scholarly journals Effect of pistil age on pollen tube growth, fruit development and seed set in Cucurbita pepo L.

2014 ◽  
Vol 70 (3) ◽  
pp. 165-172 ◽  
Author(s):  
Ettore Pacini ◽  
Massimo Nepi
Keyword(s):  
Pollen Tube ◽  
Fruit Development ◽  
Pollen Tube Growth ◽  
Cucurbita Pepo ◽  
Seed Set ◽  
Fruit Weight ◽  
Tube Growth ◽  
Transmitting Tissue ◽  
Stigma Receptivity ◽  
Different Parts

The effects of pistil age on pollen tube growth, fruit development and seed set were studied in <em>Cucurbita pepo</em> L., the flower of which opens for only six hours. Stigma receptivity lasts four days, from one day before until two days after anthesis. Style receptivity lasts three days, from the day before to the day after anthesis. Ovule receptivity lasts two days: the day of anthesis and the day before. The rate of pollen tube growth varies in different parts of the pistil and in relation to pistil age. In the stigmatic and stylar region, the tubes grow faster if pollination occurs the day before anthesis; in the ovary they grow faster when pollination occurs at anthesis. In the receptacle region, where the transmitting tissue is reduced, the growth rate decreases independently of the time of pollination. The fruits are larger and heavier with more seeds when pollination occurs at anthesis. There is a positive correlation between seed number and fruit weight when pollination occurred at anthesis and the day before.

Onset and duration of stigma receptivity in Kunzea pomifera (Myrtaceae)

2006 ◽  
Vol 54 (6) ◽  
pp. 559 ◽  
Author(s):  
T. Page ◽  
G. M. Moore ◽  
J. Will ◽  
G. M. Halloran
Keyword(s):  
Pollen Tube ◽  
Reproductive Biology ◽  
Peroxidase Activity ◽  
Pollen Tube Growth ◽  
Seed Set ◽  
Stigma Receptivity ◽  
Controlled Pollination ◽  
Germinated Pollen ◽  
New Crop ◽  
Days After Anthesis

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.

scholarly journals Localised and non-localised promotion of fruit development by seeds in Arabidopsis

2006 ◽  
Vol 33 (1) ◽  
pp. 1 ◽  
Author(s):  
Catherine M. Cox ◽  
Stephen M. Swain
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Seed Set ◽  
Fruit Size ◽  
Fruit Growth ◽  
Tube Growth ◽  
Gene Encoding ◽  
Pollen Tube Elongation ◽  
The Relationship ◽  
Silique Length

In Arabidopsis, as in the majority of flowering plants, developing seeds promote fruit growth. One method to investigate this interaction is to use plants with reduced seed set and determine the effect on fruit growth. Plants homozygous for a transgene designed to ectopically express a gene encoding a gibberellin-deactivating enzyme exhibit reduced pollen tube elongation, suggesting that the plant hormone gibberellin is required for this process. Reduced pollen tube growth causes reduced seed set and decreased silique (fruit) size, and this genotype is used to explore the relationship between seed set and fruit elongation. A detailed analysis of seed set in the transgenic line reveals that reduced pollen tube growth decreases the probability of each ovule being fertilised. This effect becomes progressively more severe as the distance between the stigma and the ovule increases, revealing the complex biology underlying seed fertilisation. In terms of seed-promoted fruit growth, major localised and minor non-localised components that contribute to final silique length can be identified. This result demonstrates that despite the relatively small size of the fruit and associated structures, Arabidopsis can be used as a model to investigate fundamental questions in fruit physiology.

Demographics of pollen tube growth in Cucurbita pepo

1995 ◽  
Vol 73 (4) ◽  
pp. 583-589 ◽  
Author(s):  
James A. Winsor ◽  
Andrew G. Stephenson
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Cucurbita Pepo ◽  
Uv Light ◽  
Pollen Tubes ◽  
Tube Growth ◽  
Pollen Competition ◽  
Stigmatic Surface ◽  
Germinated Pollen ◽  
Female Flowers

Pollen tube growth rates and pollen tube attrition were examined in Cucurbita pepo plants grown in an experimental garden. Two separate studies were performed utilizing controlled hand-pollinations. First, female flowers were hand-pollinated and collected at intervals over a 22-h period. Examination of stained pollen tubes in these pistils under reflected UV light revealed variation in growth rate: after approximately 7 h, the fastest growing pollen tubes grew at nearly twice the rate of the mass of the pollen tubes. The faster growing tubes reached the top of the ovary well ahead of most of the pollen tubes. Second, density of pollen application was varied and counts of germinated pollen and pollen tubes were made at four points from the stigmatic surface to the receptacle. Attrition was high for all pollen densities, but significantly higher rates occurred at high and medium densities just below the stigmatic surface. Pollen tube attrition at other points in the pistil was associated with constrictions in the stylar tissue and possibly with levels of nutrients in the pistil. Key words: Cucurbita pepo, pollen competition, pollen tube attrition.

scholarly journals Competition between anthocyanin and kaempferol glycosides biosynthesis affects pollen tube growth and seed set of Malus

