scholarly journals ОСОБЕННОСТИ РАЗВИТИЯ МУЖСКОГО ГАМЕТОФИТА СОСНЫ ОБЫКНОВЕННОЙ PINUS SILVESTRIS L. В УСЛОВИЯХ ГОРОДСКОЙ СРЕДЫ

Author(s):  
L.P. Khlebova ◽  
O.V. Bychkova

<p>The peculiarities of the development of the male gametophyte of Pinus silvestris L. in the urban environment were studied. Quality of pollen was evaluated by laboratory experiments through germination at the nutrient medium and by histochemical staining to determine the presence of redox enzymes. It was shown that pollen viability is closely linked to climatic and weather conditions during the period of microsporogenesis and mass pollination. Atmospheric pollution affected the pollen significantly. Low temperatures and high humidity in the background of the weak capacity of self-purification of the atmosphere led to a reduction of the potential pollen viability. The ability of the pollen grains to germinate was reduced, the number of abnormal pollen tubes was increased, and the proportion of cells containing active peroxidase was decreased. We revealed a close positive correlation between the frequency of germinated pollen grains and the presence of active peroxidase, as well as a negative correlation between the percentage of colored pollen and the frequency of pollen tube anomalies, which confirmed the role of peroxidase activity not only in the induction of pollen germination, but also the formation of pollen tubes.<br />A ranking of the urban territory on the strength of unfavorable environmental factors has been carried out. The reaction of male gametophyte of pine allowed us to consider it as a biological indicator of unfavorable ecological situation in the urban environment.</p>

2021 ◽  
Vol 7 (3) ◽  
pp. 64-69
Author(s):  
L. Bayramov

Abstract. The zones of distribution of varieties and forms of quince on the territory of the Nakhchivan Autonomous Republic have been established, phenological observations have been carried out, their flowering and fruiting have been studied. On the territory of the Autonomous Republic, flowering of varieties and forms of quince begins in the second decade of April, depending on the distribution zone, with an average daily temperature of 12–13 °C and lasts 12–13 days, depending on weather conditions. Each flower has 10–12 stamens arranged in one row. The article also studied the viability of pollen in a number of quince varieties. Pollen viability was studied in the varieties Sary, Tursh, Ordubad, Gara and wild forms. Pollen fertility was determined by staining with acetocarmine. Pollen germinates in 2–5–10–15 and 20% glucose solution. Counting of germinated pollen grains was carried out under a microscope. The study showed that of all the experimental varieties, the pollen fertility of the Sary quince and Tursh quince varieties is high (up to 96.6–97.1%). The best medium for the germination of quince pollen is a 10–15% glucose solution. Pollen germination in this solution reaches 47.4–88.0%. In distilled water (control), the germination of quince pollen reached from 9.7% to 35.6% for varieties. Quince pollen remains viable for 31–43 days.


HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 496e-496
Author(s):  
Mary Stuart ◽  
Pablo Jourdan

The regal pelargonium (P. x domesticum) is generally characterized by low fertility and poor seed set. In studys designed to assess factors that contribute to low fecundity in this crop we have examined genotype interactions among various cultivars and have identified lines that differ in degree of male and female fertility. The objective of this study was to examine genotypic variation, other than self-incompatibility, of P. x domesticum pistils in supporting the development of the male gametophyte. Variation in pollen germination and growth was assessed after crossing either a male of high fertility or a mate of poor fertility to nine different selections of varying female fertility. Styles were harvested 2 hours after pollination and examined using fluorescence microscopy to determine the number of germinated pollen grains on the stigma and the number of pollen tubes growing down the style. Female selections displayed large differences in their ability to support pollen tubes. Styles from different females pollinated with the same male varied in average number of pollen tubes from 30 to 2.


