The Role of Di-1-p-menthene and Drought Signalling in Yield Formation in Spring Wheat

Mpande, W. (2021) The Role of Di-1-p-menthene and Drought Signalling in Yield Formation in Spring Wheat. Doctoral thesis, Harper Adams University.

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Abstract

Drought is an important abiotic stress affecting wheat production across the globe. The film antitranspirant, di-1-p-menthene, has been shown to ameliorate drought and improve wheat grain yield but the mechanisms involved have not been established. As drought induces an accumulation of endogenous ABA, we tested the hypothesis that application of di-1-p-menthene improves grain yield of droughted spring wheat by reducing the endogenous concentration of this hormone. To test the hypothesis, we conducted four field experiments and two glasshouse experiments, studying four main objectives: (i) to measure endogenous concentration of ABA in well-watered, droughted and droughted-di-1-p-menthene-treated spring wheat plants and relate it to yield and yield components. (ii) To relate the timing of di-1-p-menthene application on droughted plants to sensitivity to yield formation; (iii) to compare the effects of exogenous application of ABA to the effects of di-1-p-menthene on droughted plants and to well-watered plants on yield and yield components and (iv) to compare the effects of exogenous application of the ABA inhibitor, fluridone, to the effects of di-1-p-menthene in droughted plants and to well-watered plants. We found evidence that di-1-p-menthene reduces endogenous ABA, photosynthesis and transpiration, and ameliorates terminal drought stress, improving grain yield; and that applications during stem elongation were the most effective. We failed to find evidence that application of exogenous ABA reduced grain yield and yield components. The opposite effect was observed as exogenous ABA ameliorated drought. In contrast, despite fluridone also reducing endogenous ABA and photosynthesis, like di-1-p-menthene, it had no effect on transpiration and did not ameliorate drought stress. Overall, the results suggest that di-1-p-menthene improvement of droughted spring wheat is linked to mechanisms that involve curtailing the accumulation of endogenous ABA and suppressing transpirational water loss.

Item Type: Thesis (Doctoral)
Divisions: Agriculture and Environment (from 1.08.20)
Depositing User: Ms Kath Osborn
Date Deposited: 29 Jun 2021 11:03
Last Modified: 22 Jul 2021 11:30
URI: https://hau.repository.guildhe.ac.uk/id/eprint/17711

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