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.

Malus domestica ADF1 severs actin filaments in growing pollen tubes

2017 ◽  
Vol 44 (4) ◽  
pp. 455 ◽  
Author(s):  
Qing Yang ◽  
ShengNan Wang ◽  
ChuanBao Wu ◽  
QiuLei Zhang ◽  
Yi Zhang ◽  
...  
Keyword(s):  
Pollen Tube ◽  
Actin Cytoskeleton ◽  
Malus Domestica ◽  
Pollen Tube Growth ◽  
Actin Filaments ◽  
Germination Rate ◽  
Tube Growth ◽  
Sequence Alignments ◽  
Gene Encoding ◽  
Domain Structures

A dynamic actin cytoskeleton is essential for pollen tube growth and germination. However, the molecular mechanism that determines the organisation of the actin cytoskeleton in pollen remains poorly understood. ADF modulates the structure and dynamics of actin filaments and influences the higher-order organisation of the actin cytoskeleton in eukaryotic cells. Members of the ADF family have been shown to have important functions in pollen tube growth. However, the role of this gene family remains largely unknown in apple (Malus domestica Borkh.). In this study, we identified seven ADFs in the apple genome. Phylogenetic analysis showed that MdADF1 clusters with Arabidopsis thaliana (L.) Heynh. AtADF7, ADF8, ADF10 and AtADF11. We performed sequence alignments and analysed the domain structures of the seven MdADF proteins and identified the chromosome locations of the encoding genes. We cloned the gene encoding MdADF1 from ‘Ralls Janet’ apple and found that it was strongly expressed in pollen. Biochemical assays revealed that MdADF1 directly bound to and severed F-actin under low Ca2+ conditions. We demonstrated that knockdown of MdADF1 inhibited pollen tube growth and reduced the pollen germination rate, but rendered the pollen insensitive to treatment with Latrunculin B, an actin depolymerising agent. Taken together, our results provide insight into the function of MdADF1 and serve as a reference for studies of ADF in other plants.

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.

Pollen‒pistil interaction in Lilium longiflorum : the role of the pistil in controlling pollen tube growth following cross- and self-pollinations

1982 ◽  
Vol 215 (1198) ◽  
pp. 45-62 ◽  
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Active Component ◽  
Lilium Longiflorum ◽  
The Self ◽  
Tube Growth ◽  
Self Incompatibility ◽  
System A ◽  
Pollen Tube Elongation

By cytophysiological methods, the self-incompatibility mechanism of the breeding system in Lilium longiflorum has been examined with particular reference to the synthesis, location and nature of the stylar factors involved in the control of pollen tube development. A ‘bioassay’ has been developed by which the effect of stylar extracts on pollen tube elongation may be investigated. With use of this system, a crude fraction of proteins from the stylar fluid has been shown to inhibit pollen tube growth only when protein fractions from ‘self’ styles are used. The proteins of this fraction have been analysed by thin-layer gel electrofocusing. Changes in the profiles thus obtained following selfing and a heat treatment known to inactivate the self-incompatibility response indicate a highly polarized glycoprotein to be an active component of the system. The various ways by which such a glycoprotein could control pollen tube elongation are considered in detail, and these events in Lilium are discussed in the light of our knowledge of other self-incompatibility systems operating in angiosperms.

scholarly journals Rac Homologues and Compartmentalized Phosphatidylinositol 4, 5-Bisphosphate Act in a Common Pathway to Regulate Polar Pollen Tube Growth

1999 ◽  
Vol 145 (2) ◽  
pp. 317-330 ◽  
Author(s):  
Benedikt Kost ◽  
Emmanuel Lemichez ◽  
Pius Spielhofer ◽  
Yan Hong ◽  
Kimberly Tolias ◽  
...  
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Intracellular Localization ◽  
Small Gtpases ◽  
Tube Growth ◽  
Yeast Cells ◽  
Common Pathway ◽  
Pollen Tube Elongation ◽  
Rho Family ◽  
Phosphatidylinositol 4