2021 ◽  
pp. 16-21
Author(s):  
T. I. Saltanovish ◽  
L. I. Andronic ◽  
L. P. Antosh ◽  
A. N. Doncila

Relevance. The action of viral phytopathogens changes the quality of the male gametophyte, which ultimately leads to a decrease in plant productivity. So, information on the features of the variability of morphofunctional characteristics of the microgametophyte becomes topical. Taking into account the expression of a part of the plant genome in pollen, the male gametophyte can be used as a reliable system for assessing the response of genotypes to the action of viral pathogens. Presuming that the problems of variability of characteristics of the male gametophyte in conditions of viral pathogenesis have not been enough studied, as well as the main factors determining the variability have not been identified, the aim of the research was to study the effect of viral phytopathogens on the male gametophyte characters in tomato.Material and methods. Hybrids F1 and varieties of tomato were used in the experiments. Plants were grown in a greenhouse. They were inoculated with tobacco mosaic virus (TMV) or tomato aspermia virus (TAV) in the 4-5 leaf phase. To determine the quality of pollen, flowers of control and infected plants were collected; pollen was isolated and sown on a nutrient medium. The preparations were analyzed under microscope. The viability of the pollen and the length of the pollen tubes were assessed, and the ratio of these indicators was calculated.Results. Infection of plants with viruses changes some functional characteristics of the male gametophyte. The responses manifested as stimulation, inhibition, or neutral effect. The main sources of variability in characters of pollen were the genotype and viral agents. In viral pathogenesis, unequal indicators of pollen grains were found in terms of the rate of germination and growth of pollen tubes (PT). Analysis of the heritability coefficients of the ratio of pollen viability and PT length (experiment / control) revealed positive dominance and overdominance in 70% of cases. Genotypes have been identified that combine a high level of viability when infected with different viruses. The prospect of their use in further research is proposed. 


2018 ◽  
Vol 18 (4) ◽  
pp. 162-174 ◽  
Author(s):  
Mikhail Surso

Pollination and fertilization are the most important and responsible stages in sexual reproduction of coniferous plants. The period of high concentrations of juniper pollen in overhead during pollination period is no more than 4–6 hours and within one calendar day. This dependence remains invariable from year to year, and does not depend neither from weather conditions, nor the peculiarities of the place where juniper grows. Influence of external agents on dynamics of exudation of a juniper pollination droplet is studied. The duration of exudation and volume of secretory liquid exuded by tissues of ovules during the period of prescription in the juniper depend from presence of external agents on a surface of pollination droplet, their sizes and physical and chemical properties. The pollination droplet chemical compound is studied. In sugars composition of juniper pollination droplet there are only two monosaccharides: glucose and galactose. the amino acids composition is prevailed by arginine, aspartic and glutamic acids. The results of the studies confirm complex chemical composition and multifunctionality of juniper pollination droplet. The pollination mechanism of juniper is effective and selective. The morphological structure of pollen grains of juniper predetermines the processes of pollen germination at early stages. The hydrophilic capsule, formed pollen hydration, promotes to exine rupture and shedding. This capsule remains until the fertilization. The distal tip of pollen tube remains in itduring all time of its growth. In culture in vitro development of pollen tubes of juniper proceeds non-uniformly. At definition of juniper pollen viability it is necessary to consider a stage of pollen tubes development.


2018 ◽  
Vol 143 (2) ◽  
pp. 130-135 ◽  
Author(s):  
Chunqing Sun ◽  
Zhihu Ma ◽  
Zhenchao Zhang ◽  
Guosheng Sun ◽  
Zhongliang Dai

In interspecific hybridizations of water lily (Nymphaea), the existence of cross barriers makes it difficult to obtain hybrids and seriously influences the utilization of admirable characters from tropical water lilies. To determine the causes, pollen viability, pistil receptivity, and embryo and endosperm development were investigated in three water lily crosses, including Nymphaea odorata ‘Peter Slocum’ × Nymphaea micranthar (PM), ‘Peter Slocum’ × Nymphaea gigantea (PH), and ‘Peter Slocum’ × Nymphaea colorata (PC). The results indicated that the viability of pollen grains was 17.3% for ‘Peter Slocum’, 19.3% for N. colorata, 10.3% for N. micrantha, and 17.6% for N. gigantea. In the self-pollinated ‘Peter Slocum’, the number of germinated pollen grains on stigmas peaked at 12 hours after pollination (HAP), indicating its good pollen germinability. However, only a few pollen grains germinating on the sigma between 2 and 24 HAP in the crosses of PM, PH, and PC. In addition, a high percentage (81.2%) of normal embryos developed to different stages within 20 d after pollination in the self-pollinated ‘Peter Slocum’. But only 3.5% and 3.7% of normal globular embryos were observed in the PC and PM combinations, respectively. Moreover, no normal embryos were observed in the PH cross. At the same time, no seeds were obtained in PM, PC, and PH crosses. The results suggest that prefertilization barriers existed in the PH cross, whereas pre- and postfertilization barriers existed together in the PC and PM crosses. These may be the main causes resulting in the failure of interspecific hybridizations in water lily.


