Pollen Viability Tests Research Articles

Morphology, pollen viability, and meiotic index of nance (Byrsonima cydoniifolia [A.] Juss)

Byrsonima cydoniifolia (nance), a forest species from the Malpighiaceae family, is widely distributed across Brazil, predominantly in the North, Northeast, and Central-West regions. This study aimed to analyze pollen morphology, viability, and the meiotic index in different native populations of nance in the eastern region of Mato Grosso state. For each population, five individuals were selected, and floral buds were collected during various developmental stages. The morphological characterization of pollen grains was conducted using the acetolysis protocol, followed by photography, measurement, and classification based on size, shape, ornamentation, and polar area index. The meiotic index was determined by counting post-meiotic products. Pollen grains were found to be spheroidal, small, 3-colporate, with a colpus, identified as tricolporate grains with a large polar area. The exine in the polar area was microreticulate. The meiotic index varied among populations and individuals, exceeding 95%. Pollen viability tests effectively distinguished between viable and non-viable pollen, with viability rates over 90%. The pollen grains contained starch and lipids as reserve substances. The species demonstrated high stability and meiotic regularity. The findings from this study contribute to our understanding of the ecology, conservation, dispersal, and propagation potential of nance, which supports the reproductive success of the species.

Evaluating the precision of staining methods in determining pollen viability and in vitro pollen germination in two endemic varieties of Humboldtia brunonis Wall. (Fabaceae-Detarioideae)

The genus Humboldtia, restricted to the Western Ghats of India and Sri Lanka, is mainly propagated by the seeds. However, the seed set is very low in a few species, which includes Humboldtia brunonis and its varieties. One important factor that restricts seed formation may be the viability of the pollen grain employed in cross-pollination operations. Considering this, the present study aims to report the pollen viability and pollen germination of H. brunonis var. brunonis and H. brunonis var. raktapushpa. Pollen viability was determined by Fluorochromatic reaction test (FCR) and 3, 3’- Diamino benzidine test (DAB) based on the pollen and in vitro pollen germination was determined in different sucrose concentrations of Brewbaker and Kwack (BK) medium. The pollen viability test using DAB revealed that more than 73 % of pollen was viable. However, 68.6 % of pollen in H. brunonis var. brunonis and 67.8 % of pollen in H. brunonis var. raktapushpa showed viability under FCR test. More interestingly, at the same time, only 67.27 % of pollen germination was exhibited in the BK medium. Pollen viability by FCR and in vitro pollen germination significantly correlates with the results; on the contrary, in vitro germination is not correlated with the DAB test. Along with the in vitro staining and in vitro pollen germination, detailed macro-morphology and pollen morphology of the selected taxa are given herewith.

Temperature dependence of pollen germination and tube growth in conifers relates to their distribution along an elevational gradient in Washington State, USA.

Pollen germination and tube growth are essential processes for successful fertilization. They are among the most temperature-vulnerable stages and subsequently affect seed production and determine population persistence and species distribution under climate change. Our study aims to investigate intra- and inter-specific variations in the temperature dependence of pollen germination and tube length growth and to explore how these variations differ for pollen from elevational gradients. We focused on three conifer species, Pinus contorta, Picea engelmannii, and Pinus ponderosa, with pollen collected from 350 to 2200m elevation in Washington State, USA. We conducted pollen viability tests at temperatures from 5 to 40°C in 5°C intervals. After testing for four days, we took images of these samples under a microscope to monitor pollen germination percentage (GP) and tube length (TL). We applied the Gamma function to describe the temperature dependence of GP and TL and estimated key parameters, including the optimal temperature for GP (Topt_GP) and TL (Topt_TL). Results showed that pollen from three species and different elevations within a species have different GP, TL, Topt_GP, and Topt_TL. The population with a higher Topt_GP would also have a higher Topt_TL, while Topt_TL was generally higher than Topt_GP, i.e., a positive but not one-to-one relationship. However, only Pinus contorta showed that populations from higher elevations have lower Topt_GP and Topt_TL and vice versa. The variability in GP increased at extreme temperatures, whereas the variability in TL was greatest near Topt_TL. Our study demonstrates the temperature dependences of three conifers across a wide range of temperatures. Pollen germination and tube growth are highly sensitive to temperature conditions and vary among species and elevations, affecting their reproduction success during warming. Our findings can provide valuable insights to advance our understanding of how conifer pollen responds to rising temperatures.

