Flower Lifetime Research Articles

Floral traits variation in Oenothera drummondii subsp. drummondii across a wide latitudinal range of native and non-native populations

Plant species with specialized pollination and wide geographic distribution can show variation in the size of floral traits related to environmental local conditions. We studied the floral traits of native and non-native populations of Oenothera drummondii under greenhouse conditions to test if their variation is related to latitude, or their native or non-native origin but displaying similar floral integration. Plants were obtained from seeds collected in six native and six non-native populations distributed across five continents. Eight floral traits were recorded in the flowers produced and examined across latitudinal variation between native and non-native ranges. The floral traits differed between the native and non-native populations, with corolla size the main contributor. Although each floral feature varied independently in response to the latitude and environmental conditions of the populations, there is a clear tendency for size reduction of the structures with latitudinal increase. In contrast, floral integration and flower lifetime remained similar across latitude. The floral traits variation of O. drummondii throughout its native and non-native distribution is the result of the latitudinal gradient and the local population environment. The similarity in floral integration and flower lifespan may favor the specialized reproduction in native populations, whereas flower size-reduction suggests potential local adaptation for pollinators in the non-native populations. The study of flower visitors will help to understand the local adaptation of Oenothera drummondii in each population.

Performance, Effectiveness, and Efficiency of Honeybees as Pollinators of Coffea arabica (Gentianales, Rubiaceae).

Studies in crop plants analyzing floral biology in conjunction with effectiveness and efficiency of pollinators on pollen transfer and fruit formation are not common, although they are essential to provide better management actions. On this base, we selected a farm in Bahia, Brazil, to study pollination on coffee plants (Coffea arabica L.). Specifically, we want to analyze if nectar traits influence visitor's performance throughout flower lifetime and if honeybees (Apis mellifera scutellata Lepeletier, 1836) are effective and efficient for coffee pollination comparing fertilization and fructification among four experimental treatments: open (OP), wind (WP), cross (HCP), and single-visit bee pollination (SVBP). We found that honeybees collect both nectar and pollen from coffee flowers and transfer pollen on stigmas even after one visit. No differences were found among treatments regarding the number of pollen grains transferred on the stigmas (effectiveness). OP flowers showed a comparative lower efficiency (pollen tubes and fruit set) probably due to pollination failure as those flowers have a higher variability on the number of deposited pollen grains. Two of the treatments (HCP and SVBP) showed higher fertilization (measuring tubes until the end of the style). Pollen loads seem to be limited by a peak of pollen transference by pollinators, followed by the stabilization in the number of pollen grains deposited per stigma. Thus, reproduction of the coffee can be limited by the quality of pollen grains moved by pollinators instead of quantity. Management strategies should focus on monitoring bee density on plants for increasing pollen quality transfer on flowers trough maintaining the adequate proportions of seminatural habitats and/or the number of hives on agricultural fields according to the flowering of the crop.

Primary hybrid of cattleya forbesii x cattleya loddigesii, a new brazilian orchid

Abstract The hybrid of Cattleya forbesii x Cattleya loddigesii has a short stature and early flowering, a light lilac tending to white color and a labellum with a velvety purple lobe and corrugated edges. The flower lifetime lasts approximately 20 days.

Biochemical Traits in the Flower Lifetime of a Mexican Mistletoe Parasitizing Mesquite Biomass.

Psittacanthus calyculatus is a hemiparasitic plant that infects a wide range of trees. Mainly the biology reproduction of this mistletoe lies in bright colored flower development. Furthermore, it uses the nectar secretion as the only reward to engage different flower visitors. We investigated the physiological mechanisms of the flower phenology per hour and per day to analyze the spatial-temporal patterns of the nectar secretion, Cell Wall Invertase Activity (key enzyme in the quality of nectar), nectar chemistry, volatile organic compounds (VOCs) emission, synthesis of carotenoids and frequency of floral visitors. Flowers lasted 4 days, total nectar was loaded just before the anthesis and the secretion was maintained over day 1 and 2, decreased on day 3, and stopped on day 4. The diurnal nectar secretion dynamic per hour on day 1 and 2 showed similar patterns with high production on the morning and a decrease in the afternoon, the secretion declined on day 3 and ceased on day 4. On the other hand, CWIN activity per day was less before the anthesis and increased on day 1 and 2, this enzymatic activity decreased on the old flower phenology. Moreover, diurnal CWIN activities showed different patterns in the morning, noon, and lastly in the afternoon. Nectar chemistry varied significantly throughout of the flower lifetime, sucrose decreased along the flower phenology increasing glucose and fructose. Amino acids showed the prevalence of proline and oxo-proline, both increased on the day 1 and diminished in subsequent old flower stages. The spatial VOCs emission showed the presence of 11 compounds being β-ocimene the main volatile; its release increased on day 1 and remained constant in the flower lifetime. Lutein, lycopene, and β-carotene were concentrated in old stages of the flowers. In field, the most frequent flower visitors were the hummingbirds that usually foraging in all phenologic flower stage and their foraging events decreased with the phenological flower lifetimes. The results showed that these traits presented by P. calyculatus flowers are able to engage and manipulate the behavior of flower visitors and contribute to the reproduction of the parasitic plant.

