Massive Flowering Research Articles

Phenology and floral visitors of Psychotria nuda (Rubiaceae) in an urban fragment of the Atlantic Forest in south Brazil

Psychotria nuda is a tree native to Brazil, occurring in the Dense Ombrophylous Forest, which has massive flowering and fruiting, attracting many pollinators and dispersers. This study aimed to know the phenophases of P. nuda and its pollinators, relating them to environmental factors on a temporal scale, with emphasis on flowering, as well as the diversity of pollinators and their phenology. The study area comprises a remnant of forest located in Santa Catarina, southern Brazil. Phenological and pollination observations were performed fortnightly, from July/2016 to July/2017. The results indicated that the peak of senescent leaves, budding, flowering and mature fruits coincided with the hottest and rainy months of the year. Immature fruits persisted almost year-round. There was a low synchrony of phenological activity in the population. Thirteen species of pollinators were recorded, with eight new interactions for P. nuda . The entomophilic syndrome was preponderant, but the pollinator species do not have the same temporal pattern of visitation. It is concluded that P. nuda has shared pollination, predominantly entomophilic, variation of intrapopulational phenological activity and constitutes an important resource for the ornitofauna and entomofauna in the Atlantic Forest since its pollinators use their resources in a non-uniform way. Keywords: phenological activity, entomophilia, dense ombrophillous forest, animal-plant interaction.

Distribution, abundance, and effect on plant species diversity of Sasa borealis in Korean forests

BackgroundSasa borealis (Hack.) Makino, a clonal dwarf bamboo, is widespread in Korean forests. Although S. borealis is native to that country, its growth habit can cause considerable harm when occupying particular areas where it dominates and influences those forested communities. However, few reports have described the extent of its inhibitory effects on the vigor of co-existing plant species. Therefore, we investigated the distribution, abundance, and diversity of other plant species in the communities where this plant occurs in the east-central forests on the Korean Peninsula.ResultsS. borealis was most commonly found at an elevational range of 800 to 1,200 m, on gentle, usually lower, and near valley northern slopes. Out of the 13 forest communities based on 447 forest stands that we surveyed, S. borealis was detected in eight communities, mostly where Quercus mongolica dominates. In particular, it was more common in late-successional mixed stands of Q. mongolica, other deciduous species, and the coniferous Abies holophylla. Because of their ability to expand rapidly in the forest, this plant covered more than 50% of the surface in most of our research plots. Species diversity declined significantly (F = 78.7, p = 0.000) as the abundance of S. borealis increased in the herb stratum. The same trend was noted for the total number of species (F = 18.1, p = 0.000) and species evenness (F = 91.5, p = 0.000).ConclusionsThese findings clearly demonstrate that S. borealis is a weed pest and severely hinders species diversity. Authorities should be implementing various measures for ecological control to take advantage of declining chance after the recent synchronized massive flowering of S. borealis.

НЕКОТОРЫЕ ОСОБЕННОСТИ ЭКОЛОГИИ BULBOCODIUM VERSICOLOR (KER-GAWL.) SPRENG. (COLCHICACEAE, MAGNOLIOPHYTA) В НИЖНЕМ ПОВОЛЖЬЕ

The paper presents the results of our four-year observation of Bulbocodium versicolor (Ker-Gawl.) Spreng populations in the Saratov and Volgograd regions. A low ecological plasticity of the species was established. Although the species grows in steppe phytocenoses that vary in composition and structure, the specimens’ morphology was rather conservative, which can be explained by the homogeneity of the species’ vegetation conditions over the territory under study during active vegetation and flowering. It is shown that in the Lower Volga region, B. versicolor is characterized by the reduced stress component of its life strategy and a low index of size plasticity. The species uses a ‘patient’ strategy. Morphologically, plants respond to stress by a diminishment of the reproductive organs and the reproductive-to-vegetative transition. The ecotopic and phytocenotic tolerance of B. versicolor manifests itself in the species’ capacity to retain the occupied territory for a long time and to avoid competition via habitat selection. According to the conservation priority index, the majority of B. versicolor populations in the Lower Volga region are at high risk of becoming endangered and their preservation requires immediate action. The decline in the species’ size in the region is most likely induced by the climate aridization and direct human impact, specifically the transformation of wild lands to croplands. There is no decisive proof that overgrazing and gathering for bouquets have had any significant negative impact on the species. It may be attributed to the secluded location of the remaining species’ habitats that makes the species practically inaccessible in the period of massive flowering.

