A study of the reproductive biology of blue-flowered Conospermum species (Proteaceae)

2006 ◽  
Vol 54 (6) ◽  
pp. 543 ◽  
Author(s):  
Lynley M. Stone ◽  
Kevin A. Seaton ◽  
Margaret Byrne ◽  
Jen A. McComb

Blue-flowered Conospermum species are endemic to Western Australia, and are highly sought after in the horticulture industry. Aspects of the reproductive biology of several species were investigated. The paniculate inflorescences of Conospermum eatoniae E.Pritz. contain 6–10 florets; however, the uppermost two or three florets never open and only the basal one or two florets in an inflorescence set seed. When insect pollinators are excluded, flowers do not self-pollinate and set seed. Stigma receptivity occurred for up to 6 days following triggering of the style and was variable between C. eatoniae, C. amoenum Meisn. subsp. amoenum, C. caeruleum R.Br. and C. brownii Meisn. Hand-pollination with 10 pollen genotypes and two maternal C. eatoniae parents showed that although pollen tubes were observed in the style, no seed was set. Genetic analysis of open-set seed progeny showed that C. eatoniae outcrossed infrequently when grown in clonal rows in a plantation, but outcrossing was common in wild plants. This study demonstrates that the reproductive biology of blue-flowered Conospermum is complex and requires further investigation if the species are to be widely cultivated for horticulture.


1993 ◽  
Vol 41 (5) ◽  
pp. 611 ◽  
Author(s):  
EA James ◽  
RB Knox

We studied the reproductive biology of Australian species of Pandorea to facilitate a breeding program designed to develop elite cultivars for the horticultural industry. P. pandorana is protogynous whereas anther dehiscence and stigma receptivity occur at the same time in P. jasminoides and P. baileyana. The stigmas of all species are receptive prior to anthesis and can be artificially pollinated at this stage provided that the stigma lobes can be separated. Pollen viability, tested for P. pandorana and P. jasminoides, deteriorated during the flower life although pollen samples with a low Fluorescein diacetate response (5-14%) still produced many pollen tubes which grew to the base of the style. For all species tested, pollen tubes grew into the ovary in both outcross pollinations and in self pollinations which are known to be incompatible indicating that the incompatibility barrier is within the ovary. Pollen-ovule ratios, determined for P. pandorana and P. jasminoides, were low compared with other published pollen-ovules ratios for taxa with breeding systems based on outcrossing.



Author(s):  
Muzaffar Ahmad Ganie ◽  
Amit Kumar Pal ◽  
Nazeer Ahmad

It is now clear that over use of pesticides and intensive management of orchards can lead to drastic declines in apple pollinator abundance and crop failures. During the period of study a grower’s survey was conducted to know about knowledge of farmers on native insect pollinators, pollinator management practices, their perceptions of the importance and utility of native pollinators, and their attitudes regarding pesticide application. Despite of having significant knowledge of managed pollination, only few farmers (2%) adopted supplementary methods of pollination (renting honey bee colonies, hand pollination etc.). In Pulwama, 60% of farmers had knowledge about native insect pollinators and 40% did not have any idea of native pollinators and in case of Shopian, the figures were fifty-fifty i.e. 50% had knowledge about native insect pollinators and 50% were unaware. During the period of investigation, native insect pollinators were sampled from different apple orchards under different management systems in early spring during apple flowering. A total of 17 species of insect pollinators belonging to 11 families and 3 orders_ Hymenoptera, Diptera and Lepidoptera registered their occurrence at all the studied apple orchards of the Kashmir Valley. At all the study sites i.e. apple orchards under different management systems, family Halictidae and Empididae registered their presence as dominant groups. The % family contribution of the former at different orchard types decreased with increase in the intensity of the management system and the % family contribution of the later however, showed a direct relationship with the management system found, i.e. the more intense the system, the more abundant was the group. Other groups in general did not show any greater differences in abundances at different sites studied.



2016 ◽  
Vol 10 (2) ◽  
pp. 195
Author(s):  
Erniwati Erniwati ◽  
Sih Kahono

The role of the wild plants in relation to the conservation of the Indonesian insectpollinators was studied at several areas of Java. Three of direct observationmethods were applied: study of biodiversity and observation on the wild flowersand the insect pollinators as well, and the behaviour of the insects. The flowersof wild plants were relatively smaller and paler in colour, however they were moreattractive to insect pollinators than cultivated plants. Flowering time of the wildplants was mostly during wet seasons, contrary to that of the cultivated plantswhich was mostly during dry seasons. Our observation indicated that these wildplants are the food resources of insect pollinators during wet seasons. Observationdata support the importance of wild plants to supply food to insect pollinatorsduring wet seasons. Management of wild and cultivated plant environments isnecessary to conserve insect pollinators.



