Flowering Synchrony Research Articles

Local records of long-term dynamics of bamboo gregarious flowering in northern Laos and regional synchronicity of Dendrocalamus membranaceus in two flowering sites

Bamboos are widely distributed in mainland Southeast Asia and have abundant biomass. They are characterized by prolonged vegetative growth and semelparity. Where bamboos are dominant, their synchronous flowering and death has a major impact on forest vegetation. Although the small-scale dynamics of this process have become clearer in recent years, the history, geographical scale and synchronicity of bamboo flowering over broad areas remains unknown. This study focused on the flowering history of six bamboo species, Bambusa tulda, Cephalostachyum virgatum, Dendrocalamus hamiltonii, Dendrocalamus membranaceus, Indosasa sinica and Oxytenanthera parvifolia, over 40 years across a broad area of northern Laos. We also examined the synchronicity of flowering in D. membranaceus. We visited 49 villages in northern Laos and surveyed knowledgeable inhabitants about bamboo flowering history. The timing, scale and synchronicity of gregarious flowering varied among species. D. hamiltonii and D. membranaceus showed higher flowering synchronicity than other species. All the species except I. sinica had both sporadic and gregarious flowering traits, and showed conspicuous variability in their flowering scale. The flowering bamboo population at two gregarious flowering sites for D. membranaceus was surveyed. While this species had the highest synchronicity in this study, its synchronicity was lower than other species in previous studies worldwide. We found that the gregarious flowering of bamboos in northern Laos over the last 40 years showed lower synchronicity than bamboo flowering reported in other areas of the world. The historical dynamics and scale of bamboo flowering must be further clarified to understand the vegetation composition of this area.

Flowering phenology of Catopsis compacta (Bromeliaceae), a dioecious epiphyte in an oak forest

Background: Knowledge of the flowering phenology of species with an epiphytic habit and a dioecious sexual system is scarce.
 Questions: We studied the flowering phenology of a population of the dioecious epiphytic bromeliad, Catopsis compacta , in an oak forest in Oaxaca, Mexico, to answer the following questions: 1) what type of flowering period is exhibited by this population of C. compacta ? 2) what is the degree of synchrony between the male and female flowering periods? and 3) what is the flowering synchrony index of the population?
 Methods: In February 2006, in a 20 m × 20 m plot, we marked and measured 151 individuals of C. compacta ? 10 cm in height (minimum reproductive size). We recorded the number of flowers and fruits present in each individual every month for one year.
 Results: Our results showed that the flowering period in both sexes lasted for three months (May–July). Only 23 marked individuals flowered (15.23 %): of these 12 (52.17 %) were female and 11 (47.83 %) were male. The index of synchrony between females and males was 0.958 ± 0.013 and the flowering synchrony index of the population was 0.833 ± 0.189.
 Conclusions: The high flowering synchrony between the sexes, together with a flowering season that coincided with the period of highest rainfall when the number of arthropods (potential pollinators) is the highest, could favor breeding and, therefore, reproductive success.

Flowering Phenology and Floral Visitors in Distylous Populations ofPsychotria carthagenensis(Rubiaceae) in Brazilian Cerrado

Flowering synchrony has a relevant role in pollinator attraction. In distylous species, synchronous blooming between individuals of both morphs means that the chances of intermorph crosses are increased, which is important for the maintenance of the heterostylous system. The aim of the present study was to describe the flowering phenology and the behavior of the floral visitors in three populations of Psychotria carthagenensis Jacq. (Rubiaceae) between January 2008 and January 2010. Flower and pollinator censuses were conducted at three urban forest fragments in Brazil. Psychotria carthagenensis flowering occurred between October and December, with a high degree of synchrony within populations as well as between floral morphs. The exotic Apis mellifera L. (Apidae) was the main pollinator in the three populations. A high degree of similarity was found in the behavior of floral visitors as well as in nectar production. Visitation rates did not differ between floral morphs. Similar floral recompenses (flower availability and nectar) as well as no preference in pollinators' visiting are thought to be contributing to a greater intermorph visitation to pin and thrum flowers in P. carthagenensis.