Studies of Pollen Characteristics in Plants of Fruitless Tecomella undulata (Sm.) Seem. (Bignoniaceae) in Golparaki Region of Jiroft City, Iran

Tecomella undulata is valued for beautiful flowers, resistance against extreme temperature and drought, stabilizing shifting sand dunes, medicinal properties and wood production. In spite of massive flowering, the species is seedless. The present study examines the causes of its sterility indicating on pollen characteristics. Flowers were hand pollinated by pollen of either self- or outcross pollen. Some flowers were tagged as open pollination treatment. Pollen structure, in situ and in vitro pollen germination and pollen tube growth were analyzed. Mature pollen grains are heteromorphic, mostly heterogeneous sized as small and large. Both pollen grains types are prolate and tricolpate with rugulate–reticulate sculpture. Flowers are protandrous and have long stylus; a nectariferous tissue secreting abundant nectar exists in the ovary base. No effective pollinator visited flowers during the observation period. No pollen germination and pollen tube growth were observed in self- and cross-pollinated styles and under in vitro condition. It seems that pollen heterogeneity, lack of pollinators and pollen limitation, the failure of autogamy due to protandry or long styli as well as self-incompatibility resulted in pollen sterility and seedlessness. In addition, probably polyploidy and cytomixis affect infertility too that needs to be studied in detail in the future.

Phenological changes in triterpenic and phenolic composition of Thymus L. species

Abundant phenolic and triterpenic compounds constitute a characteristic chemical profile of the Thymus species. Phenolic acids and flavone glycosides (rosmarinic acid, caffeic acid, luteolin-7-rutinoside, luteolin-7-glucoside and apigenin-7-glucoside) were identified and quantified in the samples of the Thymus austriacus Bernh. ex Rchb., Thymus praecox Opiz ssp. arcticus (Durand) Jalas, Thymus serpyllum L., Thymus pulegioides L., Thymus sibthorpii Benth, Thymus x citriodorus Schweig. et Korte and Thymus x oblongifolius Opiz, Thymus longicaulis C. Presl. The content of these compounds varied significantly at different phenological phases. The amounts of phenolic compounds were the greatest at the budding and massive flowering phases, declined during fruiting and were the lowest at the end of vegetation. Rosmarinic acid was determined as a predominant phenolic compound. Four triterpenic acids, oleanolic, ursolic, corosolic and betulinic were identified in the samples. Ursolic acid was found to be predominant triterpene followed by oleanolic, betulinic and corosolic acids, on the average 9594±654μg/g, 4334±351μg/g, 319±38μg/g, 84±22μg/g, respectively. Accumulation pattern of ursolic acid varied significantly depending on the Thymus species investigated. The phenolic-dominant and the triterpenic-dominant types of the Thymus species could be distinguished.

Genetic analysis of thrips resistance in cowpea (Vigna unguiculata [L.] Walp.)

Flower bud thrips, Megalurothrips sjostedti is the most severe field pest of cowpea that causes massive flower abortion which eventually results to substantial yield reduction in Africa. There is paucity of information on the mode of gene actions controlling inheritance of resistance to flower bud thrips in cowpea in the literature. The objectives of study were to assess the genetic variability for thrips resistance among the cowpea germplasm, determined the mode of inheritance of genes that conferred resistance and both broad and narrow-sense heritability estimates for the inheritance of thrips resistance in cowpea. Twelve cowpea lines were used in crosses in the screen house at IITA, Ibadan. The mating was accomplished using North Carolina design II to generate 48F1 hybrids, which were eventually evaluated with the parents. Data on number of peduncles, number of pods and number of thrips per flower were recorded and subjected to analysis of variance using random model by SAS 9.2. Significant variability was observed for most agronomic and thrip-adaptive traits among the cowpea germplasm, parental-lines and F1 genotypes evaluated. General combining ability (GCA) and specific combining ability (SCA) mean squares were significant (P < 0.01) for number of pods per plant and other traits under the research environment. The GCA effect accounted for 68.82–80.07% of the total variation among hybrids for all traits except days to flowering; SCA explained less than 50% of the total variation. Narrow-sense heritability estimates ranged from 7.53 (days to flower) to 63.92% (number of peduncles per plant). Additive gene action largely controlled the inheritance of yield components and other traits under thrips infestation and these traits were moderately heritable.

