Pollination of northeastern North American Spiranthes (Orchidaceae)

1983 ◽  
Vol 61 (4) ◽  
pp. 1080-1093 ◽  
Author(s):  
Paul M. Catling

Most northeastern North American Spiranthes are adapted to pollination by long-tongued bees (e.g., Bombus spp. and Megachilidae). The salient features of this adaptation are (i) a long, flat viscidium which attaches the pollinia readily to the flat rigid galea of the insect's proboscis, (ii) the nectar secreted into the base of the floral tube, (iii) the flowers are protandrous and sequential beginning at the base. In contrast, Spiranthes lucida apparently is pollinated largely by halictine bees. It differs from other northeastern taxa of Spiranthes in (i) having an oval viscidium which attaches the pollinia to the clypeus below the antennae, (ii) having the nectar available on the under side of the column behind the stigmatic surface, and (iii) in lacking protandry. In the characteristically Bombus-pollinated taxa, protandry is accomplished by a change in the position of the terminal portion of the column with respect to the lip, apparently due to cell elongation in both the column and the lip. The present investigation documents protandry in S. cernua var. cernua, S. lacera var. lacera, S. lacera var. gracilis, S. laciniata, S. magnicamporum, S. ochroleuca, S. romanzoffiana, S. tuberosa, and S. vernalis. Bees moving up the spike from the older female flowers to the younger male flowers act initially as pollen donors and later as pollen receivers; thus cross-fertilization is enhanced. Halictines occasionally act as pollinators of characteristically Bombus-pollinated taxa by visiting the flowers upside down so that the pollinia are inconspicuously attached to the lower side of the prementum. Data presently available for northeastern North American Spiranthes fail to establish pollinator specificity as significant in speciation except perhaps with respect to the separation of S. lucida from the other 14 northeastern taxa.

Agrotek ◽  
2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Liz Yanti Andriyani

<em>The objective of the experiment was to observe the best Hydrasil� concentration to the flowering of �melon� to increase the yield of melon </em>(<em>Cucumis melo</em> L.)<em> . The experiment was conducted at Jambi University experimental station, which is located in an altitude of ��35 m above the sea level.� The experimental� design was randomized complete block design with 4 replications and 6 treatment levels of Hydrasil concentration, ie. : H<sub>0 =� </sub>none� Hydrasil treatment, H<sub>1 =� </sub>100 ppm� Hydrasil, H<sub>2 =� </sub>200 ppm�� Hydrasil, H<sub>3 =� </sub>300 ppm� Hydrasil, H<sub>4 =� </sub>400 ppm� Hydrasil, H<sub>5 =� </sub>500 ppm� Hydrasil. The results� showed that Hydrasil concentration� significantly affected number of female �flowers and number of male� flowers per plant. �Hydrasil concentration at� 200 ppm�� gave �more� number of female �flowers �per plant and� less �number of male �flowers per plant than the other treatments.</em>


1996 ◽  
Vol 74 (6) ◽  
pp. 898-908 ◽  
Author(s):  
Denis Barabé ◽  
Charles Bertrand

The floral development of Culcasia saxatilis, Culcasia tenuifolia, and Cercestis stigmaticus has been analyzed. These two genera possess unisexual flowers without perianth. In these species, the cylindrical inflorescence carry male flowers in the upper part and female flowers in the lower part. In C. tenuifolia, the separation between the female zone and the male zone is very sharp. There is no intermediate zone. In C. saxatilis and C. stigmaticus, we may observe rudimentary bisexual flowers between the two zones. In this intermediate zone, flowers located near the male zone possess male appendages more developped than those located near the female zone. On the other hand, the flowers located near the female zone possess female appendages more developped than those located near the male zone. The results suggest the existence of a morphogenetic gradient in the inflorescence of some species of Araceae. Keywords: morphogenesis, gradient, flower, development, inflorescence.


HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 462D-462
Author(s):  
H. Chris Wien ◽  
Dale Riggs

Reports of sharply reduced feral bee populations (Apis mellifera) due to harsh winters and prevalence of several bee diseases have raised concerns that pollination and fruit set in pumpkin fields will be adversely affected. In 1995 and 1996, five and eight pumpkin (Cucurbita pepo) fields, respectively, were inventoried on three occasions per season for pollinator activity and percent fruit set. Pollen removal from male flowers was determined visually using a rating scale, while deposition of pollen on stigmata of female flowers was judged by rating fluorescence of pollen on the stigmatic surface under a “black light.” Samples were taken from 15 to 30 locations in each field, and female flowers tagged. These were considered set if they had enlarged to fist size within 14 days. In both years, the amount of pollen remaining on male flowers was negatively correlated with female flower fluorescence ratings. Neither pollen on male flowers nor stigma fluorescence were significantly correlated with percent fruit set. Fifty-two percent of tagged flowers set fruit in both years, with a range of 24% to 84%, and 17% to 78% in 1995 and 1996, respectively. Presence of bee hives in or near the fields had no effect on fruit set. The results indicate that the pollen removal and deposition ratings used were not reliable for predicting fruit set in farmers' fields. In these 2 years, bee hives were not needed in the sampled fields.


HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 872b-872 ◽  
Author(s):  
Peter J. Dittmar ◽  
Jonathan R. Schultheis ◽  
David W. Monks

Pollen from triploid (seedless) watermelon (Citrullus lanatas) is nonviable. Diploid (seeded) watermelons are required in seedless watermelon production for pollination and fruit set. In 2004, markets continued to increase for triploid watermelon but decrease for diploid watermelons. Seed companies are commercializing diploid cultivars (pollenizers) specifically designed as a pollen source for triploid watermelon production. The objectives of this research were to characterize the vegetative, floral, and fruit growth and development of these pollenizers. Five cultivars were evaluated: `Companion', `Mickylee', `Mini Pool', `SP-1', and `Jenny'. When measuring the longest vine, `Companion' produced the smallest plants reaching a maximum vine length of 183 cm, 31 days after transplant (DAT). `Mickylee', `Mini Pool', `SP-1', and `Jenny' had similar vine lengths reaching maximum lengths ranging 294–335 cm, 31 DAT. The compact growth of `Companion' is consistent with the shorter node length of 3.8 cm, while the other pollenizers had a node length of 9.9–10.9 cm. `SP-1' produced more male flowers than the other pollenizers beginning 24 DAT and produced 30–40 male flowers per plant per day, 31–55 days after transplant. `Mickylee', `Mini Pool', and `Jenny' produced 9–15 male flowers per plant per day, 24–55 days after transplant. Early production of male flowers by `Companion' was similar to `Mickylee', `Mini Pool' and `Jenny'; however, flower production became the lowest compared with all pollenizer cultivars 24 DAT. `SP-1' produced more female flowers resulting in the most fruit production (4 fruit per plant). In contrast, `Companion' produced the fewest female flowers and produced 2 fruit per vine. `Mickylee' had the largest fruit weighing 5.9 kg, and `SP-1' and `Jenny' produced the smallest fruit weighing 3.1 kg. The use of specific pollenizers may provide the opportunity to customize production for specific cultivars for either early and or late harvests.


Author(s):  
Gregory J Anderson ◽  
Julia Pérez De Paz ◽  
Mona Anderson ◽  
Gabriel Bernardello ◽  
David W Taylor

