Floral Biology of an Alabama Population of the Federally Endangered Plant, Xyris tennesseensis Kral (Xyridaceae)

Castanea ◽  
2011 ◽  
Vol 76 (3) ◽  
pp. 255-265 ◽  
Author(s):  
Robert S. Boyd ◽  
Allison Teem ◽  
Michael A. Wall
2018 ◽  
Vol 44 (4) ◽  
pp. 605-611
Author(s):  
Anca Manole ◽  
Cristian Banciu

The phenology of Angelica palustris seeds including maturation, germination requirements, and dormancy class, is still unknown. In opposite to the results reported from other species of Angelica, present findings showed that A. palustris produced seeds with embryo underdeveloped (the ratio between the embryo and the whole seed length was between 0.19 and 0.12) and physiologically dormant which corresponded to Morphophysiological Dormancy class. Dormancy breakdown requires a post maturation period (at least 30 days) at 18 - 20ºC for a complete embryo development, and also up to 30 days of cold stratification at 4°C. The best germination indices were obtained when fruit was removed. Germination energy (Ge) was achieved within 19 days after imbibition and was 25.8 + 0.03 and germination per cent (Gp) was achieved within 28 days and was 64.7 + 0.14. Fruit structure (lateral wings with air cavities) and physiology (essential oil production) are adaptations to facilitate seed dispersal and dormancy/germination balance.


2020 ◽  
Vol 105 (3) ◽  
pp. 281-299
Author(s):  
Javier Carreño-Barrera ◽  
Luis Alberto Núñez-Avellaneda ◽  
Maria José Sanín ◽  
Artur Campos D. Maia

Solitary, dioecious, and mostly endemic to Andean cloud forests, wax palms (Ceroxylon Bonpl. ex DC. spp.) are currently under worrisome conservation status. The establishment of management plans for their dwindling populations rely on detailed biological data, including their reproductive ecology. As in the case of numerous other Neotropical palm taxa, small beetles are assumed to be selective pollinators of wax palms, but their identity and relevance in successful fruit yield were unknown. During three consecutive reproductive seasons we collected data on population phenology and reproductive and floral biology of three syntopic species of wax palms native to the Colombian Andes. We also determined the composition of the associated flower-visiting entomofauna, quantifying the extent of the role of individual species as effective pollinators through standardized value indexes that take into consideration abundance, constancy, and pollen transport efficiency. The studied populations of C. parvifrons (Engel) H. Wendl., C. ventricosum Burret, and C. vogelianum (Engel) H. Wendl. exhibit seasonal reproductive cycles with marked temporal patterns of flower and fruit production. The composition of the associated flower-visiting entomofauna, comprised by ca. 50 morphotypes, was constant across flowering seasons and differed only marginally among species. Nonetheless, a fraction of the insect species associated with pistillate inflorescences actually carried pollen, and calculated pollinator importance indexes demonstrated that one insect species alone, Mystrops rotundula Sharp, accounted for 94%–99% of the effective pollination services for all three species of wax palms. The sequential asynchronous flowering of C. parvifrons, C. ventricosum, and C. vogelianum provides an abundant and constant supply of pollen, pivotal for the maintenance of large populations of their shared pollinators, a cooperative strategy proven effective by high fruit yield rates (up to 79%). Reproductive success might be compromised for all species by the population decline of one of them, as it would tamper with the temporal orchestration of pollen offer.


2011 ◽  
Vol 29 (1) ◽  
pp. 58-63
Author(s):  
Yong-Hui LIN ◽  
Xing-Bing HE ◽  
Wen-Yong HU ◽  
Qi-Jian TIAN ◽  
Ping HE

2010 ◽  
Vol 58 (5) ◽  
pp. 373 ◽  
Author(s):  
L. Baskorowati ◽  
M. W. Moncur ◽  
J. C. Doran ◽  
P. J. Kanowski

Melaleuca alternifolia (Maiden & Betche) Cheel is commercially important as the source of essential oil for the Australian tea tree-oil industry. Information on reproductive biology of M. alternifolia is important to the Australian breeding program directed at improving the quality and quantity of tea tree oil. Flowering in three geographically separated sites – two planted seed orchards and one managed natural population, all in NSW – was observed in the present study, with supporting data obtained from glasshouse-grown plants in Canberra. The majority of the work was conducted from 2004 to 2007, although the study also drew on some prior observations. M. alternifolia has spikes of flowers that open acropetally over a 6-day period. No strong separation of male and female phases was found in any individual flower; pollen was shed by 1.4 days after anthesis and the stigma reached peak receptivity 3–5 days after anthesis. Dichogamy and acropetal floral development may lead to geitonogamy. Flowering occurred during the months of October–November, with the peak in November, and was synchronous across all three sites. Flowering intensity and success in producing capsules appeared to be associated with total spring rainfall. Initiation of flowering in M. alternifolia appears to be correlated with daylength, or an environmental parameter closely correlated with daylength. Flowering intensity varied considerably among the years surveyed, sites and families, and appears to be promoted by a period of winter minimum temperatures below 5°C. In M. alternifolia, the morphological development of buds, flowers and fruit leading to the development of mature seed takes place over a period 16–18 months from flowering. M. alternifolia differed significantly in the number of viable seeds per capsule from individual trees, from 26 ± 3.8 to 57 ± 3.8 germinants.


1993 ◽  
Vol 9 (2) ◽  
pp. 199-211 ◽  
Author(s):  
Rogério Gribel ◽  
John D. Hay

ABSTRACTThe floral biology, breeding system and pollination of Caryocar brasiliense were studied in the cerrado vegetation of Central Brazil. The large, yellowish-cream, brush-like flowers are pollinated mainly by glossophagine bats (Glossophaga soricina and Anoura geoffroyi). Three non-glossophagine bats (Phyllostomus discolor, Vampyrops lineatus and Carollia perspicillata) and two short probosisced hawk moths (Erinyis ello and Pseudosphinx tetrio) may also act as occasional pollinators. Caryocar brasiliense is self-compatible although it sets significantly more fruits when crossed than when selfed. The natural fruit set (fruit/flower ratio) and seed set (seed/ovule ratio) are 3.1% and 1.0% respectively. Most of the fruits and seeds are formed through the action of the flower visitors, despite the fact that about 20% of the non-visited flowers receive self pollen on at least one stigma.


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