Estimate Pollen Viability Research Articles

Determining appropriate methods for estimating pollen viability and germination rates in lisianthus

Crossbreeding is a multi-stage process with inherent challenges and risks in developing new varieties. Success hinges on selecting highly fertile parents. In species like lisianthus, uncertainty persists regarding the optimal methods for assessing pollen quality, which is crucial for evaluating pollen parent fertility. This study seeks to identify the most reliable techniques for this purpose. Fresh and dead pollen from four lisianthus (Eustoma grandiflorum) varieties was used. The dead pollen was obtained by thermal inactivation. Five chemical staining methods (iodine-potassium iodide, 2,3,5-triphenyltetrazolium chloride – TTC, lactophenol cotton blue, safranin, acetocarmine) were employed to assess pollen viability, and two biological methods (Petri dishes, hanging drops) were used to determine the germination rate. Four solid medium cultures were employed in Petri dishes, while the hanging drop utilised four liquid medium cultures. Thirteen tests were conducted for each variety, evaluating fresh and dead pollen. The study found significant variations in pollen quality among lisianthus varieties and methods. Fresh pollen showed viability rates ranging from 56.87% to 99.41% and germination rates from 0.20% to 45.11%. TTC exhibited the lowest viability rate across all varieties, while the highest germination rate was observed in the liquid culture medium with only boric acid and PEG1500. Notably, TTC was the sole viability method that did not stain dead pollen, and no germination occurred in any method for dead pollen. TTC is the most reliable staining method, and a liquid culture medium with boric acid and PEG1500 effectively determines lisianthus pollen quality. Varying boric acid and PEG1500 concentrations are advisable.

Evaluation of Growth and Pollen Viability (Fertility) in Relation to Fruit Set among Five Varieties of Tomato

The evaluation of pollen viability and fruit setting capacity are two essential criteria for pollinator’s characterization. This study was carried out to evaluate pollen Fertility/ viability in five Varieties of Tomatoes. We analyzed the viability of pollen grains of five different varieties of tomatoes grown in ITM University, Gwalior, Madhya Pradesh, India. Aceto- carmine method is used to estimate pollen viability. The germination percentage, pollen viability and Fruit setting rate were recorded at different stages respectively. Pollen viability in relation to fruit set was analyzed while growth parameters and fruit yield per plant of each variety were also collected and analyzed. Results displayed that the highest pollen viability rate (100%) was obtained in SWEAKAR-448 Variety followed by Arka Vikas (95%), ARJUN-135 (93%), 9005-SIRI (90%) and PKM-1 (80%). The highest percentage of germination (95%) was shown by 9005-SIRI Variety and maximum fruit setting (15-20 Fruits per plant) was recorded in the SWEAKAR-448 Variety. The results showed significant vegetative growth variations and correlations between pollen viability and fruit setting characters. In addition, it was found a noticeable variation in Pollen viability/fertility, was not proportional to fruit setting percentage. In general Pollen viability was directly linked to fruit set, whereas formation and fruit set were not in the tomato varieties that were investigated. Pollen viability was high, which was accompanied through a reduction in the number of fruit sets, fruit size and pollen viability in the field is highly variable, indicating that differences in microenvironment may have a profound effect on fruit setting and pollen viability.

A Survey of Verbena xutha Lehm. (Gulf Vervain) Morphological and Cytological Characteristics

Gulf vervain (Verbena xutha) is a herbaceous perennial native to the southern United States. The species produces attractive spike inflorescences that provide a source of food for many pollinators. Besides botanical classifications, pollen morphology and cytological traits of this species have not been documented until now. Gulf vervain was found to have 2n = 42 chromosomes, with the first report of 2C nuclear DNA content of 2.95 pg. Convex-triangular pollen grains averaged 37.18 μm in diameter, with 84% stainability after cotton blue staining to estimate pollen viability. This information brings light to the genetic makeup of gulf vervain and may aid in future breeding programs.

