Page 218 - PC2019 Program & Proceedings

PLANT CANADA 2019

P9. Bioactive compounds in salt-stressed Hypericum perforatum: role of proline, salicylic acid and
ascorbic acid pretreatments
2
1
1
Renault, S. ; S. Alinian Joozdani ; J. Razmjoo ; F. Daayf ; L. Adam
1
2
1 University of Manitoba
2 Shakhekord University
Hypericum perforatum is a medicinal plant vulnerable to environmental stresses. A field study was
designed to test the effects of saline water (2, 6 and 10 dS/m) and foliar application of salicylic acid (0.25
mM), ascorbic acid (3 mM) and proline (1.75 mM) on the main active compounds (hyperforin, hypericin
and pseudohypericin) of Hypericum perforatum flowers. Irrigation with saline water (6 and 10 dS/m)
decreased hyperforin, hypericin and pseudohypericin yields. The effect of salicylic acid depended on the
salinity stress intensity, a decrease in hyperforin yield was observed at moderate salt concentration (6
dS/m), whereas hypericin and psodohypericin yields were increased at 10 dS/m. At moderate and high
level of salt, foliar application of ascorbic acid resulted in hyperforin, hypercin and pseudohypericin
yields remaining at the same level than the control plants. There was an increase in the yield of
hyperforin, hypericin and pseudohypericin at 10 dS/m and foliar application of proline while at 6 dS/m
the response varied depending on the bioactive compound. Our results show that irrigation with saline
water up to 10 dS/m would result in a 33% average loss in polyphenols yield in H. perferatum. Foliar
application of salicylic acid, proline and to a lower extent ascorbic acid at high salinity level could
alleviate, at least in part, the negative impact of salinity on the main active compounds.

Sylvie Renault (Sylvie.Renault@umanitoba.ca)

P10. Conditioning of nursery plants using irrigation scheduling and mycorrhizae for improving
post-transplant success rates
*
Keary, K. ; T. Graham; M. Dixon
University of Guelph

Global fresh water reserves are both limited and degraded. This is a significant concern for nursery
operators that rely heavily on irrigation to maintain production. As the impacts of climate change
continue to manifest, the pressure on these degraded water reserves will mount. Typical nursery practices
are not sufficiently flexible, nor do they rely on timely and objective data to dictate irrigation events. The
result being watering schedules that tend toward significant over-watering. Previous work quantified the
relationship between cumulative plant water stress (cWS) and cumulative vapour pressure deficit (cVPD),
identifying species-specific water stress thresholds in relation to cVPD. The objective of this study was to
base irrigation on cVPD thresholds for the containerized ornamental plant Spiraea japonica 'Goldflame’,
such that water use would be reduced while maintaining market quality. A split-plot field trial with
irrigation as the main-plot factor and mycorrhizae as the split-plot factor was employed. Three irrigation
schedules were applied via overhead irrigation: (1) conventional practice, (2) moderate water stress, and
(3) high water stress. Three mycorrhizae treatments were examined in combination; (1) inoculation at
time of potting, (2) inoculation at time of potting and transplant, and (3) no inoculation. The growth and
quality of the plants were recorded throughout a growing season. The results indicate that water use can
be reduced by 64% compared to conventional practices while maintaining marketable quality.

Katherine Keary (kkeary@uoguelph.ca)

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