Rare nationwide synchronized massive flowering and decline event of Sasa borealis (Hack.) Makino in South Korea

Sasa borealis, a monocarpic species of dwarf bamboo, is widely distributed throughout Korea. It dominates forest floors, thereby inhibiting mainly the biodiversity. Although it flowers very rarely, examples have recently been observed in multiple locations, providing a good opportunity to study reproduction phenomena, and to aid in biodiversity restoration. Therefore, we investigated the nationwide timing of flowering events by using data collected from a social network service (SNS). We also more closely examined flowering and decline event, focusing at the patch and culm levels on Mt. Jeombong. We then analyzed the main factors affecting flowering. Our SNS and survey results showed that S. borealis is in a current flowering cycle that started in 2013 and continues to the present (83% of all events happening within this period) with a peak in 2015 (48% of the cases occurring in that year). This clearly demonstrated nationwide, synchronized, and massive flowering. Although the culm density in patches was not related to flowering, patches with large culms tended to flower (F = 8.241, p = 0.01). We suspected that this nationwide flowering event was triggered by prolonged drought during the spring months of 2014 and 2015 (F = 5.207, p < 0.05), which led to concurrent, massive flowering in patches mature enough to do so. Because this species prefers a wet habitat, we concluded that severe, prolonged drought induced environmental stress for those plants. After flowering, culms in those particular patches tended to die off within one year. This large-scale synchronized decline should have an enormous effect on the vegetation dynamics of a forest dominated and suppressed by Sasa. Future investigations might incorporate methods of ecological control and manipulation to increase biodiversity there.

Experimental evidence that honeybees depress wild insect densities in a flowering crop.

While addition of managed honeybees (Apis mellifera) improves pollination of many entomophilous crops, it is unknown if it simultaneously suppresses the densities of wild insects through competition. To investigate this, we added 624 honeybee hives to 23 fields of oilseed rape (Brassica napus L.) over 2 years and made sure that the areas around 21 other fields were free from honeybee hives. We demonstrate that honeybee addition depresses the densities of wild insects (bumblebees, solitary bees, hoverflies, marchflies, other flies, and other flying and flower-visiting insects) even in a massive flower resource such as oilseed rape. The effect was independent of the complexity of the surrounding landscape, but increased with the size of the crop field, which suggests that the effect was caused by spatial displacement of wild insects. Our results have potential implications both for the pollination of crops (if displacement of wild pollinators offsets benefits achieved by adding honeybees) and for conservation of wild insects (if displacement results in negative fitness consequences).

Two invasive acacia species secure generalist pollinators in invaded communities

Exotic entomophilous plants need to establish effective pollinator interactions in order to succeed after being introduced into a new community, particularly if they are obligatory outbreeders. By establishing these novel interactions in the new non-native range, invasive plants are hypothesised to drive changes in the composition and functioning of the native pollinator community, with potential impacts on the pollination biology of native co-flowering plants. We used two different sites in Portugal, each invaded by a different acacia species, to assess whether two native Australian trees, Acacia dealbata and Acacia longifolia, were able to recruit pollinators in Portugal, and whether the pollinator community visiting acacia trees differed from the pollinator communities interacting with native co-flowering plants. Our results indicate that in the invaded range of Portugal both acacia species were able to establish novel mutualistic interactions, predominantly with generalist pollinators. For each of the two studied sites, only two other co-occurring native plant species presented partially overlapping phenologies. We observed significant differences in pollinator richness and visitation rates among native and non-native plant species, although the study of β diversity indicated that only the native plant Lithodora fruticosa presented a differentiated set of pollinator species. Acacias experienced a large number of visits by numerous pollinator species, but massive acacia flowering resulted in flower visitation rates frequently lower than those of the native co-flowering species. We conclude that the establishment of mutualisms in Portugal likely contributes to the effective and profuse production of acacia seeds in Portugal. Despite the massive flowering of A. dealbata and A. longifolia, native plant species attained similar or higher visitation rates than acacias.

