foraging behaviour of pollinator guilds varies depending on flowering phenology and canopy structure. A positive effect of tree mean flowering effort was found on insect visitation, while bat visitation was predicted by tree height and by the number of trees simultaneously bearing flowers. Moreover, introduced honeybees were observed frequently, performing 73% of detected flower visits. Conversely, nectar-feeding birds and mammals were observed sporadically with lorikeets and honeyeaters each contributing to 11% of visits. Fruit bats, represented solely by the grey-headed flying fox, performed less than 2% of visits. Genotyping at six microsatellite markers in 301 seeds from 17 families sampled from four of Queensland's native forests showed that CCV displays a mixed-mating system that is mostly outcrossing (t _m = 0.899 ± 0.021). Preferential effective pollination from near-neighbours was detected by means of maximum-likelihood paternity analysis with up to 16% of reproduction events resulting from selfing. Forty to 48% of fertilising pollen was also carried from longer distance (>60 m). Marked differences in foraging behaviour and visitation frequency between observed pollinator guilds suggests that the observed dichotomy of effective pollen movement in spotted gums may be due to frequent visit from introduced honeybees favouring geitonogamy and sporadic visits from honeyeaters and fruit bats resulting in potential long-distance pollinations.     

华山松种子园无性系开花习性研究

云南楚雄华山松种子园的无性系,其雌球花着生在树冠外围枝条,而雄球花主要着生在树冠的内膛枝条。在水平方向上,雌球花多着生在树冠南部,雄球花的分布比较均衡;在垂直方向上,雄球花基本分布在树冠的中下部,雌球花则分布在树冠的中上部。大多数无性系的雄球花散粉期比雌花可授期早2~4 d;不同无性系间的雌雄花期具有一定的同步性。各无性系间雌、雄球花数量存在极显著差异,且有明显的偏雌或偏雄特性。雄球花量与无性系生长性状间存在显著正相关,雌球花量与树体生长相关性不显著。