Floral and pollination biology, breeding system and nectar traits of Callistemon citrinus (Myrtaceae) cultivated in India

This study reports the influence of habitat on floral (flower and nectar characteristics, phenology) and pollination biology (flower visitors and breeding system) on Callistemon citrinus (syn. Callistemon lanceolatus), an Australian species of family Myrtaceae. In India, this small ornamental tree is cultivated in gardens, avenues and road sides and flowers throughout the year. At Agra (Uttar Pradesh, northern India) this species flowers twice a year (February–May and August–November). Flowers open early in the morning and can be characterized as protandrous for a brief period. Fresh open flowers presented ca. 25% of total produced nectar. Nectar sugar composition consisted of only glucose and fructose. A wide array of visitors (honey bees (Apis dorsata), butterflies, wasps, ants, moth, hover flies, several birds and Indian palm squirrel) visit flowers either for pollen or nectar or for facilitating self- and cross-pollination by their intra- and inter-tree movements. Among these, honey bees are dominant in number and in the amount of pollen on their body, while butterflies, ants, wasps, sunbirds, parrots, oriental white-eye sparrow and squirrels forage only for nectar and can be considered occasional pollinators or nectar thieves. Although flowers are highly visited, nectar in standing crop showed that flower visitors did not consume the total nectar produced. Nectar replenishment decreased with age in both bagged- and exposed flowers, showing the capability of secreting nectar after removal during the entire flower lifetime. Experimental hand-pollinations showed that naturalized C. citrinus fruits matured through autogamy, geitonogamy or xenogamy as was reported for native Australian populations. C. citrinus displays an interesting reproductive strategy, shows phenotypic plasticity of flowering periodicity and interacts with a generalized pollinator system, attracts a wide array of animal species with a conspicuous amount or replenished nectar after removals, and uses both compatibility strategies – xenogamy and autogamy – to ensure successful pollination and seed production at native or naturalized habitats.

Synergistic interactions of ecosystem services: florivorous pest control boosts crop yield increase through insect pollination.

Insect pollination and pest control are pivotal functions sustaining global food production. However, they have mostly been studied in isolation and how they interactively shape crop yield remains largely unexplored. Using controlled field experiments, we found strong synergistic effects of insect pollination and simulated pest control on yield quantity and quality. Their joint effect increased yield by 23%, with synergistic effects contributing 10%, while their single contributions were 7% and 6%, respectively. The potential economic benefit for a farmer from the synergistic effects (12%) was 1.8 times greater than their individual contributions (7% each). We show that the principal underlying mechanism was a pronounced pest-induced reduction in flower lifetime, resulting in a strong reduction in the number of pollinator visits a flower receives during its lifetime. Our findings highlight the importance of non-additive interactions among ecosystem services (ES) when valuating, mapping or predicting them and reveal fundamental implications for ecosystem management and policy aimed at maximizing ES for sustainable agriculture.

