Ultraviolet screening increases with elevation in translucent bracts of Rheum nobile (Polygonaceae), an alpine ‘glasshouse’ plant from the high Himalayas

2020 ◽  
Vol 193 (2) ◽  
pp. 276-286 ◽  
Author(s):  
Bo Song ◽  
Yongqian Gao ◽  
Jürg Stöcklin ◽  
Minshu Song ◽  
Lu Sun ◽  
...  
Keyword(s):  
Pollen Tube ◽  
Sexual Reproduction ◽  
Uv Radiation ◽  
Pollen Tube Growth ◽  
Pollen Germination ◽  
Pollen Grains ◽  
Tube Growth ◽  
Uv Absorbance ◽  
Uv Reflectance ◽  
High Himalayas

Abstract Specialized bracts of Himalayan ‘glasshouse’ plants are well known for adapting to diverse stresses in alpine environments, thus ensuring normal sexual reproduction. However, little information is available on how such specialized plants cope with the elevational increase in stress. In this study, we determine the elevational pattern of ultraviolet (UV) protection provided by the translucent bracts of Rheum nobile, a giant ‘glasshouse’ plant species, endemic to the high Himalayas, and examine its effect on pollen germination and pollen tube growth. Both UV-A and UV-B radiation in the open air increased with elevation, but their intensity beneath bracts remained constant with elevation, suggesting that the bracts of R. nobile growing at higher elevations have an increased ability to screen UV radiation. Enhanced UV-B radiation, equivalent to that experienced at higher elevations (4800 m a.s.l.) compared to that at lower elevations (4200 m a.s.l.), significantly reduced pollen germination and pollen tube growth. Pollen grains from plants at higher elevations were not more tolerant to UV-B radiation. UV absorbance and the content of flavonoids in bracts increased with elevation, but a similar trend was not found in either UV reflectance or adaxial trichome density, suggesting that bract UV absorbance may play a more active role than bract UV reflectance in helping plants cope with the increasing UV radiation. Our results indicate that the bracts of R. nobile have the ability to cope with enhanced UV radiation with increasing elevation through increased UV absorbance, thus protecting pollen grains from injury caused by higher levels of UV radiation, and consequently ensuring normal sexual reproduction in stressful high-alpine conditions.

Lack of visible post-pollination effects in pollen grains of two Dendrobium cultivars: relationship with pollinia ACC, pollen germination, and pollen tube growth

2008 ◽  
Vol 35 (2) ◽  
pp. 152 ◽  
Author(s):  
Kanjana Luangsuwalai ◽  
Saichol Ketsa ◽  
Apinya Wisutiamonkul ◽  
Wouter G. van Doorn
Keyword(s):  
Pollen Tube ◽  
Ethylene Production ◽  
Pollen Tube Growth ◽  
Pollen Germination ◽  
Flower Colour ◽  
Pollen Grains ◽  
The Other ◽  
Tube Growth ◽  
Colour Changes ◽  
Acc Content

Dendrobium flowers, pollinated with pollinia from individuals of the same cultivar or other cultivars, usually show rapid post-pollination effects such as floral epinasty, a change in flower colour and early perianth senescence. However, pollination with the pollinia of cv. Karen or cv. Kenny flowers did not produce these effects. We compared these two cultivars with cvv. Pompadour, Willie and Sakura, and tested the hypotheses that the differences were related to levels of 1-aminocyclopropane-1-carboxylic acid (ACC) in the pollinia, ethylene production by the pollinated flower, pollen germination, or pollen tube growth. The pollinia of cvv. Karen and Kenny contained as much ACC as the pollinia of cv. Pompadour, but less than the pollinia of cvv. Willie and Sakura. Ethylene production after pollination with cvv. Karen and Kenny pollinia was much lower than after pollination with pollinia from the other cultivars tested. The pollen grains showed normal germination, but cvv. Karen and Kenny pollen grains exhibited much less tube growth than those of the other cultivars. Pollen tube growth in cv. Pompadour was positively affected by ethylene. Ethylene was required and sufficient for the induction of epinasty, rapid perianth colour changes and early perianth senescence, very similar to the changes after pollination. The absence of these effects after pollination with cvv. Kenny and Karen seems to be due to the low ethylene production induced by the pollinia of these cultivars. This low ethylene production could not be accounted for by the ACC content in the pollinia of cvv. Kenny and Karen.