1992 ◽  
Vol 2 (2) ◽  
pp. 211-213 ◽  
Author(s):  
Serge Gudin ◽  
Laurence Aréne

Flowers of two cultivars of Rosa hybrida were treated or not with putrescine before being pollinated from 2 to 8 days after anther emasculation. On both cultivars the 10-3 M putrescine treatment extended the effective pollination period, as shown by the best hip formation rates and mean number of seeds per hip. On one cultivar, the 10-5 M putrescine treatment increased fertilization efficiency (more hips obtained). The effect of putrescine was proportionally more important on the cultivar characterized by the highest stigmatic exudate pH. Putrescine also influenced in vitro pollen germination by increasing the length of emitted pollen tubes (10-3 and 10-5 M-putrescine) and the quantity of germinated pollen grains (10-5 M putrescine).


2019 ◽  
Vol 180 (1) ◽  
pp. 66-72 ◽  
Author(s):  
S. Yu. Orlova ◽  
A. V. Pavlov ◽  
V. G. Verzhuk

Background. Sweet cherry is an unconventional fruit crop for the Northwestern region of Russia. Identification of cultivars adapted to the conditions of the northwest requires a comprehensive study of cultivars of different ecogeographic origin and, specifically, morpho-physiological characteristics of pollen, which ensure the productivity of sweet cherries.Materials and methods. The field sweet cherry collection maintained at Pushkin and Pavlovsk Laboratories of VIR served as the material for the study carried out in 2017 at the Plant Diversity Long-Term Storage Laboratory. Twenty-four sweet cherry accessions belonging to five different groups were studied: I – Northwestern (bred at VIR); II – Central; III – Central Black Soil (all three are regions in Russia); IV – Belarus; and V – Estonia. Viability of pollen was assessed by germinating on an artificial medium with 10% sucrose and 0.6% agar. Pollen viability results were statistically processed using StatSoft Statistica 13.0 and Microsoft Excel.Results. The initial viability of pollen for almost all varieties in 2017 was low. High percentage of pollen germination was characteristic of cvs. ‘Krasnaya sladkaya’ (gr. I, 50.0%), ‘Leningradskaya rozovaya’ (gr. I, 61.8%), ‘Adelina’ (gr. III, 53.5%) and ‘Zarya Vostoka’ (gr. III, 60.3%). After storage in liquid nitrogen, the level of pollen germination increased in all cultivars of groups I and V as well as in a number of cultivars from group II (‘Raditza’, ‘Iput’, ‘Rechitsa’ and ‘Fatezh’), group III (‘Zarya Vostoka’, ‘Rondo’ and ‘Orlovskaya rozovaya’) and group IV (‘Severnaya’ and ‘Vityaz’). Pollen viability after cryopreservation significantly decreased by 8.7‑17.3% in cvs. ‘Bryanochka’ (gr. II), ‘Alebastrovaya’ (IV),’ Bryanskaya rozovaya’ (II) and ‘Adelina’ (III). Pollen viability parameters (length of pollen tubes and percentage of germinated pollen grains) positively correlated prior to immersion into liquid nitrogen from r = 0,54 (gr. III) to r = 0,76 (gr. II), while after cryopreservation, they showed weak correlation (r = 0,28) in gr. I, and strong one (r = 0,79) in group IV. In the length of pollen tubes and the level of viability, the parent cv. ‘Leningradskaya chernaya’ had practically no connection with cv. ‘Raditsa’ (r = 0.09), while with cv. ‘Meelika’ the correlation was medium negative (r = –0.49); correlations between the parent cv. ‘Krasnaya plotnaya’ and cvs. ‘Sopernitsa’, ‘Bryanochka’ and ‘Vityaz’ were medium (r = 0.57) and high (r = 0.78 and r = 0.83), respectively.Conclusion. In their level of pollen viability, the introduced sweet cherry cultivars are similar to or even exceed the cultivars native to the northwest (bred at VIR).


2020 ◽  
Vol 11 ◽  
Author(s):  
Elizabeth Feldeverd ◽  
Brad W. Porter ◽  
Christen Y. L. Yuen ◽  
Kaela Iwai ◽  
Rina Carrillo ◽  
...  