Offspring performance and recruitment of the pioneer tree Acacia caven (Fabaceae) in a fragmented subtropical dry forest

AbstractThe process of habitat fragmentation results in the breaking apart of originally continuous habitats, causing multiple changes in biotic and abiotic interactions. Alterations in resource availability and in mutualistic and antagonistic plant–animal interactions may impact plant offspring quantity and quality. Currently, several old fragmented systems evidence a process of flora homogenization, where shade‐tolerant species are replaced by pioneer light‐demanding species. Notably, the relationship between quantity and quality parameters of plant offspring production and the successful recruitment of pioneer species in fragmented forests has been poorly explored. Here, we assess population size, sapling recruitment and offspring performance of one of the most widespread tree species of subtropical South America, the native pioneer Acacia caven (Fabaceae). Population size of adults and saplings increased from small to continuous forests, whereas the sapling recruitment per adult tree (sapling/adult ratio) showed no significant differences among forests of different size. Seedling performance was negatively related to forest area and population size, implying potential superior competitive ability of seedlings produced in smaller populations compared to larger ones. Our results show that A. caven is resilient to habitat fragmentation effects, which may be ascribed to a set of advantageous ecological traits such as outcrossing, massive flowering, generalist pollination, drought resistance, rapid growth and re‐sprouting. Thus, this pioneer tree benefits from the availability of vacant sites and resources released by declining plant populations of other species, eventually becoming the dominant species in fragmented habitats. Pioneer native plant species with ecological traits such as A. caven may represent the silent successful survivors and new colonizers of fragmented habitats, the ubiquitous landscapes of the future.

Two alien invasive acacias in Italy: Differences and similarities in their flowering and insect visitors

In Italy, alien acacias have been introduced for ornamental and reforestation purposes, and some species became invasive occupying patches of the Mediterranean landscape. On the Island of Elba (Central Italy), Acacia dealbata and A. pycnantha form dense stands at short distance, showing an impressive massive flowering at the end of the winter/early spring. Our aim was to investigate the behaviour of the two species in relation to the flowering features, from phenology to floral characteristics, and their replay to the observed flower visitors. Differences between the two species emerged on all the parameters considered. A. pycnantha peak of flowering occurred later than A. dealbata and showed larger flower heads (FHs), more flowers/head, stamens/flower and polyads. On A. dealbata, we recorded longer racemes and more FHs/raceme, determining a more flower-dense crown. Even if contacts with flower visitors were generally low on both species, A. dealbata showed a more heterogeneous visitor assemblage. Both acacias species interacted with local generalist pollinators, as bumblebees and honey bees. Flower handling and resource collection strategy by the honey bee indicate a long-term relationship between the bee and the acacias, with bees investing longer time on the larger A. pycnantha flower heads.

Reproductive biology and success of invasive Australian acacias in Portugal

Reproductive traits are crucial for the establishment and maintenance of populations in new areas, and therefore for the invasion process. This work aimed to study the reproductive biology of four aggressive invasive Australian Acacia spp. in Portugal. Fruit and seed set, seed weight and germinability, and seedling growth were assessed for self- and outcross treatments in invasive populations of A. dealbata, A. longifolia, A. melanoxylon and A. saligna. Acacia spp. showed different investments in the production of reproductive units and in natural reproductive success, with A. dealbata, the most aggressive species, having the highest investment and reproductive success. Acacia melanoxylon showed a different reproductive strategy, andromonoecy, contrasting with the other hermaphroditic species. Acacia spp. were shown to be predominantly self-incompatible, but a low level of spontaneous selfing enabled the production of viable offspring. Acacia dealbata and A. longifolia suffered pollen limitation. Self-progeny had lower viability than progeny from outcrossing for A. dealbata and A. melanoxylon. Acacia spp. did not show higher compatibility rates in comparison with the native area. They had low fruit set but, as a result of their massive flower production, their realized reproductive success was high and could have contributed to the invasion. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 174, 574–588.