A protocol for Chenopodium quinoa pollen germination

BackgroundQuinoa is an increasingly popular seed crop frequently studied for its tolerance to various abiotic stresses as well as its susceptibility to heat. Estimations of quinoa pollen viability through staining methods have resulted in conflicting results. A more effective alternative to stains is to estimate pollen viability through in vitro germination. Here we report a method for in vitro quinoa pollen germination that could be used to understand the impact of various stresses on quinoa fertility and therefore seed yield or to identify male-sterile lines for breeding.ResultsA semi-automated method to count germinating pollen was developed in PlantCV, which can be widely used by the community. Pollen collected on day 4 after first anthesis at zeitgeber time 5 was optimum for pollen germination with an average germination of 68% for accession QQ74 (PI 614886). The optimal length of pollen incubation was found to be 48 h, because it maximizes germination rates while minimizing contamination. The pollen germination medium’s pH, boric acid, and sucrose concentrations were optimized. The highest germination rates were obtained with 16% sucrose, 0.03% boric acid, 0.007% calcium nitrate, and pH 5.5. This medium was tested on quinoa accessions QQ74, and cherry vanilla with 68%, and 64% germination efficiencies, respectively.ConclusionsWe provide an in vitro pollen germination method for quinoa with average germination rates of 64 and 68% on the two accessions tested. This method is a valuable tool to estimate pollen viability in quinoa, and to test how stress affects quinoa fertility. We also developed an image analysis tool to semi-automate the process of counting germinating pollen. Quinoa produces many new flowers during most of its panicle development period, leading to significant variation in pollen maturity and viability between different flowers of the same panicle. Therefore, collecting pollen at 4 days after first anthesis is very important to collect more uniformly developed pollen and to obtain high germination rates.

Differences in stomatal and pollen grain dimensions and pollen viability between Paspalum rawitscheri populations

The objective of this study was to evaluate stomatal and pollen grain size and to estimate pollen viability of individuals from different populations of Paspalum rawitscheri (Parodi) Chase ex G.H. Rua Valls. To analyze stomatal size, slides were made of the adaxial leaf epidermis using the epidermal impression method. The height and width of 100 stomata per population were analyzed. Pollen was obtained from inflorescences to evaluate pollen grain size and pollen viability. Pollen grains were stained with 2% acetic orcein, 2% acetic carmine, or Alexander’s reactive stain. Per population, 1600 grains of pollen were observed for viability, and 50 grains of pollen were measured. There were significant differences between populations in stomatal height and pollen grain height and width. The populations also differed in pollen viability, with the Santa Maria population showing the lowest viability. The differences in stomatal and pollen grain size suggest genetic variability in the evaluated populations. Moreover, low pollen viability in one population indicates that its decline may be related to low fertility. Keywords: Grass. Ploidy. Fertility. Threatened species.

Floral Biology and Pollen Viability of Passiflora edulis Sims

Yellow passion fruit is a native tropical fruit tree whose cultivation has evolved very rapidly in Brazil; therefore, studies on the ecology of reproduction are needed. The study of pollen viability is an important tool to observe the male potential of the species. The objective of this study was to estimate pollen viability, pollen/ovule ratio and floral biology of Passiflora edulis Sims in organic cultivation located in Bananeiras, PB, and Brazilian. The study was developed in a completely randomized design, using ten flower buds in the pre-anthesis. The analyses performed in the biology laboratory of the Center of Human, Social and Agrarian Sciences of the Federal University of Paraiba. For the pollen viability analysis, all the anthers of the ten flower buds were used, five anthers per flower, which were crushed on a glass slide and with the aid of Alexander dye, the purple pollen grains were considered viable and the green ones unviable. To measure flower morphology and biometrics, a digital pachymeter, analytical balance and ruler were used. Five stamens form the androecium; the fillets are of short length inserted below the ovary. The flowers have three stigmas with an average height of 16.5mm, an average of 32,136 viable pollens, 58 unviable pollen grains and 140 ovules per ovary, having a pollen viability of 99.8% and a pollen/ovule ratio of approximately 95/1 pollen grains per ovule. Their structures are uniform, with no biometric variations in the amount of petals, sepals, anthers and stigma length. Alexander's reactive dye was effective in staining the pollen grains of yellow passion fruit. The pollen/ovule ratio indicates that this species performs facultative autogamy as well; however, this classification alone is not sufficient to affirm its reproductive system.

