The effect of pollination intensity and incompatible pollen on seed set in Turnera ulmifolia (Turneraceae)

1984 ◽  
Vol 62 (6) ◽  
pp. 1298-1303 ◽  
Author(s):  
Joel S. Shore ◽  
Spencer C. H. Barrett
Keyword(s):  
Regression Analysis ◽  
Seed Set ◽  
Pollen Grains ◽  
The Self ◽  
Time Intervals ◽  
Pollination Experiments ◽  
Controlled Pollination ◽  
Incompatible Pollen ◽  
Turnera Ulmifolia ◽  
Compatible Pollen

Controlled pollination experiments were performed on the self-incompatible distylous herb Turnera ulmifolia L. to investigate the effects of pollination intensity and large amounts of incompatible pollen on seed set. In the first experiment, known numbers of compatible pollen grains ranging from 1 to 100 were applied to stigmas of the floral morphs. In both morphs, increasing amounts of pollen generally resulted in increased levels of seed set, although considerable variance was observed at all pollination intensities. Approximately two to seven pollen grains are required to produce a single seed and more than 95 grains are required to achieve maximum seed set in T. ulmifolia. Regression analysis of the seed set data failed to detect a difference in the response of the floral morphs to pollination intensity. In the second experiment, known proportions of compatible and incompatible pollen were applied to stigmas at various time intervals. Most treatments involving mixtures of compatible and incompatible pollen had no significant effect on seed set when compared with the controls. Clogging was only observed in the long-styled morph when one anther of compatible pollen was applied to stigmas 1.5 and 3.0 h after pollination with five anthers of incompatible pollen. The clogging of stigmas by incompatible pollen seems unlikely to have played a major role in the evolution and maintenance of distyly in Turnera ulmifolia.

Incompatibility, stamen movement and pollen economy in a heterostyled tropical forest tree, Cratoxylum formosum (Guttiferae)

1982 ◽  
Vol 214 (1195) ◽  
pp. 273-283 ◽  
Keyword(s):  
Critical Level ◽  
Pollen Grains ◽  
Forest Tree ◽  
Incompatible Pollen ◽  
Insect Visitation ◽  
Small Pollen ◽  
Evolutionary Step ◽  
Novel Method ◽  
Compatible Pollinations ◽  
Compatible Pollen

Cratoxylum formosum shows all the classical features of a distylic species. The two types are: long-styled plants with short stamens and small pollen grains and short-styled plants with long stamens and large pollen grains. Compatible pollinations are only between the two types; incompatible pollen tubes are inhibited in the style. A significant morphological feature distinguishes Cratoxylum from distylic plants in other families. Instead of having a small number of anthers making well separated narrow discs in the two types, Cratoxylum has many anthers (144) and they are arranged on staminal bundles that produce long cylinders of anthers that partially occupy similar height zones in the two types of flower. A novel method of separation of the two height zones is achieved by the bending of the stamens of the long-styled type when the flower opens, which converts the cylinder to a narrow disc of anthers at the same height as the ‘short’ stigma. The bending coincides with anther dehiscence and is slightly later than the first daily insect visitation. The anthers return to the upright position later in the day, when the pollination is complete. There was a 20-fold difference between the amounts of pollen deposited on the two types of stigmas. The ‘long’ stigmas received 1200 pollen grains per flower, in the ratio of 46 ‘long’ to 54 ‘short’, which is close to the ratio of two types of pollen produced in the population. This random deposition of pollen on ‘long’ stigmas is, however, more than adequate for the 36 seeds produced per flower. ‘Short’ stigmas received only 64 pollen grains per flower, in the ratio of 90 ‘long’ to 10 ‘short’, and several flowers had below the critical level of 36 compatible pollen grains for full seed production. Pollen loads of the pollinating bee, Apis javana , consisted of ‘long’ and ‘short’ pollen on the thorax in the ratio found on the ‘long’ stigma, and on the head of the bee in a ratio close to the 9:1 found on the ‘short ’ stigma. The corbicular loads reflected accurately the pollen of the tree in which the bee was caught. For Cratoxylum the accurate positioning of the anthers of the long-styled plant in relation to the visiting bees head was an important evolutionary step in the effective pollination of the short-styled form, which, at least in this species, is one critical and highly selected feature of the system.

