Dr. Hao Xu

Research Scientist

Dr. Xu leads the tree fruit physiology program at Summerland Research and Development Centre. Her team aim to elucidate how fruit production and crop resilience of apple and sweet cherry respond to environmental stresses and horticultural management practices.

Agriculture and Agri-Food Canada

4200 Highway #97, Summerland, B.C.

Current research and/or projects

Dr. Xu's current research projects investigate the impacts of horticultural managements on reducing biotic and abiotic stress pressure, enhancing plant resilience, stabilizing yield, and improving fruit quality, in apple and sweet cherry. The horticultural approaches of focus are adjusting leaf-fruit ratio by pruning and crop load management, scheduling irrigation based on plant needs, as well as selecting suitable rootstocks for specific cultivars and micro-environments. On the fundamental level, the research team tries to elucidate how photosynthetic source-sink relations and rootstock resource use efficiency influence floral bud quality, fruit dry matter accumulation and carbohydrate allocation within the tree crops. The knowledge generated can facilitate decision making on how to maintain tree canopy, how to manage crop load, and how to select the most suitable rootstock-scion combination, for a more sustainable future of tree fruit production.

Research and/or project statements

A list of her key publications in the field of plant physiology

1. H Xu, Y Watanabe, D Ediger, et al. 2022. Characteristics of Sunburn Browning Fruit and Rootstock-Dependent Damage-Free Yield of Ambrosia™ Apple after Sustained Summer Heat Events. Plants 11: 1201.

2. C Lu, H Xu. 2021. Summer fruitlet thinning enhanced quality attributes of Ambrosia™ apple at harvest and after 4 months of cold air storage. Canadian Journal of Plant Science, 101: 1041-1050.

3. H Xu, D Ediger, A Singh, et al. 2021. Rootstock–scion hydraulic balance influenced scion vigor and yield efficiency of Malus domestica cv. Honeycrisp on eight rootstocks. Horticulturae, 7(5): 99.

4. H Xu, D Ediger. 2021. Rootstocks with different vigor influenced scion–water relations and stress responses in AmbrosiaTM apple trees (Malus Domestica var. Ambrosia). Plants, 10: 614.

5. H Xu, JJ Zwiazek. 2020. Fungal aquaporins in ectomycorrhizal root water transport. Frontiers in Plant Science 11: 302.

6. P Zhang, Z Cui, H Xu, et al. 2020. Thirst or Malnutrition: The impacts of invasive insect Agrilus mali on the physiological status of wild apple trees. Forests 11: 440.

7. X Tan, H Xu, S Khan, et al. 2018. Plant water transport and aquaporins in oxygen-deprived environments. Journal of Plant Physiology 227: 20-30.

8. JJ Zwiazek, H Xu, X Tan, et al. 2017. Significance of oxygen transport through aquaporins. Scientific Reports 7: 1-11.

9. H Xu, M Kemppainen, W El Kayal, et al. 2015. Overexpression of Laccaria bicolor aquaporin JQ585595 alters root water transport properties in ectomycorrhizal white spruce (Picea glauca) seedlings. New Phytologist 205: 757-770.

10. A Navarro‐RóDenas, H Xu, M Kemppainen, et al. 2015. Laccaria bicolor aquaporin LbAQP1 is required for Hartig net development in trembling aspen (Populus tremuloides). Plant, Cell & Environment 38: 2475-2486.

11. H Xu, JEK Cooke, JJ Zwiazek. 2013. Phylogenetic analysis of fungal aquaporins provides insight into their possible role in water transport of mycorrhizal associations. Botany 91: 495-504.

12. H Xu, Y Li, G Xu, T Zou. 2007. Ecophysiological response and morphological adjustment of two Central Asian desert shrubs towards variation in summer precipitation. Plant, Cell & Environment 30: 399-409.

13. H Xu, Y Li. 2006. Water-use strategy of three central Asian desert shrubs and their responses to rain pulse events. Plant and Soil 285: 5-17.

14. Y Li, H Xu, S Cohen. 2005. Long‐term hydraulic acclimation to soil texture and radiation load in cotton. Plant, Cell & Environment 28: 492-499.

Professional activities / interests

The current research activities include:

- Apple fruit dry matter and fruit quality under horticultural management practices

- Sweet cherry fruit set under abiotic stresses and horticultural mitigations

- Impacts of rootstocks on tree crop resilience and fruit production

Besides her currently ongoing research in tree fruit production physiology, Dr. Xu looks into opportunities for the use of biological ingredients such as mycorrhiza and plant-based fertilizers in horticulture of woody perennials. She also remains strong interest in the roles of aquaporins in plant-water relations.

