The site of action of crossability genes (Kr 1, Kr 2) between Triticum and Secale. II. Proportion of pistils containing pollen tubes and effects of alternate pollination on seed set

Euphytica ◽  
1981 ◽  
Vol 30 (1) ◽  
pp. 105-112 ◽  
Author(s):  
B. S. Jalani ◽  
J. P. Moss
Keyword(s):  
Seed Set ◽  
Pollen Tubes ◽  
Site Of Action

Early events in the embryo sac after intraspecific and interspecific pollinations in Rhododendron kawakamii and R. retusum

1986 ◽  
Vol 64 (2) ◽  
pp. 282-291 ◽  
Author(s):  
V. Kaul ◽  
J. L. Rouse ◽  
E. G. Williams
Keyword(s):  
Seed Set ◽  
Embryo Sac ◽  
Pollen Tubes ◽  
Interspecific Crosses ◽  
Primary Endosperm Nucleus ◽  
Kalmia Latifolia ◽  
Taxonomic Grouping ◽  
Similarities And Differences ◽  
Normal Fertilization

Early events in the embryo sac of Rhododendron kawakamii and R. retusum have been studied after compatible self-pollinations and eight interspecific crosses, using sectioned ovaries, pistil squashes, and seed-set data. Ovules of Rhododendron kawakamii and R. retusum are anatropous, unitegmic, and tenuinucellate, with a typical eight-nucleate, seven-celled embryo sac. Fertilization normally occurs 4–5 days after pollination. The zygote lays down a callose wall but remains undivided during the first 13–15 days after pollination. The primary endosperm nucleus divides soon after fertilization, and development is cellular ab initio. Crosses of R. kawakamii (♂) with R. santapaui and R. retusum and crosses of R. retusum (♂) with R. kawakamii, R. santapaui, R. ovatum, and R. tashiroi showed apparently normal fertilization in a majority of ovules entered by pollen tubes. In crosses of R. kawakamii (♂) with R. quadrasianum and Kalmia latifolia entry of pollen tubes into ovules was delayed and frequently abnormal. Apart from compatible self-pollinations of R. kawakamii an R. retusum, only the cross of R. kawakamii (♂) with R. santapaui produced healthy seedlings. Of the remaining seven interspecific crosses only three showed significant embryo development in control pistils left to mature in situ. Similarities and differences in the breeding behaviour of R. kawakamii and R. retusum are discussed with reference to their taxonomic grouping within subsection Pseudovireya.

Buzz pollination in the Epacridaceae

2002 ◽  
Vol 50 (1) ◽  
pp. 83 ◽  
Author(s):  
T. F. Houston ◽  
P. G. Ladd
Keyword(s):  
Seed Set ◽  
Corolla Tube ◽  
Pollen Tubes ◽  
Pollination Syndrome ◽  
Native Bees ◽  
Buzz Pollination ◽  
The Family

Conostephium (Epacridaceae) has flowers that conform with a buzz-pollination syndrome but, unlike most plants with this form of pollination, the anthers are hidden within the corolla tube. Vibrations generated by bees grasping the apices of the corolla tubes must be transferred via short broad filaments to the anthers. The anthers do not have pores but each dehisces from the apex by a slit that elongates over the time the flowers take to senesce (up to 10 days). This may limit self-fertilisation as the stigma is receptive as soon as it appears from between the very short corolla lobes, so little pollen is released at first but later this would increase as the slit elongates. Visitation by pollinators has rarely been seen but several observations of native bees (Leioproctus and Lasioglossum) working the flowers are presented. The bees visit the nectarless flowers of Conostephium only for pollen and must forage at other kinds of flowers to obtain nectar. Pollen tubes occurred in the stigmas of most older flowers of C. pendulum, so pollen delivery does not seem to limit seed set. Despite this, the species sets few fruit. From examination of the taxonomic positions of likely buzz-pollinated taxa in the family, it appears that pollination by sonication has arisen independently several times in the Epacridaceae, with primarily two different floral configurations.

The possible role of embryo sac degeneration in yield reduction of summer turnip rape cultivar Candle

1995 ◽  
Vol 75 (3) ◽  
pp. 595-598
Author(s):  
Xiuying Tian ◽  
L. Van Caeseele ◽  
M. J. Sumner
Keyword(s):  
Brassica Rapa ◽  
Seed Set ◽  
Embryo Sac ◽  
Pollen Tubes ◽  
Yield Reduction ◽  
Turnip Rape ◽  
Key Words:Brassica

When pollination occurred within 24 h after anthesis, 69.2% of the pods of Brassica rapa cultivar Candle contained at least 50% fertilized ovules. If pollination occurred later than 4 d after anthesis, an occasional ovule near the base of the pistil was fertilized; however, no significant seed set was observed. Pollen tubes were observed entering the locules of the ovary from pollinations carried out as late as 5 d after anthesis. At 3 d after anthesis, in unpollinated flowers, a general deterioration of the embryo-sac contents began and gradually increased to include integumentary cells by 6 d after anthesis. Some ovules swelled as though they were fertilized, but no embryos were present. The results suggest that yield reductions in this species may occur because of the reduction of fertilization potential through rapid degeneration of embryo sacs following anthesis. Key words:Brassica rapa, embryo sac, yield

Breeding Systems of Disjunct Populations of Christmas Bells (Blandfordia grandiflora R.Br., Liliaceae): Variation in Self-Fertility and an Ovular Mechanism Regulating Self-Fertilisation