NIGHTSHADE NECTAR: A MULTIFACETED DIVE INTO MEDICINAL, POLLEN, AND STEM ANATOMIES OF FIVE SOLANACEAE WONDERS

This comprehensive study delves into the intricate anatomy and reproductive biology of five prominent members of the Solanaceae family: Capsicum frutescens L., Solanum lycopersicum L., Solanum torvum Sw., Datura stramonium L., and Solanum melongena L. Through detailed anatomical examinations, including stem structure analyses, and investigations into pollen germination processes, this research elucidates the unique characteristics and adaptations of each species. Additionally, the study provides essential insights into the materials required for free-hand sectioning and pollen viability testing, facilitating further research in plant anatomy and reproductive physiology. With a focus on both morphological and physiological aspects, this work contributes to a deeper understanding of Solanaceae plant species and their ecological significance.

Optimized Protocol for in vitro Pollen Germination in Brinjal (Solanum melongena L.)

Background: Understanding floral and pollen biology is essential for efficient artificial hybridization in hybrid seed production. This knowledge helps ensure proper fertilization of the ovary and optimal fruit and seed set. Selecting suitable pollen parents and preserving pollen for future use allows for better control and optimization of hybridization practices in brinjal breeding programs. To achieve this, a robust protocol for pollen collection and viability testing is necessary to monitor pollen quality in the field and during storage. This information is crucial for maintaining desired characteristics and genetic traits in the resulting hybrid seeds. Methods: This study; aimed at optimizing the pollen germination assessment protocol for brinjal. The step wise modification standard medium composition was done, the optimal growth condition was tested and in vivo predictions were made. So, the study aimed to standardization of media for in vitro pollen germination evaluate and viability in brinjal in ambient as well as cold storage conditions. The pollen germination was tested in vitro as well in vivo, by incubating the pollen grains for 3 hours at 25°C in different concentrations of sucrose, boron and agar media and distilled water at interval of 12 hours. Result: The most favorable germination of fresh pollen was achieved with a treatment consisting of 1% Agar, 12% Sucrose and 300 ppm Boron. Comparing the two storage conditions, pollen stored in the refrigerator exhibited higher in vitro germination percentages compared to ambient storage conditions. The highest in vitro pollen germination and viability percentages were observed in fresh pollen collected within 12 hours (95.00%). As the duration of pollen storage increased in both storage conditions, the in vitro pollen germination decreased. This decline in in vitro pollen germination was reflected in the in vivo fertilization fruit set percentage. The highest fruit set percentage was observed when pollen was stored in the refrigerator (64.52%) and when female flowers were pollinated with pollen stored for less than 12 hours (84.66%).

Evaluation of reproduction biology of Prunus cerasoides

Prunus cerasoides have a high value in phytochemistry and pharmacology. It was classified as the Least Concern globally based on the IUCN red list due to its widespread distribution in eastern Asia. This research aims to evaluate the reproductive biology of P. cerasoides through the study of pollen morphology, pollen viability, stigma receptivity, and pollination in the Cibodas Botanical Garden, located in the Cibodas subdistrict of West Java, Indonesia. The pollen morphology was observed using SEM. Moreover, the pollen viability test was followed by the staining method (aceto-orcein 2%, I2KI 1%, TTC 1%) and in vitro pollen germination with thirteen treatments (aquadest [control]; 5-30% sucrose; and 5-30% sucrose + 5 ppm boric acid). Stigma receptivity was observed daily, from 7 days before anthesis until the anthesis stage. Furthermore, several types of pollination were evaluated, including open pollination, autogamy, geitonogamy, and allogamy. The results showed that the best staining method on P. cerasoides was aceto-orcein 2%, with pollen viability at 87.87%. The sucrose concentration of 25% at 72 hours of observation gave the highest pollen viability results, 52.48%. Stigma receptivity was optimal in the two days before anthesis until anthesis. The highest pollination efficiency was cross-pollination at 53.33%, with an average percentage of the total fruit set of 24.17%.