Unravelling the inheritance, QST and reproductive phenology attributes of the tetraploid tropical grass Brachiaria ruziziensis (Germain et Evrard)

AbstractThe autotetraploid forage Congo signal grass (Brachiaria ruziziensis) is an important component in the Brachiaria breeding programme. As with other tropical forage grass species, the association between flowering and seed yield components, the mode of inheritance and the effects of population structure on phenotypic breeding are lacking. Seventeen characteristics evaluated in 59 half‐sib progeny of seven subpopulations were analysed using a mixed model methodology. According to the commonality analysis, the total seed yield (0.67) and number of days to flowering (0.22) had a greater influence on the filled‐seed yield. The flowering synchrony, total number of panicles, filled‐seed yield, green matter yield and dry matter yield presented statistically significant additive genetic variance between and within the subpopulations. The QST estimates ranged from 0.09 for the flowering synchrony index to 0.31 for the filled‐seed yield. The effects of population structure and its use in breeding programmes are further discussed.

Flowering synchronization in hybrid rice parental lines

The cultivation of hybrid rice is a technology that allows for an increase in grain yield of 30% relative to the grain yield of conventional cultivars. However, the main challenge for this technology is related to seed production, which has high production costs and low seed yields. Therefore, agronomic techniques that could enhance flowering synchrony of parental lines in the field are essential for an efficient production system of hybrid rice seeds. The objective of this work was to study the effects of sowing depth, plant density and fertilization with nitrogen or phosphorus as potential techniques to increase the pollen availability in the field and, consequently, the flowering synchrony between parental lines in the production of hybrid rice seeds. The experiments were conducted during two growing seasons in the Central Region of Brazil. All of the experiments were conducted as a randomized complete block in a split plot scheme; however, the experiment with P fertilization had a factorial design. Our research allow inferring that nitrogen fertilization technique applied to the soil or foliar at the time of panicle differentiation does not affect the time of onset of flowering of rice varieties INTA Puita CL and L106R, which are potential R lines for the production of hybrid rice. Agronomic techniques of variation in sowing depth, seeding rate and the phosphate fertilization affect the time of onset of flowering from 10 to 19 degree-days, which could represent two days in the crop cycle, for the line L106R. Such techniques constitute potential alternatives for use in hybrid rice seed production systems and could be applied in alternated blocks of R lines in the field to obtain longer periods of pollen availability in the field.

Grain yield performance and flowering synchrony of CIMMYT’s tropical maize (Zea mays L.) parental inbred lines and single crosses

AbstractMaize production constraints in sub-Saharan Africa (SSA) are being addressed by CIMMYT and partners through an array of projects, focusing on developing and evaluating parental inbred lines and single-crosses as well as formulating, evaluating and releasing high-yielding and stress resilient hybrids adapted to different agro-ecologies. The objectives of the present study were to (1) evaluate the grain yield performance of parental elite inbred lines developed over the years, and single crosses; and (2) ascertain the flowering synchrony among inbred lines and single-cross hybrid parents. Parental inbred lines and single-crosses were evaluated at seven locations in two countries in 2014. Combined analysis of variance revealed differences (P < 0.01) among genotypes for grain yield (GY) and among different years/era of release of the inbred lines. The improvement in GY of inbred lines was estimated to be 1.4 % per year. Under irrigated conditions GY of some single-cross hybrids was over 16 t ha−1. Some single-cross and inbred line parents showed acceptable flowering synchrony, good producibility, and stable performance across testing environments, suggesting that these have high potential for seed production. Further research is needed to determine the physiological and morphological characteristics that contributed to the GY improvement in the parental inbred lines. Information generated from this study will enhance the use of CIMMYT’s tropical mid-altitude parental germplasm by breeders working in both private and public breeding programs for developing and deploying high-yielding maize hybrids for the benefit of small-scale farmers in SSA.