Tree size and its relationship with flowering phenology and reproductive output inWildNutmeg trees

Reproductive strategies, sexual selection, and their relationship with the phenotype of individuals are topics widely studied in animals, but this information is less abundant for plants. Variability in flowering phenology among individuals has direct impact on their fitness, but how reproductive phenology is affected by the size of the individuals needs further study. We quantified the flowering intensity, length, and reproductive synchronization of two sympatric dioecious Wild Nutmeg tree species (Virola, Myristicaceae) in the Brazilian Atlantic forest, and analyzed its relationships with tree size. Two distinct strategies in flowering timing and intensity were found between species (annual versus biennial flowering), and among individuals in the annual flowering species (extended versus peak flowering). Only for the annual flowering species the reproductive output is related to tree size and large trees present proportionally higher flower coverage, and lower synchronization than smaller ones. Flowering is massive and highly synchronized in the biennial species. Sex ratios are not different from 1:1 in the two species, and in the two segregated reproductive subgroups in the biennial flowering species. The biennial flowering at individual level is a novelty among reproductive patterns in plants, separating the population in two reproductive subgroups. A proportional increase in the reproductive output with size exists only for the annual flowering species. A biennial flowering can allow resource storage favouring massive flowering for all the individuals diluting their relationship with size.

Flowering of the seagrass Posidonia oceanica in NW Mediterranean: is there a link with solar activity?

Time series on the leaf biometry and rhizome production of the endemic Mediterranean seagrass Posidonia oceanica (L.) Delile were investigated in a meadow of the Ligurian Sea (NW Mediterranean) in order to assess changes in the plant growth during a massive flowering event occurred in 2003, in coincidence with the warmest summer temperatures recorded in the last centuries. P. oceanica exhibited the highest values of leaf surface area during the flowering year and the highest values of rhizome production in the previous year. The years immediately following the flowering event were characterized by a decrease in both parameters. Comparison of the years of massive flowering events reported in the literature at the whole Mediterranean-wide spatial scale with the historical series (spanning the last 50 years) of the air temperature and of the sunspot number suggested that intense solar activity, and not warmer temperature per se, was likely to be the main trigger of massive flowering events in Posidonia oceanica.

HELICONIA CHARACTERISTICS FOR LANDSCAPE USE

The plants belonging to Heliconia genus, Heliconiaceae family, have exotic inflorescences in vibrant colors of yellow, orange, red, and pink assigned for tropical garden. There are about 182 species in the genus Heliconia, nevertheless, due to the lack of knowledge of the individual characteristics of each species, only a few are used by landscape designers for ornamental purposes. This work was carried out to characterize Heliconia genotypes for landscape use. The experiment was conducted at Heliconia Germplasm Collection of Federal Rural University of Pernambuco (UFRPE) - Brazil, in full sun conditions for 12 months. Qualitative and quantitative characteristics related to clump and inflorescence aspects were analyzed in: H. psittacorum × H. spathocircinata ‘Golden Torch Adrian’ and ‘Golden Torch’; H. psittacorum ‘Suriname Sassy’ and ‘Red Opal’; H. collinsiana; H. rostrata; H. foreroi and H. bihai. Except for ‘Red Opal’, H. psittacorum cultivars and their interspecific hybrids were considered to be short plants (less than 1.51 m height) and adequately as a massive flower bed they would not interfere in the open views of the gardens. The species H. bihai, H. collinsiana, H. rostrata and H. foreroi formed inflorescences which last longer than 78 days in good conditions in the clump, which is a remarkable aspect in the landscape. H. bihai inflorescences were difficult to visualize, its bracts accumulated water, attracted insects and had repulsive odor. The evaluated genotypes have traits that cause acceptation and adequacy to landscape design, allowing landscape designers to diversify plant indications.

In vitro flowering and seed formation in lentil (Lens culinaris Medik.)