Determination of Self-Compatibility of the 'Arsel' Olive Cultivar Obtained by Hybridization Breeding

This study was aimed to determine the fertilization biology of the 'Arsel' olive cultivar obtained by hybridization breeding. For this reason, treatments of open pollination, cross pollination, and self-pollination were performed for 2 years and self-compatibility and appropriate pollinators of this new cultivar were investigated. Among the varieties included as pollinators (‘Memecik’, ‘Gemlik’, ‘Uslu’, ‘Ayvalık’ and ‘Eğriburun Nizip’), the highest fruit set was achieved with ‘Memecik’ and ‘Gemlik’ varietes in both years (2.64%, 1.37% and 1.75%, 1.39%). For this reason, ‘Memecik’ and ‘Gemlik’ cultivars were the best pollinator for ‘Arsel’ olive was thought. On the other hand, considering the statistical analyzes and productivity index values, ‘Arsel’ variety was found to be self-incompatible. However, the data also indicated that cross pollination was effective in increasing fruit set. Therefore, it is thought that the use of pollinator cultivar in orchard establishment would be beneficial in terms of yield. Pollen viability and germination tests were performed by using 2,3,5 Triphenyl Tetrazolium Chloride (TTC) and agar in petri (15% sucrose + 1% agar + 100 ppm H3BO3) methods in the study. The highest pollen viability rate was observed in ‘Memecik’ cultivar in 2020 and there isn’t statistical differences between olive cultivars in 2018. The highest pollen germination rate was observed in ‘Arsel’ cultivar in 2018. Accordingly, differences were determined between pollen viability and germination rates of examined olive cultivars in terms of years.

Ectopic expression of pigeonpea Orf147 gene imparts partial sterility in Cicer arietinum

Orf147, a cytotoxic peptide, has been found to cause cytoplasmic male sterility (CMS) in Cajanus cajanifolius (pigeonpea). In our study, Orf147 was introduced into self-pollinating Cicer arietinum (chickpea) using Agrobacterium-mediated transformation for induction of CMS. The stable integration and expression of the transgene has been assessed through PCR and qRT-PCR analysis. In addition, phenotypic sterility analysis has been performed, considering developmental parameters like flower development, pod formation and flower drop. Transgene inheritance analysis demonstrates that out of the five PCR positive events in the T0 generation, two events have segregated according to the Mendelian segregation ratio (3:1) in the T2 generation. Further, pollen viability test using microscopic analysis confirms the induction of partial CMS in transgenic chickpea. The study holds significant value regarding the heterosis of self-pollinating legumes like chickpea. As a part of the prospect, exploring inducible promoters of species-specific or related legumes would be the next step to developing a two-line hybrid system.

Marker-Assisted Selection of Male-Sterile and Maintainer Line in Chili Improvement by Backcross Breeding

Cytoplasmic genic male sterility (CGMS) is a male sterility system that uses the maternal line for hybrid production, ensuring no obscurity of F1 seed purity and reducing the cost of hybrid seed production. Identification of the male sterility gene is important for plant improvement and classification when using the molecular marker-assisted selection (MAS) method. This study aimed to produce a new maternal line (A-line) and its maintainer line (B-line) by transferring a male-sterile line (A-line) and its maintainer line (B-line) gene from another variety to restorer lines (C-line) to achieve future hybrid seed production. In the process, the CGMS line (A-line) and B-line transferred to C1 and C3 lines, which finally resulted in new A-line (BC2F2A1 × C1, BC2F2A1 × C3), and B-line (BC1F2B1 × C1, BC1F2B1 × C3), and then used the MAS method for detecting genes and pollen viability test in the newly improved lines. The results indicated that the 3336-last2-SCAR (1639 bp) and 4162-SCAR (1046 bp) DNA markers classified the Rf locus, and the CMS-SCAR130/140 marker confirmed the S or N cytoplasm. The BC2F2A1 × C1 and BC2F2A1 × C3 lines represented both male-fertile (SRf_) and male-sterile (Srfrf) progenies in a Mendelian ratio of 3:1. Moreover, stained pollen grains with 1% acetocarmine confirmed abnormal pollen in male-sterile plants. The molecular markers that detect maintainer lines (Nrfrf) are BC1F2B1 × C1-14, BC1F2B1 × C3-10, and BC1F2B1 × C3-11. The 3336-last2-SCAR (1639 bp) and CMS-SCAR130/140 markers successfully identified the male-sterile line (Srfrf) and maintainer line (Nrfrf), and 4162-SCAR (1046 bp) detected the presence of the RfRf or Rfrf genotype in chilies at the seedling stage. The use of these markers was highly accurate and confirmed the results at the early generation stage of a conventional breeding program. It can be concluded that the CGMS and maintainer gene in chilies were successfully transferred during early generation using the backcross method.