The formation of the tryphine coating the pollen grains of Raphanus , and its properties relating to the self-incompatibility system

1973 ◽  
Vol 184 (1075) ◽  
pp. 149-165 ◽  
Keyword(s):  
Granular Material ◽  
Pollen Grains ◽  
The Self ◽  
Self Incompatibility ◽  
Pollen Maturation ◽  
Incompatible Pollen ◽  
Incompatibility System ◽  
Two Stages ◽  
Stimulation Of ◽  
Incompatible Pollen Tube

The tryphine that coats the pollen grains of Raphanus is tapetally synthesized and is composed of a fibro-granular and a lipidic component. The fibro-granular material is proteinaceous and is secreted by cisternae of the endoplasmic reticulum. The lipidic component is derived, mainly, from degraded elaioplasts. The fibro-granular material is applied to the pollen exine first, followed by the lipidic mass. The tryphine condenses during the final stages of pollen maturation and dries down to form a thick, highly viscous coating. The major part of the condensation appears to result from dehydration. The tryphine, extracted from the pollen by a centrifugal method and mounted in a membrane, appears to be capable of penetrating the outer layers of a stigma of the same species and, if the pollen from which it was derived is incompatible with respect to the stigma, the stimulation of the production of the callosic reaction body in a manner similar to an incompatible pollen tube. It is proposed that, in Raphanus , substances responsible for the initiation of at least two stages in the self-incompatibility system are held in the tryphine.

ENHANCEMENT OF POLLEN GERMINATION BY PROMOTIVE FACTORS IN INCOMPATIBLE POLLEN

1999 ◽  
Vol 47 (3) ◽  
pp. 165-168
Author(s):  
Dan Eisikowitch ◽  
Hazel Y. Wetzstein
Keyword(s):  
Pollen Grains ◽  
Commercial Production ◽  
In Vitro Assays ◽  
Viable Seed ◽  
Inhibitory Effects ◽  
Incompatible Pollen ◽  
Elemental Analyses ◽  
Compatible Pollen ◽  
Selection Of

Cultivated and wild almonds are self-incompatible and thus require outcrossing by insect pollinators to produce viable seed. In commercial production, considerable efforts are directed towards placement and selection of cultivars for cross-pollination. However, since honeybees do not distinguish between the different cultivars, stigmas are usually covered by a mixture of both compatible and incompatible pollen. Using in vitro assays, we demonstrated that pollen extracts promoted germination in self pollen with no inhibitory effects observed. Elemental analyses of pollen extracts showed that enhanced levels of Ca, Mg, K, Na, and P were eluted from the grains. From this, we raise the question of possible interaction between compatible and incompatible pollen, and speculate that incompatible pollen grains may support and enhance germination of adjacent compatible pollen.

scholarly journals Characterization of the role of several COPI complex isoforms during the early acceptance of compatible pollen grains in Arabidopsis thaliana

2018 ◽  
Author(s):  
Daniel A. Cabada Gomez ◽  
M. Isabella Chavez ◽  
Emily Indriolo
Keyword(s):  
Pollen Tube ◽  
Seed Set ◽  
Contact Point ◽  
Pollen Grains ◽  
Retrograde Transport ◽  
Pollen Grain ◽  
Knock Out ◽  
Pollen Tube Penetration ◽  
Compatible Pollen

AbstractCOPI is a seven subunit coatomer complex, consisting of α, β, β′, γ, δ, ε, and ξ; in A. thaliana, COPI is necessary for retrograde transport from the Golgi to the Endoplasmic Reticulum, Golgi maintenance, and cell-plate formation in plant cells. Vesicle recruitment to the pollen contact point is required for pollen hydration and pollen tube penetration. To determine what other aspects of trafficking may be involved in the stigmatic papillae acceptance of compatible pollen, knock-out lines of several isoforms of the COPI complex were characterized in their roles during compatible pollination. Isoforms that were studied included α1-COPI, β-COPI, β′-COPI, γ-COPI and ε-COPI. Each mutant line was characterized in regards to pollen grain adherence, pollen tube penetration, and seed set. Of the mutant lines examined, α1-copi had the strongest phenotype with issues with compatible pollen grain adherence, tube germination and reduction in seed set while other lines had milder but visible retardation in compatible pollen acceptance. The data presented here are the first study of the role of the COPI complex in compatible pollinations and that certain subunit isoforms are required for compatible pollen acceptance.

scholarly journals Pollen Germination, Pollen Tube Growth, Fruit Set, and Seed Development in Schlumbergera truncata and S. ×buckleyi (Cactaceae)

1995 ◽  
Vol 120 (2) ◽  
pp. 313-317 ◽  
Author(s):  
Thomas H. Boyle ◽  
Renate Karle ◽  
Susan S. Han
Keyword(s):  
Seed Set ◽  
Genotypic Variation ◽  
Pollen Grains ◽  
Pollen Tubes ◽  
Flower Opening ◽  
Stigma Surface ◽  
Series Of Experiments ◽  
Time Required ◽  
Compatible Pollen ◽  
Fruit Harvest