Browsing for improved grain quality characteristics in rice hybrids developed from indica CMS lines and aerobic rice cultures

In the present study, 88 hybrids were evaluated under aerobic and flooded conditions, out of which 35 hybrids were identified for grain quality analysis based on single plant yield, grain type, and parental line flowering synchronization. The grains of 35 high yielding hybrids and their respective parents were subjected to grain quality analysis as per the procedures given in the standard evaluation system. The released rice hybrids ADTRH 1 and CORH 2 and the popular fine grain varieties ADT 43 and BPT 5204 were used as standard checks for effective comparison. Data were recorded for the following quality characters like milling quality traits, physical grain quality traits and cooking quality traits. The hybrid COMS 14A × IR 62161-184-3-1-3-2 was identified as the best hybrid since it recorded the highest total score followed by IR 68888A × IR 69715-72-1-3, IR 68888A × WGL 32100, IR 68897A × IR 72875-94-3-3-2, COMS 14A × IR 69715-72-1-3 and COMS 14A × WGL 14, COMS 14 A × IR55838-B2-2-3-2-3 and IR 68897 A × IR 71604-4-1-4-7-10-2-1-3. These hybrids had good scores for more number of quality traits such as milling per cent, head rice recovery, chalkiness, volume expansion, intermediate GT, soft gel consistency and amylose content. The parents of these hybrids also had higher total score for most of the quality traits. These hybrids with higher yield and good grain quality, can be exploited commercially for grain yield and quality improvement. The male parents viz., WGL 14, IR 71604-4-7-10-2-1-3, IR 62161-184-3-1-3-2, IR55838-B2-2-3-2-3, IR 62030-54-1-2-2, PSBRC 82, IR 36,and female parents viz., IR 68888A, IR 68897A and COMS 14A, with desirable grain quality had produced hybrids with superior grain quality. These parents could also be exploited further for developing heterotic rice hybrids with improved grain quality.

Parent Identification in a Multi Location Trial Seed Orchard of Acacia Mangium Using Microsatellite Markers

Variation of parent gametes' contribution might affect the growth patterns among offspring produced from seed orchards. This paper studies the mating system statuses and to identify parent trees that produce good growth performance of offspring in seedling seed orchard of A. mangium . The study was conducted in two seed orchards, i.e. a first generation seedling seed orchard (F1 SSO) of A. mangium, used as the parent population hereafter and a multi location trial (MLT) as an offspring population. Based on 10 microsatellite markers, mating system in the F1 SSO was under panmictic equilibrium condition. The good growth trees in the MLT originated from various parent genes contribution in the F1 SSO. Several behaviors were observed: a). the best trees in MLT dominantly originated from singlepair trees, between maternal and paternal trees, in F1 SSO; b). a maternal tree was pollinated by two paternal trees; c). a paternal tree pollinated several maternal trees. Flowering synchronization and genetic compatibility among trees might be responsible for these mating system patterns. In order to maximize seeds production, studies on male and female flowers characteristic should be employed to assess flowering synchronization among individual trees in the seed orchard.

Studies on cross compatibility inDendrobiumspecies and hybrids

Gene pool of Dendrobium species from Eastern Himalayan region is largely unexploited in India. Cross compatability was studied in 23 species and 14 hybrids of Dendrobium for two consecutive years, based on synchrony of flowering. The success of pod setting in species vs species was recorded limiting to 8.97% in direct crosses and 18.75% in respective possible reciprocal crosses. However, 34.37% pod formation was observed in direct crosses in species vs hybrids vs hybrids combinations and 50% success in their reciprocal crosses. Among the species, cane orchid (Dendrobium moschatum) is compatible as both male and female parents, apart from hybrids ‘Emma White’ and ‘Thongchai Gold’. Twelve species failed to get pod formation as both male and female parents that belong to section-II of Eugenanthe (Dendrobium), Callista and Aporum that are native to Eastern Himalayan region. The larger group of Indian Dendrobium species that grouped in Dendrobium section was found to be incompatible with other sections and the success of intra-sectional combinations was limited to only 5.8%. However, species from sections Callista followed by Eugenanthe and Dendrobium were cross compatible with hybrids with 85.7%, 40% and 33.3% success of pod formation, respectively. These findings suggest intermediary approaches to develop bridge crosses to overcome incompatibility barriers in Dendrobium improvement programmes.