The importance of autonomous selfing in preventing hybridization in three closely related plant species

Summary In plants that are able to self‐fertilize, autonomous selfing has been hypothesized to function as an effective mechanism that prevents heterospecific mating. However, there have only been few studies that have assessed the relative and absolute contribution of different modes of selfing to total reproductive isolation acting between species. Because selfing can be expected to increase fitness costs when offspring are sired from more outcrossing sister taxa, it can be hypothesized that the contribution of post‐zygotic barriers to total reproductive isolation becomes stronger in selfing than in more outcrossing relatives. To assess the efficiency of different modes of selfing against heterospecific mating, we conducted mixed‐pollination experiments in three Centaurium species showing strong differences in mating system (i.e. delayed selfing in Centaurium erythraea, competing selfing in C. littorale and prior selfing in C. pulchellum). The contribution of selfing to total reproductive isolation was further examined by quantifying the strength of three pre‐zygotic (flowering phenology, pollinator fidelity and pollen production) and four intrinsic post‐zygotic (seed set and germination, survival and flowering capacity) barriers for each of the six species pair combinations. Although autonomous selfing as a reproductive barrier was unable to completely impede gene flow, its efficiency as a mechanism to prevents heterospecific pollination strongly depended on the mode of selfing, with prior selfing being by far the most efficient mechanism and delayed selfing only offering a limited protection against hybrid fertilization at the end of a flower's lifetime. Apart from the prevention effect of selfing, differences in pollinator fidelity and pollen production also contributed substantially to total reproductive isolation. Post‐zygotic hybrid costs were high and most prevalent for seed production and germination success. Reductions in hybrid vigour were significantly associated with the mating system of the maternal species, with the highest reductions in the most selfing C. pulchellum and the lowest reductions in predominant outcrossing C. erythraea. Synthesis. Our findings indicate that selfing may prevent species from interspecific gene flow and hybridization. The association between the capacity to self‐autonomously and hybrid vigour further suggests that selfing may foster post‐zygotic costs following hybridization.

Nectar yeasts in Delphinium nuttallianum (Ranunculaceae) and their effects on nectar quality

Abstract Microorganisms colonize the nectar of many angiosperms. Variable diversity and spatio-temporal dynamics of nectar-inhabiting microorganisms (e.g., yeasts) may drive variation in nectar sugar composition and subsequent plant–pollinator interactions. We assessed yeast frequency of occurrence and density in the nectar of the perennial herb, Delphinium nuttallianum , across multiple spatio-temporal scales, including flower lifetime and sex-phase transition, flowering season, populations, and years. We tested the hypothesis that pollinators vector yeasts by comparing densities between virgin flowers and those open to visitation. Finally, we identified yeasts using molecular methods and tested for an association between yeast density and nectar composition using ultra-performance liquid chromatography. Yeasts were frequent colonists of Delphinium nectar, occurring in all populations and years sampled. Yeast frequency of occurrence and density varied across most spatio-temporal scales examined. Pollinators were vectors of yeast: virgin flowers remained yeast-free, while those open to visitation became inoculated. Nectar samples were species-poor, with a majority colonized by Metschnikowia reukaufii . Finally, increasing yeast density was correlated with a decrease in sucrose and an increase in monosaccharides. Our results document that yeasts form species-poor communities in populations of this hermaphroditic perennial, in addition to highlighting their spatio-temporal dynamics and effects on nectar quality. Spatio-temporal variation in frequency of occurrence, density, and changes in nectar may have important implications for the nature and strength of interactions between Delphinium and its pollinators.

Flowering pattern, the structure of nectary surface and nectar secretion in two varieties of Ocimum basilicum L.

The studies conducted in the years 2003-2004 covered two varieties of <i>Ocimum basilicum</i> L.: var. <i>purpurascens</i> Benth. and var. <i>lactucaefolium</i> I. The flower lifetime, daily flowering pattern, morphology of pollen grains and the abundance of nectar secretion of flowers were compared. The surface of the nectaries of <i>O. basilicum</i> var. <i>lactucaefolium</i> was observed using scanning electron microscopy (SEM). The automorphic nectaries of basil formed the following parts: a flat part from the side of the upper lip and a convex part with three protrusions on the opposite side. On the top of two outer protrusions, stomatal areas were located, responsible for nectar secretion. The stomata occurred at the level of other epidermal cells. On the average, nectar contained 42% of sugars. The sugar yield of flowers of var. <i>lactucaefolium</i> was 36% higher than this feature in var. <i>purpurascens</i>. In terms of their size, the pollen grains were rated as medium-sized. Their viability ranged 88-96%. The shape of the pollen grains was described as oblate and suboblate.

