POLLEN GERMINATION Research Papers - Academia.edu (original) (raw)

2025, Botanical Journal of the Linnean Society

2025, Acta Biologica Cracoviensia Series Botanica

We used different tests to assess the effect of high soil concentrations of heavy metals on pollen viability in plants from metallicolous (MET) and nonmetallicolous (NONMET) populations. The frequency of viable pollen depended on the test applied: MET plants showed no significant reduction of pollen viability by acetocarmine, Alexander, MTT and X-Gal dye testing, but a drastic reduction of pollen viability in MET flowers (MET 56% vs 72% NONMET) by the FDA test. There was no correlation between pollen viability estimated in histochemical tests and pollen germination in vitro or in vivo. We discuss the terminology used to describe pollen viability as determined by histochemical tests.

2025, Theoretical and Applied Genetics

The map locations and effects of quantitative trait loci (QTLs) were estimated for eight flower and fruit traits in sour cherry (Prunus cerasus L.) using a restriction fragment length polymorphism (RFLP) genetic linkage map constructed from a double pseudo-testcross. The mapping population consisted of 86 progeny from the cross between two sour cherry cultivars, Rheinische Schattenmorelle (RS)×Erdi Botermo (EB). The genetic linkage maps for RS and EB were 398.2 cM and 222.2 cM, respectively, with an average interval length of 9.8 cM. The RS/EB linkage map that was generated with shared segregating markers consisted of 17 linkage groups covering 272.9 cM with an average interval length of 4.8 cM. Eleven putatively significant QTLs (LOD >2.4) were detected for six characters (bloom time, ripening time, % pistil death, % pollen germination, fruit weight, and soluble solids concentration). The percentage of phenotypic variation explained by a single QTL ranged from 12.9% to 25.9%. Of the QTLs identified for the traits in which the two parents differed significantly, 50% had allelic effects opposite to those predicted from the parental phenotype. Three QTLs affecting flower traits (bloom time, % pistil death, and % pollen germination) mapped to a single linkage group, EB 1. The RFLP closest to the bloom time QTL on EB 1 was detected by a sweet cherry cDNA clone pS141 whose partial amino acid sequence was 81% identical to that of a Japanese pear stylar RNase.

2025

Simple methods to evaluate the viability and to preserve Agave tequilana Weber var. azul and A. angustifolia Haw pollen were established. Pollen viability was assessed by improving a growing media and evaluating three common pollen germination media components: sucrose, boric acid, and calcium ion. Optimal germination of pollen was obtained at 0.300 M sucrose, 0.324 mM boric acid, and 1.219 mM calcium nitrate and incubated at a temperature of 25°C. Agave pollen was preserved in olive oil and organic solvents. Olive oil, which is immiscible with water, provides an anhydrous environment and limits available oxygen, conditions similar to those provided by some organic solvents. Fresh pollen was put into eppendorf tubes containing n-butanol, n-propanol, isopropanol, extra virgin olive oil and preserved at -20, 4, and 25°C. The germination of the preserved pollen was scored at different time periods during preservation employing the optimal germination medium. The viability of pollen gra...

2025, Mediterranean Journal of Basic and Applied Sciences (MJBAS)

Among Genus Ephedra species only Ephedra foliata is reported in Rajasthan. It belongs to family Ephedraceae and it is distributed in temperate and sub-tropical area of world. It has several traditional uses for treatment in Chinese and other medicine. It contains alkaloids Ephedrine and pseudo ephedrine, which are of great importance. It is propagated by seed but due to low seed germination, micropagation is used from mass propagation. Ephedra foliata is a mild CNS stimulant & also have cardio vascular effect.

2025

Skewed gender ratio of unisexual plants in a population could be detrimental to optimal fruit/seed-set and sustenance of a species. In instances of non-availability of sufficient pollen donors or quality pollen donors, storage of pollen for supplemental pollination has proved to be a reliable strategy. However, testing the germinability and viability of pollen grains under in vitro conditions at the time of collection or after storage is a pre-requisite. Optimization of pollen germination media, especially in case of threatened and endemic plant species, may help in their breeding and conservation to ensure seed formation in years of low yield and poor recruitment. Here, we present the details of a standardized pollen germination medium for Pittosporum eriocarpum, an endangered tree species, which does not respond to Brewbaker and Kwack’s (BK) medium, usually employed to ascertain pollen germinability. The optimized BK medium, improves pollen germination and the pollen tube growth r...