浙江低山地区多用途植物无患子的开花物候特征

PDF HTML阅读 XML下载 导出引用 引用提醒 浙江低山地区多用途植物无患子的开花物候特征 DOI: 10.5846/stxb201501130107 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 林业公益性行业科研专项（201404104，200804032）；浙江省-中国林科院省院合作项目（2013SY01）；浙江省重大科技专项重点农业项目（2011C12015） Flowering phenology of the multipurpose tree species Sapindus mukorossi Gaertn. in low mountain areas of Zhejiang Province Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:无患子（Sapindus mukorossi Gaertn.）是我国长江以南地区传统的重要绿化树种，其果皮富含皂苷，种仁富含油脂，是国家林业局审定的新型木本油料树种之一。为研究多用途树种无患子在浙江低山地区的开花特征，2012年和2013年连续两年对位于浙江省天台县9年生无患子人工林在群体、个体、花序和单花水平进行开花物候观测和比较，并运用开花日期、相对开花强度和同步性等指数研究了无患子开花物候特征。观察结果显示：无患子花呈浅黄白色，花的类型有雄花和两性花，没有发现雌花。雄花较两性花大（花径分别为5.09 mm和3.72 mm），雄蕊多为8枚，个别7或9、10枚；雌蕊退化仅留下浅绿色凸起。两性花花萼稍抱拢，花药藏于花被片下，雄蕊大多8枚，极少数7枚或9枚，柱头高于花药并伸出花苞，子房一般具3室，极少数4室或仅2室。无患子2012年的开花进程略早于2013年，其花期集中在在5月中旬至6月上旬，单花从花蕾膨大到花朵凋谢一般为8-9 d。在2012年和2013年，无患子在群体、个体和花序水平的花期约为30 d、20 d、11 d和28 d、19 d、13 d。个体水平的开花振幅均呈单峰曲线，年际间相似性较高；开花同步性在个体水平同步性较高（同步指数为0.868），表现出一种大量、集中的开花式样；相对开花强度在单株间分布范围相对宽泛，但主要分布在30%-40%，在年际间和年际内均呈现极显著差异。花期同步指数在两年的变异范围分别是0.81-0.97和0.70-0.98，不同单株开花同步性在年际内差异极显著，但在年际间差异性则不显著。由此可见，无患子的生殖资源分配存在明显的时空差异，较长的花期可以减少非法花粉的干扰、保持其种群基因多样性，遗传因子是决定无患子开花物候的主要因素，生态环境对无患子开花物候的影响还需进一步研究，本研究以期为探索无患子开花的主要限制因子奠定基础。 Abstract:Sapindus mukorossi Gaertn. is a traditional and important virescent tree species in southern China with peel and seed oil rich in saponins. This tree species is one of the newly developed woody-oil species approved by the State Forestry Administration of China. To investigate the flowering phenology and characteristics of this multipurpose tree species, we observed and compared 9-yr-old plantations of S. mukorossi at population, individual, inflorescence, and single-flower levels in Zhejiang Province, Tiantai County, from 2012 to 2013, based on the first flowering date, relative flowering intensity, flowering synchrony, and so on. The results showed that the flower color of S. mukorossi was yellowish white and the flowers were either male or bisexual. The male flower (5.09 mm in diameter) was larger than the bisexual flower (3.72 mm in diameter). There were usually eight stamens in the male flower; however, a few flowers had seven, nine, or ten. The pistil of the male flower was degenerated and only a slight, light-green protuberance was preserved. The calyx of the bisexual flower folded together lightly and the anthers were under the perianthes. There were generally eight stamens in the bisexual flower, but some also had seven or nine. The chapiter was higher than the anther and was outside the bud. Generally, the ovary had three chambers, but had two or four in rare cases. S. mukorossi flowered earlier in 2012 than in 2013, and the flowering period of the test populations was from the middle of May to late June. The development of the single flower was 8-9 d long from the flower bud to wilting stages. In 2012 and 2013, the florescences of the population, individuals, and inflorescences were approximately 30, 20, and 11 d, and 28, 19, and 13 d, respectively. The flowering amplitude of individuals and inflorescences showed a single peak, sharing a high similarity from year to year. The temporal patterns of flowering of S. mukorossi were very similar at the population level, with a well-defined peak and marked synchrony. The index of synchronicity was about 0.868. The relative flowering intensity was distributed over a wide range, but was concentrated between 30% and 40%. The flowering intensity showed an extremely significant (P=0.01) correlation annually and over different years. The range of variation of flowering synchrony was 0.81-0.97 and 0.70-0.98 in 2012 and 2013, respectively. The flowering synchrony correlation was extremely significant (P=0.01) annually, but not in different years. This suggested that there were temporal and spatial differences in the allocation of S. mukorossi reproductive resources, with longer flowering periods and higher flowering synchronization. Long flowering periods can alleviate the interference of illegal pollen and maintain population gene diversity. Heredity is the main factor affecting flowering phenology in S. mukorossi populations. The effects of ecological and environmental factors on flowering phenology need to be researched further. 参考文献 相似文献 引证文献