2021 ◽  
Vol 154 (2) ◽  
pp. 207-216
Author(s):  
Isys Mascarenhas Souza ◽  
Frederic Mendes Hughes ◽  
Ligia Silveira Funch ◽  
Luciano Paganucci de Queiroz

Background and aims – Copaifera coriacea, a species in the resin-producing clade Detarioideae (Leguminosae), is an endemic and abundant species found in sand dunes in Brazilian Caatinga domain vegetation – a Quaternary paleodesert. We investigated floral traits and aspects of pollination biology, focusing on the pollination system of C. coriacea. Material and methods – Anthesis duration, stigma receptivity, pollen viability, nectar concentration, and the presence of osmophores and pigments reflecting UV light were assessed. Floral visitors were classified as potential pollinators, occasional pollinators or thieves, based on the time and foraging behaviour and resource collected. Pollination effectiveness were assessed for potential pollinators by the detection of pollen tubes on the stigma or stylar canal by epifluorescence microscopy.Key results – The species has white and small flowers, with anthesis beginning in the dark (ca 00:30) and the flowers are completely opened approximately 3 h later, when a sweet odour is perceptible. The onset of stigma receptivity and pollen grain viability occurs only after the completion of flower opening, and a concentrated nectar is available during the day. The presence of pollen tubes confirmed the efficiency of the main insects in the transfer of pollen. Conclusion – Our result demonstrates that C. coriacea has a generalist pollination system mediated mainly by two distinct guilds of insect pollinators: moths (nocturnal, searching for nectar) and bees (diurnal, pollen collectors). This finding can provide more information about diversification in the genus Copaifera.



2006 ◽  
Vol 54 (6) ◽  
pp. 559 ◽  
Author(s):  
T. Page ◽  
G. M. Moore ◽  
J. Will ◽  
G. M. Halloran

The onset and duration of stigma receptivity in K. pomifera was evaluated by observing stigma peroxidase activity, pollen-tube growth and seed set, following controlled pollination of flowers of different ages. Peroxidase activity was negligible from 1 day before to 4 days after anthesis, increasing to a peak of 65% at Day 13. The percentage of pistils bearing germinated pollen and ovaries exhibiting pollen-tube entry increased when pollen was applied to the stigma from the day before anthesis, to a maximum at Days 6 and 7 after anthesis, respectively, followed by a decline by Day 9. Under greenhouse conditions the optimum pollination period, measured as the level of set seed after pollination, ranged from 2 to 11 days after anthesis. The knowledge of this aspect of the species reproductive biology is of considerable value in controlled pollinations for its improvement as a new crop.



2003 ◽  
Vol 142 (2) ◽  
pp. 369-379 ◽  
Author(s):  
S. Wilson ◽  
M. Meekan ◽  
J. Carleton ◽  
T. Stewart ◽  
B. Knott


1987 ◽  
Vol 65 (1) ◽  
pp. 107-111 ◽  
Author(s):  
Candace Galen ◽  
R. C. Plowright

Stigma peroxidase activity was tested in flowers of Pedicularis canadensis and Clintonia borealis at discrete age-classes during the course of anthesis. For recipient flowers of each age-class pollen adhesion, rate of pollen germination, and total number of grains germinating on stigmas were scored following hand-pollination. In P. canadensis, the onset of detectable peroxidase activity occurred at the transition from the juvenile to pollen-dehiscing age-class. Concurrently, the stickiness of the stigma surface and total number of grains germinating on the stigma increased significantly. Stigma peroxidase was present to some degree throughout anthesis in C. borealis. However, the percentage of the stigma surface in which peroxidase was detectable increased significantly between straight-sided and medium-curled flower age-classes. Again, corresponding increases occurred in the stickiness of the stigma surface and total number of grains germinating. Results suggest that for both species stigma peroxidase activity is a reliable indicator of receptivity.