Generation of Asynaptic Mutants in Potato by Disrupting StDMC1 Gene Using RNA Interference Approach.

Fixing the genomic composition and multiplication through true potato seed (TPS) is an important challenge in autotetraploid potato. Disrupted meiotic cDNA (DMC1) is a meiotic gene that plays a central role in DNA recombination through crossing over in meiosis. Using the Arabidopsis DMC1 (AtDMC1) gene sequence, we retrieved Solanum tuberosum DMC1(StDMC1) from the diploid potato genome, and subsequently, sense and antisense regions of the StDMC1 gene were amplified in potato cv. Kufri Jyoti. The sense and antisense fragments were confirmed by Sanger-sequencing and cloned in the pRI101 vector. Agrobacterium-mediated transformation of the RNAi construct resulted in 44% transformation efficiency, and a total of 137 mutant lines were obtained. These mutant lines were further validated through pollen viability testing, and selected lines were used for gene expression analysis. The acetocarmine-based pollen staining showed reduced pollen viability ranging from 14 to 21% in four DMC1 mutant lines (DMC4-37, DMC4-41, DMC6-20, and DMC6-21), as compared to the Kufri Jyoti control plants, which on average exhibited 78% pollen viability. The phenotypic data was supported by the reduced expression of the StDMC1 gene in these four mutant lines compared to the control Kufri Jyoti. The results confirmed the generation of StDMC1 knockdown lines. This is the first report of StDMC1 mutant line generation in tetraploid potatoes and will be a step forward in generating non-recombinant mutants through sexual reproduction in potatoes.

A rare cultivar of horse chestnut (Aesculus hippocastanum L. ˈBaumaniiˈ) in Slovakia: morphological, molecular and antioxidant analysis

Aesculus hippocastanum L. ˈBaumaniiˈ (syn.: A. hippocastanum L. ˈFlore Plenoˈ; A. hippocastanum ˈPlenaˈ) is a rarely cultivated cultivar characterized by fully white and sterile flowers, and as a result it does not produce fruit. For identification and characterization of the morphological, molecular, and biochemical parameters of this cultivar, we performed the pollen viability test, morphological analysis of flowers, assay of miRNA-based markers and biochemical analyses. The results show that the germination of pollen grains in artificial media reached 0 % and the pistil in flowers was undeveloped. The antioxidant activity, total polyphenol and flavonoid content exhibited the highest values of all three tested parameters (1.5540 mg TEAC/g FM; 3.7278 mg GAE/g FM and 1.328 mg CAE/g FM) in the extracts from A. hippocastanum ˈBaumaniiˈ. The applied miRNA-based markers showed a sample-specific and tissue-specific genomic polymorphism. Various DNA fingerprinting profiles between the flowers and leaf samples of fruiting and barren trees were noted. URL: https://www.upjs.sk/pracoviska/botanicka-zahrada/odborne-aktivity/contents-abstracts/

Viabilitas Serbuk Sari dan Keberhasilan Persilangan antara Durian Montong dan Sitokong pada Tiga Waktu Berbeda