Spatial and temporal patterns of floral scent emission in Dianthus inoxianus and electroantennographic responses of its hawkmoth pollinator

Scent emission is important in nocturnal pollination systems, and plant species pollinated by nocturnal insects often present characteristic odor compositions and temporal patterns of emission. We investigated the temporal (day/night; flower lifetime) and spatial (different flower parts, nectar) pattern of flower scent emission in nocturnally pollinated Dianthus inoxianus, and determined which compounds elicit physiological responses on the antennae of the sphingid pollinator Hyles livornica. The scent of D. inoxianus comprises 68 volatile compounds, but is dominated by aliphatic 2-ketones and sesquiterpenoids, which altogether make up 82% of collected volatiles. Several major and minor compounds elicit electrophysiological responses in the antennae of H. livornica. Total odor emission does not vary along day and night hours, and neither does along the life of the flower. However, the proportion of compounds eliciting physiological responses varies between day and night. All flower parts as well as nectar release volatiles. The scent of isolated flower parts is dominated by fatty acid derivatives, whereas nectar is dominated by benzenoids. Dissection (= damage) of flowers induced a ca. 20-fold increase in the rate of emission of EAD-active volatiles, especially aliphatic 2-ketones. We suggest that aliphatic 2-ketones might contribute to pollinator attraction in D. inoxianus, even though they have been attributed an insect repellent function in other plant species. We also hypothesize that the benzenoids in nectar may act as an honest signal (‘nectar guide’) for pollinators.

Biologia da reprodução de Mimosa bimucronata: uma espécie ruderal

Com o objetivo de estudar a biologia reprodutiva de Mimosa bimucronata, o presente estudo foi realizado em Botucatu e Cachoeira Paulista, SP, no período de novembro de 2003 a junho de 2005. Determinou-se o número de flores por glomérulo, sua duração, os eventos da antese e outras características florais, como tamanho, formato, coloração, odor, presença de néctar e localização de osmóforos. A receptividade do estigma e a viabilidade do pólen foram avaliadas. Flores foram examinadas e documentadas em microscópio eletrônico de varredura, após tratamento adequado. Foram feitos testes para a determinação do sistema reprodutivo, visando avaliar a dependência dos polinizadores. A presença de visitantes florais foi observada no campo, sendo registrada a quantidade de visitas e o comportamento dos visitantes, além do tempo médio de permanência dos visitantes junto às flores. O padrão de floração de M. bimucronata é anual. Os grãos de pólen encontram-se reunidos em políades compostas por oito células, o que pode ser interpretado como uma adaptação para minimizar o efeito da mistura das cargas de pólen depositadas sobre o diminuto estigma. A formação de frutos em condições naturais foi baixa e não ocorreu agamospermia. A morfologia das flores e das inflorescências permite o acesso aos recursos florais para uma ampla variedade de visitantes (Hymenoptera, Diptera e Coleoptera). A maioria das visitas foi realizada por abelhas (56,4%). Os resultados permitem considerar que, embora M. bimucronata seja dependente de vetores de pólen para sua reprodução, é espécie entomófila generalista e, portanto, bastante adaptada aos ambientes ruderais, onde sua ocorrência é predominante.

Reproductive Biology of Erythrina falcata (Fabaceae: Papilionoideae)1

ABSTRACTReproductive phenology, floral biology, degree of self‐incompatibility, and floral visitors of Erythrina falcata were studied in an Argentinean population. Flowering occurs during the dry season from late August to late October. Flower lifetime is 5–6 d. Phylogenetic studies indicate that E. falcata, together with E. fusca and E. crista‐galli, are included in a basal clade within Erythrina. Its phylogenetic position, floral morphology, and nectar characteristics suggest a hummingbird–passerine mixed pollination system. The flowers are nontubular, and the vexillum (the upper petal of the corolla) covers the other remaining floral parts until displaced by a visiting passerine (Icterus cayanensis) or a hummingbird (Amazilia chionogaster). Both birds act as pollen vectors. Bees were observed as occasional pollinators. Nectar production begins at anther dehiscence and coincides with maximum stigmatic receptivity. The base of the keel forms a secondary nectar reservoir. Controlled pollinations showed that this species is self‐incompatible, although a few fruits develop from selfing. Pollen:ovule ratio (43,200:7) is as expected for a xenogamous plant. Only 1 percent of the flowers set seeds under natural conditions. Possible explanations for the low reproductive success are discussed.