scholarly journals Pollen Germination Potential Influences by Carbohydrates and Proteins in Pollen Grains of Asian Pear

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 762A-762
Author(s):  
Wol-Soo Kim* ◽  
Sang-Hyun Lee
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Pollen Germination ◽  
Germination Rate ◽  
Pollen Viability ◽  
Pollen Grains ◽  
Tube Growth ◽  
Con A ◽  
Asian Pear ◽  
Pollen Surface

In order to investigate the cause of differences of mature pollen in Asian pear (Pyrus phyfolia) that are collected from various sources for the artificial pollination, various factors were measured as below: the composition of nonstructural carbohydrate in bud at 30 days after full bloom, the contents of crude protein in skin, cytosol and membrane, and the affinity for lectin (CON-A: Concanavalin, type III A) of glycoprotein in cytosol of pollen were measured. Contents of sucrose and glucose in buds influenced pollen germination rate and pollen tube growth, respectively. Therefore, soluble types of carbohydrates stored in bud were regarded as influencing on pollen germination rate and pollen tube growth. Pollen, which showed low activity, had low affinity on CON-A, lectin of glycoprotein, because it had fragile membrane, proteins in cells were denatured to pollen surface and certain enzymes concerned in pollen germination lost stability and activity. Pollens that showed high activity contained 92 kDa protein while others not. This was assumed as influencing on control of pollen viability.

BcSKS11, a SKS gene from pollinated pistils of Chinese cabbage pak choi, is expressed continuously during the male gametophyte development, pollen germination and pollen-tube growth processes

2013 ◽  
Vol 61 (6) ◽  
pp. 446
Author(s):  
Zhixian Zhang ◽  
Jiashu Cao ◽  
Lin Qiu ◽  
Jingjing Jiang ◽  
Baohua Wu
Keyword(s):  
Cell Wall ◽  
Pollen Tube ◽  
Chinese Cabbage ◽  
Pollen Tube Growth ◽  
Pollen Germination ◽  
In Situ Hybridisation ◽  
Pollen Grains ◽  
Tube Growth ◽  
Mature Pollen ◽  
Pak Choi

Cell wall-related genes and proteins are crucial for fertilisation-related events such as pollen germination and pollen-tube growth. Recent studies have focussed on the molecular mechanism of cell-wall synthesis and regulation of these processes; however, limited information is available on the mechanism and modification of the crucial cell-wall materials. We isolated a gene that is potentially involved in cell-wall metabolism from pollinated pistils of the male sterile line ‘Bcajh97-A’ in Chinese cabbage pak choi (Brassica campestris SKewed5 Similar 11, BcSKS11). BcSKS11 has several features of SKewed5 Similar (SKS) proteins, which are structures that are similar to plant multicopper oxidase but lack the 10 necessary residues of two copper-binding sites. A phylogenetic tree constructed from 49 SKS proteins found four clades, with BcSKS11 being in a clade with tobacco sequences. Reverse transcription–polymerase chain reaction and in situ hybridisation revealed that BcSKS11 was specifically expressed in uninucleate microspores, mature pollen grains and growing pollen tubes of pollinated pistils. These results suggest that BcSKS11 might be stored in mature pollen grains, in preparation for pollen germination and pollen-tube growth.

scholarly journals The effect of temperature on pollen germination and pollen tube growth of sour cherry cultivars

2014 ◽  
Vol 59 (1) ◽  
pp. 45-52 ◽  
Author(s):  
Dragan Milatovic ◽  
Dragan Nikolic
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Pollen Germination ◽  
Pollen Grains ◽  
Sour Cherry ◽  
Tube Growth ◽  
Effect Of Temperature ◽  
Different Temperatures ◽  
Influence Of Temperature On

The study was carried out to determine the effect of three different temperatures (5, 15 and 25?C) on in vitro pollen germination and pollen tube growth of five sour cherry cultivars: ?Heimanns Konservenweichsel?, ?Kelleriis 14?, ?Oblacinska?, ?Rexelle? and ?Sumadinka?. Pollen germination a % agar % Temperature significantly affected pollen germination. High germination rates (50-70%) were obtained at both 15?C and 25?C. Satisfactory germination rates (42-51%) were also obtained at 5?C in some cultivars (?Rexelle?, ?Sumadinka? and ?Heimanns Konservenweichsel?). The influence of temperature on the pollen tube growth was more prominent. The length of pollen tubes was three to six times higher at 15?C and 25?C in comparison with 5?C. This has led to the conclusion that the temperature of 5?C, although it could be adequate for pollen germination, is not high enough for optimal pollen tube growth. was determined by germinating pollen grains in culture medium containing 0.7agar-and 15sucrose.