Plants adapt to heat via thermotolerance pathways in which the activation of protein folding chaperones is essential. In eukaryotes, protein disulfide isomerases (PDIs) facilitate the folding of nascent and misfolded proteins in the secretory pathway by catalyzing the formation and isomerization of disulfide bonds and serving as molecular chaperones. In Arabidopsis, several members of the PDI family are upregulated in response to chemical inducers of the unfolded protein response (UPR), including both members of the non-classical PDI-M subfamily, PDI9 and PDI10. Unlike classical PDIs, which have two catalytic thioredoxin (TRX) domains separated by two non-catalytic TRX-fold domains, PDI-M isoforms are orthologs of mammalian P5/PDIA6 and possess two tandem catalytic domains. Here, PDI9 accumulation was found to be upregulated in pollen in response to heat stress. Histochemical staining of plants harboring the PDI9 and PDI10 promoters fused to the gusA gene indicated they were actively expressed in the anthers of flowers, specifically in the pollen and tapetum. Immunoelectron microscopy revealed that PDI9 localized to the endoplasmic reticulum in root and pollen cells. transfer DNA (T-DNA) insertional mutations in the PDI9 gene disrupted pollen viability and development in plants exposed to heat stress. In particular, the pollen grains of pdi9 mutants exhibited disruptions in the reticulated pattern of the exine and an increased adhesion of pollen grains. Pollen in the pdi10 single mutant did not display similar heat-associated defects, but pdi9 pdi10 double mutants (DMs) completely lost exine reticulation. Interestingly, overexpression of PDI9 partially led to heat-associated defects in the exine. We conclude that PDI9 plays an important role in pollen thermotolerance and exine biogenesis. Its role fits the mechanistic theory of proteostasis in which an ideal balance of PDI isoforms is required in the endoplasmic reticulum (ER) for normal exine formation in plants subjected to heat stress.


2012 ◽  
Vol 81 (3) ◽  
pp. 223-228 ◽  
Author(s):  
Agnieszka K. Kowalkowska ◽  
Hanna B. Margońska

The conditions favouring self-pollination are determined for a species of <em>Dendrobium </em>Sw. A survey of gynostemium micro­morphology in collected flowers of <em>Dendrobium biflorum </em>revealed two stages of a unique form of autogamy: on germination of pollen tetrads, pollen tubes reached the stigmatic region without the pollen being displaced from the anther locules. This is the first time for this type of autogamy to be reported in <em>Dendrobium biflorum</em>. Pollen grains germinated directly from the locules, bypassing the stigma or falling or sliding down onto the stigmatic surface. The pollen tubes were long and reached the stylar canal. On The Society Islands, differences in exposure of the habitats to weather conditions and altitude gradients influence both composition and form of the vegetation, as well as the occurrence of pollinators. The form of autogamy described here may be the usual method of pollination found on The Society Islands (and even the whole of French Polynesia), where suitable pollinators are absent and/or growth conditions stressful.


Author(s):  
D.V. Starikova ◽  
◽  
Yu.D. Syrova ◽  
L.A. Gorlova ◽  
◽  
...  

The environments have a direct impact on formation and functioning of the generative organs in plants. Parameters characterizing viability of pollen grains are closely linked with weather conditions, especially temperature and air moisture. Very often a phase of a beginning of flowering of winter rapeseed (end of March – beginning of April) lasts in unfavourable conditions. In April 2020, we studied influence of the main weather factors (frosts, low moisture) on germination of pollen grains of the varieties Loris, Sarmat and hybrids 40059 × Jesper 16– 132 and 40008 × INRA of winter rapeseed bred in VNIIMK. Pollen viability was determined by B.A. Trankovsky’s method, accounting amount of germinating pollen grains on the artificial nutrient medium, calculating a percentage of germinating pollen grains to their total quantity. We determined optimal concentration of sucrose solution (20%) in a nutrient medium for germination of pollen of winter rapeseed varieties and hybrids. Due to our results, lowered air temperatures (from -0.5 to -1.9 оС) combined with air moisture from 39 to 86% in a period of beginning of crop flowering negatively influenced on germination of pollen grains. Viability of pollen of the varieties Loris and Sarmat was in average 47 and 37%, respectively. Pollen grains of the hybrids (F1 40059 × 52 Jesper 16-132 and F1 40008 × INRA) had less viability – 38 and 21%, respectively, this certifies higher susceptibility of tissues of the reproductive organs to low temperature and moisture.


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