1993 ◽  
Vol 41 (1) ◽  
pp. 35 ◽  
Author(s):  
M Ramsey ◽  
N Prakash ◽  
S Cairns

The breeding systems of disjunct tableland and coastal populations of Christmas bells were determined using hand-pollination experiments. In both populations, 90% or more of self-pollinated plants produced seeds. Tableland plants were significantly more self-fertile than coastal plants (ratio of self seed set to cross seed set: tableland, 0.55 ± 0.03; coast, 0.08 ± 0.02). Significant variation among plants for self-fertility was found in both populations. Autofertility was 1.6% or less in both populations indicating that pollen vectors are necessary for seed set. Seed set by agamospermy in both populations was less than 0.1%. Percentage seed abortion was greater in self-pollinated plants than cross-pollinated plants in both populations. In both self- and cross-pollinated plants, seed abortion was twice as great in the coastal population than in the tableland population. No evidence was found for stigmatic or stylar self-incompatibility. Self and cross pollen adhered to and germinated equally well on stigmas in both populations (72 - 77% germination). Similarly, there were no differences between pollination treatments or populations in the percentage of ovules penetrated by pollen tubes (82 - 89% penetration). When self-pollination preceded cross-pollination by 24 h or longer seed set was significantly reduced compared to flowers that were cross-pollinated only, suggesting ovules were pre-empted by self pollen tubes. Collectively these results strongly suggest that self seed set was reduced by a mechanism operating at the ovule level, such as early-acting inbreeding depression due to recessive seed-aborting genes, although incomplete late-acting self-incompatibility cannot be ruled out. For coastal plants, this ovular mechanism largely prevents selfing, indicating plants were predominantly outcrossing although most produced some self seed. For tableland plants, substantial seed set by selfing may occur under natural conditions.



1985 ◽  
Vol 12 (6) ◽  
pp. 641 ◽  
Author(s):  
JS Pate ◽  
NE Casson ◽  
J Rullo ◽  
J Kuo

The growth, longevity, mineral relationships and reproductive biology of 18 species of fire ephemerals were examined in sclerophyllous shrubland, located mainly within the Jurien : Badgingarra region of the Northern Sandplains of the kwongan of SW. Australia. Ten of the species were monocarpic, completing their life cycle within the 6-8 month winter growing season after a summer or autumn fire. The remaining species were polycarpic, commencing reproduction in their second season and surviving and reproducing for a further two to eight seasons (depending on species). Detailed study was made of growth and dry matter allocation in the dioecious, sexually dimorphic, polycarpic species Tersonia brevipes (Gyrostemonaceae). Monocarpic species tended to produce smaller seeds, and exhibited greater seed output per unit biomass and higher harvest indices for dry matter and minerals than polycarpic species. Certain monocarpic species showed great plasticity in final dry weight, e.g. a 2700-fold difference between largest and smallest individuals in a sample of 250 plants of Stipa elegantissima (Poaceae), and a 180-fold range in a similarly sized sample of Macarthuria apetala (Aizoaceae). The fire ephemerals studied generally exhibited faster seedling growth rates, greater concentrations of P and N (but not of Ca, Mg and K) in seedling dry matter, but usually lesser concentrations of P and N (but not of Ca, Mg and K) in seed dry matter than in cohabiting obligate seeder or sprouter species with potential life spans exceeding 15 years. The above-mentioned features of fire ephemerals are suggested to be of special adaptive significance within the context of exploitation of transiently non-limiting habitat resources immediately following fire.



2021 ◽  
Vol 26 (2) ◽  
pp. 85-91
Author(s):  
Janis Damaiyani

Parmentiera cereifera Seem. is an endangered species in the family Bignoniaceae. Related to the conservation effort, information about the reproductive biology of this species is very limited. Based on that, the objectives of this study were to provide knowledge about the reproductive properties such as floral biology and breeding system of P. cereifera. The research was conducted at Purwodadi Botanic Garden, from October 2019 to February 2021. Several important aspects of reproductive biology, including flower biology, pollen viability and stigma receptivity, pollen morphology and breeding system were investigated. The viability was tested with TTC (2, 3, 5–triphenly tetrazolium chloride) and stigma reseptivity was tested with hydrogen peroxide. The breeding system was determined based on outcrossing index (OCI) using Cruden's method. The results showed that P. cereifera flower was monoecious, had morphological character that supported nocturnal pollination. Stigma and anthers spatially separated, but there was no temporal separation of stigma receptivity and anther dehiscence. Based on the flower biology, the pollen ornamentation (reticulate type), and the Out-Crossing Index (OCI=4), the breeding system was outcrossing but partially self-compatible, required pollinators (zoophily)



Sign in / Sign up

Export Citation Format

Share Document