Sonic-induced cellular vibrations unzip intertwined anther cone trichomes to trigger floral self-pollination and boost tomato fruit size

Abstract

Artificial tomato pollination methods rely on cellular vibrations from air displacement, electric vibration wands and trellis tapping, which have potential to spread pathogens. Bioacoustic frequencies emitted from buzzing bees to ultrasonication can vibrate plant cells without physical contact. The effects of frequency-dependent sonication on the poricidal anther cone sheath, self-pollination, seed set, and fruit size remain unclear. We engineered devices to investigate the frequency-dependent power-law behaviour of floral living cells from greenhouse-grown tomato varieties—contrasting contact-induced oscillations from a vibrating wand and mechanical shaker arm with precision noncontact sonication emitted by a subwoofer speaker. The velocity and acceleration of vibrating flowers and impact on poricidal anther cone sheath cellular structures, self-pollination, and fruit development were assessed. Sonic frequencies ranging from 50 to 10 000 Hz increased pollination, fruit size, weight, and seed set in Sweetelle, Endeavour, Paulanca, and Managua commercial varieties. Scanning electron microscopy revealed sonication separated the intertwined trichomes and unzipped their meshed network that locks the lobes of the anther cone sheath together thereby releasing pollen grains. Near ultra-sonic frequencies boosted fruit size, whereas seed set remained constant thereby challenging the floral cell power-law rheological characteristics under different frequency scales. Tomato flowers displayed a low power-law cell behaviour to frequency-dependent sonication enabling its effectiveness as a precision noncontact technology to boost pollination and tomato fruit size without a substrate-borne component.

Acknowledgements

We thank Richard Wuhrer and Daniel Fanna from Western Sydney University (WSU) for assistance with the Scanning Electron Microscopy at the Advanced Materials Characterization Facility. We thank Troy Topp and Naresh Singh from Perfection Fresh (Australia Pty Ltd. Homebush, Australia) for their valuable discussions and insights into pollination strategies utilized in the Australian tomato protected-cropping industry. We also thank Nigel Warwick and Paul Kristiansen from the University of New England for co-supervision of Angus Dingley’s honours research. This research article has been prepared using funding provided by the Future Food Systems Cooperative Research Centre (CRC) and Perfection Fresh (P2-010) awarded to Christopher Cazzonelli (WSU) and Chun-H Wang (UNSW). This grant also supported Sidra Anwar’s PhD scholarship extension. Happy was supported by the Government of India National Overseas Scholarship.

Author contributions

Conceptualization: C.I.C. and C.H.W.

Methodology: S.A., H., T.V., A.D., L.G., and W.L.

Figure Preparation: S.A. and H.

Investigation—data analysis: S.A., H., T.V., and A.D.

Supervision: S.A. and H. by C.I.C., A.D. by B.M.S. and C.I.C., and T.V. by C.H.W.

Writing—original draft: S.A., H., and A.D.

Writing—review and editing: C.I.C.

Data availability

All data are available in the main text or the supplementary materials. The data that support the findings of this study are available from the corresponding author upon reasonable request.

Conflict of interest statement

We declare no competing interests.

References

[1] Aizen MA, Garibaldi LA, Cunningham SA. et al.Long-term global trends in crop yield and production reveal no current pollina-tion shortage but increasing pollinator dependency. Curr Biol. 2008;18:1572-5

[2] Benton TG, Vickery JA, Wilson JD. Trends Ecol Evol.Farmland biodiversity: is habitat heterogeneity the key? 2003;18:182-8

[3] Velthuis HH, Van Doorn A.A century of advances in bumblebee domestication and the economic and environmental aspects of its commercialization for pollination. Apidologie. 2006;37:421-51

[4] Goodwin M.Pollination of Crops in Australia and New Zealand. RIRDC; 2012

[5] Bruno EM, Goodrich B, Sexton RJ.The outlook for California’s almond market. Calif Almond Acreage Rep. 2021;24:9-11

[6] Esau TJ, Zaman QU, MacEachern C. et al.Economic and man-agement tool for assessing wild blueberry production costs and financial feasibility. Appl Eng Agric. 2019;35:687-96

[7] Hogendoorn K, Gross CL, Sedgley M. et al.Increased tomato yield through pollination by native Australian Amegilla chlorocyanea (hymenoptera: Anthophoridae). J Econ Entomol. 2006;99:828-33

[8] Owen R, Scheerlinck J-P, Stevenson M.Modelling the spread of resistance to varroa in Australian feral honeybee populations. bioRxiv. 2022

[9] Makhal A, Robertson K, Thyne M. et al. Normalising the “ugly” to reduce food waste: exploring the socialisations that form appearance preferences for fresh fruits and vegetables. J Consum Behav. 2021;20:1025-39