Floral biology and breeding system of the narrow endemic Dianthus morisianus Vals. (Caryophyllaceae)

Dianthus morisianus Vals. (Caryophyllaceae) is a narrow endemic species of Sardinia, growing with only one natural population on the Portixeddu coastal dune system (southwest Sardinia). In this work we investigated the ex situ phenology and the breeding system through hand-pollination experiments to investigate whether this endemic plant presents inbreeding depression. D. morisianus had a floral lifespan of a week; the maximum flowering moment occurred in June and the cultivated plants presented high flowering synchrony. Among several traits measured, there were only differences in fruit set and first leaf appearance between geitonogamous and xenogamous treatments, and we detected differences in the number of seeds and first leaf appearance in accordance to the origin of the mother plant (mother effect). The plants cultivated ex situ present inbreeding depression only in germination time (T50), and the cumulative inbreeding depression was negligible. D. morisianus is self-compatible and presents facultative xenogamy as its breeding system. Our data suggest that inbreeding depression should not be a major issue in D. morisianus. The results of this study are of value for further conservation actions on natural population of this threatened endemic plant.

Disparity in Onset Timing and Frequency of Flowering and Fruiting Events in Two Bornean Peat‐Swamp Forests

AbstractThe timing and frequency of flowering and fruiting events are key tropical forest characteristics that have substantial influence on fauna. Although our understanding of geographic variation in habitat‐wide timing and frequency of flowering and fruiting is advancing, corresponding information for individual tree species is limited. Thus, we compared climate and reproductive phenology of 16 tree species over 70 mo at two Bornean tropical peat‐swamp forest sites. We found significant inter‐site correlations in rainfall and temperature, and only small absolute temperature differences. In both sites, most species exhibited within‐site synchrony in flowering and fruiting onset. Broad‐scale flowering and fruiting onset frequency classifications showed high congruence between sites. Significant correlations in flowering and fruiting onset timing between sites were found for only 19 and 17 percent of the species, respectively. This remained the case when applying 1‐ and 2‐month lag periods for both sites, with neither site consistently lagging behind. Significant differences in the exact frequency of new flowering and fruiting events were detected for 44 and 58 percent of species, respectively, and no significant relationships between the onset timing synchrony and exact frequency of new reproductive events were found for either flowers or fruit. We conclude that inter‐site climatic and ecological similarities do not necessarily lead to high inter‐site synchrony in either onset timing or exact frequency of tree reproductive events. Potential reasons for this are discussed, as are the implications for understanding tropical forest ecology and improving forest restoration project seed collections.

INDEKS OVERLAP DAN SINKRONISASI PEMBUNGAAN DALAM KEBUN BENIH KAYUPUTIH (Melaleuca cajuputi) DI PALIYAN, GUNUNGKIDUL

Flowering synchrony will support the extent of random mating among families and hence the genetic gain in the resultant progeny. In the study, synchrony among families for flowering and peak flowering was estimated through the phenogram as well as the overlapping index. Research was carried out at cajuput (Melaleuca cajuputi sub species cajuputi) seed orchard in two flowering periods (2010 and 2011) at Paliyan, Gunungkidul. The observation results showed that peak flowering occurred in the middle of January and more than 75% families in cajuput seed orchard have the same flowering time. More than 90% families have overlapping index value greater than 0.8 in contrast to 2 families originated from Western and Northern Australia which revealed very low (<0.6) overlapping index. Seeds harvested from the cajuput seed orchard showed high genetic potencial, as 75% trees in Paliyan seed orchard produced seeds simultaneusly.