The success of durian pollination in nature is very low (<5%) due to high self-incompatibility in durian flowers. Artificial cross-pollination is an alternative method that can be used to increase the successful pollination of durian. So, information on the pollen viability of the durian flower and the time of artificial cross-pollination accurate and effective is required. This research aimed to examine the pollen viability of the durian varieties of Montong and Sitokong varieties at three different times and to determine the success rate of artificial cross-pollination between both varieties at three different times. This research was carried out at the Morpoyan Seed Center and the Genetic and Breeding Laboratory of the Faculty of Agriculture, UIN Suska Riau. Pollen viability testing used the staining method. Artificial cross-pollination between the Montong durian and the Sitokong durian was carried out reciprocally at three different times (11.00–13.00, 15.00–17.00, and 19.00–21.00). The total number of flowers crossed was 300. The results of this study showed that the percentage of pollen viability of Montong durian at 11.00–13.00, 15.00–17.00, and 19.00–21.00 was 94.91, 97.67, and 97.23%, respectively. While the pollen viability of Sitokong durian was 93.33% at 11.00–13.00, 94.45% at 15.00–17.00, and 94.76% at 19.00–21.00. The successful rate of crosses of durian Montong (♀) x Sitokong (♂) at 11.00–13.00, 15.00–17.00, and 19.00–21.00, respectively were 46, 26, and 34%, while the percentage of success of durian Sitokong crosses (♀) x Montong (♂) is 48% at 11.00–13.00, 54% at 15.00–17.00, and 22% at 19.00–21.00. Successful artificial cross-pollination between Montong and Sitokong durian or vice versa was higher at 11.00–13.00 compared to other times. The results of this study can be utilized to formulate the timing of artificial cross-pollination of durian in the future.

Cytological Study of Anthers for Pollen Sterility in the F7 Generation of a Rice (Oryza sativa L.) Cross

The present research work was proficiently done at the experimental plot of Birsa Agricultural University, Kanke under the rainfed conditions of Jharkhand, India during kharif 2021. The F7 generation seeds of the cross Pusa-1176 x BPT-5204 was sown as panicle to progeny rows in the seed bed nursery and thereafter transplanted into the field. In this investigation, the study has been oriented more towards the male sterility as it is more sensitive than female gametes based on the observation recorded in previous generation (F6) regarding spikelet sterility percentage. Henceforth, the study has been focussed on the microscopic study of pollen grains to validate the reason behind the cause of spikelet sterility in the panicles. To understand this phenomenon, pollen viability test was done by staining the anthers with 1% Iodine- potassium iodide in order to know the extent of fertility or sterility present in the pollen grains of the rice segregants. Through microscopic study, segregation was observed in the pollen sterility % among the families studied which might be due to the change in the environmental conditions such as temperature, photoperiod and humidity etc. The expected genetic ratio obtained was 9:3:3:1(partially sterile+highly fertile/completely fertile/ highly sterile/completely sterile) revealing that it is controlled by 2 genes since the ratio fitted in digenic ratio.

Pollen storage, viability and effect of growth hormones on in vitro pollen germination in two medicinal plants (Clerodendrum colebrookianum Walp. and Clerodendrum infortunatum L.) of the tropical moist forest of North-east India

Clerodendrum colebrookianum Walp. and Clerodendrum infortunatum L. are well known for their medicinal uses in treating various human ailments traditionally. Pollen biology study was done in both plant species to decipher pollen viability, in vitro pollen germination, and pollen storage in varied temperature conditions. Pollen viability tests was done by 2, 3, 5-triphenyl tetrazolium chloride (TTC test) for which pollen grains were collected at the anthesis stage that ascertained high viability, ranged between 71.97%±4.30 % in C. colebrookianum and 81.63%±3.23 in C. infortunatum. In vitro pollen germination was conducted under different hormones (IBA, IAA, GA3, and Kinetin) with concentrations of 100 mg L-1, 200 mg L-1 and 300 mg L-1. Highest germination percentage of 52.10±5.30% and 61.91±1.76% in GA3 (200 mg L-1) was the most suitable growth hormone concentration for inducing in vitro pollen germination in both Clerodendrum species. Statistically, the response of all the concentrations of treatments, sucrose, and hormones, with their time on in vitro pollen germination of C. colebrookianum and C. infortunatum was found significantly different (p<0.05). In contrast, non-significant differences were recorded for in vitro pollen germination between the medicinal plant species. Pollen storage under temperature gradient conditions exhibited a similar trend in the viability for both C. colebrookianum, and C. infortunatum, i.e., the pollen remained viable up to 28 days at -20°C and 6°C, respectively. This study will be helpful in future breeding, hybridization, and conservation efforts for both the Clerodendrum species.