IntroductionGrain legumes, commonly known as pulses, are one of themost important agricultural crops worldwide. Pulses areamongst the ancient food crops that have been traditionallycultivated, particularly in Asia, Latin America, and Africa.In many developing nations, grain legumes are gainingincreased importance in view of the acute shortage in pro-duction of animal proteins and widespread protein malnu-trition (Bressani 1973). Apart from this, grain legumes arealso considered as the main source of protein for livestockfeed and inland fish production. Moreover, grain legumeshave the unique ability to fix nitrogen symbiotically therebyimprove overall soil fertility.Among the pulses, lentil is the most popular and ranksfirst in terms of human consumption in Indian subcontinent.The protein and nutritional qualities of lentil varieties havebeen reported to be superior to other pulse crops (Singh etal. 1968; Bhatty 1988). Thus lentil plays an integral role inagricultural systems of South Asian countries, with increas-ing annual demands due to its nutritional quality and popu-larity. Even so, this crop is typically characterized by lowyield potential.Several factors arebelieved toberesponsiblefor the reduced yields, including susceptibility to pests anddiseases, massive flower drop, and post-harvest losses(Erskine 1984). Diseases of lentil, at various stages ofgrowth, are caused by fungi, bacteria, viruses, and nematodeinfestations (Gowda and Kaul 1982).A number of attempts have been made to improve lentilvarieties using conventional breeding techniques, but theseefforts have failed to achieve desired results due to a narrowgenetic base and lack of available and suitable germplasmfor lentil improvement. Under these circumstances, there isconsiderable scope to embrace biotechnological approachesfor lentil improvement. Indeed, a number of studies havebeen previously conducted to develop suitable in vitro re-generation systems, and to explore the possibility of apply-ing biotechnology to lentil improvement programmes(Saxena and King 1987; Polanco et al. 1988; Warkentinand Mchughen 1993; Sarker et al. 2003).However, improvement of lentil through biotechnologi-cal methods has proven to be difficult due to its recalcitrantnature, particularly pertaining to the development of aneffective in vitro root induction system. Previous studieshave indicated that rooting in microsperma type of lentil isespecially difficult and appears to be a major constraint inobtaining fully regenerated plants through in vitro techni-ques (Khanam et al. 1995;Sarkeret al. 2003). Micro-grafting has been attempted to obtain in vitro-derived plant-lets (Gulati et al. 2001), but this approach was fraught withdifficulties especially in case of microsperma lentil varieties.Under these circumstances, in vitro flowering and fullydeveloped seed formation have been considered as a viablealternative to obtain plant progenies. It is believed that invitro flowering and pod production may significantly con-tribute towards the genetic improvement of lentil through abiotechnological approach.The main objective of the present investigation was todevelop an alternative regeneration system for Lens culina-ris Medik. from regenerated shoots of lentil, avoiding the invitro root formation stage. The necessary first step was todetermine suitable media for in vitro flowering and seedformation. Several reportsare available onin vitroflowering

Post-fire flowering and fruiting in Vellozia sincorana, a caulescent rosette plant endemic to Northeast Brazil

Vellozia sincorana L.B. Sm. &amp; Ayensu, an endemic of campos rupestres, is an endangered species collected by local people to start cooking fires due to the flammability of its resinous stems. A massive flowering of V. sincorana following a wildfire in October 1999 raised some questions: Does fire affect flowering and fruiting of V. sincorana? Is the height of individuals correlated with flowering and fruit production? A wildfire event on 8 November 2008 provided an opportunity to explore these questions. Two populations of V. sincorana in two campos rupestres sites (12º31'S - 41º29'W; 12º36'S - 41º28'W) on ridgetops in the Chapada Diamantina National Park (Brazil) were monitored, one burned in the November 2008 fire and the other unburned since the 1999 fire. In both sites, 25 individuals were randomly labeled and monitored. Nine plant samplings were conducted between 2008 and 2010, during which the number of flowers and fruits were tallied and the heights measured. Spearman's rank correlation coefficient and linear regression were used to evaluate the relationship between the height of individuals and phenology. Flowering and fruiting occurred only in the recently burnt population, about 40 days after the fire, in 24 of the 25 individuals monitored (96%). The quantity of flower and/or fruit was positively and significantly correlated with plant height. The abundant flowering after fire suggests that fire triggers this phenological phase. Estimates of age of the taller individuals and the periods of flowering can be used to estimate fire frequency in the V. sincorana population sites, which contributes to the knowledge of fire ecology and is useful for conservation biology and fire management of campos rupestres.

