Page 186 - Plant Canada 2024 Proceeding

PLANT CANADA 2024

field (115 t/ha) and high-tunnel (81 t/ha) production systems. The ‘Baby Bok Choy’ cv. Mei-Qin Choi
produced the highest marketable yield under both field (61 t/ha) and high-tunnel (52 t/ha) production
systems. ‘Early’ planted Bok Choy produced higher marketable yields, larger, and more attractive heads
compared to the ‘Late’ planted crop under both production systems. Kale cv. White Russian produced
the highest marketable leaf yield under both field (27 t/ha) and high-tunnel (37 t/ha) production. Under
field-production, late planting adversely (about 50% lower) affected leaf yield relative to early planting.
However under high-tunnel, planting date had no effect on leaf yield. The effects production system and
planting dates on the performance attributes of Bock Choy and kale will be discussed in detail.

*[O161] OPTIMIZATION OF LIGHT INTENSITY FOR GROWTH OF MINT (MENTHA SPP.) IN
CONTROLLED ENVIRONMENTS. Andrew Burns, Mike Dixon, Mike Stasiak, and Youbin Zheng.
Controlled Environment Systems Research Facility, School of Environmental Sciences, University of
Guelph, Guelph, ON, N1G 2W1, Canada
Correspondence to: aburns07@uoguelph.ca

Controlled environment agriculture (CEA) is a versatile technology that has the potential to reduce the
environmental impact of commercial farming while simultaneously enhancing crop yield and quality. This
technology is particularly promising for medicinal plants, as it offers opportunities to increase the content
of valuable compounds. Innately antimicrobial, medicinally active, and valued for its desirable flavor and
aroma, mint (Mentha species) is a historically and economically significant herb of the Lamiaceae family.
The essential oil, which is mainly found in glandular trichomes on leaf and stem surfaces, is the most
economically important component of the plant for its use in food, cosmetics, and hygienic products.
Challenges presented by traditional field farming of mint, namely diseases such as verticillium wilt and
increasingly unpredictable weather extremes, may be addressed in CEA. This research was conducted to
optimize environmental parameters such as light intensity, photoperiod, and carbon dioxide concentration
for mint growth and production of high-quality essential oil. The capital (e.g., fixtures) and energy costs
associated with crop lighting are substantial crop inputs for all CEA production systems. Therefore, to
optimize lighting inputs, it is necessary to determine how the quantity of photosynthetically active radiation
(PAR) affects mint growth and essential oil production in CEA. A gradient design was employed in which
a mint crop was grown in a heterogeneous lighting environment where individual plants were exposed to
unique and well-characterized light levels. Key growth and yield parameters were collected and related to
individual plants’ light levels using regression-style analyses. A subset of plants representative of the
various light level acclimations were subjected to whole-plant net carbon exchange rate (NCER)
measurements to assess the reliability of extrapolating short-term NCER measurements to model longer
term mint growth and yield dynamics.

*[O162] HARNESSING CONTROLLED ENVIRONMENT SYSTEMS FOR ENHANCED PRODUCTION
1
1
2
OF MEDICINAL PLANTS. Ajwal Dsouza , Mike Dixon , Mukund Shukla , and Thomas Graham .
1 1
Controlled Environment Systems Research Facility, School of Environmental Sciences, University of
Guelph, Guelph, ON, N1G 2W1, Canada; and Department of Plant Agriculture, University of Guelph,
2
Guelph, ON N1G 2W1, Canada
Correspondence to: ajwal@uoguelph.ca

Medicinal plants (MPs) are valued for their contributions to human health. However, the growing demand
for MPs and the concerns regarding their quality and sustainability have prompted the reassessment of
conventional production practices. Controlled environment cropping systems, such as vertical farms, offer
a transformative approach to MP production. By enabling precise control over environment factors, such
as light, carbon dioxide, temperature, humidity, nutrients, and airflow, controlled environments can
improve the consistency, concentration, and yield of bioactive phytochemicals in MPs. This presentation
explores the potential of controlled environment systems for enhancing MP production. First, I will
describe how controlled environments can overcome the limitations of conventional production in
improving the quality of MP. Next, I will propose strategies based on plant physiology to manipulate
environment conditions for enhancing the levels of bioactive compounds in plants. These strategies
include improving photosynthetic carbon assimilation, light spectrum signalling, purposeful stress
elicitation, and chronoculture. I will describe the underlying mechanisms and practical applications of
these strategies. Finally, I will highlight the major knowledge gaps and challenges that limit the application
of controlled environments, and discuss future research directions.

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