[10] Chavan SG, Chen Z-H, Ghannoum O. et al.Current technologies and target crops: a review on Australian protected cropping. Crops. 2022;2:172-85

[11] Dingley A, Anwar S, Kristiansen P. et al.Precision pollination strategies for advancing horticultural tomato crop production. Agronomy. 2022;12:518

[12] Nahir D, Gan-Mor S, Rylski I. et al.Pollination of tomato flowers by a pulsating air jet. Trans ASAE. 1984;27:894-0896

[13] Cooley H, Vallejo-Marín M.Buzz-pollinated crops: a global review and meta-analysis of the effects of supplemental bee pollination in tomato. J Econ Entomol. 2021;114:505-19

[14] Simonne EH, Ozores-Hampton M.Fertilizer and nutrient man-agement for tomato. In: Ozores-Hampton M, Snodgrass C (eds.), Florida Tomato Institute Proceedings. Gainesville:University of Florida Cooperative Extension Service,Institute of Food and Agriculture Sciences, 2010:37-40

[15] Amala U, Shivalingaswamy T.Role of native buzz pollinator bees in enhancing fruit and seed set in tomatoes under open field conditions. J Entomol Zool Stud. 2017;5:1742-4

[16] Vallejo-Marín M. How and why do bees buzz?Implications for buzz pollination. JExp Bot. 2021;73:1080-92

[17] De Luca PA, Vallejo-Marín M.What’s the ‘buzz’ about? The ecology and evolutionary significance of buzz-pollination. Curr Opin Plant Biol. 2013;16:429-35

[18] Cocroft RB, Rodríguez RL.The behavioral ecology of insect vibra-tional communication. Bioscience. 2005;55:323-34

[19] Jankauski M, Ferguson R, Russell A. et al.Structural dynamics of real and modelled Solanum stamens: implications for pollen ejection by buzzing bees. J R Soc Interface. 2022;19:20220040

[20] Beach JH.Pollinator foraging and the evolution of dioecy. Am Nat. 1981;118:572-7

[21] Harder LD, Barclay RMR.The functional significance of poricidal anthers and buzz pollination: controlled pollen removal from Dodecatheon. Funct Ecol. 1994;8:509-17

[22] Hossaert-McKey M, Soler C, Schatz B. et al.Floral scents: their roles in nursery pollination mutualisms. Chemoecology. 2010;20: 75-88

[23] Raju AS, Ezradanam V.Pollination ecology and fruiting behaviour in a monoecious species, Jatropha curcas L.(Euphorbiaceae). Curr Sci. 2002;83:1395-8

[24] Castellanos MC, Wilson P, Keller SJ. et al.Anther evolution: pollen presentation strategies when pollinators differ. Am Nat. 2005;167:288-96

[25] Wu M, Bian X, Huang B. et al.HD-Zip proteins modify floral struc-tures for self-pollination in tomato. Science. 2024;384:124-30

[26] Glover BJ, Bunnewell S, Martin C.Convergent evolution within the genus Solanum: the specialised anther cone develops through alternative pathways. Gene. 2004;331:1-7

[27] Holstein N, Gottschling M.Flowers of Halgania (Ehretiaceae, Bor-aginales) are set up for being buzzed and the role of intertwining anther trichomes. Flora. 2018;240:7-15

[28] Nevard L, Russell AL, Foord K. et al.Transmission of bee-like vibrations in buzz-pollinated plants with different stamen architectures. Sci Rep. 2021;11:13541

[29] De Luca PA, Bussière LF, Souto-Vilaros D. et al.Variability in bumblebee pollination buzzes affects the quantity of pollen released from flowers. Oecologia. 2013;172:805-16

[30] King M, Buchmann S.Sonication dispensing of pollen from Solanum laciniatum flowers. Funct Ecol. 1996;10:449-56

[31] Rosi-Denadai CA, Araújo PCS, Campos LA. et al.Buzz-pollination in Neotropical bees: genus-dependent frequencies and lack of optimal frequency for pollen release. Insect Sci. 2020;27:133-42

[32] Nitsch J.Plant hormones in the development of fruits. QRevBiol. 1952;27:33-57

[33] DeTar WR, Haugh C, Hamilton J.Acoustically forced vibration of greenhouse tomato blossoms to induce pollination. Trans ASAE. 1968;11:0731-5

[34] Kemp JE, Vallejo-Marín M.Pollen dispensing schedules in buzz-pollinated plants: experimental comparison of species with con-trasting floral morphologies. Am J Bot. 2021;108:993-1005

[35] Vallejo-Marín M.Buzz pollination: studying bee vibrations on flowers. New Phytol. 2019;224:1068-74

[36] Buchmann SL, Hurley JP.A biophysical model for buzz pollina-tion in angiosperms. J Theor Biol. 1978;72:639-57

