Terminal Inflorescence Research Articles

Polinização de Caryocar villosum (Aubl.) Pers. (Caryocaraceae) uma árvore emergente da Amazônia Central

Caryocar villosum is a common emergent tree of Central Amazonia. It is an important timber tree and source of fruit for men and animals. We study the floral biology, pollination, and breeding system of C. villosum. Data was collected from trees in an urban area, forest fragments and a continuous forest. Floral characteristics and plant-pollinator interactions were described and controlled hand-pollinations were undertaken to study breeding system. The flowers of C. villosum are brush-shaped, yellow and exposed above the canopy in terminal inflorescences. They have nocturnal anthesis, last for one nigth only and produce ca. 750 mL of nectar per nigth, which are typical traits associated with bat pollination. The especies was visited by Phyllostomus discolor and glossophaginae bats, as well as arboreal marsupials and Sphingidae moths. Hand pollinations revealed that C. villosum is self-compatible, but the number of fruits formed from cross-pollination was higher than that from self-pollination.

Effect of Cooling of Medium on Fruit Set in High-bench Strawberry Culture

We demonstrated the effect of cooling of the medium on the fruit set of strawberries (Fragaria × ananassa Duch.) grown on high benches for forcing culture. The cooling by water evaporation promoted by a fan enabled to cool the medium by an average of several degrees compared with no cooling. When runner plants were transplanted in late summer, cooling accelerated flower bud emergence almost 10 days on the primary axillary branch compared with plants grown in uncooled medium. Also, with cooling, fruit was harvested from the inflorescence of the primary axillary branch almost 10 days earlier. We expect that this technique will allow early transplanting around the end of summer and will shorten the time between fruit set on the terminal inflorescence and that on the inflorescence of the primary axillary branch.

Floral meristem indeterminacy depends on flower position and is facilitated by acarpellate gynoecium development in Impatiens balsamina

* Floral meristems are generally determinate. Termination of their activity varies with species, occurring after carpel or ovule development, depending on the placentation type. In terminal flowering Impatiens balsamina (cv. Dwarf Bush Flowered) some flowers exhibit meristem indeterminacy; they produce organs from the placenta after ovule development. * Here we provide a detailed description of gynoecium development in this line and explore the basis of the indeterminate nature of some of its floral meristems. * We find that the placenta is sometimes established without complete carpel fusion. Proliferative growth derives from meristematic remnants of the placenta and is more common in the terminal inflorescence. RNA in situ hybridization reveals that IbLFY (Impatiens LFY homologue) is expressed in all meristem states, even in proliferating meristems. Expression of IbAG in axillary flowers is as expected in the meristem, stamens and carpels but absent from the proliferating meristem. * We conclude that I. balsamina has cauline placentation. Incomplete suppression of inflorescence identity in flowers of the terminal inflorescence leads to floral meristem proliferation after ovule development in this species.

Estrutura sexual e ecologia reprodutiva de Amaioua guianensis Aubl. (Rubiaceae), uma espécie dióica de formações florestais de cerrado

The breeding biology of Amaioua guianensis was studied in a forest area at Parque do Sabia in Uberlândia, MG, Brazil, between September 2003 and April 2005. Phenology, breeding system, flower morphology, pollinator and disperser's assemblages, and sexual structure of the reproductive individuals were investigated. Amaioua guianensis is a woody dioecious species common in Brazilian forest areas. Flowers are hexamerous, tubular, whitish and odoriferous, pollinated by relatively specialized vectors as large bees and hawkmoths. Pistilate flowers produced nectar earlier and in larger amounts than the staminate ones. Staminate flowers were produced in larger numbers per inflorescence and were significantly larger than the pistilate ones. Flowers were presented in terminal inflorescences, composite umbels in the staminate and simple ones in pistilate individuals. Both male and female flowers produced non-functional sexual structures of the opposite morph, but the style of male flowers act as a pseudo-stamen, a secondary pollen presentation mechanism which is common in the tribe Gardenieae but had not been described previously to the species. Sexual ratio was significantly male biased and gender was distributed contagiously in the area, probably due in both cases to vegetative multiplication and disturbance. Natural pollination was as high as 98.6% and fruit set was 75.7%. Apomictic fruit production was very low (3.4%). Fruits were dispersed by birds. Floral morphology and relatively specialized pollinator's fauna rendered efficient pollination service and fruit production in the species even in the relatively disturbed study area.