2025, Crop and Pasture Science

Increased temperature due to global warming may reduce pollen germination and induce spikelet sterility in rice crops. Anthesis is the most sensitive stage in rice and exposure to high temperature during this period may cause reduction in floral reproduction. Increased temperature will have different effects on different rice varieties. In the present study the effect of high temperature on pollen as well as on spikelet sterility in basmati (aromatic) and non-basmati (non-aromatic) rice varieties was quantified. Rice varieties were grown at 11 different sowing dates, to see the effect of varying temperature on pollen and spikelet sterility. Rise in temperature increased pollen sterility and reduced germination of pollen grains on the stigma. Temperature above 33°C during anthesis gradually increased pollen sterility in all rice cultivars. At 35.5°C, variety Pusa Sugandh 2 (basmati) recorded a pollen sterility of 17% and 26% reduction in pollen germination. The principal cause of ste...

2025, Turkish Journal of Agricultural and Natural Science

2025, Proceedings of the National Academy of Sciences of the United States of America

2025

Umeå 2013 transcript is not expressed in the meristem. Taken together, this study shows that Arabidopsis AIP1s interact with actins, and that interaction of AIP1-2 with ACT7 and ACT2 does not require other plant proteins in vitro. AIP1-2 is transcriptionally upregulated in hair cell files and its overexpression may shift root hair positioning apically, suggesting a regulatory role for AIP1-2 in planar polarity.

2025, Planta

Pollination is essential for seed reproduction and for exchanges of genetic information between individual plants. In angiosperms, mature pollen grains released from dehisced anthers are transferred to the stigma where they become hydrated and begin to germinate. Pollen grains of wild-type Arabidopsis thaliana do not germinate inside the anther under normal growth conditions. We report two Arabidopsis lines that produced pollen grains able to in situ precociously germinate inside the anther. One of them was a callose synthase 9 (cs9) knockout mutant with a T-DNA insertion in the Callose Synthase 9 gene (CalS9). Male gametophytes carrying a cs9 mutant allele were defective and no homozygous progeny could be produced. Heterozygous mutant plants (cs9/+) produced approximately 50% defective pollen grains with an altered male germ unit (MGU) and aberrant callose deposition in bicellular pollen. Bicellular pollen grains germinated precociously inside the anther. Another line, a transgenic...

2024, Genetics

Gametes are produced in plants through mitotic divisions in the haploid gametophytes. We investigated the role of EXPORTIN1 (XPO1) genes during the development of both female and male gametophytes of Arabidopsis. Exportins exclude target proteins from the nucleus and are also part of a complex recruited at the kinetochores during mitosis. Here we show that double mutants in Arabidopsis XPO1A and XPO1B are gametophytic defective. In homozygous-heterozygous plants, 50% of the ovules were arrested at different stages according to the parental genotype. Double-mutant female gametophytes of xpo1a-3/1; xpo1b-1/ xpo1b-1 plants failed to undergo all the mitotic divisions or failed to complete embryo sac maturation. Double-mutant female gametophytes of xpo1a-3/xpo1a-3; xpo1b-1/1 plants had normal mitotic divisions and fertilization occurred; in most of these embryo sacs the endosperm started to divide but an embryo failed to develop. Distortions in male transmission correlated with the occurrence of smaller pollen grains, poor pollen germination, and shorter pollen tubes. Our results show that mitotic divisions are possible without XPO1 during the haploid phase, but that XPO1 is crucial for the maternal-to-embryonic transition.

