scholarly journals 950 PB 443 DOES WOUNDING BEFORE POLLINATION INCREASE SEED PRODUCTION IN SOLANACEOIJS PLANTS?

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 570a-570
Author(s):  
Ellen K. Muchmor ◽  
Loverine P. Taylor
Keyword(s):  
Natural Product ◽  
Seed Production ◽  
Pollen Germination ◽  
Seed Set ◽  
Pollen Grains ◽  
Inbred Lines ◽  
Nicotiana Tobacum ◽  
Solanaceous Plant ◽  
Number Of Seeds

Seed set is affected by many factors. One of the most important is the number of pollen grains that germinate on the stigma. Our research has shown that kaempferol (a plant natural product) is required for pollen germination. Pollen lacking kaempferol does not germinate, but this defect can be reversed by adding powdered kaempferol to the stigma at pollination. Within 24 hours of wounding the corolla or stamens of V26, a Petunia inbred, high levels of kaempferol accumulate in the stigma. The requirement for kaempferol in pollen germination, and the high levels that can accumulate in the stigma, suggested that seed set might be enhanced by wounding 24 hours before pollination. We tested this hypothesis in two inbred lines of Petunia, a Petunia outcross, and another solanaceous plant Nicotiana tobacum cv. Samsum. The number of seeds per capsule were correlated with the levels of kaempferol in the stigma in wounded and non-wounded flowers.

What determines the number of seed produced in a flowering event? A case study of Calyptrogyne ghiesbreghtiana (Arecaceae)

2000 ◽  
Vol 48 (5) ◽  
pp. 659 ◽  
Author(s):  
Saul A. Cunningham
Keyword(s):  
Resource Allocation ◽  
Seed Production ◽  
Natural Variation ◽  
Seed Set ◽  
Plant Seed ◽  
Flower Production ◽  
Number Of Seeds ◽  
Female Flowers

Calyptrogyne ghiesbreghtiana Linden ex. H. Wendl. is an understorey palm that occurs at La Selva Biological Station, Costa Rica. In this paper I combine analysis of natural variation and results of experimental manipulations to ask (1) what limits seed production? and (2) what processes cause variation in seed production by C. ghiesbreghtiana? The number of seed produced per inflorescence ofC. ghiesbreghtiana was limited substantially by the loss of female flowers to floral herbivores. Much variation in the number of seed produced perinflorescence of C. ghiesbreghtiana was due to losses of developing fruits to predators. Together these phenomena illustrate the influential role of natural enemies in the reproductive success of this plant. Seed-set efficiency (number of seeds/number of female flowers) was highly variable in this species, and such high levels of variation appear to be common in other species. For species with highly variable seed-set efficiency, the role of resource allocation to flower production in determining differences in seed production among individual plants is likely to be relatively small.

scholarly journals Putrescine Increases Effective Pollination Period in Roses

1992 ◽  
Vol 2 (2) ◽  
pp. 211-213 ◽  
Author(s):  
Serge Gudin ◽  
Laurence Aréne
Keyword(s):  
Pollen Germination ◽  
Pollen Grains ◽  
Pollen Tubes ◽  
Rosa Hybrida ◽  
In Vitro Pollen Germination ◽  
Stigmatic Exudate ◽  
Germinated Pollen ◽  
Number Of Seeds

Flowers of two cultivars of Rosa hybrida were treated or not with putrescine before being pollinated from 2 to 8 days after anther emasculation. On both cultivars the 10-3 M putrescine treatment extended the effective pollination period, as shown by the best hip formation rates and mean number of seeds per hip. On one cultivar, the 10-5 M putrescine treatment increased fertilization efficiency (more hips obtained). The effect of putrescine was proportionally more important on the cultivar characterized by the highest stigmatic exudate pH. Putrescine also influenced in vitro pollen germination by increasing the length of emitted pollen tubes (10-3 and 10-5 M-putrescine) and the quantity of germinated pollen grains (10-5 M putrescine).

Induced tetraploidy and trisomic production of Helianthus annuus L.

Genome ◽  
1988 ◽  
Vol 30 (5) ◽  
pp. 647-651 ◽  
Author(s):  
C. C. Jan ◽  
J. M. Chandler ◽  
S. A. Wagner
Keyword(s):  
Helianthus Annuus ◽  
Chromosome Pairing ◽  
Chromosome Pair ◽  
Seed Set ◽  
Chromosome Doubling ◽  
Meiotic Chromosome ◽  
Pollen Grains ◽  
Inbred Lines ◽  
Pollen Stainability ◽  
Normal Seed