Biologia reprodutiva e polinização de duas espécies de Polystachya Hook. no Sudeste do Brasil: evidência de pseudocleistogamia em Polystachyeae (Orchidaceae)

Phenology, floral biology, pollinators, breeding system and natural fruit set of Polystachya estrellensis Rchb. f. and P. concreta (Jacq.) Garay & H. R. Sweet were studied in mesophytic forests at Serra do Japi, and in mangroves at a seashore plain at Picinguaba, respectively. Both study areas are natural reserves in southeastern Brazil. Both species flower in summer, are epiphytes and produce terminal inflorescences with up to 150 non-resupinate flowers. The flowers produce a citric fragrance, mainly in the warmest hours of the day. Both species are pollinated by solitary and social small native bees, which collect pseudopollen from the lip of the flowers. The pollinarium is placed frontally on the head of the bees, when they are collecting pseudopollen. Polystachya estrellensis and P. concreta are self-compatible. The majority of flowers of P. estrellensis (96,7%) is cleistogamous, while P. concreta produces only chasmogamous flowers. The cleistogamous flowers of P. estrellensis present dimensions and number of floral elements identical to the chasmogamous, a phenomenon called pseudocleistogamy. The chasmogamous flowers of P. estrellensis, as well as all flowers of P. concreta are pollinator dependent. The natural fruit set of P. estrellensis was higher than that of P. concreta as a consequence of pseudocleistogamy. In mesophytic forests of the Serra do Japi, in which the fruit set of several orchid species is low, mainly because of pollinator scarcity, the strategy presented by P. estrellensis is an important factor that increases the reproductive success of this species, compared with to the non-autogamous members of Epidendroideae that occur in the same region.

A New Heterophyllous Spermacoce Species (Rubiaceae) from the Marungu Highlands, Democratic Republic of the Congo

Spermacoce heteromorpha Dessein (Rubiaceae, Spermacoceae) is newly described and illustrated. It grows on the Marungu highlands of the Democratic Republic of the Congo (D.R. Congo) at altitudes of 1800 to 1900 m. The species resembles the Tanzanian Spermacoce taylorii Verdcourt, from which it mainly differs in having terminal inflorescences, only slightly exserted anthers, and densely pubescent stems. Moreover, Spermacoce heteromorpha features marked heterophylly, with long leaves at the plant's base and much shorter cauline leaves, a type of heterophylly rarely observed in Spermacoce or in the Rubiaceae as a whole. The finding of this species exemplifies the unique floristic richness of this under-explored part of D.R. Congo.

Morphological and anatomical development in the Vitaceae. VIII. Comparative development of three Cyphostemma (Vitaceae) species reveals important vegetative and reproductive differences among the species

Vegetative and floral development of Cyphostemma simulans (C.A. Small) Wild & Drummond, Cyphostemma juttae (Dinter & Gilg) Descoings, and Cyphostemma mappia (Lam) Galet were compared using epi-illumination light microscopy and paraffin sectioning. Cyphostemma simulans is a liana with leaf-opposed tendrils and inflorescences, which both arise from the shoot apical meristem, whereas the other two species are shrubs that lack tendrils and their main shoot terminates in an inflorescence. A shoot apical meristem of C. simulans can be overtopped by an inflorescence, making the architecture appear to develop like a sympodium, which is the architecture shared by the other two species. On the other hand, a terminal inflorescence of C. juttae or C. mappia can be placed in a leaf-opposed position by a precocious axillary branch, making the architecture appear to develop like a monopodium, which is the typical architecture of the Vitaceae. The floral development of all three species is similar in early ontogeny, except for a difference in calyx development between C. mappia and the other two species. Later developmental differences of the septum and gynoecium, in addition to flower colour and phenology, are distinct characteristics that distinguish flowers of each species. Therefore, this study is the first to demonstrate differences in the floral characteristics of Cyphostemma. In addition, it shows how each architecture type (monopodium or sympodium) can resemble the other and so provides stronger evidence about how the unique architecture of the Vitaceae has originated.