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Weifeng Chen ◽  
Zhengcao Xiao ◽  
Yule Wang ◽  
Jinxiao Wang ◽  
Rui Zhai ◽  
...  
Keyword(s):  
Pollen Tube ◽  
Calcium Signaling ◽  
Pollen Tube Growth ◽  
Auxin Transport ◽  
Seed Set ◽  
Anthocyanin Biosynthesis ◽  
Tube Growth ◽  
Auxin Signaling ◽  
Kaempferol Glycoside ◽  
Shock Proteins

AbstractFlavonoids play important roles in regulating plant growth and development. In this study, three kaempferol 3-O-glycosides were identified and mainly accumulated in flowers but not in leaves or fruits of Malus. In Malus, flower petal color is normally white, but some genotypes have red flowers containing anthocyanin. Anthocyanin biosynthesis appears to be in competition with kaempferol 3-O-glycosides production and controlled by the biosynthetic genes. The white flower Malus genotypes had better-developed seeds than the red flower genotypes. In flowers, the overexpression of MYB10 in Malus domestica enhanced the accumulation of anthocyanin, but decreased that of kaempferol 3-O-glycosides. After pollination the transgenic plants showed slower pollen tube growth and fewer developed seeds. Exogenous application of different flavonoid compounds suggested that kaempferol 3-O-glycosides, especially kaempferol 3-O-rhamnoside, regulated pollen tube growth and seed set rather than cyanidin or quercetin 3-O-glycosides. It was found that kaempferol 3-O-rhamnoside might regulate pollen tube growth through effects on auxin, the Rho of plants (ROP) GTPases, calcium and the phosphoinositides signaling pathway. With the inhibition of auxin transport, the transcription levels of Heat Shock Proteins (HSPs) and ROP GTPases were downregulated while the levels were not changed or even enhanced when blocking calcium signaling, suggesting that HSPs and ROP GTPases were downstream of auxin signaling, but upstream of calcium signaling. In summary, kaempferol glycoside concentrations in pistils correlated with auxin transport, the transcription of HSPs and ROP GTPases, and calcium signaling in pollen tubes, culminating in changes to pollen tube growth and seed set.

scholarly journals Effective Pollination Period in Almond Cultivars

HortScience ◽  
2004 ◽  
Vol 39 (1) ◽  
pp. 19-22 ◽  
Author(s):  
E. Ortega ◽  
J. Egea ◽  
F. Dicenta
Keyword(s):  
High Temperature ◽  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Fruit Set ◽  
Fruit Trees ◽  
Prunus Dulcis ◽  
Tube Growth ◽  
Stigma Receptivity ◽  
Flower Density

In almond [Prunus dulcis (Mill.) D.A. Webb], a high flower density and fruit set rate is important, because yield increases with higher fruit set ratio. Furthermore, because the ovule of some cultivars mature at anthesis, rapid pollination and pollen tube growth along the style are essential to ensure fertilization of a viable ovule. In this work, we studied the effective pollination period (EPP) of four almond cultivars of different bloom time by studying pollen tube growth and fruit set. EPP in almond was longer than in other fruit trees, and its duration was determined by stigma receptivity, which decreased with high temperature. An acceptable fruit set for all cultivars was obtained following pollination from day 0 to day 4 after emasculation.

scholarly journals Pollination Biology of Hydrangea macrophylla

HortScience ◽  
2005 ◽  
Vol 40 (2) ◽  
pp. 335-338 ◽  
Author(s):  
Sandra M. Reed
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Pollen Germination ◽  
Pollen Tubes ◽  
Tube Growth ◽  
Self Incompatibility ◽  
Stigma Receptivity ◽  
Hydrangea Macrophylla ◽  
Significant Difference ◽  
Days After Anthesis

Little information is available on the reproductive behavior of Hydrangea macrophylla (Thunb. Ex J.A. Murr.) Ser. The objectives of this study were to investigate time of stigma receptivity, viability of pollen from sterile flowers, and self-incompatibility in this popular ornamental shrub. Pollen germination and pollen tube growth in styles were examined using fluorescence microscopy. Stigma receptivity was examined in cross-pollinations made from 1 day before anthesis to 8 days after anthesis. Maximum stigma receptivity for the two cultivars examined occurred from anthesis to 4 days after anthesis. Viability of pollen from sterile flowers was evaluated through pollen staining and observations of pollen tube growth. No significant difference in percent stainable pollen between fertile and sterile flowers was observed in any of the six taxa examined. Pollen germination and pollen tube growth were studied in cross-pollinations made using pollen from fertile and sterile flowers of two cultivars. For both cultivars, pollen tubes from fertile and sterile flowers grew to the same length and had entered ovules by 72 hours after pollination. Self-incompatibility was evaluated by comparing pollen germination and pollen tube growth in cross- and self-pollinations. In the five taxa examined, self pollen tubes were significantly shorter than cross pollen tubes in flowers that were examined 72 hours after pollination. This finding indicates the presence of a gametophytic self-incompatibility system in H. macrophylla.

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