2024, Revista Colombiana …

Las poliaminas están ampliamente distribuidas en todos los organismos y existen numerosas evidencias que las relacionan con un gran número de procesos biológicos esenciales (Galston y Sawhney, 1990; Slocum y Flores, 1991). Se ha visto que... more

2024, Sexual Plant Reproduction

The pollen specificity of the Arabidopsis arabinogalactan protein (AGP) genes AGP6 and AGP11 suggests that they are integral to pollen biogenesis, and their high percent of sequence similarity may indicate a potential for overlapping function. Arabidopsis agp6 agp11 double null mutants have been studied in our laboratory, and in the present work, we characterize the germination and growth of its pollen. When compared to wild type, mutant agp6 agp11 pollen displayed reduced germination and elongation, both in vivo and in vitro, and precocious germination inside the anthers, provided that sufficient moisture was available. This characteristic was not observed in wild type plants, even in water content conditions which for the mutant were sufficient for pollen germination. Therefore, an additional distinctive phenotypic trait of arabinogalactan proteins AGP6 and AGP11 may be to avert untimely germination of pollen. Such AGPs may control germination through water uptake, suggesting an important biological function of this gene family in pollen. Keywords agp6 Á agp11 Á Arabidopsis Á Arabinogalactan proteins Á Pollen tube Communicated by Hugh Dickinson.

2024

Present investigations pertain to germination and viability of Solanum melongena L., (Solanaceae) pollens up to 48 weeks. Pollen germination was made by the hanging drop technique in different concentration of sucrose and boric acid solutions (10%-100%). Viability under storage was determined by storing pollen in different conditions, like refrigerator, freezer, in vacuum over silica gel and in organic solvents (Acetone, Benzene, and Choloroform). Pollen stored at low temperature (-30°C, -20°C) showed better germination percentage compared to pollen stored at +4°C and fresh. Freeze dried pollen (-60°C) showed the best of germination. The study indicates that 30% and 40% solutions favoured pollen germination. Benzene showed more germination than acetone and chloroform.

2024, HortScience

Flowers of Swainsona formosa (G. Don) J. Thompson (syn. Clianthus formosus) developed through seven floral stages from buds to open flowers in 17 days. Floral stages were correlated with the sigmoidal growth pattern of the peduncle. Self-pollination was prevented in the species by the presence of a stigmatic cuticle that precluded pollen germination until ruptured, exposing the receptive surface below. Cuticular rupture occurred in nature during bird-pollination and was emulated manually by lightly rubbing a pollen-covered finger across the stigma. The species was self-compatible, and to ensure cross-fertilization when breeding, emasculation before anther dehiscence was essential.

2024, HortScience

Pollen of the California almond cultivars Nonpareil, Ne Plus Ultra, Sonora, and Peerless was evaluated for viability following storage over 12 months at 4, 0, -20, and -80 °C. The proportion of viable pollen exceeded 80% for all cultivars and for all temperatures evaluated after 2 months of storage. Following 12 months of storage at 4 °C, germination decreased to 8% for `Nonpareil', 10% for `Ne Plus Ultra', 50% for `Sonora', with no germination observed for `Peerless'. Storage at sub-freezing temperatures maintained pollen viability above 70% in `Nonpareil', `Ne Plus Ultra', and `Sonora' and above 40% in `Peerless'. Cultivars differed significantly in their tolerance to low temperature pollen storage. Within cultivars, differences in pollen germination following storage at 0, -20, or -80 °C were nonsignificant.

2024, HAL (Le Centre pour la Communication Scientifique Directe)

2024

GENETICS OF AN ALBINO MUTANT IN SMOOTH BROMEGRASS (BROMUS INERMIS LEYSS)

2024, Tropical Plant Pathology

2024, IV International Symposium on Pistachios and Almonds

The purpose of this research was to study the effect of different doses of the mineral elements K, Ca, S, Ca, and Mg on pollen and its germination in vitro, of six genotypes of almond. The pollen of the six selected genotypes of almond were collected and analyzed by atomic absorption in a complete random design experiment (CRD). The results showed that the level of mineral elements in the pollen influences the pollen germination, and we observed significant differences between treatments. The pollen of selected genotypes encoded as A-13, A-2, A-12, A6, A9 and A-15 had relatively the highest levels of Ca, K, P, Ca, Mg, and K. It was also noted that pollen with high levels of Ca, had the highest germination capacity, and a high correlation was found between them.

