Effect of stigma exudate on pollen germination in pomegranate

Fresh pollen of 16 promising genotypes of gladiolus was tested for their pollen viability. Modified cellophane method was employed to assess the pollen viability. Pollen germination media consisted of 15% sucrose supplemented with 300 ppm calcium nitrate, 200 ppm magnesium sulphate, 100 ppm potassium nitrate and 100 ppm boric acid. Highly significant variations were observed for percentage of pollen germination, non-germinated pollen and sterile pollen. The highest pollen germination (76.41%) was in genotype Hybrid selection 88-10-22, and did not differ significantly from Gladiolus callianthus (75.41%), Sapna (75.10 %), Hybrid selection 86-32-11, (73.28 %), Kum Kum (69.41%), Poonam (69.22 %), Hybrid selection 87-22-1 (67.87 %), Hybrid selection 87-1-1 (67.61 %), Psittacinus hybrid (64.64%) and Darshan (63.97%). The lowest non- germinated pollen (10.47%) was in genotype Gladiolus callianthus, and insignificantly followed by Hybrid selection 88-10-22 with 18.77 % and Hybrid selection 87-22-1 with 18.95 %. The lowest percentage of sterile pollen was noticed in genotype Sapna (2.82%) followed by Poonam with 4.00 % Hybrid selection 88-10-22 with 4.82% and Hybrid selection 82-11-27 with 5.22%. Key words: Gladiolus; germination; pollen DOI: 10.3126/njst.v11i0.4089Nepal Journal of Science and Technology 11 (2010) 47-50

Download Full-text

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.

Download Full-text

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

The Journal of Agricultural Science ◽

10.1017/s002185961900056x ◽

2019 ◽

Vol 157 (04) ◽

pp. 283-299 ◽

Cited By ~ 3

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.

Download Full-text

Signalling pathways in pollen germination and tube growth

PROTOPLASMA ◽

10.1007/s00709-006-0162-6 ◽

2006 ◽

Vol 228 (1-3) ◽

pp. 21-30 ◽

Cited By ~ 43

Author(s):

R. Malhó ◽

Q. Liu ◽

D. Monteiro ◽

C. Rato ◽

L. Camacho ◽

...

Keyword(s):

Pollen Germination ◽

Tube Growth ◽

Signalling Pathways

Download Full-text

Calcium: A Critical Factor in Pollen Germination and Tube Elongation

International Journal of Molecular Sciences ◽

10.3390/ijms20020420 ◽

2019 ◽

Vol 20 (2) ◽

pp. 420 ◽

Cited By ~ 13

Author(s):

Ren Zheng ◽

Shun Su ◽

Hui Xiao ◽

Hui Tian

Keyword(s):

Calcium Ion ◽

Pollen Germination ◽

Higher Plants ◽

Male Gametophyte ◽

Embryo Sac ◽

Critical Factor ◽

Sperm Cells ◽

Critical Element ◽

Major Function ◽

Spatial And Temporal Characteristics

Pollen is the male gametophyte of higher plants. Its major function is to deliver sperm cells to the ovule to ensure successful fertilization. During this process, many interactions occur among pollen tubes and pistil cells and tissues, and calcium ion (Ca2+) dynamics mediate these interactions among cells to ensure that pollen reaches the embryo sac. Although the precise functions of Ca2+ dynamics in the cells are unknown, we can speculate about its roles on the basis of its spatial and temporal characteristics during these interactions. The results of many studies indicate that calcium is a critical element that is strongly related to pollen germination and pollen tube growth.

Download Full-text

Effects of floral thermogenesis on pollen function in Asian skunk cabbage Symplocarpus renifolius

Biology Letters ◽

10.1098/rsbl.2009.0064 ◽

2009 ◽

Vol 5 (4) ◽

pp. 568-570 ◽

Cited By ~ 27

Author(s):

Roger S. Seymour ◽

Yuka Ito ◽

Yoshihiko Onda ◽

Kikukatsu Ito

Keyword(s):

Growth Rate ◽

Pollen Germination ◽

Narrow Range ◽

Temperature Tolerance ◽

Early Spring ◽

Long Period ◽

Pollen Tube Growth Rate ◽

Skunk Cabbage ◽

Effects Of Temperature

The effects of temperature on pollen germination and pollen tube growth rate were measured in vitro in thermogenic skunk cabbage, Symplocarpus renifolius Schott ex Tzvelev, and related to floral temperatures in the field. This species has physiologically thermoregulatory spadices that maintain temperatures near 23°C, even in sub-freezing air. Tests at 8, 13, 18, 23, 28 and 33°C showed sharp optima at 23°C for both variables, and practically no development at 8°C. Thermogenesis is therefore a requirement for fertilization in early spring. The narrow temperature tolerance is probably related to a long period of evolution in flowers that thermoregulate within a narrow range.

Download Full-text