Abstract Island plants provide special opportunities for the study of evolution and ecology. In field and greenhouse studies we characterized a model reproductive system for Plocama pendula, endemic to the Canary Islands. This species has a complicated and not immediately obvious reproductive system. Pollination is biotic, and all flowers are morphologically hermaphroditic, but half of the plants characteristically bear flowers with nectar, pistils with reflexed stigmatic lobes and pollen-less anthers (i.e. they are functionally female flowers). The other half bear nectar-less flowers with abundant pollen and full-sized pistils that mostly have un-reflexed stigmatic lobes (i.e. they are hermaphroditic flowers functioning mostly as males). However, experiments show these pollen-bearing flowers to be self-compatible. Thus, the functionally male flowers have a breeding system that allows selfing in limited circumstances, but the functionally male flowers produce far fewer fruits than do functionally female flowers. With morphologically gynodioecious, functionally largely dioecious flowers, sometimes capable of selfing, the reproductive system of this species could be labelled as ‘leaky’ in many respects. Thus, we propose that P. pendula has colonized new habitats and persists in substantial populations at least in part because it manifests a reproductive system that is a model for successfully balancing the often-conflicting evolutionary demands of colonization, establishment and persistence.


2004 ◽  
Vol 82 (10) ◽  
pp. 1459-1467 ◽  
Author(s):  
Denis Barabé ◽  
Christian Lacroix ◽  
Bernard Jeune

In Philodendron, pistillate flowers are initiated on the proximal portion of the inflorescence and staminate flowers are initiated on the distal portion. Between the staminate and pistillate flowers, there is a transition zone consisting of sterile male flowers adjacent to the male zone and a row of atypical bisexual flowers between the sterile male zone and the female zone. The portion of the atypical bisexual flower facing the male zone forms stamens, and the portion facing the female zone develops into an incomplete gynoecium with few carpels. The atypical bisexual flowers of Philodendron are believed to be a case of homeosis where carpels are replaced by sterile stamens on the same whorl. In Philodendron melinonii Brongniart ex Regel, Philodendron pedatum (Hooker) Kunth, Philodendron squamiferum Poeppig., and Philodendron solimoesense A.C. Smith, there is a significant quantitative relationship between the number of carpels and the number of staminodes involved in the homeotic transformation in atypical bisexual flowers. On the other hand, such a significant correlation does not exist in Philodendron fragrantissimum (Hooker) Kunth and Philodendron insigne Schott, and Philodendron callosum K. Krause. There is a one to one organ replacement in homeotic flowers in both P. pedatum and P. squamiferum whereas, in P. solimoesense, an average of 2.56 staminodes replace one carpel. The average number of organs developing on an atypical bisexual flower and the number of organs involved in a homeotic transformation appear to be two independent phenomena. The number of carpels in female flowers is correlated with the maximum total number of appendages (carpels and staminodes) that can develop in atypical bisexual flowers.Key words: development, inflorescence, gradient, position, information.


1992 ◽  
Vol 6 ◽  
pp. 305-305
Author(s):  
Mahito Watabe

The late Miocene Chinese hipparions are morphologically diversified showing similarity to both western Old World's and North American forms. Two Chinese taxa that are phylogenetically related to western Old World's forms are Hipparion fossatum (= H. forstende) from Baode (Shanxi) and H. hippidiodus from Qingyang (Gansu) and Baode. The former is related to H. mediterraneum and the latter to H. urmiense - platygenys from the Turolian localities in the western Old World. H. fossatum and H. hippidiodus are associated with the “dorcadoides” (open-land) and “mixed” faunas in northern China. Hipparion fossatum that is characterized by POF located close to the orbit co-occurs with large and morphologically specialized form, H. dermatorhinum in Baode (Loc.30). H. hippidiodus with reduced POF is discovered with smaller H. coelophyes in Loc. 43, 44 (Baode) and Loc. 115 (Gansu).The hipparions associated with the “gaudryi” (forest) fauna are characterized by well defined and small POF located far from the orbit. Those forms are: H. platyodus from Loc. 70; H. ptychodus from Loc. 73; H. tylodus from Hsi-Liang in Yushe - Wuxiang basins; and H. sefvei from Loc. 12 at Xin-an in Henan province. H. coelophyes from Baode (Loc.43 & 44) and Qingyang (Loc. 115) also show similar facial morphology to the these forms, although it has small size and shallow POF. Those forms are similar in facial and dental morphology to Hipparion sensu stricto and some species of Cormohipparion in North America.The assemblages of Chinese hipparions are composed of two groups whose members are phylogenetically similar to the forms from both western part of Eurasia and North America. The “gaudryi” fauna is considered younger than the other two on the basis of faunal analyses. The similarity in hipparionine taxonomy between northern China and North America in the latest Miocene is an evidences for possible faunal interchange(s) occurred during that period, as suggested by taxonomic analyses on carnivores and proboscideans in eastern half of Eurasia and North America.