2024

Temperate fruits including pome fruits, especially apple are important fruit crops which mostly for fruit set needs the pollination of flowers and followed by pistil fertilization. Therefore, to achieve this act, pollen viability and its germination capability is essential. For that reason, test of pollen viability and understand its quality is important. By the same token, test to optimize the pollen medium of apple and determination best medium for it with 16 types of culture medium containing different concentrations of boric acid (0 and 100mg/1), ...

2024, International Journal of Nuts and Related Sciences (IJNRS)

In this study the artificial pollination of pistachio was investigated. Two types of pollen of local selective genotypes (Q1 and Q2) which were different pollinizers were used. The experiment had six treatments. Qazvini and Ohadi cultivars were pollinated with supplementary pollinations as treatment which was covered with cotton bag, natural pollination as a control which was not covered and two types of pollen of local selective genotypes (Q1 and Q2) which were prepared. Results showed that supplementary ...

2024

Pistachio trees (Pistacia vera L.) are dioecious and pollination is necessary in order to get filled nuts. The effects of suspension media containing agar (A) and boric acid (B) combined with either 0.05% or 0.15% (w/v) pollen (P) used for spray pollination on pollen grain viability were investigated in pistachio (Pistacia vera L.) cv. Owhadi. We also evaluated the effects of spray pollination on fruit set, fruit and kernal quality. The pollen grain viability was measured by germination rates. It was determined that the pollen grain has the ability of germination in suspension media and the pollen grain germination percentage significantly increased by the application of the media containing agar and boric acid as compared with other media. Application of medium containing agar (A) and 0.01 % boric acid (B1) combined with 0.15% (w/v) pollen (P2) produced better fruit set than suspension media without boric acid. The medium containing agar and 100 mg L-1 boric acid combined with 0.05% (w/v) pollen increased fresh and dry weight of kernel. Moreover the pollination treatments affected kernel nutrient elements concentration so that highest concentration of the kernel P, Ca, Mg, Cu and Fe were obtained with spray pollination method. Our finding showed that the spray pollination may be the effective method in pistachio trees.

2024, Indonesian Journal of Agronomy

The purpose of the research was to examine the pollen germination process and growth rate of pollen tubes of papaya. Pollen tube growth of nine genotypes of papaya (IPB 1, IPB 2, IPB 3, IPB 4, IPB 5, IPB 7, IPB 8, IPB 9, and IPB 10) was investigated in this experiment in order to study their pollen germination rate and pollen viability. The fresh pollen were excised from the fl owers of papaya grown at Tajur Field Station of Research Center for Tropical Fruit, Bogor Agricultural University (IPB), Bogor. The extracted pollen was cultured aseptically on the Brewbaker and Kwack medium (pH 7.3) at ambient temperature of 26-28 °C. Pollen germination and pollen tube growth was observed under optical microscope with 100 and 400 magnifi cation. Papaya pollen viability was not associated with size-based categories of papaya fruits. IPB 4 had the longest pollen tube at fi rst 30 minutes after germination (115.5 µm), whereas IPB 10 had the shortest (99.5 µm). The distance from stigma to ovary ...

2024

Yield instability is a common problem in Ceratonia Siliqua grown in Jordan. This study was conducted to evaluate the responsibility of the plant itself on pollination failure and to assess the compatibility of hermaphrodite flowers. Flowers of Ceratonia Siliqua were subjected to three flower removal treatments: 1) Removal of late flowers and 2) Removal of late and intermediate flowers and 3) Non-removed flowers (control). To assess self-compatibility of Ceratonia Siliqua pollen grains; self, cross and geitonogamy pollination treatments were conducted on Ceratonia Siliqua trees producing hermaphrodite flowers. Results of non-removal treatment indicated that the average number of matured pods of late flowers was significantly higher than that of center and base flowers. The removal of the apical flowers significantly improved the fruit set of both the intermediate and late flowers. Removal of the late flowers (Remove of the apex) did not significantly increase in both pod length, weig...