Pollen tube cells elongate based on actin- dependent targeted secretion at the tip. Rho family small GTPases have been implicated in the regulation of related processes in animal and yeast cells. We have functionally characterized Rac type Rho family proteins that are expressed in growing pollen tubes. Expression of dominant negative Rac inhibited pollen tube elongation, whereas expression of constitutive active Rac induced depolarized growth. Pollen tube Rac was found to accumulate at the tip plasma membrane and to physically associate with a phosphatidylinositol monophosphate kinase (PtdIns P-K) activity. Phosphatidylinositol 4, 5-bisphosphate (PtdIns 4, 5-P2), the product of PtdIns P-Ks, showed a similar intracellular localization as Rac. Expression of the pleckstrin homology (PH)-domain of phospholipase C (PLC)-δ1, which binds specifically to PtdIns 4, 5-P2, inhibited pollen tube elongation. These results indicate that Rac and PtdIns 4, 5-P2 act in a common pathway to control polar pollen tube growth and provide direct evidence for a function of PtdIns 4, 5-P2 compartmentalization in the regulation of this process.

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 459 PB 338 SELF INCOMPATIBILITY (SI) IN DISTYLOUS LYTHRUM ALATUM, WINGED LOOSESTRIFE

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 497a-497 ◽  
Author(s):  
Neil O. Anderson ◽  
Peter D. Ascher
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Seed Set ◽  
Tube Growth ◽  
Self Incompatibility ◽  
Visual Identification

Lythrum species (Lythraceae), found both in the Old and New Worlds, possess heterostyly (macroscopic differences in anther and style lengths). SI is linked with heterostyly in tristylous L. salicaria, allowing for visual identification of compatibility relationships. Five Minnesota populations of distylous L. alatum (short & long styles/anthers) were examined for fertility and linkage between distyly and SI. Pollen was not inhibited from germination, stigmatic penetration, or stylar growth in compatible crosses. Average cross-compatible seed set for each population was 7-33 seeds/capsule for short- and 27-69 for long-styled plants. With the exception of the Iron Horse Prairie population, there were no significant differences in mean seed set/capsule between genotypes, style morphs, or their interaction for compatible crosses. Zero self seed set predominated, although 0.8±1.8 seeds/capsule were produced by short styles and 1.2 ±2.3 by long styles from Iron Horse Prairie. In those individuals that were SI, pollen tube growth was inhibited following self pollinations.

Factors limiting hybridization between Penstemon spectabilis and Penstemon centranthifolius

2001 ◽  
Vol 79 (12) ◽  
pp. 1439-1448 ◽  
Author(s):  
Jeannie Chari ◽  
Paul Wilson
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Fruit Set ◽  
Seed Set ◽  
Pollen Grain ◽  
Tube Growth ◽  
Natural Hybridization ◽  
Poor Growth ◽  
Pollen Grain Germination ◽  
Isolating Mechanisms

Speciation involves the formation of reproductive isolating mechanisms such as a difference in pollinators, incompatibility between pollen tubes and stylar tissue, hybrid seed abortion, or poor growth of hybrid seedlings. We studied reproductive isolating mechanisms in naturally sympatric populations of Penstemon spectabilis Thurber and Penstemon centranthifolius (Benth.) Benth. where F1 hybrids occurred at very low frequency. We compared conspecific crosses, backcrosses, and heterospecific crosses in terms of pollen grain germination, pollen tube growth, fruit set, seed set, and offspring performance. We found several postpollination barriers to hybridization. When P. spectabilis was the ovule parent, the lack of natural hybridization was partially explained by the presence of two isolating factors: reduced pollen tube growth and reduced seed set. When P. centranthifolius was the recipient, the barrier to hybridization was nearly 100% effective and occurred primarily at the stages of pollen grain germination and fruit set. The success of backcrossing was generally intermediate between conspecific and heterospecific crossing. For these two species, it is likely that partial pollinator specificity in addition to strong postpollination reproductive isolating mechanisms contribute to maintaining the species boundary.Key words: speciation, hybridization, introgression, Penstemon, reproductive isolating barriers.

Sign in / Sign up

Export Citation Format

Share Document