The reproductive biology of Schlumbergera truncata (Haworth) Moran and S. xbuckleyi (T. Moore) Tjaden was examined in a series of experiments. At anthesis, pollen grains are spherical, 54 to 62 μm in diameter, and tricellular. The receptive surface of the stigma is densely covered with elongated papillae and is devoid of exudate during the period of flower opening. When compatible pollen was applied to mature stigmas, germination occurred between 20 and 30 minutes after pollination and pollen tubes penetrated the stigma surface between 30 and 40 minutes after pollination. Pollen tubes exhibited a nonlinear pattern of growth in the upper two-thirds of the style, and the maximum rate of growth (≫1.9 mm·h-1) occurred between 12 and 18 hours after pollination. Full seed set was attained between 32 and 48 hours after pollination. Genotypic variation in the time required to achieve full seed set was partly attributable to differences in stylar length. Seeds were fully mature 6 months after pollination, but delaying fruit harvest until 8 months after pollination did not affect seed germination.

POLLEN PRODUCTION AND DISSEMINATING PROPERTIES OF TRITICALE RELATIVE TO WHEAT

1972 ◽  
Vol 52 (4) ◽  
pp. 569-574 ◽  
Author(s):  
K. C. YEUNG ◽  
E. N. LARTER
Keyword(s):  
Seed Set ◽  
Marker Gene ◽  
Pollen Grains ◽  
Triticum Aestivum L ◽  
Hybrid Seed Production ◽  
Pollen Production ◽  
Hexaploid Triticale ◽  
Anther Length ◽  
Anther Extrusion ◽  
Wide Range

A study of the pollen production properties of three hexaploid triticale strains (Triticale hexaploide Lart.) showed that their anther length was significantly greater than that of wheat anthers (Triticum aestivum L. em Thell.) and the estimated number of pollen grains per anther ranged from 15,000 to 21,000. In comparison, a total of 8000 grains per anther was estimated for wheat, cult Manitou. Eighty-nine percent anther extrusion occurred in triticale cult Rosner, while Manitou averaged 70% anther extrusion. The period of anthesis of triticale varied according to strain but generally was of longer duration than in Manitou and thereby promoted outcrossing. Using a triticale strain carrying a dominant marker gene, 50% seed-set was obtained at a distance of 12 m leeward of the pollen source; however, a small percentage was still obtained at a distance of 30 m. It would appear from the limited number of triticales used in this study that a wide range of variability exists within this species in its pollen production and disseminating properties. With appropriate selection pressures, strains with an outbreeding habit could be developed for the purpose of hybrid seed production.

CYTOLOGY OF 2n POLLEN FORMATION IN DIPLOID ALFALFA, MEDICAGO SATIVA

1979 ◽  
Vol 21 (4) ◽  
pp. 525-530 ◽  
Author(s):  
Nicholi Vorsa ◽  
E. T. Bingham
Keyword(s):  
Medicago Sativa ◽  
Seed Set ◽  
Pollen Grains ◽  
Genetic Constitution ◽  
2N Pollen ◽  
Diploid Parent ◽  
2N Gamete ◽  
Medicago Sativa L ◽  
Pollen Formation ◽  
Mother Cells

Four diploid (2x) clones of alfalfa, Medicago sativa L., which produced good seed set when used as male parents in 4x-2x crosses were selected for study. The 2x clones descended from 2x haploids of cultivated 4x alfalfa. Fertility in the 4x-2x cross was due to the production of pollen with the unreduced chromosome number (2n pollen) from the 2x parent. The cytological mechanism of 2n pollen formation was found to be disorientation of spindles at metaphase II in up to 38% of the pollen mother cells. Thus, both n and 2n pollen were produced by all four diploids examined. Normal spindles at metaphase II were oriented such that they defined the poles of a tetrahedron and resulted in normal tetrads in a tetrahedral arrangement. Disoriented spindles were basically parallel to each other and resulted in formation of dyads and occasionally a triad. Dyads developed into two 2n pollen grains; triads developed into one 2n and two n pollen grains. Since both n and 2n pollen grains are produced by the diploids, they can be maintained as diploids or they can be used as male parents in crosses to tetraploids. The genetic constitution of 2n pollen resulting from parallel spindles is similar to that expected after first division restitution of meiosis and much of the heterozygosity of the diploid parent is conserved in the gametes. The 2n gamete mechanism has potential application in germplasm transfer and in maximizing heterozygosity in tetraploid hybrids.

