The Role of Male Flowers and Bearing Status on Pollen Germination in Olive (Olea europaea L.)

Document Type : Original Article

Authors

1 Crop and Horticultural Research Department, West Azerbaijan Agricultural and Natural Resources Research Center, Agricultural Research, Education and Extension Organization (AREEO), Urmia, Iran

2 Plant Diseases Research Department, Iranian Research Institute of Plant Protection, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran

10.22126/atic.2024.10995.1157

Abstract

Olive is an andromonoecious plant producing both male and perfect flowers. This study was performed to determine the pollen germination percentage and growth rate of male and perfect flowers of Zard and Roghani cultivars in 2015 at the Tarom olive research station. Three trees from each cultivar (On and Off bearing) were selected. Pollen was collected from male and perfect flowers on the flowering shoots at flower opening stage. These anthers insert the capped glasses. Pollens were incubated in a modified medium that contained 0.8% agar, 10% sucrose, and 100-ppm boric acid. Pollens were spread using a modified medium, separately collected pollens of male and perfect flowers were spread on Petri dishes containing the medium, and then transferred into the incubator for germination at 25°C. After six hours of incubation, the number of germinated pollen grains was enumerated and recorded. The Zard olive cultivar had a higher pollen germination percentage (39.95%) than the Roghani olive cultivar (29.8%). In both cultivars, the male flowers exhibited a pollen germination rate of 48.01%, whereas the perfect flowers demonstrated a lower germination rate of 21.73%. Moreover, the germination rate of perfect flowers was significantly greater in the Zard cultivar (35.2%), in contrast to the Roghani cultivar (20.7%). In both cultivars, the pollen germination rate was 39.48% in the Off-season trees, surpassing the germination rate of 36.38% observed in the On-season trees. Moreover, the Zard cultivar exhibited a significantly higher germination rate of 41.13%, compared to a germination rate of 38.27% found in pollen from the Off-season of the Roghani cultivar. The overall results showed that male flowers of olive trees play an important role in the fertility and fruit set of perfect flowers.

Graphical Abstract

The Role of Male Flowers and Bearing Status on Pollen Germination in Olive (Olea europaea L.)

Highlights

  • Research reveals the role of male flowers in pollination and fruit set in Zard and Roghani olive cultivars.
  • Alternate bearing in olive cultivars affects pollen germination in both male and perfect flowers.
  • The pollen germination rates of the Zard olive cultivar are higher than those of the Roghani cultivar.
  • Male flowers of olive trees play a crucial role in the fertility of perfect flowers.