Flowering phenology, fruit set and seed mass and number of five coexisting Gymnocalycium (Cactaceae) species from Córdoba mountain, Argentina1

Abstract Flowering phenology may play a critical role in plant coexistence, allowing not only a temporal partitioning of resources but also conditioning the relationship between seed mass and number in these species. We analyzed how flowering phenology was related to seed mass and number, and how these seed traits were related in five coexisting Gymnocalycium (Cactaceae) species in two consecutive flowering seasons. The flowering phenology of each species was characterized in terms of timing (onset and peak), duration, and flowering synchronicity. Although species showed differences in duration and synchronicity, the earliest flowering species tend to have higher reproductive success than species flowering later. However, we did not find a clear relationship between the flowering time and seed traits. A trade-off between seed mass and number in these species was highlighted, as species with higher seed mass were those producing a lower number of seeds per fruit and individual, whereas species with lower s...

Fenologia Reprodutiva de Cinco Espécies Arbóreas em Ecossistema de Terra Firme na Amazônia Brasileira

O trabalho objetivou estudar a fenologia de cinco especies arboreas, Dinizia excelsa Ducke, Manilkara paraensis (Huber) Standl. , Lecythis sect. poiteaui S.A. Mori , Peltogyne paradoxa Ducke e Goupia glabra Hubl., atraves das fenofases de floracao e frutificacao associadas a precipitacao pluviometrica. O estudo foi desenvolvido em uma area de floresta densa de terra firme de aproximadamente 1200 hectares, situada no municipio de Mazagao, Estado do Amapa. O monitoramento teve duracao de 26 meses, compreendido entre outubro de 1997 a novembro de 1999, sendo as matrizes monitoradas a cada 30 dias. As especies Dinizia excelsa , Peltogyne paradoxa e Goupia glabra demonstraram suas fenofases de floracao iniciadas na epoca chuvosa (dezembro a julho) e finalizadas na epoca de estiagem (agosto a novembro) e frutificacao abrangendo a transicao seco/chuvoso. A especie Manilkara paraensis apresentou floracao persistente no periodo de estiagem e frutificacao para os periodos seco e chuvoso, iniciando durante o periodo de menor precipitacao pluviometrica. A especie Lecythis poiteaui manifestou o evento de floracao e frutificacao durante o periodo chuvoso, sendo notado para as cinco especies estudadas tendencias ao padrao anual de floracao e frutificacao. As especies Dinizia excelsa , Manilkara paraensis , Peltogyne paradoxa e Goupia glabra apresentaram indice de sincronismo alto para as fenofases de floracao e frutificacao, ao passo que a especie Lecythis poiteaui apresentou indice de sincronismo de floracao perfeito com Z=1 e sincronia de frutificacao alta com maior predominância. Palavras-chave: manejo florestal, ecologia, precipitacao, fenofases.

Conservation biology of two endemic Beyeria species (Euphorbiaceae) from southern Western Australia

Beyeria cockertonii Halford & R.J.F.Hend. and Beyeria villosa Halford & R.J.F.Hend. (Euphorbiaceae) are two short-range endemic monoecious congeners from southern Western Australia. We sought to determine whether life-history characteristics were responsible for their limited distribution and to identify aspects of their ecology that might render them vulnerable to current threatening processes. We investigated reproductive phenology in relation to climate, pollinator activity and synchronicity of male and female flowering. In addition seed dispersal, regeneration, demography and seed viability were examined and ex situ germination experiments conducted to determine seed-dormancy mechanisms. Flowering in the conservation-listed B. cockertonii was significantly correlated with temperature, whereas fruit set was correlated with pollinator abundance and movement; male and female flowering showed limited synchrony. The presence of soil-stored seeds lacking a caruncle at sites absent of adult plants of either species suggests that seed may be ant-dispersed (myrmecochory). Fresh seeds of B. cockertonii were significantly more viable than those of its more common congener, B. villosa (72 vs 0.5%, P < 0.001). Fresh B. cockertonii seeds would not germinate with an intact caruncle; caruncle removal elicited germination of 64% and 60% (10°C and 15°C, respectively). Aqueous smoke further stimulated germination to 72% and 83% germination (10°C and 15°C, respectively), providing a link between fire and germination. Beyeria villosa was affected by high levels of pre-dispersal predation (up to 70%) and seed abortion (88%) and appeared to have lower reproductive fitness than B. cockertonii. Life-history strategies did not explain the greater abundance and wider distribution of B. villosa than those of the conservation-listed B cockertonii, nor was the greater rarity of B. cockertonii fully explained by habitat specificity, with both species being restricted to ultra-mafic volcanic rock associated with Achaean greenstone. However, an apparent dependence of B. cockertonii on a specific insect pollinator from the family Miridae may render this species vulnerable to threatening processes.

