The Role of Boron, Silicon and Nucleic Bases on Pollen Tube Growth of Lilium longiflorum (L.)

Abstract It is possible to obtain pollen germination and pollen tube growth in vitro if boric acid is present. In this work the effect was studied using as a semiquantitative parameter the mean length (l̄) of Lilium longiflorum pollen tubes. Pollen tube growth was examinated in dependence on boric acid, ortho-silicic acid, nucleic bases, Ca2+ and Zn2+ in 10% sucrose solution. The maximum of l̄ is obtained for concentrations between 2-20 ppm boron. The simultaneous supply of silicon added as water glass leads to a synergistic stimulation effect on pollen tube growth and facilitates branching. The silicon action is preceded of a pollen tube growth inhibition period during 3 h. Adenine and guanosine are able to substitute partially boron as pollen germination and pollen tube growth stimulator. Concentrations of 100 ppm adenine leads to half the boron effect. The same stimulation effect is obtained by guanosine. Ca2+ can partially substitute boron as well. The stimulation action of boron is significantly attenuated by Zn2+ and by the herbicide Dicuran. These and preceding results from physiological studies indicate that boron and silicon should be essential trace elements for the regulation of molecular biological processes.

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In Vitro Germination of Eucalyptus Pollen: Response to Variation in Boric Acid and Sucrose

Australian Journal of Botany ◽

10.1071/bt9890429 ◽

1989 ◽

Vol 37 (5) ◽

pp. 429 ◽

Cited By ~ 19

Author(s):

BM Potts ◽

JB Marsden-Smedley

Keyword(s):

Pollen Tube ◽

Boric Acid ◽

Pollen Tube Growth ◽

Pollen Germination ◽

Sucrose Concentration ◽

Response Surfaces ◽

Tube Growth ◽

Pollen Competition

The effect of boric acid (0-450 ppm) and sucrose (0-40%) on pollen germination and pollen tube growth in Eucalyptus globulus, E. morrisbyi, E. ovata and E. tirnigera was examined in vitro. Over the con- centrations tested, sucrose had by far the largest effect upon both pollen germination and tube lengths. The optimum sucrose concentration for pollen germination (30%) and pollen tube growth (20%) differed markedly with very little (<lo%) germination occurring in the absence of sucrose. The interaction of sucrose and boric acid was significant. However, in general both pollen germination and pollen tube growth were increased by the addition of up to 100 ppm boric acid, but above this level the response plateauxed. The four species differed significantly in their pattern of response to both boric acid and sucrose and the predicted optima derived from analysis of response surfaces differed between species. The predicted sucrose concentration for optimal germination and growth of E. urnigera pollen was consistently less than the other species and in terms of the optimal level of boric acid for pollen tube growth species can be ranked in the order E. globulus > E. ovata > E. morrisbyi = E. urnigera. Pollen germination and tube growth of all four species on a medium comprising 20% sucrose and 200 ppm boric acid would not differ significantly from the observed maximum response of each species and this could suffice as a generalised medium. However, if only percentage germination is to be assessed 30% sucrose would be preferable. It is argued that subtle interspecific differences in optimal in vitro con- ditions for pollen germination and pollen tube growth are likely to reflect differences in pollen physiology which in vivo may have important implications for the success of hybridisation where pollen competition occurs.

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Hyperoside promotes pollen tube growth by regulating the depolymerization effect of actin-depolymerizing factor 1 on microfilaments in okra

Horticulture Research ◽

10.1038/s41438-021-00578-z ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Biying Dong ◽

Qing Yang ◽

Zhihua Song ◽

Lili Niu ◽

Hongyan Cao ◽

...

Keyword(s):

Pollen Tube ◽

Pollen Tube Growth ◽

Pollen Germination ◽

Pollen Tubes ◽

Tube Growth ◽

Actin Depolymerizing Factor ◽

Specific Mechanism ◽

Promoting Effect ◽

New Research

AbstractMature pollen germinates rapidly on the stigma, extending its pollen tube to deliver sperm cells to the ovule for fertilization. The success of this process is an important factor that limits output. The flavonoid content increased significantly during pollen germination and pollen tube growth, which suggests it may play an important role in these processes. However, the specific mechanism of this involvement has been little researched. Our previous research found that hyperoside can prolong the flowering period of Abelmoschus esculentus (okra), but its specific mechanism is still unclear. Therefore, in this study, we focused on the effect of hyperoside in regulating the actin-depolymerizing factor (ADF), which further affects the germination and growth of pollen. We found that hyperoside can prolong the effective pollination period of okra by 2–3-fold and promote the growth of pollen tubes in the style. Then, we used Nicotiana benthamiana cells as a research system and found that hyperoside accelerates the depolymerization of intercellular microfilaments. Hyperoside can promote pollen germination and pollen tube elongation in vitro. Moreover, AeADF1 was identified out of all AeADF genes as being highly expressed in pollen tubes in response to hyperoside. In addition, hyperoside promoted AeADF1-mediated microfilament dissipation according to microfilament severing experiments in vitro. In the pollen tube, the gene expression of AeADF1 was reduced to 1/5 by oligonucleotide transfection. The decrease in the expression level of AeADF1 partially reduced the promoting effect of hyperoside on pollen germination and pollen tube growth. This research provides new research directions for flavonoids in reproductive development.

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Impact of Manganese on Pollen Germination and Tube Growth in Lily

Acta Agrobotanica ◽

10.5586/aa.746 ◽

2021 ◽

Vol 74 ◽

Author(s):

Thomas Sawidis ◽

Gülriz Baycu ◽

Elżbieta Weryszko-Chmielewska ◽

Aneta Sulborska

Keyword(s):

Pollen Tube ◽

Pollen Germination ◽

Surrounding Medium ◽

Pollen Grains ◽

Lilium Longiflorum ◽

Tube Growth ◽

Low Concentrations ◽

Main Effect

Abstract In vitro culture of Lilium longiflorum pollen grains was carried out to determine the role of manganese in pollen germination and pollen tube growth. Pollen germination was adversely affected by the presence of manganese (>10 −8 M), whereas low concentrations (10 −12 –10 −10 M) stimulated the process. Manganese caused morphological anomalies during tube growth, characterized by irregular pollen tube thickening and swollen tips. The main effect was the anomalous cell wall formation at the tip, in which the presence of several organelles reduced the number of secretory vesicles. A loose network of fibrillar material and spherical aggregates, mostly in the tip region, was detected, and this material was progressively loosened into the surrounding medium. As a response to potential toxicity, the excess manganese was isolated in vacuoles, which formed an internal barrier against penetration of manganese to the tip area. Elevated manganese concentrations might affect plant reproduction, resulting in anomalies in gamete development. Consequently, the loss in genetic diversity and decreased fruit set ultimately lower yield.

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