1993 ◽  
Vol 41 (1) ◽  
pp. 35 ◽  
Author(s):  
M Ramsey ◽  
N Prakash ◽  
S Cairns
Keyword(s):  
Seed Set ◽  
Pollen Tubes ◽  
Breeding Systems ◽  
Seed Abortion ◽  
Self Incompatibility ◽  
Coastal Plants ◽  
Hand Pollination ◽  
Disjunct Populations ◽  
Pollen Vectors ◽  
Blandfordia Grandiflora

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.

scholarly journals Self-incompatibility in Cornus florida

HortScience ◽  
2004 ◽  
Vol 39 (2) ◽  
pp. 335-338 ◽  
Author(s):  
Sandra M. Reed
Keyword(s):  
Growth Rate ◽  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Seed Set ◽  
Pollen Tubes ◽  
Cornus Florida ◽  
Self Incompatibility ◽  
Flowering Dogwood ◽  
Pollen Tube Growth Rate ◽  
Upper Third

Low seed set has been reported following self-pollinations of flowering dogwood (Cornus florida L.). The objective of this study was to verify the presence of self-incompatibility in C. florida. `Cherokee Princess' stigmas and styles were collected 1, 2, 4, 8, 12, 24, 48, and 72 hours after cross- and self-pollinations, stained with aniline blue and observed using a fluorescence microscope. Pollen germinated freely following self-pollinations, but self-pollen tubes grew slower than those resulting from cross-pollinations. By 48 hours after cross-pollination, pollen tubes had reached the bottom of the style while pollen tubes in self-pollinated flowers had only penetrated the upper third of the style. Evidence of reduced pollen tube growth rate in self-pollinations of `Cherokee Chief' and `Cherokee Brave' was also obtained. This study provides evidence of a gametophytic self-incompatibity system in C. florida. It was also determined that stigmas of C. florida `Cherokee Princess' are receptive to pollen from 1 day prior to anthesis to 1 day after anthesis.

Self-incompatibility in Eucalyptus globulus ssp. globulus (Myrtaceae)

2002 ◽  
Vol 50 (3) ◽  
pp. 365 ◽  
Author(s):  
L. M. Pound ◽  
M. A. B. Wallwork ◽  
B. M. Potts ◽  
M. Sedgley
Keyword(s):  
Fluorescence Microscopy ◽  
Seed Production ◽  
Eucalyptus Globulus ◽  
Pollen Tubes ◽  
The Self ◽  
Self Incompatibility ◽  
Seed Maturity ◽  
Significant Difference ◽  
Site Of Action ◽  
Ovule Penetration

Controlled pollinations with self- and cross-pollen were applied to individual flowers of five mature Eucalyptus globulus Labill. ssp. globulus trees to investigate the site of action of the self-incompatibility mechanism. Growth of pollen tubes in styles at 2 weeks after pollination and ovule penetration by pollen tubes at 2 and 4 weeks after pollination were investigated by fluorescence microscopy. Some pollinated flowers were left to develop to seed maturity, then harvested to quantify the level of self-incompatibility of each tree. Trees ranged from 76 to 100% self-incompatible. There was no significant difference in the number of pollen tubes in the style between treatments although variation was present between trees. The number of pollen tubes present was similar to the number of ovules present within flowers. Penetration of ovules by pollen tubes over all five trees combined revealed no difference between treatments at 2 weeks after pollination; however, there was slightly greater penetration by cross-pollen tubes at 4 weeks after pollination. This difference was not large enough to account for the near complete lack of selfed-seed production, suggesting late pre- or post-zygotic arrest of selfed ovules.

Pollination in vitro: effects on the growth of pollen tubes, seed set and gametophytic self-incompatibility in Trifolium pratense L. and T. repens L.

1990 ◽  
Vol 80 (5) ◽  
pp. 657-664 ◽  
Author(s):  
N. Leduc ◽  
G. C. Douglas ◽  
M. Monnier ◽  
V. Connolly
Keyword(s):  
Trifolium Pratense ◽  
Seed Set ◽  
Pollen Tubes ◽  
Self Incompatibility ◽  
Trifolium Pratense L ◽  
In Vitro Effects

scholarly journals Immunological analysis of incompatibility (S) proteins and of cross-reacting material in a self-compatible mutant of Oenothera organensis

1962 ◽  
Vol 3 (3) ◽  
pp. 352-363 ◽  
Author(s):  
Y. L. A. Mäkinen ◽  
D. Lewis
Keyword(s):  
Pollen Tube ◽  
Pollen Grains ◽  
Pollen Tubes ◽  
Cross Reaction ◽  
The Self ◽  
Agar Gel ◽  
Immunological Analysis ◽  
Normal Site ◽  
Site Of Action ◽  
S Proteins

Proteins of pollen of Oenothera organensis from heterozygous S2S3, S2S6, S3S6 and S4S6 and homozygous S6S6 genotypes produce characteristic precipitation lines in agar-gel plates against antisera prepared from the pollen. The maximum number of precipitation lines was three, and with some genotypes only one line was formed. The lines were characteristic of the different S alleles, but there was a strong cross-reaction between S4 pollen and S6 antiserum. The S protein diffused out from intact pollen grains as readily as from macerated pollen indicating that the normal site of action of the S protein, when the pollen tubes are growing down the style, is near the surface of the pollen tube. The self-compatible mutant S6′S6 in which the S6′ allele has lost the ability to produce an active pollen S protein, has a protein which cross-reacts strongly with S6 antiserum.

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.

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