[37] Hang J-T, Xu G-K, Gao H.Frequency-dependent transition in power-law rheological behavior of living cells. Sci Adv. 2022;8:eabn6093

[38] Caicedo-Lopez LH, Contreras-Medina LM, Guevara-Gonzalez RG. et al.Effects of hydric stress on vibrational frequency patterns of Capsicum annuum plants. Plant Signal Behav. 2020;15:1770489

[39] Brito VLG, Nunes CEP, Resende CR. et al.Biomechanical proper-ties of a buzz-pollinated flower. R Soc Open Sci. 2020;7:201010

[40] Brenya E, Pervin M, Chen ZH. et al.Mechanical stress acclimation in plants: linking hormones and somatic memory to thigmomor-phogenesis. Plant Cell Environ. 2022;45:989-1010

[41] Peet M,Welles G. In: Heuvelink E, Wallingford,ed.Crop Production Science in Horticulture Series. UK:CABI Publishing, 2005, 257-304

[42] Mishra RC, Ghosh R, Bae H.Plant acoustics: in the search of a sound mechanism for sound signaling in plants. JExp Bot. 2016;67:4483-94

[43] Teixeira da Silva JA, Dobránszki J.Sonication and ultrasound: impact on plant growth and development. Plant Cell Tissue Organ Cult (PCTOC). 2014;117:131-43

[44] Sueur J. Sound Analysis and Synthesis with R.Cham: Springer; 2018:

[45] Veits M, Khait I, Obolski U. et al.Flowers respond to pollinator sound within minutes by increasing nectar sugar concentration. Ecol Lett. 2019;22:1483-92

[46] Nakano R, Ito A, Tokumaru S.Sustainable pest control inspired by prey-predator ultrasound interactions. Proc Natl Acad Sci. 2022;119:e2211007119

[47] Sekine T, Takanashi T, Onodera R. et al.Potential of substrate-borne vibration to control greenhouse whitefly Trialeurodes vapo-rariorum and increase pollination efficiencies in tomato Solanum lycopersicum. J Pest Sci. 2023;96:599-610

[48] Kim JY, Lee H-J, Jeong M-J.Epigenetic regulation for delaying tomato fruit ripening through histone modification by spe-cific sound wave treatment. Postharvest Biol Technol. 2023;197: 112211

[49] De Luca PA, Buchmann S, Galen C. et al.Does body size predict the buzz-pollination frequencies used by bees? Ecol Evol. 2019;9: 4875-87

[50] Arroyo-Correa B, Beattie C, Vallejo-Marín M.Bee and flo-ral traits affect the characteristics of the vibrations experi-enced by flowers during buzz pollination. JExp Biol. 2019;222: jeb198176

[51] Banda HJ, Paxton RJ. E288 edn. Leuven, Belgium: International Society for Horticultural Science (ISHS), 194-198

[52] Strange JP. Bombus huntii, Bombus impatiens, andBombus vos-nesenskii (Hymenoptera: Apidae) pollinate greenhouse-grown tomatoes in Western North America. J Econ Entomol. 2015;108: 873-9

[53] Silva-Neto C d. M. e.. et al.The stingless bee mandaçaia (Melipona quadrifasciata Lepeletier) increases the quality of greenhouse tomatoes. JApicRes. 2019;58:9-15

[54] MartÃ-n-Closas L, Puigdomènech P, Pelacho AM.761 edn. Leu-ven, Belgium: International Society for Horticultural Science (ISHS), 327-332

[55] Da¸sgan HY, Özdo ˘gan A, Kaftano ˘glu O. et al.Effectiveness of bumblebee pollination in anti-frost heated tomato greenhouses in the Mediterranean basin. Turk J Agric For. 2004;28:73-82

[56] King MJ.Buzz foraging mechanism of bumble bees. JApicRes. 1993;32:41-9

[57] Russell AL, Leonard AS, Gillette HD. et al.Concealed floral rewards and the role of experience in floral sonication by bees. Anim Behav. 2016;120:83-91

[58] Baranwal VK, Mikkilineni V, Zehr UB. et al.Heterosis: emerging ideas about hybrid vigour. JExp Bot. 2012;63:6309-14

[59] Cucinotta M, di Marzo M, Guazzotti A. et al.Gynoecium size and ovule number are interconnected traits that impact seed yield. JExpBot. 2020;71:2479-89

[60] Ghosh R, Mishra RC, Choi B. et al.Exposure to sound vibrations lead to transcriptomic, proteomic and hormonal changes in Arabidopsis. Sci Rep. 2016;6:1-17

[61] Corbet SA, Huang S-Q.Buzz pollination in eight bumblebee-pollinated Pedicularis species: does it involve vibration-induced triboelectric charging of pollen grains? Ann Bot. 2014;114: 1665-74