Biologia floral e sistema reprodutivo de Byrsonima coccolobifolia (Kunth) em uma savana amazônica

A biologia reprodutiva de Byrsonima coccolobifolia, foi avaliada em uma população de savana do Estado de Roraima. A espécie é constituída de arbustos e arvoretas com altura inferior a 3m, de flores hermafroditas zigomorfas, pentâmeras, reunidas em inflorescências do tipo racemo terminal, produzidos em brotações novas, o cálice é composto por cinco sépalas, que apresentam um par de glândulas produtoras de óleo. A corola é formada por cinco pétalas albo-róseas e unguiculadas, o androceu é composto por dez estames com anteras de coloração amarela. A antese pode ser noturna ou diurna, estende-se por um período médio de 12 horas e as flores costumam ficar abertas e vistosas por um período adicional de 15 horas, quando se inicia a senescência. Foram registrados dois episódios de floração e o fogo parece ser um fator ambiental estimulador desta fenofase. Os visitantes florais predominantes foram abelhas das famílias Anthophoridae (Centris sp. e Xylocopa sp.) e Apidae (Apis mellifera e Bombus sp.). Os resultados das polinizações controladas e o cálculo do índice de auto-incompatibilidade (ISI) indicam que a espécie apresenta comportamento protogínico e é autocompatível, produzindo frutos em todos os tratamentos de autopolinização em proporções semelhantes à polinização natural, não sendo confirmada a produção de frutos apomíticos. Entretanto, os percentuais de frutos formados nos tratamentos de xenogamia foram significativamente superiores aos tratamentos de autofertilização, indicando que B. coccolobifolia apresenta um sistema reprodutivo misto com níveis elevados de alogamia e autogamia.

Competition for water between inflorescences and leaves in cut flowering stems of Grevillea ‘Crimson Yul-lo’

SummaryGrevillea cv. ‘Crimson Yul-lo’ has large bright red terminal inflorescences on leafy stems and has recognised commercial potential as a cut flower crop. A major limitation is its relatively short vase-life, often terminated by early wilting of the inflorescence despite apparently turgid leaves. An investigation of the water relations of cut Grevillea ‘Crimson Yul-lo’ stems revealed that the water potential of inflorescences on intact stems in vases was significantly higher (i.e., less negative) than that of leaves from day-0 to day-3 of vase-life. Thereafter, the water potential of inflorescences declined more rapidly than that of leaves, accompanied by visible wilting of the tepals and styles of individual florets. Removal of leaves from the stems reduced both water uptake and water loss, and delayed the onset of a negative water balance in the inflorescence. Bagging of entire stems, leaves only, or inflorescences only, with micro-perforated plastic film to reduce transpiration, reducing leaf number to reduce leaf area, or supplying abscisic acid to reduce leaf stomatal aperture, all aided relative fresh weight retention by stems and extended vase-life. Four or six leaves on a stem caused greater loss in inflorescence water content than zero or two leaves. Considered collectively, these findings show that competition for water between the inflorescence and the leaves in cut Grevillea ‘Crimson Yul-lo’ stems contributes to the onset of inflorescence wilting and their short vase-life.

Activity of Zymomonas species in palm-sap obtained from three areas in Edo State, Nigeria.