Comparing Methods of Ploidy Estimation in Potato (Solanum) Species

Ploidy manipulation and the resulting need for rapid ploidy screening can be important in potato research and breeding programs. We tested three predictors of ploidy, particularly seeking the quickest, simplest, and most reliable: Chloroplast number per guard cell (C#), guard cell length (GC), and pollen diameter (P), with a total of seven variations in methods of preparation. Time required for each preparation was assessed, and a panel of inexperienced volunteers compared these methods for accuracy using a standard set of coded samples of known ploidy. The common method of counting C# with iodine stain took longer and was no more accurate than observing C# or GC in tap water. GC from tape impressions of the underside of leaves was reliable and has the advantage of permanent slides for later reference. We recommend GC, whether in water, stained, or as tape impressions. GC is significantly different in diploids and tetraploids, but the distributions do overlap, so experience and care in selecting a representative sample of cells contributes to accuracy. The standard measurement of P after staining with aceto-carmine was faster to prep and just as reliable as epidermal methods for some technicians, even with no previous experience. Pursuit of ultra-simplified methods led us to measure P in tap water. Diameters of pollen in plain water are significantly larger, but only for living pollen, suggesting this method might also be developed into a rapid and reliable way to estimate pollen viability.

Production and viability of Fraxinus pollen and its relationship with aerobiological data in the northwestern Iberian Peninsula

The efficient evaluation of the potential pollen production of plants can provide preventive measures for the allergic population. For this purpose, a comparative study of three methods was carried out to evaluate pollen production (volumetric method, Neubauer chamber and Coulter cell counts), as well as other three methods to estimate pollen viability (fluorometry, colorimetry and germination) of Fraxinus. Our results indicate that the Neubauer chamber and the colorimetric response to two stains (acetic carmine with glycerol, ACG; 2, 3, 5-triphenyltetrazolium chloride, TTC) are the most adequate methods to determine, respectively, pollen production and quality, according to criteria of low cost, speed and reliability of the obtained data. Climate change is likely to influence vegetation, with consequent changes in growth and reproductive cycles, and therefore in pollen production. Considering the data obtained during the last two decades (1997–2017), we detected a statistically significant trend toward the increase in the airborne total annual pollen integral of Fraxinus pollen in NW Spain.

EFFICIENCY OF COLORIMETRIC TESTS TO DETERMINE POLLEN VIABILITY IN PEPPERS

Estimating pollen viability is important for analyzing genetic flow, evaluating the masculine reproduction potential of a species, and for genetic improvement programs. In order to gather more information about different pepper accessions (Capsicum sp) held in the Active Germplasm Bank of the Federal University of Piauí (BAG-UFPI), Brazil, we analyzed the pollen viability of eight pepper accessions using four colorimetric methods: 2% acetic carmine; 2% acetic orcein; fuchsin; and Lugol’s iodine. Pre-anthesis floral buds were collected and fixed in ethanol:acetic acid (3:1) for 24 hours and subsequently held in 70% ethanol under refrigeration until the slides were prepared using the squashing technique. An entirely randomized methodology was used, and the data compared using the Scott-Knott test at a 5% probability level. The four colorimetric methods were found to be efficient for estimating pollen viability in the different plant accessions, with all of them demonstrating high pollen viability (above 70%) – an important index for studies of genetic improvement.

Effects of Foliar-Applied Brassinosteroid on Viability and In Vitro Germination of Pollen Collected from Bisexual and Functional Male Flowers of Pomegranate

ABSTRACTEvaluation of pollen viability and its germination capacity are essential criteria for pollinator’s characterization. Hormones have been used to increase yield and quality of pomegranates without any reference to effects on pollen viability or germination. With this point of view, effects of field-applied 22S, 23S-homobrassinolide (HBR) after bud break at concentrations of 0.001, 0.01, and 0.1 mg L−1 were evaluated on pollen quality of Mayhoş-8 pomegranate cultivar. After collection of the flowers of both sexual morphs (bisexual and functionally male), colorimetric test of 2,3,5-triphenyl tetrazolium chloride (1%) were used to estimate pollen viability. Later, pollen germination was determined in vitro on a medium containing 1% agar and 20% sucrose. Results showed that pollen viability was under the influence of both the types of the flower and the concentration of the HBR. The highest pollen viability (96%) was obtained from both functional male and bisexual flowers treated with 0.1 mg L−1 HBR. Germination ratio, on the other hand, was only affected by the hormone concentrations, and it increased significantly as the concentration was higher.

Efficiency of two methods for eggplant (Solanum melongena L. cv. Lila criolla) pollen viability evaluation

Pollen viability influences the production and fruit quality of cultivated species. Its study is necessary in breeding pro-grams, especially when trying to produce hybrid cultivars. The research was carried out at Monteria, Cordoba, Colom-bia, in order to compare the efficiency of two methods for assessing pollen viability of the eggplant (Solanum melon-gena L. cv. Lila criolla): in vitro germination and tetrazolium salt- under tropical conditions, and to determine its potential use in hybrid seed production. The viability test with the te-trazolium salt showed that the concentration of 0.25% allows differentiating, qualitatively and quantitatively, viable pollen grains, and it also presented significant linear decrease per unit of concentration of salt. In the in vitro method, the linear increase was significant for each hour of incubation. Both methods were reliable for estimating pollen viability in the cultivar studied.