Flower Structure and Reproductive Biology of Bougainvillea stipitata (Nyctaginaceae)

Abstract: Bougainvillea stipitata displays inflorescences with three pendant greenish flowers. Flowers open at sunset and last five days. Flower perianth is constricted in the middle and forms a tube that ends in five lobes. Fragrance is emitted by the papillae located on the lobe margins of the perianth. The nectary is located at the base of the staminal tube. It secretes fructose‐dominant nectar with amino acids, phenols and reduced acids. Nectar secretion is continuous during flower lifetime and the flowers do not recover the reward. Mainly moths visit flowers. Pollen load on stigmas indicates that most flowers received more than 50 pollen grains, which are deposited by pollinators within the first two days of the flower life. Although the low natural fruit set of this self‐incompatible species may be due to intraplant pollen flow, pollinators play an essential role for B. stipitata fruit production.

Pollinators and Reproductive Success of the Wild Cucurbit Cucurbita maxima ssp. andreana (Cucurbitaceae)

Abstract: We studied the reproductive success and pollinators of Cucurbita maxima ssp. andreana in different disturbed habitats where it grows naturally. Data were obtained from three populations. One grew within a soybean crop, the other within a corn crop, and the third in an abandoned crop field. Cucurbita maxima ssp. andreana is an annual vine with a flowering period from December to April. Male flowers appear first, thereafter female and male flowers appear together. Flower lifetime (9 h) was similar in male and female flowers. The pollinator guild was comparable for the three populations but some differences in the frequency of the insect species were observed. Native bees were the main pollinators in the population in the abandoned field, while beetles pollinated the populations in crop fields. These differences were not linked with the pre‐emergent reproductive success, fruit and seed set, or fruit quality. This is a self‐compatible plant. Fruit and seed set and fruit traits (total mass, width and length of fruits, number of seeds per fruit, and seed mass) did not show significant differences between hand‐cross and hand‐self pollinated flowers. This wild cucurbit is a generalist with respect to pollinator guild, and flower visitors seem to be highly efficient in pollen transference. Cucurbita maxima ssp. andreana is well adapted to disturbed habitats because plants ripened fruits successfully, regardless of the group of insects visiting flowers.

Nectar Production in Louisiana Iris Hybrids.

Nectar is an important attractant for pollinators, and a plant's success in sexual reproduction can be influenced by the amount and concentration of nectar produced by its flowers. We studied nectar production over flower lifetime in Iris fulva, Iris brevicaulis, and four classes of hybrids-reciprocal F1's and backcrosses-between these species. Iris fulva produced less concentrated nectar than did I. brevicaulis, whereas I. brevicaulis flowers had a shorter life span. Hybrids were not intermediate, but they had the high nectar concentration of I. brevicaulis combined with the long life span of I. fulva flowers. Nectar production and concentration declined after the first day in all classes, but flowers continued to produce nectar until they were completely wilted. Backcrosses did not show a shift in mean or increased variation for the characters that distinguished the parental species; backcrosses toward I. fulva retained the high nectar concentration of I. brevicaulis, and backcrosses toward I. brevicaulis did not have a reduced flower life span. Overall, F1 hybrid flowers produced the highest amounts of nectar and nectar sugar over their life spans. These results, together with previously obtained data on pollinator choice in mixed arrays of the same flower classes, show that F1 hybrids between these species do not suffer from reduced attractiveness to pollinators. F1 individuals produced more nectar and nectar sugar than did their parents, and thus, they are possibly even more attractive to pollinators that forage for nectar.

Male-biased sex ratio and promiscuous pollination in the dioecious island treeLaurus azorica (Lauraceae)

Pollination ofLaurus azorica (Lauraceae), a dioecious Macaronesian tree, was studied. Male and female trees had the same size distribution. The population had 2.5 times as many male trees as females. In addition, males produced more flowers, and their inflorescences lasted longer. Individual flower lifetime and length of flowering season were the same in both sexes. Between the years of observation, one tree changed sex. Pollinators wereHalictinae bees and the flyTachina canariensis. The bees collected pollen and nectar and the fly collected nectar from both sexes. Both species visited other plants as well. The evolution of breeding systems inLauraceae is discussed.