CORRELATED RESPONSE IN BROWN SARSON

1970 ◽  
Vol 12 (4) ◽  
pp. 905-913 ◽  
Author(s):  
T. Swamy Rao
Keyword(s):  
Gamma Irradiation ◽  
Seed Set ◽  
Previous History ◽  
The Self ◽  
Correlated Response ◽  
History Of ◽  
Self Compatibility ◽  
Selection For ◽  
Direction Opposite ◽  
Brown Sarson

The correlated response with changes in self-compatibility in three varieties of brown sarson subjected to gamma irradiation was examined. Selection for improved seed set in the irradiated populations showed that substantial correlated response can result for a constellation of other characters in which the self-compatible and self-incompatible forms differ. The correlated response was in a direction opposite to that of the previous history of selection.

PENGARUH SELF ASSESSMENT SYSTEM DAN SISTEM INFORMASI PERPAJAKAN TERHADAP KEPATUHAN WAJIB PAJAK

2017 ◽  
Vol 13 (1) ◽  
pp. 31
Author(s):  
Endang Satyawati ◽  
Mardanung Patmo Cahjono
Keyword(s):  
Information System ◽  
Regression Analysis ◽  
Tax Compliance ◽  
Assessment System ◽  
The Self ◽  
Analysis Tool ◽  
Self Assessment ◽  
Independent Variables ◽  
Tax Payers ◽  
Positive Effect

Taxes are a financial source for state revenues, so that the tax authorities as the tax collector must perform outreach to tax payers and improve tax compliance. This study aims to determine the effect of the self-assessment system and the information system of taxation on tax payer compliance. The analysis tool used regression analysis to examine the effect of independent variables on the dependent variable. The result of research that the self-assessment system and the information system of taxation positive effect on tax compliance. The study is expected to contributed positively both to the tax office and can be used as a reference for further research.Keywords: self-assessment system, the information system of taxation, and tax compliancePajak adalah sumber keuangan untuk penerimaan negara, sehingga otoritas pajak sebagai pemungut pajak harus melakukan penjangkauan ke wajib pajak dan memperbaiki kepatuhan pajak. Penelitian ini bertujuan untuk mengetahui pengaruh sistem self-assessment dan sistem informasi perpajakan terhadap kepatuhan wajib pajak. Alat analisis yang digunakan adalah analisis regresi untuk menguji pengaruh variabel bebas terhadap variabel dependen. Hasil penelitian bahwa sistem self-assessment dan sistem informasi perpajakan berpengaruh positif terhadap kepatuhan pajak. Penelitian ini diharapkan dapat memberikan kontribusi positif baik terhadap kantor pajak maupun dapat dijadikan referensi untuk penelitian lebih lanjut.Kata kunci: sistem asesmen diri, sistem informasi perpajakan, dan kepatuhan pajak

scholarly journals Why so many flowers? A preliminary assessment of mixed pollination strategy enhancing sexual reproduction of the invasive <i>Acacia longifolia</i> in Portugal

Web Ecology ◽  
2018 ◽  
Vol 18 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Manuela Giovanetti ◽  
Margarida Ramos ◽  
Cristina Máguas
Keyword(s):  
Invasive Plant ◽  
Seed Set ◽  
Pollen Grains ◽  
Striking Difference ◽  
Pollination Syndromes ◽  
Pollination Success ◽  
Relative Contribution ◽  
Acacia Longifolia ◽  
Exclusion Experiments ◽  
Pollination Strategy

Abstract. Acacia longifolia, a native legume from Australia, has been introduced in many European countries and elsewhere, thus becoming one of the most important global invasive species. In Europe, its flowering occurs in a period unsuitable for insect activity: nonetheless it is considered entomophilous. Floral traits of this species are puzzling: brightly coloured and scented as liked by insects, but with abundant staminate small-sized flowers and relatively small pollen grains, as it is common in anemophilous species. Invasion processes are especially favoured when reshaping local ecological networks, thus the interest in understanding pollination syndromes associated with invasive plant species that may facilitate invasiveness. Moreover, a striking difference exists between its massive flowering and relatively poor seed set. We introduced a novel approach: first, we consider the possibility that a part of the pollination success is carried on by wind and, second, we weighted the ethological perspective of the main pollinator. During the flowering season of A. longifolia (February–April 2016), we carried on exclusion experiments to detect the relative contribution of insects and wind. While the exclusion experiments corroborated the need for pollen vectors, we actually recorded a low abundance of insects. The honeybee, known pollinator of acacias, was relatively rare and not always productive in terms of successful visits. While wind contributed to seed set, focal observations confirmed that honeybees transfer pollen when visiting both the inflorescences to collect pollen and the extrafloral nectaries to collect nectar. The mixed pollination strategy of A. longifolia may then be the basis of its success in invading Portugal's windy coasts.

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