Assessment of Pollen Viability, Germination, and Tube Growth in Eight Tunisian Caprifig (Ficus caricaL.) Cultivars

The evaluation of pollen viability and its germination capacity are two essential criteria for pollinator’s characterization. This study was carried out to evaluate pollen quality of eight caprifigs grown in the center-east and north-west of Tunisia. Two colorimetric tests 2,3,5-triphenyl tetrazolium chloride (TTC) and acetocarmine were used to estimate pollen viability. Germination rate and pollen tube growth in a culture medium containing 5% sucrose, 5 ppm boric acid (H3BO3) and 1% agar were registered after 24, 48, and 72 hours (H) of incubation. Results showed that the highest pollen viability rate (84%) was obtained by TTC test in caprifig Assafri, followed by Jrani (80.2%), Djebba 2 (77.8%), and Djebba 1 (73.6%). That of other caprifigs did not exceed 50% for the two tests. In all caprifig types, germination rate and pollen tube growth varied according to the incubation period. The highest percentage of germination (72%) and maximum pollen tube length (960 μm) were recorded after 72 H of incubation in caprifigs Assafri and Jrani, respectively. Among the caprifigs studied, four types (Assafri, Jrani, Djebba 1, and Djebba 2) appeared to be suitable pollinators with respect to the criteria investigated.

Pollen viability of Polygala paniculata L. (Polygalaceae) using different staining methods

Polygala paniculata L. is a medicinal plant that grows in the Brazilian Atlantic coast, known as 'barba-de-São-João', 'barba-de-bode', 'vassourinha branca', and 'mimosa'. In this study, pollen viability was estimated by three different staining methods: 2% acetic orcein, 2% acetic carmine, and Alexander's stain. The young inflorescences of twenty accessions were collected and fixed in a solution of ethanol: acetic acid (3:1) for 24 hours, then stored in ethanol 70% under refrigeration. Six slides per plant, two for each stain, were prepared by squashing, and 300 pollen grains per slide were analyzed. Pollen viability was high (> 70%) for most accessions of P. paniculata using the Alexander's stain, which proved the most adequate method to estimate pollen viability.

Implementation and Evaluation of an Image Analysis System for Determining Viability of Pollen Grains in Temperate Rice

Geographical and climatic factors limit the production of temperate rice (Oryza sativa L.) in Chile. Large thermal fluctuations of air and water temperatures affect the viability of pollen, causing high levels of spikelet sterility (”blanking”), resulting in reduced yields per hectare. Counting viable pollen grains, at the time of anthesis, may allow determining, ahead, whether there will be yield losses by spikelet sterility; besides, knowing the potential pollen viability serves as a powerful tool for material selection in breeding programs, and for determining which management factors may influence ”blanking”. If performed manually, counting total and viable pollen grains can be extremely tedious, producing highly variable results. The present work had for objectives to develop and evaluate a system, based on imagery analysis, for counting total and viable pollen in rice anthers. At the time of anthesis, three panicles were collected from plot treatments of two field experiments in which the effects of different management factors (variety, water height, N rate, and spatial arrangement) on spikelet sterility were evaluated. Two spikelets and four anthers were sampled from each panicle; pollen grains were extracted from anthers and photographed. Manual and digital counts were made on the images to determine total and viable pollen. Digital count was performed with the software SigmaScan Pro, setting some parameters on the imagery before counting. Precision and accuracy of the digital method were estimated. The results indicated that the digital pollen count showed a very good precision and accuracy and could be used to estimate pollen viability, and as a response variable to compare management treatments.

Viability of eggplant pollen

This study aimed to test methodologies to evaluate the pollen viability of eggplant. The pollen germination was tested in vitro, incubating the pollen during 0.5 and 16 hours in different sucrose concentrations (0; 2.5; 5.0; 7.5 and 10.0 g L-1). For the in vivo germination test, the pollen was placed during 4 and 24 hours in the flower stigma and after that stained with aniline blue and evaluated in an ultraviolet light microscope. The viability of the pollen grains was also evaluated in tetrazolium solutions (at the concentrations of 1%; 0.75% and 0.5%) and the staining was evaluated after 24 hours. The highest in vitro pollen germination was 10.8%, showing the necessity for a better calibration of the culture medium. The in vivo pollen germination was 66%, showing that this is an adequate methodology to estimate pollen viability in eggplant. The methodologies involving tetrazolium solution weren't efficient to estimate pollen viability evaluation, because of the deficient pollen staining.