The bacterium Zymomonas mobilis was isolated from fresh palm-sap samples from three different locations as to determine the contribution of the bacterial isolate to alcohol production in palm-wine. Carbohydrate (sugar) fermentation, alcohol tolerance, and growth of the bacterium at different pH and temperature values were determined; and a comparison of sugar fermentation by Z. mobilis and Saccharomyces cerevisiae was also determined. Z. mobilis contributes much to the fermentation of palm-wine due to its ability to ferment sucrose, glucose and fructose which are the main sugars in palm-sap. The bacterium reached its maximum density of 2.72 x 10 7 cells/ml between 12 and 15 hrs after tapping of the palm-sap. Z. mobilis is acid and alcohol tolerant being able to grow at pH values between 4.0 and 7.0 and in alcohol concentration of between 2.5% and 15% respectively. Z. mobilis was also found to ferment sugars at a faster rate than Saccharomyces cerevisiae. Statistical analysis of the data obtained using ANOVA showed that there is no significant difference at p = 0.05 level of significance in the growth of isolates of Z. mobilis obtained from the three locations under different pH, alcohol and temperature values. @JASEM Palm-wine is an alcoholic beverage obtained from the fermentation of the sugary sap of various palm species in Nigeria. It is usually obtained from Raphia vinifera, Raphia hookeri, and Elaeis guineensis by methods described by Bassir (1965), Faparusi (1966) and Okafor (1972). Raphia palms usually yield more sap than oil palms although raphia palms can only be tapped once in its life time because its terminal inflorescence is destroyed during tapping (Okafor, 1977).

Strawberry Growth and Flowering

Strawberry is an herbaceous perennial that can be easily propagated by stolons or by crown division. Seedlings have a few months in the juvenile period. The growth is determined with a terminal inflorescence as a modified stem or cyme. Flower induction is sensitive to thermo-photoperiod and to several agronomic and nutritional factors. The strawberry plant is highly adapted to diverse temperate climates and to production under forced artificial growing conditions. In the present study, a dynamic architectural model of growth is described and discussed in order to reveal strawberry development under different cultivation systems. The aim is to improve the cultural knowledge and understanding of the physiological control of axillary meristems, which can enhance the Strawberry fruit production.

Effects of fruit position on fruit mass and seed germination in the alien species Heracleum mantegazzianum (Apiaceae) and the implications for its invasion

The aims of this paper are to determine whether the effect of position of fruit on a plant affects the germination characteristics of seed of Heracleum mantegazzianum (Apiaceae), a Caucasian species invasive in Europe, and the germination potential of this species. Reproductive characteristics of H. mantegazzianum were studied at seven sites in the Czech Republic where this species is abundant. Fruits were collected and weighed from eight plants at each site, from three umbel types (terminal, satellite and branch) and two fruit positions within an umbel (central or marginal). Characteristics of individual umbels (duration of flowering, size) and plants (fecundity, age, height, basal diameter) were recorded. Percentage germination and germination rate (time to when 50% of the seeds had germinated) were assessed. At each site, fruit mass and percentage germination varied greatly among plants. Fruits from terminal inflorescences were heavier than those from satellites and branches, and those produced in the centre of an umbel were heavier than those from the margin. Mean percentage germination was 91%, which varied among sites but was not affected by fruit position on a plant. Germination rate increased with fruit mass. Neither umbel size nor time of flowering had a significant effect on germination characteristics. At some sites, there was a negative relationship between fruit mass and plant height. A combination of reproductive traits (high fecundity, high germination capacity, opportunistic behaviour associated with limited effect of fruit position on a plant on germination characteristics) might determine this species ability to successfully invade new habitats.

The Sap Flow in the Peduncle of the Mango (Mangifera indica L.) Inflorescence as Measured by the Stem Heat Balance Method

The transpired mass flow of water from the inflorescence was monitored continuously and compared with the flow in the whole shoot attached to the inflorescence by the stem heat balance method. The transpiration was compared with the chamber method. The stem heat balance method is able to continuously measure the intact sap flow of water. Modified sap flow gauges were adapted to obtain precise measurements of minute fluctuations in the flow. The stem sap flow fluctuated with the solar radiation, reaching a maximum at midday. The flow was also affected by the saturation deficit. At midday, a sap flow rate was 60 g · h−1 at the shoot base (11.5 mm in diam.); the shoot subtended 55 leaves between the shoot base and the terminal inflorescence. At the peduncle of the inflorescence, the maximum sap flow rate occurred during the morning. Subsequently, the flow tended to decrease gradually and steadily, hardly affected by the solar radiation and the saturation deficit. An entire inflorescence with a peduncle diameter of 11.2 mm exhibited a maximum transpiration rate of 15 g · h−1 during late morning. The daily water consumption of the inflorescence was estimated to be 130 g, representing 22% of the water consumption by the entire shoot. The chamber method indicated similar results as the stem heat balance method.