Education and awards

Ph.D. in Forest Biology and Management, University of Alberta

Ph.D. in Plant Ecology, Chinese Academy of Sciences

Additional links

ResearchGate

https://www.researchgate.net/profile/Hao_Xu26

Key publications

MacDonald JL, Hannam KD, Xu H, D O'Gorman. 2023. Sudden apple decline in British Columbia: a potential link between fungal cankers, invasive Sesiidae moths, and abrupt hydraulic failure. The Canadian Tri-Societies Meeting: Agroecosystem Resiliency Under a Changing Climate. Ottawa ON, Canada. 20 June 2023.
2023 - View publication details
2023. Annual meeting, the Canadian phytopathological society, 2022/Réunion annuelle, la société canadienne de phytopathologie, 2022, Canadian Journal of Plant Pathology, 45:3, 210-235, DOI: 10.1080/07060661.2023.2202486
2023 - View publication details
Xu, Hao, Danielle Ediger, and Mehdi Sharifi. 2023. "Horticultural Practices in Early Spring to Mitigate the Adverse Effect of Low Temperature on Fruit Set in ‘Lapins’ Sweet Cherry" Plants 12, no. 3: 468. https://doi.org/10.3390/plants12030468
2023 - View publication details
King, L., Forge, T., Munro, P., Xu, H., Jones, M. 2021. The root-lesion nematode, Pratylenchus penetrans, has similar effects on early growth and physiology of M.9, G.41 and G.935 apple rootstocks under field conditions. British Columbia regional meeting, 2021/Réunion régionale de la Colombie-Britannique, 2021, Canadian Journal of Plant Pathology, 45:1, 1-5, DOI: 10.1080/07060661.2022.2102280. Published online: 29 Jul 2022.
2023 - View publication details
NC-140 Regional Rootstock Research Project State Report: British Columbia. 2022. nc140.org
2022 - View publication details
MacDonald JL, Hannam KD, Xu H. 2022. Signs and symptoms of sudden apple decline in British Columbia: Impacts on tree physiology, and the potential role of environmental stressors. Canadian Phytopathological Society Annual Meeting. Virtual. 4 July 2022. Oral Presentation
2022 - View publication details
Xu H, MacDonald JL, Singh A, Pagliocchini C, Ediger D. 2022. Apple
rootstock vigor and production: effects of rootstock on Honeycrisp.
Agriculture and Agri-Food Canada, Summerland, BC, Canada. 11p.
2022 - View publication details
NC-140 Regional Rootstock Research Project State Report: British Columbia. 2021. nc140.org
2021 - View publication details
Proper balanced nutrition is important in all crops; however, knowing what the right nutrient needed at the right time for the right reasons with the right product can be very different between commodities, orchards, and seasons. There are several different sampling methods that can be utilized to assess the nutrient status of a block and help aid in nutrient management decisions. The main assessment methods are leaf, fruitlet, and soil analysis. There are some other techniques, such as sap analysis, that are being tested and may be more available in the future.
2021 - View publication details
NC-140 Regional Rootstock Research Project State Report: British Columbia. 2020. nc140.org
2020 - View publication details
Autio, W, Robinson, T, Blatt, S, Cochran, D, Francescato, P, Hoover, E, Kushad, M, Lang, G, Lordan, J, Miller, D, Minas, I, Parra Quezada, R, Stasiak, M and Xu, H. 2020. Budagovsky, Geneva, Pillnitz and Malling apple rootstocks affect ‘Honeycrisp’ performance over eight years in the 2010 NC-140 ‘Honeycrisp’ apple rootstock trial. Journal of the American Pomological Society 74: 182-195.
2020 - View publication details
MacDonald JL, Forge T, Hannam K, Judd G, Moffat C, O'Gorman D, Sanfacon H, Xu H. 2020. 'Apple Decline' in the Okanagan Valley. Summerland Research and Development Centre via Instagram and Facebook.
2020 - View publication details
Tan, X., Xu, H., Khan, S., Equiza, M.A., Lee, S.H., Vaziriyeganeh, M., Zwiazek, J.J. (2018). Plant water transport and aquaporins in oxygen-deprived environments. Journal of Plant Physiology, [online] 227 20-30. http://dx.doi.org/10.1016/j.jplph.2018.05.003
2018 - View publication details