2024

Bu calisma, Erzincan yoresinde seleksiyon sonucu elde edilmis olan umitvar genotiplerin bazi polen performanslarinin belirlenmesi icin yapilmistir. Zerdali genotiplerinin cicek tozu canlilik oranlari, cicek tozlarinin cimlenme oranlari ve cim borusu uzunluklari belirlenmistir. Ortalama cicek tozu canlilik degerleri %66.13 (158) ile %88.63 (Egri Cigit) arasinda degismistir. Cicek tozu cimlenme orani inkubasyon suresi boyunca paralel olarak artis gostermis ve maksimum cimlenme oranina 48 saat sonunda ulasilmistir. En uzun cim borulari 158 nolu genotipte (419.00 µm) olculurken, en kisa cim borusuna sahip olan genotip Egri Cigit (217.71 µm) olarak belirlenmistir.

2024, Yüzüncü Yıl Üniversitesi Tarım Bilimleri Dergisi

Bazı koşullarda tür ve çeşitlere göre polen tüpü gelişimi yavaş olmakta ve bu süreçte de yumurta canlılığını kaybedebilmektedir. Bu sebeple seleksiyon ıslahı ile ülkemize ve Dünyaya kazandırılan 4 zerdali genotipinin polen performanslarının bazı kimyasal uygulamalar ile nasıl tepkiler verdiği ve bu tepkilerin ileri ıslah çalışmalarında temel bir bilgi olacağı düşünülerek bu çalışma gerçekleştirilmiştir. Çalışmada, Erzincan yöresinden selekte edilmiş ve ümitvar görülen Güzeriği, Mahmudun Eriği, Eğri Çiğit ve 158 nolu zerdali genotiplerinin çiçek tozları kullanılmıştır. Bu genotiplerin çiçek tozu sayımları yapılmıştır. Bazı kimyasalların 4 zerdali genotipindeki çiçek tozu çimlenme oranına ve çiçek tozu çim borusu uzunluklarına etkisini incelemek için, 10 ppm gibberellik asit (GA3), 50 ppm potasyum nitrat (KNO3), 5 ppm indol asetik asit (IAA), 25 ppm borik asit (H3BO3) kontrol çimlendirme besin ortamlarına eklenmiştir. Kontrol besin ortamı olarak %1 agar ve %10 sakkaroz içeren ortam kullanılmıştır. Sonuçta, kullanılan büyüme düzenleyicilerin ve mineral maddelerin çiçek tozu çimlenmesine ve çiçek tozu çim borusuna etkileri genotiplere göre farklılık göstermiştir. Borik asit uygulamaları hem çiçek tozu çimlenmesini hem de çiçek tozu çim borusu uzunluğunu artırmıştır.

2024, Plant Physiology

Transcripts of the ntp303 gene accumulate abundantly throughout pollen development, whereas the protein only accumulates to detectable levels after pollen germination. In an attempt to explain the divergence in the accumulation profiles of the mRNA and the protein, we investigated the role of the untranslated regions (UTRs) in enhancing ntp303 translation during the transition from developing to germinating pollen. Luciferase reporter gene fusion constructs containing the ntp3035′-UTR gave rise to luciferase activity that was up to 60-fold higher during pollen tube growth than that of constructs containing different 5′-UTRs. No apparent differences in the luciferase activity of these constructs were observed during pollen development. Thentp303 5′-UTR-mediated increase in luciferase activity was not significantly influenced by coding region or 3′-UTR sequences. Furthermore, enhanced luciferase activity directed by thentp303 5′-UTR occurred predominantly at the post-transcriptional l...

2024, FEBS Letters

The tobacco ntf4 mitogen‐activated protein (MAP) kinase gene (and its encoded protein p45Ntf4) is expressed at later stages of pollen maturation. We have found that the highly related MAP kinase SIPK is also expressed in pollen and, like p45Ntf4, is activated upon pollen hydration. The MAP kinase kinase NtMEK2 activates SIPK, and here we show that it can also activate p45Ntf4. In an attempt to inhibit the function of both MAP kinases simultaneously we constructed a loss‐of‐function mutant version of NtMEK2, which, in transient transformation assays, led to an inhibition of germination in the transformed pollen grains. These data indicate that NtMEK2, and by inference its substrates p45Ntf4 and/or SIPK, are involved in pollen germination.