The Xenia Effect Promotes Fruit Quality and Assists in Optimizing Cross Combinations in ‘O’Neal’ and ‘Emerald’ Blueberry

Cross-pollination can improve the fruit set and quality of blueberry (Vaccinium spp.) for growers and consumers. However, the xenia effect in southern highbush blueberry remains unclear. Therefore, we selected eight cultivars of southern highbush blueberry (Vaccinium corymbosum L., interspecific hybrids) and applied pollination treatments (i.e., artificial self-pollination, artificial pollination with mixed pollen, or artificial pollination with individual cultivar pollen) to explore the xenia effects on the fruit set and quality of ‘O’Neal’ and ‘Emerald’. Pollen viability tests indicated that all of the cultivars are capable of fertilization. The highest fruit set came from ‘Bluerain’ pollen for ‘O’Neal’, while ‘Gulfcoast’ pollen increased fruit set the most in ‘Emerald’. Principal component analysis revealed that the cross combinations ‘Emerald’ × ‘Gulfcoast’ and ‘O’Neal’ × ‘Gulfcoast’ optimized the external and interior quality of the fruit. SSR was applied to determine which pollen source yielded the most seedlings. Results indicated that ‘Emerald’ × ‘Gulfcoast’ and ‘O’Neal’ × ‘Bluerain’ increased seedling production. Our results demonstrate that the xenia effects of ‘Gulfcoast’ pollen may increase ‘Emerald’ yields and promote fruit quality, while pollen from ‘Bluerain’ or ‘Jewel’ can improve ‘O’Neal’ fruit quality and seed number. Hence, these cross combinations may be utilized in blueberry production to increase fruit set, yield, and quality.

Optimization of in vitro pollen germination and viability testing of some Australian selections of date palm (Phoenix dactylifera L.) and their xenic and metaxenic effects on the tissue culture–derived female cultivar “Barhee”

Optimization of in vitro pollen germination and viability testing of some Australian selections of date palm (Phoenix dactylifera L.) and their xenic and metaxenic effects on the tissue culture–derived female cultivar “Barhee”

Hybridization of Castor Bean (Ricinus communis L.) in Morelos, México

Objective: To determine the stigma receptivity and the pollen viability in order to make manual crosses and obtain viable progeny in castor bean (Ricinus communis L.).Design/Methodology/Approach: Pollen viability tests were made on breeding materials by staining with acetocarmine solution. In elite materials, the receptivity of the stigma was evaluated with hydrogen peroxide. From the inflorescences, the male ones were removed and the female ones were preserved, which were covered with a glassine bag. After six days, they were checked and when they were considered receptive, manual pollinations were carried out between viable pollen materials and receptive stigma. The pollen of the male parent was impregnated in the stigmas and the inflorescence was covered again.Results: The breeding materials exhibited viable pollen since they were stained red. Whereas, the application of hydrogen peroxide to the stigmas of the elite materials showed bubbling, indicative that they were receptive. In 2014, 400 inflorescences were pollinated with 8 flowers on average and a fruit pollinated percentage of 61.21. In 2015, 245 inflorescences with 12 flowers on average and 61.24% of fruit were pollinated.Study Limitations/Implications: Temperature and relative humidity were fundamental factors for the success of castor bean fertilization.Findings/Conclusions: The elite castor bean materials presented receptive stigmas and the improved viable pollen materials. Manual crosses produced fruits and seeds. The fruits pollinated were 61%.

Optimized Protocol for In Vitro Pollen Germination in Yam (Dioscorea spp.).