金沙江干热河谷滇榄仁开花物候与繁育系统

PDF HTML阅读 XML下载 导出引用 引用提醒 金沙江干热河谷滇榄仁开花物候与繁育系统 DOI: 10.5846/stxb201401130096 作者: 作者单位: 中国林业科学研究院资源昆虫研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 林业公益性行业科研专项(201304202);中国林业科学研究院基本科研业务费专项资金(CAFYBB2014MA008) Flowering phenology and breeding system of Terminalia franchetii (Combretaceae) in the dry-hot valley of the Jinsha River, China Author: Affiliation: Research Institute of Resources Insects, CAF Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:通过野外定点观测,并利用套袋实验、解剖实验以及花粉形态特征观察与活力检测、柱头可受性检测、花粉/胚珠比以及异交指数等,研究了金沙江干热河谷滇榄仁自然群体花部形态特征与开花进程、繁育系统特征以及传粉媒介与环境的适应性等内容。结果表明,滇榄仁始花期在每年4月上旬,群体花期持续时间为30d左右,开花同步性高,呈典型的"集中开花模式"。单花开放时,柱头先伸长和膨大,约4d后雄蕊伸出,具有雌雄异熟的特征,一定程度上避免了自交的发生。单花开放进程可划分为花蕾期、柱头伸长期、雄蕊始露期、盛开期、盛开后期、花谢期等6个时期。除了花蕾期外,整个开花期的花粉均具有活力。花粉活力与柱头可受性之间避开了最适授粉期,但也有部分重叠。滇榄仁可能同时具有风媒和虫媒传粉。繁育系统以异交为主,部分自交亲和,需要传粉者。滇榄仁花部特征、开花物候和繁育系统为其适应干热河谷恶劣气候环境提供了一定的生殖保障和进化潜力。良好的群落环境有助于促进滇榄仁异花传粉,产生更多有效的种子,从而促进林下自然更新。 Abstract:Flowering phenology and breeding system characteristics are the most important fitness factors of plants, and have an important influence on plant reproductive success. For example, plants that blossom too early or too late are unable to fruit effectively because of changes to environmental factors or due to the absence of effective pollinators. Terminalia franchetii is a characteristic plant in the dry-hot valley of the Jinsha River, southwest China. The community formed by T. franchetii represents a limited and important type of natural vegetation that grows in this region. However, today, habitat destruction and human disturbance factors are having adverse effects on T. franchetii. Although the plant produces large amounts of fruit, the seed abortion rate is extremely high, resulting in few seedlings and saplings being produced, and, consequently, poor forest regeneration. A number of studies have been conducted on the population diversity of this species, along with studies on the regeneration characteristic of seedlings, seed dispersal and seed bank characteristics, phylogeography, species differentiation, and other aspects. However, studies on the reproductive biology of this plant have not been reported. We conducted a fixed-point field investigation of the floral syndrome, flowering process, breeding system, and adaptability of pollinators to the environment of a natural population of T. franchetii in the dry-hot valley of the Jinsha River, China. The results showed that, each year, T.franchetii begins to bloom in early April, and that the flowering duration of the population is approximately 30 days. The plant has the characteristics of high flowering synchrony, and is a typical "mass flowering" species. When single flowers bloom, the stigma initially elongates and expands. Then, approximately 4 days later, the stamens protrude. Because of this dichogamy, the plant, to a certain extent, avoids self-pollination. Flowering is divided into 6 stages; namely, the bud stage, stigma elongation stage, early stamen showing stage, blooming stage, late blooming stage, and flower withering stage. In addition to the bud stage, the pollen is viable throughout the entire flowering period; although, the strongest vitality of the pollen occurs during the early stamen showing and blooming stages. Optimum pollination is avoided due to the asynchrony between pollen vitality and stigma receptivity; however, there is a certain degree of overlap between the two stages. T. franchetii might be adapted to both wind and insect pollination. In the breeding system of this species, out-crossing is predominant and, although partially self-compatible, it requires pollinators. The main pollinators are flies, such as Episyrphus sp., Chrysomyia megacephaia, Apis cerana, Sycanus croceus, and Delta conoideum. The floral characteristics, flowering phenology, and breeding system of T. franchetii provide some reproductive assurance and evolutionary potential for its ability to adapt to the complex and extremely harsh environment of dry-hot valleys; however, a favorable community environment contributes to the promotion of cross pollination of T. franchetii and more effective seed production; thus, promoting natural forest regeneration. 参考文献 相似文献 引证文献