2024, Water Air and Soil Pollution

The long-term study objective was to determine the suitability of selected species of genus Pinus (Pinus sylvestris, Pinus nigra and Pinus mugo) for use as bioindicators of environmental pollution. In these experiments a new methodology of evaluation of mitotic abnormalities was established and its potential for common use tested. The study confirmed three species of genus Pinus as suitable bioindicators. The results also indicate that trees may show adaptive changes in response to severe pollution stress.

2024

Summary A mutant with altered floral morphology, designated Appendix, was observed among the progeny of a regenerated transgenic tobacco (Nicotiana tabacum) plant. Appendix flowers had small outgrowths resemb- ling pistils on the tips of fertile anthers. No obvious morphological changes could be seen in any other part of the plant. A more careful analysis using histo- logical methods and scanning electron microscopy revealed that the outgrowths were composed only of a style and a stigma and that these added organs can support pollen germination and pollen tube growth. Examination of anther ontogeny using scanning electron microscopy indicated that the anther style and stigma of the Appendix mutant developed from a small group of cells at the anther tip coincident with development of the carpel style and stigma. Genetic analysis indicated that this mutation is nuclear, recessive and linked to the 'transferred DNA' (T-DNA) inserted during the generation of transgenic plants ...

2024, Indonesian Journal of Agronomy

2024, Scientia Horticulturae

One of the most substantial molecules for pollen germination and tube growth are polyamines. Putrescine is the most abundant polyamine and the molecule from which spermine and spermidine originate. In this study, the effects of different exogenous putrescine concentrations (0.05, 0.25, 0.5 and 2.5 mM) on pollen performance of hazelnut (Corylus avellana) were investigated. Germination ratio and tube length were induced by 0.05 and 0.25 mM putrescine treatment. Putrescine concentration above 0.25 mM inhibited the pollen germination, tube elongation and, caused morphological alterations such as apex swelling. While the 0.05 and 0.25 mM putrescine treatment did not cause significant change in callose accumulation and actin filament distribution at tube apex, concentrations above 0.25 mM caused dense callose accumulation and increased the actin filament anisotropy at tube apex. Moreover, putrescine treatment caused an increase of reactive oxygen species level at the apex, especially in swollen tube apex, at the concentration of 2.5 mM. Reactive oxygen species detoxification mechanisms, which can be examined by changes in the amount of hydrogen peroxide and enzyme activities, were not disrupted by 0.05 and 0.25 mM putrescine treatment, while they are affected by 0.5 and 2.5 mM putrescine treatment. Eventually, low doses (0.05 and 0.25 mM) of putrescine can be used as a performance enhancing agent for hazelnut pollen tube growth, while the higher concentrations (0.5 and 2.5 mM) cause adverse effects reducing fertilization success.

2024, Bioagro

Se estudiaron aspectos de importancia dentro de la biología floral de la lechosa (Carica papaya L.). La población de plantas de lechosa estudiada se obtuvo de semillas comerciales del cv. Cartagena Amarilla. La antesis se evaluó mediante observaciones directas en campo sobre flores, seleccionadas al azar, de cada uno de los tipos florales. El tipo floral I fue el más tardío en la ocurrencia de la antesis y ésta se presentó en mayor intensidad a primeras horas de la noche. La receptividad estigmática, evaluada mediante la germinación de los granos de polen in vivo, comenzó el mismo día de la apertura floral. La dehiscencia de las anteras se determinó mediante observaciones directas en campo, con ayuda de una lupa. La ruptura de las anteras ocurrió dos días antes en los tipos florales V y IV+ y una día antes en los tipos II, III y IV.

2024, Pakistan Journal of Botany

Pollen quality of 5 caprifig genotypes selected in the East Mediterranean Region was determined. Triphenyltetrazolium chloride (TTC) and fluorescent diacetat (FDA) test procedures were used in evaluating pollen viability. Germination of pollen was determined by using various concentrations of sucrose supplemented with H 3 BO 3 , KNO 3 or GA 3 in agar medium. Pollen production status of caprifig flowers was determined. The percentage of viable pollen in caprifig types ranged from 76.04 to 83.34% by TTC test and from 75.60 to 86.73% by FDA test. The germinations were higher on the media containing 20% sucrose and increased up to 74 % with the addition of H 3 BO 3 or KNO 3 , but not GA 3. The number of pollen per flower ranged from 4355 to 7169 grains. The selected caprifigs appeared to be satisfactory pollinators in respect to criteria investigated.