Biologia reprodutiva de Psychotria poeppigiana Mull. Arg. (Rubiaceae) em mata de galeria

Psychotria L. (Rubiaceae) é o gênero com mais espécies heterostílicas dentre as Angiospermas. O objetivo deste trabalho é descrever a biologia floral, fenologia, o sistema reprodutivo e os polinizadores de Psychotria poeppigiana Müll. Arg. As inflorescências são capitadas terminais, com brácteas vermelhas e flores amarelas apresentando dois morfos distintos: brevistiladas e longistiladas, caracterizadas por flores hermafroditas com diferentes comprimentos de estiletes e posicionamento oposto das anteras (hercogamia recíproca). Encontrou-se diferenças no tamanho das anteras, dos grãos de pólen e da superfície estigmática entre os morfotipos. Polinizações controladas mostraram que os morfotipos apresentam auto-incompatibilidade e intramorfo-incompatibilidade ao nível do estigma e do estilete. Os visitantes são pequenas vespas, abelhas, borboletas e beija-flores, que visitam as flores com maior freqüência no início da manhã. De acordo com a freqüência e eficiência no comportamento de transportar os grãos de pólen entre os morfos florais, o principal polinizador foi o beija-flor Thalurania furcata. O néctar é produzido em pequena quantidade (máximo de 8µl) e durante a abertura das flores, que ocorre entre 5 e 7h. A espécie forma agrupamentos devido à existência de reprodução vegetativa.

A preliminary phylogeny of the tribe Miconieae (Melastomataceae) based on nrITS sequence data and its implications on inflorescence position

Miconieae is the most diverse tribe of Melastomataceae, with 30 genera and over 2200 species. The tribe is characterized by fleshy fruits and partially to totally inferior ovaries. To test monophyly of the tribe and assess phylogenetic relationships within it, sequence data from nrITS were gathered and analyzed for 110 taxa in Miconieae and 32 putative outgroups. The tribe Miconieae is not resolved as monophyletic, but rather composed of two distinct clades: one composed of the cauliflorous genera Henriettea, Henriettella, Loreya and Bellucia, and a second clade with all other taxa in Miconieae, sister to a polytomy that includes representatives from tribes Merianieae and Blakeeae. Terminal inflorescences are optimized as basal within Miconieae, with lateral inflorescences evolving in at least four different instances. Cauliflory does not appear to be derived from truly axillary inflorescences; instead it seems to have evolved independently. The terminal–flowered genera Tococa, Conostegia, Tetrazygia, Anaectocalyx, Charianthus, Calycogonium, and Leandra pro parte seem to be derived from within the large genus Miconia, as is Clidemia, a genus with both axillary inflorescences and terminal inflorescences that are deflexed to a lateral position by an axillary branch. Maieta and Necranium, both with axillary inflorescences, are resolved as derived from within Clidemia.

Lipid Composition of in vitro Developing Seeds of Brassica campestris L.

A liquid culture technique has been developed to study lipid metabolism in seeds of Brassica campestris L. grown in vitro from terminal inflorescences detached 4 to 46 days after anthesis. Seeds developed under these conditions exhibited pattern of growth, deposition of storage products and lipid composition similar to those from intact plant.