Reproductive biology of the narrow endemic Anchusa littoreaMoris (Boraginaceae), an endangered coastal Mediterranean plant

Phenological and reproductive patterns are fundamental life-history components in the life cycle of plants. In this study, we analyzed phenological and reproductive data at the plant and population levels of the narrow endemic Anchusa littorea Moris, an endangered annual plant species growing in a few small patches at the Is Arenas dune system (SW Sardinia, Italy). Individuals from the main 2 patches were evaluated during a 4-year study period: plants were monitored on a monthly basis in each reproductive phenophase. To assess phenological variability within and among populations, an approach based on the Shannon-Wiener diversity index and the Morisita-Horn similarity index was applied. The seed output and the soil seed bank were also investigated in order to analyze the reproductive capacity of this plant species. Anchusa littorea showed a long flowering season and a high flowering synchrony between patches, which contrasted with a low within-patch synchrony. The seed production per plant was low and the species did not create a soil seed bank. Population size was characterized by considerable annual fluctuations: a significant migration occurred for A. littorea plants inside the dune system over the years. These results demonstrate the importance of the phenological pattern on the knowledge of the reproductive ecology of endangered coastal plant species and will contribute to orient management and conservation efforts.

Reproductive biology of Ziziphus mistol Griseb. (Rhamnaceae), a wild fruit tree of saline environments

Ziziphus comprises important fruit trees that inhabit arid environments of tropical and subtropical regions of the world and are able to adapt to drought and salt stress. Species of this genus are characterized by synchronous protandrous dichogamy and self-incompatibility; however, reduced seed set after hand self-pollination indicates that self-fertilization is possible and that it causes a strong inbreeding depression. We characterize the reproductive biology of Ziziphus mistol, a species typical of saline environments of Chaco American forests. For this purpose, we studied floral biology, observed foraging behavior and pollen load of captured floral visitors, and tested the breeding system through the assessment of fruit and seed set and pollen tube growth following self-, cross-, and open pollinations treatments. In addition, the dependence of a pollinator and autonomous self-pollination were evaluated by excluding floral visitors and airborne pollen. Cross-compatibility between individuals was tested through controlled hand pollinations. Results indicate that Z. mistol is predominantly outcrossing and depends on its pollinators to produce fruits and seeds. We observed high synchrony of flowering between individuals, as well as in floral anthesis between/within inflorescences within individuals. The flowers exhibit complete intrafloral dichogamy that fully prevents autonomous self-pollination, while sexual phases overlap within inflorescence; thus geitonogamy can easily occur. Manipulative experiments show that Z. mistol can set fruits and seeds after self- as well as cross-pollinations. However, reduction in fruit set and seed set after selfing and/or cessation of pollen tube growth in the style suggest a self-incompatible system. From reciprocal crosses tested (N=95), we have identified only 32.6% compatible crosses via fruit and seed trials. We suggest that in Z. mistol, as well as in other species of the genus, both synchrony in floral development and partial self-incompatibility would be evolved to reduce the costs of inbreeding.

ANTECOLOGY OF THE ENTOMOPHILOUS ALPINE PLANTS OF THE NORTH-WESTERN CAUCASUS. II. DURATION AND RHYTHM OF FLOWERING

We studied anthecological features of 84 species of alpine entomophilous plants northwestCaucasus. Duration of flowering alpine plants varies widely. Flower opened in average 6-7 days minimum has Veronica gentianoides (1 day), and the maximum Dactylorchiza euxina (17 days). Flower opened in average 6-7 days; Veronica gentianoides has a minimum value (1 day), and Dactylorchiza euxina has a maximum value (17 days). Average duration of a flower blooming on the shoot - 12 days minimum value in Taraxacum stevenii (3 days), the highest in Carum meifolium (26 days). Flowering curves of communities have unimodal shape. Species begin to blossom in the community at different times. Synchronicity of flowering is independent of the type of community.