Page 36 - CSHS 2022 Book of Abstracts - 2022-08-22 web version

CSHS 2022 Conference

(VO.2) The Role Structural Modifications in Pectin May Play in Overcoming Dehydration Stress
and Fungal Pathogens
Ariana D. Forand , Zou Finfrock , Miranda Lavier , Jarvis Stobbs , Qin Li , Sheng Wang , Chithra
1,5
2
1*
4
3
3
Karunakaran , Yangdou Wei , Supratim Ghosh , Karen K. Tanino
4
1
6
3
1. Department of Plant Sciences, University of Saskatchewan (U. Sask.), Saskatoon, SK; 2. Advanced Photo Source,
Lemont, IL, USA; 3. Canadian Light Source, Saskatoon, SK; 4. Department of Biology, U. Sask.; 5. Department of
Biochemistry, Microbiology and Immunology, U. Sask.; 6. Department of Food and Bioproduct Sciences, U. Sask.
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The ability for plants to survive stress is in part tied to their ability to resist stress. Within the cell wall, structural
modifications through pectin cross-linkages between calcium ions and/or boric acid, may play a key role in
mitigating abiotic and biotic stress. Our objective was to investigate how calcium and boron influence resistance to
multiple stresses in Allium spp. and Arabidopsis. While calcium reduced water loss in pure pectin standards, the
ability for calcium to mitigate dehydration stress in Allium spp. was inconsistent and insignificant. Nonetheless,
synchrotron confocal X-ray microscopy showed localization of exogenously applied calcium to the apoplast in
epidermal cells of Allium fistulosum. Exogenous calcium application also increased resistance to shear force in Allium
fistulosum, in addition to increasing viscosity in pure pectin. Relative to Allium cepa (freezing sensitive), Allium
fistulosum (freezing tolerant), was significantly more resistant to dehydration stress. Furthermore, the addition of
boric acid to pure pectin reduced water loss and increased viscosity. Finally, a mutation in the BOR1 transporter, a
boron transporter, was found to reduce resistance to water loss and increase susceptibility to Colletotrichum
higginsianum and Botrytis cinerea in Arabidopsis. Response to stress within plants is complex, and there is likely no
single mechanism that will act as a silver bullet to mitigate all stresses. However, our findings suggest that within the
cell wall, pectin plays a critical role in defense against dehydration stress, freezing stress, and fungal pathogens.

(VO.3) Kale response to Aged Hydrochar amended Growing Media
Dengge Qin , Quan He , Lord Abbey
2
1*
1
1. Department of Plant, Food, and Environmental Sciences, Faculty of Agriculture, Dalhousie University, Bible Hill, NS; 2.
Department of Engineering, Faculty of Agriculture, Dalhousie University, Bible Hill, NS
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Hydrochar is a relatively novel growing medium amendment, but the major concern is the potential phytotoxic
effect on plants. A study was performed to determine the response of kale (Brassica oleracea var. acephala D.C) seed
germination indices, plant growth and yield as affected by pristine hydrochar (PHC), water-washed hydrochar
(WHC), microbial-aged hydrochar (MHC), and freezing-thawing aged hydrochar (FTHC) at an application rate of
10% and 20%. The control was Promix-BX peatmoss potting mix alone. The results showed that all the hydrochar
amended growing media had varying levels of inhibition effects on the kale seed germination and plant growth
compared to the control. Treatment PHC significantly (P ˂ 0.05) inhibited seed germination by 53% compared to the
control, while MHC was the least inhibitor. The 10% MHC rate significantly (P ˂ 0.05) increased plant fresh weight
by 4.7 folds and 17.6 folds when compared to the 10% PHC and the 20% PHC rates, respectively. Scanning electron
microscopy-energy dispersive spectroscopy images showed that the surface character of MHC was filled with the
highest amount of nitrogen and oxygen compared to the other hydrochar treatments. Fourier transform infrared
spectroscopy indicated the disappearance and shift of some absorption bands on MHC compared to PHC.
Additionally, the images confirmed a different molecular structure for MHC that can be associated with high porosity
and large surface area for nutrient adsorption. Therefore, it can be suggested that hydrochar is a promising growing
medium amendment but needs pre-modification. Microbial aging seemed to be the best treatment for the reduction
of phytotoxicity effect. Further studies should consider adjusting aging conditions including raw material, aging
temperature and aging duration.

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