Keywords

Main Subjects

References

Abdelgadir H.A., Johnson S.D., Van Staden J. 2012. Pollen viability, pollen germination and pollen tube growth in the biofuel seed crop Jatropha curcas (Euphorbiaceae). South African Journal of Botany 79: 132-139. https://doi.org/10.1016/j.sajb.2011.10.005
Aksoy D., Dalkılıç Z. 2019. Determination of blooming, pollen and fruit set characteristics in Punica granatum. Notulae Botanicae Horti Agrobotanici Cluj-Napoca 47(4): 1258-1263. https://doi.org/10.15835/nbha47411216
Azimi M., Jafari H., Abdollahi A., Dastkar E. 2018. Determination of suitable pollinizers for Abou-satl and Kaissy olive cultivars (Olea europaea L.). Research Achievements for Field and Horticultural Crops 7(1): 17-29. (In Farsi). https://doi.org/10.22092/rafhc.2018.106018.1007
Azimi M., Khosrovshahli M., Golmohammadi M. 2008. Evaluation of pollination and choice of best pollinizer for some olive cultivars in the Tarom region. Pazhoohesh and Sazandegi 79: 160-168. (In Farsi).
Calviño A., Ashworth L., Moyetta N. 2014. Fruit set increases with maleness in the andromonoecious Acacia caven. Flora - Morphology, Distribution, Functional Ecology of Plants 209(9): 457-463. https://doi.org/10.1016/j.flora.2014.06.011
Cuevas J. 2024. Why olive produces many more flowers than fruit?. Horticulturae 11: 26. https://doi.org/10.20944/preprints202411.1440.v1
Dai C., Galloway L.F. 2012. Male flowers are better fathers than hermaphroditic flowers in andromonoecious Passiflora incarnate. New Phytologist 193(3): 787-796. https://doi.org/10.1111/j.1469-8137.2011.03966.x 
Dölek Gencer C., Ozkaya M.T., Eti S., Karabıyık Ş. 2023a. Evaluation of the effect of open-, self- and cross pollinations on fruit set in Domat, Gemlik and Sarı Ulak olive cultivars. Scientia Horticulturae 311: 111780. https://doi.org/10.1016/j.scienta.2022.111780
Dölek Gencer C., Özkaya M.T., Eti S., Karabıyık Ş., Taskin N., Fletcher M. 2023b. Pollen viability and germination levels with amount of pollen production of some important olive cultivars in türkiye. Turkish Journal of Agriculture Food Science and Technology 11(6): 1176-1182. https://doi.org/10.24925/turjaf.v11i6.1176-1182.5773
Gao L., Yu G., Hu F., Li Z., Li W., Peng C. 2021. The patterns of male and female flowers in flowering stage may not be optimal resource allocation for fruit and seed growth. Plants 10: 2819. https://doi.org/10.3390/plants10122819
Hechmi M., Khaled M., Echarari F. 2015. In vitro pollen germination of four olive cultivars (Olea europaea L.): Effect of boric acid and storage. American Journal of Plant Physiology 10(2): 55-67. https://doi.org/10.3923/ajpp.2015.55.67
Herbert S.W., Walton D.A., Wallace H.M. 2019. The influence of pollen-parent and carbohydrate availability on macadamia yield and nut size. Scientia Horticulturae 251: 241-246. https://doi.org/10.1016/j.scienta.2019.03.006
Ikram S., Shafqat W., Ur Rehman S., Qureshi M.A., Din S., Ikram S., Nafees M., Jaskani M.J. 2023. Floral characterization of pomegranate genotypes to improve hybridization efficiency. Plants 12(1): 165. https://doi.org/10.3390/plants12010165
Jianhua C., Jian Z., Yuncheng Z., Quangang L., Pengkai W., Yongqiang S., Shengjun D. 2024. Physiological characteristics of pistil abortion in Prunus sibirica. Trees 38(3): 655-666. https://doi.org/10.1007/s00468-024-02504-x
Kamath A., Levin R.A., Miller J.S. 2017. Floral size and shape evolution following the transition to gender dimorphism. American Journal of Botany 104(3): 451-460. https://doi.org/10.3732/ajb.1600442
Koubouris G.C., Metzidakis I.T., Vasilakakis M.D. 2012. Intraspecific variation in pollen viability, germination and ultrastructure of Olea europaea L. African Journal of Biotechnology 11(70): 13442-13446. https://doi.org/10.5897/AJB12.626
Lyu S.T., Zou T.T., Jiang Q.L., Wang X.F. 2023. Maintenance of andromonoecy in an autogamous species: Superior male function in male flowers of the endangered Sagittaria guayanensis. Plant Diversity 46(6): 783-790. https://doi.org/10.1016/j.pld.2023.03.009