Vegetative and floral shoot development of Zantedeschia ‘Black Magic’

Vegetative and floral development at the apical meristem of Zantedeschia Spreng. ‘Black Magic’ aff. Z. pentlandii (Wats.) Wittm. [syn. Richardia pentlandii Wats.] was traced through multiple seasons of growth. The growth habit was sympodial. For vegetative shoots, seven new structures were laid down on the primary axis for each season to form the over-wintering bud, from which all of the subsequent season’s visible growth arose. When a previously vegetative shoot flowered, the flower (spathe and spadix) arose directly from the apical meristem of the over-wintering bud which, at the time of planting (September; spring), was vegetative. At planting this over-wintering bud comprised six cataphylls, two leaf initials, and the as yet undifferentiated apex. For floral shoots, the terminal inflorescence consumed the original vegetative axis and a continuation shoot arose in the axil of the first leaf, the oldest leaf on the primary axis. While only the first three or four leaves of this continuation shoot actually emerged during the current season, a total of 14 structures were formed on the axis by mid-March (autumn). In the continuation bud of flowering plants a 4 month period of endo-dormancy occurred from mid-January through to mid-May (summer to late autumn). There was an apparent overlap between the onset of endo-dormancy of the continuation bud (January/February), the period when new foliage had stopped appearing (February), and attainment of the maximum number of structures in the continuation bud (March). Growers are recommended to wait until dormancy is complete (June; winter) before replanting tubers for the purposes of early forcing.

Predispersal seed predation of Amaranthus retroflexus and Chenopodium album growing in soyabean fields

SummaryField experiments were made in 1998 and 1999 to determine the influence of tillage and soyabean (Glycine max) row width on predispersal weed seed predation in Amaranthus retroflexus L. (redroot pigweed) and Chenopodium album L. (common lambsquarters). Soyabean was planted in wide (76 cm) and narrow (19 cm) rows with conventional or conservation tillage. Additional control plots without soyabean were also established. The two objectives were to determine (1) whether predispersal seed predation occurs in A. retroflexus or C. album, and (2) whether disturbance (soil tillage) or microclimate (planting pattern) influence predation level. Mean rates of seed predation were 26% and 4% in A. retroflexus and C. album, respectively. Although these levels were low at the population level, individual plants of both species had predation levels ranging from 0% to 80%, however, very few individuals of C. album had levels of predation above 10%. Differences among tillage and row width treatments occurred for A. retroflexus, but not for C. album. Amaranthus retroflexus and C. album growing within the soyabean crop received less light than those in the no‐crop plots, and produced less above‐ground biomass, smaller terminal inflorescences, and fewer seeds per inflorescence. Plant height, terminal inflorescence weight, and total seeds were correlated with predation in both weed species.

Maximizing Seed Production in Eastern Gamagrass

Use of eastern gamagrass (Tripsacum dactyloides L.) for grazing or cut forage has been partially limited because of indeterminate inflorescence development combined with low seed yields and high seed costs caused by high seed shattering. This study was conducted to observe the influence of N rate and defoliation on inflorescence appearance, seed loss, and viability of harvested seed in two cultivars of eastern gamagrass at Boone, IA, in 2000 and 2001. Treatments included application of N at 0, 56, 112, 224 kg ha−1 and spring, fall, and no defoliation. Cultivar had the greatest influence on seed yield. ‘Pete’ produced greater total numbers of terminal and lateral inflorescences and cupules than ‘Iuka’ in both years. Reductions in seed production occurred with spring defoliation in Iuka for the first year of the study and Pete during both years. In 2000, seed on lateral inflorescences was decreased 20% during the peak seed load. In 2001, seed yield for spring‐defoliated plants of Pete was less than that of fall‐defoliated plants, but not significantly different from nondefoliated plants. Addition of 56 kg ha−1 N increased seed load in the second year of the study. Optimal harvest time occurred approximately 2 wk after terminal cupules began shattering. Seed harvested 1 wk earlier than this had 5 to 15 percentage points more immature seed. Seed yield was 13 to 20% less if harvests were taken 1 wk later than the optimal date.

PLANT GROWTH RETARDANTS FOR INTRODUCTION OF NATIVE REICHARDIA TINGITANA

PLANT GROWTH RETARDANTS FOR INTRODUCTION OF NATIVE REICHARDIA TINGITANA