A method to estimate pollen viability from pollen size variation

The mean diameter of viable pollen grains is approximately 13 μm greater than the mean diameter of inviable grains in Mimulus guttatus. We show that this difference is large enough to be detected by particle counters and that these machines can be used to obtain a rapid estimate of pollen viability. While requiring a separate calibration, a size-based statistic is also strongly correlated with pollen viability in Collinsia verna. These results suggest that statistics derived from the size distribution of pollen grains may provide an alternative to more labor-intensive methods for estimating pollen viability, particularly in cases where inviability results from inbreeding depression or hybrid failure.

Pollen viability in the genus Silene (Caryophyllaceae) and its evaluation by means of different test procedures

Summary Various direct and indirect tests are used to estimate pollen viability. Results obtained with these tests, however, are contradictory for different species and do not always match with naturally occurring pollen germination. To investigate naturally occurring pollen germination of four Silene species a new method of scoring germinated pollen grains in vivo directly on the stigmas of intact flowers was developed. Germination percentages found with the in vivo test ranged from 67 to 77%. The results of two indirect tests that are commonly used to assess pollen viability, aniline blue in lactophenol staining (ALS) and fluorochromatic reaction (FeR), were compared with the results of the newly developed in vivo test for the same four species. ALS revealed high pollen viability, ranging from 82 to 93%, whereas FeR revealed lower viability, ranging from 28 to 50%. Our suspicion that ALS overestimates natural pollen germination in Silene was confirmed by testing viability of dry-stored and n-Hexane-stored pollen grains with both indirect tests. Because of the known short viability of trinucleate pollen grains, dry-stored grains should be dead. Storage in n-Hexane, however, conserves pollen viability because of its positive effect on the integrity of the pollen membrane. ALS showed high viability for both dry-stored and n-Hexane-stored pollen grains. In contrast, FeR-treated pollen showed viability only after n-Hexane-storing but not after dry-storing. Of the two indirect tests, FeR should be given preference over ALS because it reflects at least trends of viability in pollen grains, however, it is not accurate enough to reflect natural germination percentages of trinucleate Silene pollen as found with the in vivo test.

Pollen storage of Fragaria and Potentilla

Low temperature and humidity were used for the storage of pollen of four species of Fragaria (2n=14, 42 and 56) and two species of Potentilla (2n=14). The stainability of Fragaria pollen was assessed over a number of years by use of aceto-carmine stain and its viability by cross-pollinations; stainability of Potentilla pollen was assessed by acetocarmine. Fragaria pollen so stored remained stainable for seven years and showed the ability to set seed for three years. over the latter period, aceto-carmine staining gave a reasonable prediction of seed set produced by the stored pollen of Fragaria and so is of value in estimating pollen viability in that genus. Potentilla pollen remained stainable for three years.

Comparison of Procedures for Estimating Viability of Prunus Pollen

Abstract Seven assays (hanging-drop slide and agar-plate germination, acetocarmine, three tetrazolium-based stains, and Alexander’s staining procedures) were used to estimate pollen viability in Prunus armeniaca L., P. avium L., P. dulcis Webb, P. persica (L.) Batsch, and P. salicina Lindl. The two in vitro germination tests (hanging-drop and agar-plate) were the most reliable and were highly correlated (r = 0.96). The pollen staining procedures were not reliable or consistent and were not positively correlated with the in vitro assays. Acetocarmine and Alexander’s stains stained dead pollen.

THE CYTOCHEMICAL REDUCTION OF NITRO BLUE TETRAZOLIUM AS AN INDEX OF POLLEN VIABILITY

A new technique for estimating pollen viability utilizing Nitro Blue Tetrazolium (Nitro‐BT) is given. Pollen of 16 taxa was studied and scored for stainability. A comparison was made between Nitro‐BT‐stained pollen samples and aniline‐blue‐lactophenol‐stained samples, because the validity of the latter stain has been questioned in recent years. It is demonstrated that Nitro‐BT can discriminate between pollens which have a capacity for oxidative metabolism, representing potential viability, and those which do not. Suggestions for pollen stainability studies are given.