Mazzeo A., Palasciano M., Gallotta A., Camposeo S., Pacifico A., Ferrara G. 2014. Amount and quality of pollen grains in four olive (Olea europaea L.) cultivars as affected by ‘on’ and ‘off’ years. Scientia Horticulturae 170: 89-93. https://doi.org/10.1016/j.scienta.2014.02.030
Niu Y., Gong Q., Peng D., Sun H., Li Z. 2017. Function of male and hermaphroditic flowers and size-dependent gender diphasy of Lloydia oxycarpa (Liliaceae) from Hengduan Mountains. Plant Diversity 39(4): 187-193. https://doi.org/10.1016/j.pld.2017.06.001
Noormohammadi Z., Hosseini-Mazinani M., Trujillo I., Rallo L., Belaj A., Sadeghizadeh M. 2007. Identification and classification of main Iranian olive cultivars using microsatellite markers. HortScience 42(7): 1545-1550. https://doi.org/10.21273/HORTSCI.42.7.1545
Palomo-Ríos E., Narváez I., Pliego-Alfaro F., Mercado J.A. 2021. Olive (Olea europaea L.) genetic transformation: Current status and future prospects. Genes 12(3): 386. https://doi.org/10.3390/genes12030386
Paterno G.B., Silveira C.L., Kollmann J., Westoby M., Fonseca C.R. 2020. The maleness of larger angiosperm flowers. Proceedings of the National Academy of Sciences 117(20): 10921-10926. https://doi.org/10.1073/pnas.1910631117 
Pinney K., Polito V.S. 1990. Olive pollen storage and in vitro germination. Acta Horticulturae 286: 207-210. https://doi.org/10.17660/ActaHortic.1990.286.42
Reale L., Sgromo C., Ederli L., Pasqualini S., Orlandi F., Fornaciari M., Ferranti F., Romano B. 2009. Morphological and cytological development and starch accumulation in hermaphrodite and staminate flowers of olive (Olea europaea L.). Sexual Plant Reproduction 22: 109-119. https://doi.org/10.1007/s00497-009-0096-1
Riella V., Borges A., Arias-Sibillotte M., Speroni G., Speranza P. 2022. The effective pollination period of the olive cultivar ‘Arbequina’ (Olea europaea L.) in a non-traditional production region. South African Journal of Botany 151(Part A): 246-254. https://doi.org/10.1016/j.sajb.2022.10.004
Rosati A., Caporali S., Paoletti A., Famiani F. 2011. Pistil abortion is related to ovary mass in olive (Olea europaea L.). Scientia Horticulturae 127(4): 515-519. https://doi.org/10.1016/j.scienta.2010.12.002
Rosati A., Zipanćič M., Caporali S., Paoletti A. 2010. Fruit set is inversely related to flower and fruit weight in olive (Olea europaea L.). Scientia Horticulturae 126(2): 200-204. https://doi.org/10.1016/j.scienta.2010.07.010
Şenbaş A., Horuzum Ö., Dölek Gencer C., Özkaya M.T. 2022. Storage and in-vitro germination of some olive pollens. Yuzuncu Yil University Journal of Agricultural Sciences 32(4): 843-852. https://doi.org/10.29133/yyutbd.1188414
Shwe E., Wu B., Huang S.Q. 2020. Both small and large plants are likely to produce staminate (male) flowers in a hermaphrodite lily. Plant Diversity 42(3): 142-147. https://doi.org/10.1016/j.pld.2020.01.004
Vuletin Selak G., Perica S., Goreta Ban S., Bucan L., M. Poljak. 2012. Flower sterility and the germination ability of pollen as genetic traits of seven olive (Olea europaea L.) cultivars grown in Croatia. Journal of Horticultural Science & Biotechnology 87(3): 237-242. https://doi.org/10.1080/14620316.2012.11512858
Vuletin Selak G., Perica S., Goreta Ban S., Poljak M. 2013. The effect of temperature and genotype on pollen performance in olive (Olea europaea L.). Scientia Horticulturae 156: 38-46. https://doi.org/10.1016/j.scienta.2013.03.029
Zeinanloo A.A., Arji I., Taslimpour M., Ramazani Malakroodi M., Azimi M. 2015. Effect of cultivar and climatic conditions on olive (Olea europaea L.) oil fatty acid composition. Iranian Journal of Horticultural Sciences 46(2): 233-242. (In Farsi). https://doi.org/10.22059/ijhs.2015.54619
Zhang T., Tan D.Y. 2009. An examination of the function of male flowers in an andromonoecious shrub Capparis spinosa. Journal of Integrative Plant Biology 51(3): 316-324. https://doi.org/10.1111/j.1744-7909.2008.00800.x
Agrotechniques in Industrial Crops

Articles in Press, Accepted Manuscript
Available Online from 25 January 2025

Files

Share

How to cite

Statistics