Thigmomorphogenesis – plant growth regulation and quality improvement under greenhouse conditions

Plant growth of greenhouse grown crops is usually regulated by the application of chemical plant growth regulators (PGRs). This leads to reduced shoot length and compact plant structure, two key quality traits, which in turn improve transportability and marketability.
However, legal regulations and growing public demand for reduced chemical inputs require the development of innovative growth control measures.
Therefore, a new air-based production system was developed, enabling horticulturists to reduce plant growth under greenhouse conditions without PGRs.
Thigmomorphogenesis describes the morphological and structural shaping of plants as influenced by touch-like stimuli.
Consequently, the effects of air-based mechanical stimuli on plant growth and leaf net CO₂ exchange rate in tomato (Solanum lycopersicum ‘Romello’) were investigated.
Tomato plants were treated with a defined air stream intensity (4 m s^‑1) at a frequency of 40 transits per day across the plant stand for 2 weeks.
Results indicate that plant height and total leaf area were significantly reduced compared to untreated controls.
Such air stream treated plants tended to have an increased specific leaf weight and significantly increased leaf net CO₂ assimilation rates, which corresponded well with leaf nitrogen content.
The effect of various air stream frequencies and intensities on the degree of growth inhibition and phenotypical traits is currently under investigation.
Thigmo-technologies should be further explored in mechanical perturbation experiments to develop practical and reliable horticultural crop management tools and to increase sustainable plant production without the input of chemicals.

IV International Symposium on Horticulture in Europe – SHE2021

M.A. Sparke, U. Ruttensperger, M. Hegele, J.N. Wünsche

mechanically-induced stress, mechanoperception, mechanotransduction, technology, thigmomorphogenesis

https://doi.org/10.17660/ActaHortic.2021.1327.11