Dissertation
PLANT BASED DISPERSIONS ARE A NOVEL CLASS OF SPRAYABLE FROST PROTECTANTS FOR FRUIT CROP
Washington State University
Doctor of Philosophy (PhD), Washington State University
01/2021
DOI:
https://doi.org/10.7273/000003332
Handle:
https://hdl.handle.net/2376/122684
Abstract
Crop losses from cold damage are predicted to increase because of climate change; yet frost mitigation technologies used by tree fruit growers have remained mostly unchanged for half a century. Plant-based dispersions (PBD) are aqueous solutions containing plant-derived, cellulose-based nanomaterials such as cellulose nanocrystals (CNC). My objectives were to (1) investigate the ability of PBDs to protect reproductive organs at different stages of development, and (2) better understand the mechanisms of PBDs in-vivo. Several field trials were carried out in sweet cherry (Prunus avium L.) and apple (Malus domestica Borkh.) to quantify the changes in cold sensitivity using controlled freezing and differential thermal analyses. Thermography and digital scanning calorimetry (DSC) studies were carried out on dormant apple and cherry buds to investigate the freezing and thermal behavior of PBD coated buds. In field trials, PBDs could decrease the lethal temperature required for 10% mortality (LT10) by 2-5.5 °C for up to 6 days post-application. Concentration, PBD feedstock, and time post-application, each influenced the magnitude and duration of the protection. Precipitation and melting snow reduced or completely eliminated PBD efficacy in field trials. Efficacy and duration of protection decreased as floral development advanced, with no benefit to PBD treatment in open flowers. Applications of PBDs did not affect floral development nor fruit set in field trials. Thermography revealed that thermal emissivity of treated buds decreased by ca. 16% with 3% CNC dispersions. DSC results indicate lethal freezing occurs in buds coated with 3% CNC at 3.2 and 5.5 °C lower than the control at 1 and 3 days after application, respectively. The combined results of DSC, thermography, confirmed that PBDs create a thermal barrier that reduces heat loss and delays internal freezing. This work suggests PBDs could represent a viable option as a sprayable frost protectant which insulate reproductive buds and reduces cold sensitivity.
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Details
- Title
- PLANT BASED DISPERSIONS ARE A NOVEL CLASS OF SPRAYABLE FROST PROTECTANTS FOR FRUIT CROP
- Creators
- Brent Arnoldussen
- Contributors
- Matthew Whiting (Advisor)Markus Keller (Committee Member)Qin Zhang (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Horticulture, Department of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 151
- Identifiers
- 99900652005401842
- Language
- English
- Resource Type
- Dissertation