Seedlings of the Helianthus annuus inbred lines P21 and HA89 were treated with colchicine to study chromosome doubling. Frequency of tetraploids, meiotic chromosome pairing, pollen stainability, and fertility were examined. Five-hour colchicines treatments at 0.15%, pH 5.4, with 2% dimethyl sulfoxide resulted in tetraploid sectors on 42% of P21 and 11% of HA89 plants. Tetraploids had larger disk florets and larger pollen grains. Otherwise, tetraploid plants were morphologically similar to their diploid progenitors. Tetraploidy in P21 was not stable, with plants having 2n = 4x = 65 to 70 chromosomes. Tetraploid plants of HA89 had reduced vigor and did not produce seed. At diakinesis, tetraploid P21 plants had an average of 0.85 univalents, 21.12 open bivalents, 6.66 closed bivalents, 0.21 trivalents, and 2.74 quadrivalents per cell. The number of chiasma per chromosome pair in P21 was reduced from 1.50 for diploid to 1.32 for tetraploid plants. Pollen stainability in tetraploid P21 was less than 50% and the plants produced an average of eight seeds per sibbed head, about 1% of normal seed set. Reciprocal crosses of diploid and tetraploid P21 produced four triploid plants. Backcrossing triploids to P21 produced 137 plants with 2n = 34 to 47 + t. Thirty-one of these plants were trisomies having 2n = 35.Key words: Helianthus annuus, tetraploids, triploids, trisomies.

scholarly journals Self-Fertilization, Inbreeding, and Yield in Alfalfa Seed Production

2021 ◽  
Vol 12 ◽  
Author(s):  
Molly E. Dieterich Mabin ◽  
Johanne Brunet ◽  
Heathcliffe Riday ◽  
Lauren Lehmann
Keyword(s):  
Pacific Northwest ◽  
Seed Production ◽  
Inbreeding Depression ◽  
Seed Yield ◽  
Seed Set ◽  
Central Valley ◽  
Selfing Rate ◽  
Alfalfa Seed ◽  
The Impact ◽  
Number Of Seeds

Selfing (self-pollination) is the ultimate form of inbreeding, or mating among close relatives. Selfing can create yield loss when inbreeding depression, defined as a lower survival and reproduction of inbred relative to outbred progeny, is present. To determine the impact of selfing in alfalfa (Medicago sativa L.), we quantified the selfing rate of 32 alfalfa seed production fields located in three regions, namely, the Pacific Northwest (PNW), the Central Valley of California (CEV), and the Imperial Valley of California (IMP). Selfing rates (the proportion of selfed seeds) varied between 5.3 and 30% with an average of 12.2% over the 32 seed production fields. In both the parents and their progeny, we observed an excess of heterozygotes relative to Hardy–Weinberg expectations. We detected notable levels of inbreeding in parents (0.231 ± 0.007 parental inbreeding coefficient) and progeny (0.229 ± 0.005). There were a 15% decrease in the number of seeds per stem (seed set) and a 13% decline in the number of seeds per pod in selfed relative to outcrossed stems, but negligible inbreeding depression for pods per raceme and seed weight. The number of racemes on selfed stems increased significantly in fields with greater selfing rates, supporting the presence of geitonogamous or among flower selfing. Despite the significant level of inbreeding depression, seed set did not decrease in fields with higher selfing rates, where the greater number of racemes on the selfed stems increased the seed set. The effects of the field selfing rate on the seed yield metrics were mostly indirect with direct effects of the number of racemes per stem. Available data indicate that the majority of selfing in alfalfa is pollinator-mediated, and thus, eliminating selfing in alfalfa seed production would require the selection of self-incompatible varieties, which, by eliminating inbreeding depression, would provide a 15% potential increase in seed yield and an increase in future hay yield.

scholarly journals Causes of Low Double-flowered Seed Production in Breeding Zinnia

1995 ◽  
Vol 120 (5) ◽  
pp. 759-764 ◽  
Author(s):  
Daiichiro Miyajima
Keyword(s):  
Seed Production ◽  
Pollen Germination ◽  
Seed Set ◽  
Pollen Flow ◽  
High Production

The causes of low production of seeds capable of producing double-flowered plants and of high production of seeds capable of producing single-flowered plants were investigated in zinnias (Zinnia violaceu Cav.). Poor pollination was a major cause of the low seed set. A tubular floret produced abundant pollen; however, the pollen flow to ray stigmas was limited due to the infrequent visitation by pollinators. Moreover, in the double-flowered capitula, newly opened ray petals overlapped on the pistils that unfolded the previous day. These phenomena were considered to cause low seed set in double-flowered plants. Actually, capitula with more tubular florets produced more seeds than those with fewer tubular florets. Pollen germination and plants near zinnias had additional possible influences on seed production of double-flowered zinnias.