钝叶柃不同性别花的花部形态与传粉特征比较

Flowering and pollination are important processes for reproduction of flowering plants,especially for the dioecious ones.Until now,flowering and pollination of Eurya plants have not been reported.Plants of this genus are described as dioecy in most of the literatures.Hermaphrodite flowers had only been reported in Eurya japonica Thunb..In our recent study,gender variation was found in Eurya obtusifolia H.T.Chang,as well as hermaphrodite flowers.After primary investigation of its floral structure and function gender,floral morphology and pollination characteristics were studied in detail through field and lab.observation. We set four plots in Beibei District,Chongqing(one plot at Xishanpin,three others at Jinyun Mountain).Indicators related to floral morphology and pollination,such as size of flower structures,flower orientation,pollen viability,stigma receptivity,pollen resistance to water,pollen amount and nectar volume of a single flower,as well as flowering dynamics,the pollinator species,and the pollination behavior were observed or determined.The bagging experiments were also carried out at the same time.The findings were as below. E.obtusifolia is a species with short florescence,small but massive blossoms and highly-synchronous flowering,the color and the smell of both sexes of which are the same.The pollination of this species is mainly entomophilous,which depend on two Apidae insects.Insect pollination is relatively dominating compared to wind pollination(anemophilous),which plays a tiny role. The male and the female of E.obtusifolia have some similar characteristics,but also have many obvious differences in respect of the floral morphology and the pollination character.The main differences are as follows: 1) The male flower is lantern-like with non-reflexed petals,while the female flower is radial with reflexed petals.2) The male possesses significantly bigger flowers compared to the male.3) The flower apex of the males tends to vertically downwards,while which of the female tends to obliquely downward to the terminal of the branch.4) The female flower lives longer than the male one.Accordingly,the pollinators behave differently on two sexes.The gender variant individuals present some transitional traits between the male and the female.For E.obtusifolia,many features on the flowering and the pollination reflect its adaptibility to the dioecy sexual system to some extent. Morphological differences between the male and the female of E.obtusifolia have been resulted from various biotic and abiotic factors in surrounding,of which,pollinator and rain selection might play important roles.

Aspectos da ecologia reprodutiva de Pera glabrata (Schott) Poepp. ex Baill. (Euphorbiaceae) em uma área de Cerrado no estado de São Paulo

Pera glabrata é uma árvore que apresenta ampla distribuição no Brasil. A espécie vegetal é de importância para a conservação e recuperação de áreas degradadas, pois está presente em áreas impactadas, produz e dispersa grande quantidade de sementes e constitui-se em fonte alimentar para elevado número de espécies animais. Apesar da importância fitossociológica da espécie, ainda não existem estudos que abordem a sua ecologia reprodutiva. Este trabalho teve como objetivo caracterizar aspectos da fenologia reprodutiva, da morfologia floral, dos sistemas reprodutivo e de polinização e da dispersão de sementes da espécie. O estudo foi realizado em uma área de Cerrado no município de São Carlos, SP. Verificou-se que Pera glabrata é dioica e apresenta floração massiva e as flores dos dois sexos são pequenas, involucradas, amarelas e de antese diurna. As flores masculinas apresentam néctar e emitem odor adocicado, e as femininas não oferecem recursos perceptíveis aos visitantes florais. As flores foram visitadas por 32 espécies de Diptera e Hymenoptera de pequeno porte. Ocorre a formação de frutos e sementes por autogamia. Foram identificadas 25 espécies de aves visitando indivíduos com frutos maduros, das quais 16 ingeriram as sementes ariladas. Pera glabrata é autogâmica, com síndrome de polinização por diversos pequenos insetos e com dispersão ornitocórica de suas sementes.

Reproductive ecology of Shorea roxburghii G. Don (Dipterocarpaceae), an Endangered semievergreen species tree of peninsular India

Shorea roxburghii is an Endangered semievergreen tree species restricted to peninsular India in the Eastern Ghats. Leaf shedding and leaf flushing are annual events while flowering is not annual, but when it does flower, in March, it shows massive blooming. Massive blooming, drooping inflorescence with pendulous flowers, ample pollen production, gradual pollen release as a function of anther appendage and aerodynamic pollen grains - all suggest anemophily. The characteristics of nectar secretion, hexose-rich sugars and amino acids in nectar are additional adaptations for entomophily. The plant is functionally self-incompatible, obligately outcrossing and ambophilous. The natural fruit set does not exceed 15% despite the plant being ambophilous. Scarabaeid beetle by causing flower damage and bruchid beetle by using buds, flowers and fruits for breeding greatly affect fruit set rate and thus the success of sexual reproduction in this plant species is also affected. Seeds are non-dormant, the embryo is chlorophyllous while the fruits are on the plant. Healthy seeds germinate as soon as they reach the forest floor but their establishment is seemingly affected by resource constraints due to the rocky habitat. The study suggests that non-annual flowering, massive flowering for a short period, high bud/flower and fruit infestation rate, absence of seed dormancy and rocky habitat could attribute to the endangered status of S. roxburghii.