Nectar secretion pattern, removal effects, and breeding system ofLigaria cuneifolia(Loranthaceae)

Some aspects of the reproductive biology of Ligaria cuneifolia have been studied, addressing the following questions: (i) Are there temporal differences in the female and male functions? (ii) How do nectar composition, volume, concentration, and amount of sugar vary throughout the flower lifetime? (iii) How does the plant respond to nectar removal? (iv) What is the breeding system of this species? Flowers last 4 days. There is a predominance of the male function in the first days and of the female function in the last days. Chemical composition of nectar varies throughout the flower lifetime; there is a constant decrease in sucrose along with an increase in glucose. Nectar is secreted during nights, and every secretion period is followed by a cessation interval. After the final cessation, a period of active resorption follows. During the mostly male phase of the flower, nectar has more sucrose than hexose, its secretion is discontinuous, and nectar removal reduces the rate of nectar production. During the mostly female phase, nectar has more hexose than sucrose, its secretion ceases, nectar removal does not affect nectar production, and a resorption period is inferred. Tests for spontaneous autogamy and apomixis were negative. Low fruit set is obtained when autogamous, geitonogamous, and xenogamous hand pollinations are performed on flowers less than 2 days old compared with flowers at least 3 days old (0, 15, and 47% versus 19, 37.5, and 89%, respectively). These results indicate the the reproductive system of L. cuneifolia is primarily xenogamous, but reproductive success is related to flower age. Keywords: Loranthaceae, Ligaria, nectar chemistry, breeding system, flower phenology, reproductive biology.

Characteristics of Nectar Secretion by Lycium cestroides, L. ciliatum (Solanaceae), and Their Hybrid

Abstract Nectar sugar composition, nectar secretion patterns, and effects of removal are compared in a natural hybrid experimentally supported (Lycium ciliatum × cestroides) and its parental species (L. ciliatum and L. cestroides). The nectar of L. ciliatum and L. ciliatum×cestroides is hexose dominant, but each taxon shows a distinctive pattern: more glucose than fructose in the former and the opposite pattern in the latter. L. cestroides has sucrose‐rich nectar with more fructose than glucose. Both parental species show a similar sugar production pattern: the sugar content declines at the end of the flower lifetime due to nectar reabsorption. In contrast, in the hybrid, nectar secretion is continuous and there is no nectar reabsorption. Data obtained among the taxa are correlated with corolla depth: the deeper the corolla tube, the more diluted and the higher the volume of the nectar. Nectar production after removal is increased in L. cestroides whereas it is not affected in the hybrid or in L. ciliatum. Chemical composition and response to removal relate the hybrid to the maternal parent (L. ciliatum).

Characteristics of secretion of nectar in Pyrostegia venusta (Ker‐Gawl.) Miers (Bignoniaceae)

summarySecretion patterns and characteristics of nectar of an Argentinian population of Pyrostegia venusta at different times of the day are described with respect to flower age. Flowers are protandrous and hummingbird‐pollinated, producing exudate before and after anthesis. There is a concomitant increase in both concentration and volume in 1‐d‐old flowers, followed by a sharp increase in concentration and decrease in nectar volume in 2‐d‐old flowers.Removal of nectar throughout the flower lifetime increases the volume produced but reduces the concentration. Flowers with nectar removed three times produced 73% more nectar volume than the controls, and those with nectar removed twice produced 20% more. However, the total mass of sugar produced was comparable in all three sets.Two experiments were designed to determine the effect of changes in volume and concentration on nectar production: (a) the concentration was initially maintained while the volume was changed (halved, doubled and untouched as a control), and (b) the concentration was reduced to a minimum replacing nectar by different volumes of distilled water as in the previous experiment. These concentration‐volume changes do not essentially affect total nectar production irrespective of treatment. A powerful homeostatic mechanism would operate by which the plant maintains both these variables in the nectar. The differences observed in the nectar production rate among treatments would indicate its existence.

Reproductive biology, variability of nectar features and pollination of Combretum fruticosum (Combretaceae) in Argentina

Abstract Flower morphology, nectary structure, nectar features (chemical composition, secretion pattern, standing crop, removal effects) and flower visitors are analysed in an Argentinian population of Combretum fruticosum. The variability of these data was examined throughout the flower lifetime. Nectar is hexose dominant. Its chemical composition and concentration are constant for all flowering stages. Nectar volume varies as a function of flower age due to a combination of nectar secretion, cessation and resorption periods. The overall sugar production is decreased by nectar removal. The plant is self-incompatible and xenogamous. Only 16.2% of the flowers set seeds. Inflorescences with green flowers were exclusively visited by two hummingbird and three perching bird species which transfer the pollen. A clear link was observed among nectar production pattern, standing crop of nectar, and visitors' behaviour.