scholarly journals Pollen Germination and Pollen Tube Growth in Gymnosperms

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1301
Author(s):  
Maria Breygina ◽  
Ekaterina Klimenko ◽  
Olga Schekaleva
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Pollen Germination ◽  
Pollen Grains ◽  
Flowering Plants ◽  
Reproductive Physiology ◽  
Tube Growth ◽  
Seed Plants ◽  
Main Body ◽  
Physiological Studies

Pollen germination and pollen tube growth are common to all seed plants, but these processes first developed in gymnosperms and still serve for their successful sexual reproduction. The main body of data on the reproductive physiology, however, was obtained on flowering plants, and one should be careful to extrapolate the discovered patterns to gymnosperms. In recent years, physiological studies of coniferous pollen have been increasing, and both the features of this group and the similarities with flowering plants have already been identified. The main part of the review is devoted to physiological studies carried out on conifer pollen. The main properties and diversity of pollen grains and pollination strategies in gymnosperms are described.

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

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.

scholarly journals Two Expansin Genes, AtEXPA4 and AtEXPB5, Are Redundantly Required for Pollen Tube Growth and AtEXPA4 Is Involved in Primary Root Elongation in Arabidopsis thaliana

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 249
Author(s):  
Weimiao Liu ◽  
Liai Xu ◽  
Hui Lin ◽  
Jiashu Cao
Keyword(s):  
Arabidopsis Thaliana ◽  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Cell Walls ◽  
Root Elongation ◽  
Expression Patterns ◽  
Primary Root ◽  
Pollen Grains ◽  
Tube Growth ◽  
Cell Wall Binding

The growth of plant cells is inseparable from relaxation and expansion of cell walls. Expansins are a class of cell wall binding proteins, which play important roles in the relaxation of cell walls. Although there are many members in expansin gene family, the functions of most expansin genes in plant growth and development are still poorly understood. In this study, the functions of two expansin genes, AtEXPA4 and AtEXPB5 were characterized in Arabidopsis thaliana. AtEXPA4 and AtEXPB5 displayed consistent expression patterns in mature pollen grains and pollen tubes, but AtEXPA4 also showed a high expression level in primary roots. Two single mutants, atexpa4 and atexpb5, showed normal reproductive development, whereas atexpa4atexpb5 double mutant was defective in pollen tube growth. Moreover, AtEXPA4 overexpression enhanced primary root elongation, on the contrary, knocking out AtEXPA4 made the growth of primary root slower. Our results indicated that AtEXPA4 and AtEXPB5 were redundantly involved in pollen tube growth and AtEXPA4 was required for primary root elongation.

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

1989 ◽  
Vol 37 (5) ◽  
pp. 429 ◽  
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.

scholarly journals Pollen tube incompatibility reaction on the stigma in selfpollinated Sinapis alba L.

2014 ◽  
Vol 65 (1-2) ◽  
pp. 101-105 ◽  
Author(s):  
Renata Śnieżko ◽  
Krystyna Winiarczyk
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Pollen Grains ◽  
Pollen Tubes ◽  
Sinapis Alba ◽  
Pollen Grain ◽  
Tube Growth ◽  
Sinapis Alba L ◽  
Growth Changes ◽  
Incompatibility Reaction

After selfpollination of <em>Sinapis alba</em> L. pollen tubes growth is inhibited on the stigma. The pollen grains germinate 3-4 hours after pollination. The pollen give rise to one or more pollen tubes. They grow along the papillae. In the place of contact between the papilla and pollen tube the pellicula is digested. Then the direction of pollen tube growth changes completely. Pollen tubes grow back on the exine of their own pollen grain, or turn into the air. The pollen tubes growth was inhibited in 6-8 hours after selfpollination. After crosspollination usually there is no incompatibility reaction.

scholarly journals Impact of Manganese on Pollen Germination and Tube Growth in Lily

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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