Yam (Dioscorea spp.) plants are mostly dioecious and sometimes monoecious. Low, irregular, and asynchronous flowering of the genotypes are critical problems in yam breeding. Selecting suitable pollen parents and preserving yam pollen for future use are potential means of controlling these constraints and optimizing hybridization practice in yam breeding programs. However, implementing such procedures requires a robust protocol for pollen collection and viability testing to monitor pollen quality in the field and in storage. This study, therefore, aimed at optimizing the pollen germination assessment protocol for yam. The standard medium composition was stepwisely modified, the optimal growth condition was tested, and in vivo predictions were made. This study showed that the differences in yam pollen germination percentage are primarily linked to the genotype and growing conditions (i.e., medium viscosity, incubation temperature, and time to use) rather than the medium composition. The inclusion of polyethylene glycol (PEG) in the culture medium caused 67–75% inhibition of germination in D. alata. Although the in vivo fertilization was dependent on female parents, the in vitro germination test predicted the percentage fruit set at 25.2–79.7% and 26.4–59.7% accuracy for D. rotundata and D. alata genotypes, respectively. This study provides a reliable in vitro yam pollen germination protocol to support pollen management and preservation efforts in yam breeding.

Flower development, pollen viability and pollen storage test of Aeschynanthus radicans

Abstract. Damayanti F, Garvita RV, Wawangningrum H, Rahayu S. 2021. Flower development, pollen viability and pollen storage test of Aeschynanthus radicans. Biodiversitas 22: 1940-1945. Aeschynanthus radicans Jack. commonly-known as lipstick flowers, is an epiphytic plant in Gesneriaceae family. It has an attractive morphology and is easy to grow. Therefore A. radicans is used as mother species for hybridization by plant breeders. The flowers of A. radicans are dichogamous and strongly protandrous. The pollen matures before the stigma becomes receptive and bends away and down when the stigma becomes receptive. As a thought-after material for hybridization, little is known about the flower development, pollen viability, and storability. The purpose of this study was to observe the development phase of A.radicans flowers, determine the viability of pollen during flower development, and investigate the pollen storability at -20?C. Flower development was observed in phases from small buds to anthesis. Pollen viability was tested in 10%, 15%, and 20% sucrose solution for 4 hours. Pollen storage was tested at -20?C for 77 days and tested for viability every three weeks. The best sucrose concentration for the germination of fresh pollen was 20%. The highest pollen viability was at H0 was 58±3% and gradually decreased with flowerage. The lowest viability was 18±14% at flower stage H5, coinciding with the first day of stigma receptive. Pollen storage at -20?C decreased pollen viability to 30,2±2% after 42 days and to 13,54% after 77 days.

Reproductive biology of East Indian satinwood (Chloroxylon swietenia DC., Rutaceae: Sapindales), a threatened timber-yielding tree

Chloroxylon swietenia DC. (Rutaceae) is widely used in folk medicine and provides a commercial timber. In the present study, phenological events such as flowering and fruiting phenology, pollinator visitation, anthesis, pollen viability, and pollen tube germination tests were analyzed in 11 populations, in Tamil Nadu, India. The number of flowers was recorded as 82.6 ± 1.4 to 162.2 ± 4.2 during flower bud formation and reduced to 25.4 ± 0.5 to 61.8 ± 1.0 at maturity. The number of fruits per twig was 21.0 ± 0.8 to 47.2 ± 0.7 in initial stages and slightly reduced to 16.2 ± 1.8 to 34.6 ± 1.4 at maturation. Sixty-two species of insects were visiting the flowers with bees/ants as effective pollinators. The 2,5-diphenyltetrazolium bromide assay revealed more viable pollen grains in five populations, and fluorescence dye assay revealed maximum viable pollen grains in six populations. In the pollen tube germination test, the 60% sucrose concentration provides significant results, with a high number of germinated pollen grains. Principal component analysis of flowering and fruiting phenology, floral visitors, and pollen viability showed 79.5%, 79.3%, 56.7%, and 41.7% for the first factor, respectively. Our results indicated that C. swietenia depends heavily on pollinators for its reproduction. Hence, there is a need to expand this study to related species which are having agronomic, pharmacological, and economic potential.