2024, Plant Cell Reports

In contrast to model species, the self-incompatibility reaction in citrus has been poorly studied. It is assumed to be gametophytically determined and genetically controlled by the S-locus, which in other species encodes for glycoproteins (S-RNases) showing ribonuclease activity. To investigate pollen-pistil interaction, the pollen tube growth of two clementine varieties, 'Comune' (self-incompatible) and 'Monreal' (a 'Comune' self-compatible mutation) was analysed by histological assays in self-and cross-pollination conditions. Cross-pollination assays demonstrated that the mutation leading to self-compatibility in 'Monreal' occurred in the stylar tissues. Similar rates of pollen germination were observed in both genotypes. However, 'Comune' pollen tubes showed altered morphology and arrested growth in the upper style while in 'Monreal' they grew straight toward the ovary. Moreover, to identify genes putatively involved in pollen-pistil interaction and self-incompatibility, research based on the complementary DNA-amplified fragment length polymorphism technique was carried out to compare the transcript profiles of unpollinated and self-pollinated styles and stigmas of the two cultivars. This analysis identified 96 unigenes such as receptor-like kinases, stressinduced genes, transcripts involved in the phenylpropanoid pathway, transcription factors and genes related to calcium and hormone signalling. Surprisingly, a high percentage of active long terminal repeat (LTR) and non-LTR retrotransposons were identified among the unigenes, indicating their activation in response to pollination and their possible role in the regulation of self-incompatibility genes. The quantitative reverse trascription-polymerase chain reaction analysis of selected gene tags showed transcriptional differences between the two genotypes during pollen germination and pollen tube elongation. Keywords cDNA-AFLP Á Citrus clementina Hort. ex Tan. Á Gene expression Á Reproductive biology Á Retrotransposons Á Self-incompatibility Abbreviations cDNA-AFLP Complementary DNA-amplified fragment length polymorphism EST Expressed sequence tag LTR Long terminal repeat qRT-PCR Quantitative reverse trascription-polymerase chain reaction SC Self-compatible SI Self-incompatible TDF Transcript derived fragment Electronic supplementary material The online version of this article (

2024, Plant Biology

Temperatures during flower-bud development affect pollen germination, self-incompatibility reaction and early fruit development of clementine (Citrus clementina Hort. ex Tan.

2024, XII International Citrus Congress - International Society of Citriculture

Clementine mandarins, is a very important fruit group due the production of high quality fruits that can be seedless as consequence to their sexual selfincompatibility. In this study, the self-compatible/incompatible status of 40 clementine mandarins provided by the Cukurova University collection was determined by histological analysis. For this purpose, self-pollinations were performed and pistil samples were taken 3, 5, 7, 9, 11, 13, 15 and 20 days after pollination. All samples were fixed in FPA70 solution and stored at 4°C. Pistil samples were stained with aniline blue and observed by fluorescence microscope following the staining and squashing. All pollen tubes of the genotypes arrested growth in the upper or middle part of style and none reached the base of the style. As a result, all the 40 clementine cultivars tested have been identified as selfincompatible.

2024, XII International Citrus Congress - International Society of Citriculture

Self-incompatibility (SI), typical of many mandarin and pummelo varieties, is a valuable trait to obtain seedless fruits. Despite the importance of SI, its genetic basis in citrus is poorly understood. Two clementine genotypes showing divergent behaviour related to self-pollen rejection ('Comune', self-incompatible'; and 'Monreal', self-compatible) were chosen as model to study the molecular events occurring during pollen-pistil interaction and self-incompatible response. In a previous work, the comparative analysis of the floral transcriptome of these two clementine genotypes led to the identification of a set of candidate genes related to SI. The identified genes showed no homology to genes involved in SI mechanism of other species and many of them lacked annotation. Functional analyses were therefore needed to unravel their function and to confirm their role in citrus progamic phase. Our attention has been focused on 3 uncharacterized genes overrepresented in the 'Comune' transcriptome whose expression drastically increased in concomitance with the stop of pollen tube elongation. These genes, due to the abundance in aspartic acid residues in their deduced protein sequences, have been named Citrus clementina aspartic-acid rich (CcAsp-rich) protein encoding genes. A first step of the functional characterization consisted in their over-expression in tobacco plants. Moreover, the CcASP-RICH proteins were expressed in a cell-free system and purified for a biochemical characterization. The preliminary results of the functional analyses are discussed.