Predation by Insects Limits Seed Production in Banksia spinulosa var neoanglica (Proteaceae)

1990 ◽  
Vol 38 (4) ◽  
pp. 335 ◽  
Author(s):  
G Vaughton
Keyword(s):  
Seed Production ◽  
Reproductive Output ◽  
Seed Set ◽  
Control Group ◽  
Insecticide Treatment ◽  
Seed Predators ◽  
Flowering Season ◽  
Number Of Seeds

Application of insecticide to inflorescences of Banksia spinulosa var. neoanglica indicated that damage by flower and seed predators halved the number of seeds produced per plant. Both the proportion of inflorescences that produced fruits and the number of seeds produced per infructescence increased by 45% when insects were excluded. Infructescences in the insecticide treatment produced 28% more follicles than in the control group. Insects damaged the seed in 13% of follicles in the control group whereas there was no damage in the insecticide treatment. The proportion of follicles with aborted seed did not differ between the two groups. The greater seed set occurring when insects were excluded did not affect the weight of individual seeds or reproductive output in the next flowering season. Some inflorescences did not produce fruit even when insects were excluded suggesting that factors besides predation also limit fecundity of B. spinulosa.

Delayed autonomous selfing and inbreeding depression in the Australian annual Hibiscus trionum var. vesicarius (Malvaceae)

2006 ◽  
Vol 54 (1) ◽  
pp. 27 ◽  
Author(s):  
Leahwyn Seed ◽  
Glenda Vaughton ◽  
Mike Ramsey
Keyword(s):  
Inbreeding Depression ◽  
Pollen Germination ◽  
Seed Set ◽  
Pollen Grains ◽  
Reproductive Assurance ◽  
Selfed Progeny ◽  
Delayed Selfing ◽  
Hibiscus Trionum ◽  
Self Compatibility ◽  
Outcrossing Species

The Australian annual, Hibiscus trionum var. vesicarius, produces large, showy flowers typical of an outcrossing species, yet flowers autonomously self-pollinate. We used experimental pollinations to examine self-compatibility, inbreeding depression and the efficiency and mechanism of autonomous selfing. Seed set of self- or cross-pollinated flowers did not differ, indicating that plants were fully self-compatible. Seed set following autonomous selfing varied among plants, and was 11–103% of that following hand-selfing. Autonomous selfing was delayed, and styles curved and stigmas contacted the anthers before flowers closed. Delayed selfing was facultative and curvature depended on the number of pollen grains on stigmas, with 50 or more grains preventing curvature. Both self- and cross-pollen prevented curvature. Similarly to unpollinated styles, styles that were pollinated with dead pollen curved fully, indicating that either pollen germination or pollen-tube growth prevents curvature. Within flowers, the five styles acted independently, depending on the amount of pollination that each received. Although plants exhibit a high potential for selfing, crossed progeny outperformed selfed progeny and cumulative inbreeding depression was 0.64, which is high for a self-compatible annual. Despite this high inbreeding depression, delayed selfing would be advantageous under variable pollinator conditions, providing reproductive assurance.

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.

Spikelet fertility and heat shock transcription factor (Hsf) gene responses to heat stress in tolerant and susceptible rice (Oryza sativa L.) genotypes

2019 ◽  
Vol 157 (04) ◽  
pp. 283-299 ◽  
Author(s):  
C. Malumpong ◽  
S. Cheabu ◽  
C. Mongkolsiriwatana ◽  
W. Detpittayanan ◽  
A. Vanavichit
Keyword(s):  
Heat Stress ◽  
Pollen Germination ◽  
Seed Set ◽  
Oryza Sativa L ◽  
Flag Leaf ◽  
Pollen Viability ◽  
Spikelet Fertility ◽  
Anther Dehiscence ◽  
Spikelet Sterility ◽  
Plant Parts

AbstractThe reproductive stage of rice is the most sensitive to heat stress, which can lead to spikelet sterility. Thus, heat-tolerant and heat-susceptible genotypes were used to investigate their differences in terms of phenotypic responses and expression changes of Hsf genes at the pre-flowering stage under heat stress. Results clearly showed that panicles had the highest temperature compared with other plant parts under both natural and heated conditions. However, the temperatures of tolerant and susceptible genotypes were not significantly different. In terms of spikelet fertility, the tolerant lines M9962 and M7988 had high seed set because their anther dehiscence, pollen viability and pollen germination were only slightly affected. In contrast, the susceptible line Sinlek showed severe effects at all steps of fertilization, and the pollen viability of M7766 was slightly affected under heat stress but was more affected in terms of anther dehiscence and pollen germination. Both susceptible lines showed dramatically decreased seed set. In addition, the expression of six HsfA genes in the flag leaves and spikelets at the R2 stage of plants under heat stress showed different responses. Notably, expression of the HsfA2a gene was predominantly upregulated in the flag leaf and spikelets under heat stress in M9962. Therefore, it can be concluded that heat stress has severe effects on the stamen, and that different genotypes have different susceptibilities to heat stress.

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.

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