2000 ◽  
Vol 77 (11) ◽  
pp. 1569-1579
Author(s):  
W A Charlton

Wiesneria triandra (Dalzell) Micheli is an unusual annual plant of the Alismataceae with spike-like inflorescences bearing unisexual flowers. Shoot development follows the sympodial pattern of other Alismataceae, but the cycle is so condensed that initiation of each foliage leaf is followed by inflorescence formation. The plant develops a tufted habit by the formation of an unusual accesory bud adjacent to each inflorescence. Male flowers have three sepals, three petals, three stamens, and usually three carpellodes; female flowers have a similar perianth, three staminodes, and three or more carpels. Up to the first three carpels, floral parts are arranged in alternating trimerous whorls. Additional carpels may occur above and between those of the first whorl. The androecium is particularly unusual for the Alismataceae since it has conventional alternation of stamens with petals rather than the antipetalous pairs of stamens commonly perceived in the family, but the phylogenetic postion of Wiesneria within the family (as revealed by other studies) indicates that the apparently conventional androecium of Wiesneria represents a derived state rather than a primitive one. The unisexual flowers also represent a derived state.


2009 ◽  
Vol 3 (2) ◽  
pp. 129-154
Author(s):  
HENRY SPILLER

AbstractThe powerful concept of orientalism has undergone considerable refinement since Edward Said popularized the term with his eponymous book in 1978. Orientalism typically is presented as a totalizing process that creates polar oppositions between a dominating West and a subordinate East. U.S. orientalisms, however, reflect uniquely North American approaches to identity formation that include assimilating characteristics usually associated with the Other. This article explores the complex relationship among three individuals—U.S. composer Charles T. Griffes, Canadian singer Eva Gauthier, and German-trained Dutch East Indies composer Paul J. Seelig—and how they exploited the same Javanese songs to lend legitimacy to their individual artistic projects. A comparison of Griffes's and Seelig's settings of a West Javanese tune (“Kinanti”) provides an especially clear example of how contrasting approaches manifest different orientalisms. Whereas Griffes accompanied the melody with stock orientalist gestures to express his own fascination with the exotic, Seelig used chromatic harmonies and a chorale-like texture to ground the melody in the familiar, translating rather than representing its Otherness. The tunes that bind Griffes, Gauthier, and Seelig are only the raw materials from which they created their own unique orientalisms, each with its own sense of self and its own Javanese others.


2007 ◽  
Vol 23 (5) ◽  
pp. 607-610 ◽  
Author(s):  
Mathieu Chouteau ◽  
Melanie McClure ◽  
Marc Gibernau

Data on pollination ecology of Araceae are still scarce and most concern species belonging to the subfamily Aroideae (García-Robledo et al. 2004, Gibernau 2003, Ivancic et al. 2004, 2005; Maia & Schlindwein 2006). In this subfamily, inflorescences consist of unisexual flowers: female flowers are located in the lower portion and the male flowers are in the upper portion of the inflorescence (Mayo et al. 1997). In the documented neotropical Aroideae, pollinators are nocturnal beetles and pollination mechanisms take place within a floral chamber during a short flowering cycle (generally 24–48 h) with floral rewards (sterile flowers rich in proteins and/or lipids) for the beetle pollinators, the secretion of resin to secure pollen on the pollinator, and the production of heat and odours (Chouteau et al. 2007, García-Robledo et al. 2004, Gibernau & Barabé 2002, Gibernau et al. 1999, 2000, 2003; Maia & Schlindwein 2006, Young 1986).


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