2024, Plant Cell Reports

2024, Journal of Molecular Biology

1'11~ cytoplasmic non-polysomal poly(A +)mRNA found ill the frtbe messenger ribonuclooprotcill of mouse Taper ascites cells was demonstrated by nucleic acid hybridization to contain only about 400 different mRNA sequences, in contrast) to the great)er than the 8000 sequences of the total cytoplasm. Approximately 500/, hy mass of the free RNPS-mRNA was shown to consist of only 15 different mRNA sequences and the other 50% to represent 400 different mRNA sequences. The abundant, free mRNP sequences were also present, in the polysomes at one-tenth of their concentration in the free mRNP. The 400 less abundant frrc RNP-mRNAs were found to be in the middle abundant class of total cytoplasmic SP~~IPI~C~S. The 400 less abundant free RNP-mRNA sequences were also found on tlic polysomrs: 50% of these sequences were at similar concentrations in t'llr polysomrs as in t,lrr free mRNP, while 50"' were found in the polysomes at, rcducrd concentrations. Thus it is concluded that, these mouse tumor ~11s maintain a highly polarized distribution of certain subsets of mRNA species ht~twren t,hc functioning (pnlysomes) and non-functioning (free mRNP) (vmpartmrnt,s of thcx cytoplasm. G95

2024, PhytoKeys

The Chinese Lilium brownii has been much confused with the Japanese endemic species Lilium japonicum. In this paper, it is shown that L. brownii was introduced to England at least four times between 1804 and 1819. The history of L. brownii is fully discussed and its taxonomy, nomenclature and relationships are examined. A neotype is designated for the name, its correct botanical authority is given and the correct place of its publication is provided. Lectotypes are also provided for the names Lilium aduncum Stapf, Lilium australe Stapf, Lilium odorum Planch., Lilium brownii var. colchesteri E.H.Wilson and Lilium brownii var. ferum Stapf.

2024, The Plant Cell

A nove1 mitogen-activated protein (MAP) kinase signaling pathway has been identified in tobacco. This pathway is developmentally regulated during pollen maturation and is activated by hydration during pollen germination. Analysis of different stages of pollen development showed that transcriptional and translational induction of MAP kinase synthesis occurs at the mid-bicellular stage of pollen maturation. However, the MAP kinase is stored in an inactive form in the mature, dry pollen grain. Kinase activation is very rapid after hydration of the dry pollen, peaking at-5 min and decreasing thereafter. lmmunoprecipitation of the kinase activity by an anti-phosphotyrosine antibody is consistent with the activation of a MAP kinase. The kinetics of activation suggest that the MAP kinase plays a role in the activation of the pollen grain after hydration rather than in pollen tube growth.

2024, FEBS Letters

2024, Biochemical and Biophysical Research Communications

Profilin is a small actin-binding protein and is expressed at high levels in mature pollen where it is thought to regulate actin filament dynamics upon pollen germination and tube growth. The majority of identified plant profilins contain a MAP kinase phosphorylation motif, P-X-T-P, and a MAP kinase interaction motif (KIM). In in vitro kinase assays, the tobacco MAP kinases p45 Ntf4 and SIPK, when activated by the tobacco MAP kinase kinase NtMEK2, can phosphorylate the tobacco profilin NtProf2. Mutagenesis of the threonine residue in this motif identified it as the site of MAP kinase phosphorylation. Fractionation of tobacco pollen extracts showed that p45 Ntf4 is found exclusively in the high-speed pellet fraction while SIPK and profilin are predominantly cytosolic. These data identify one of the first substrates to be directly phosphorylated by MAP kinases in plants.