Page 319 - PC2019 Program & Proceedings

PLANT CANADA 2019

P211. Context is everything: benefits of carbonatite rock fertilizers depend strongly on growing
conditions and plant type
1
2
Jones, J. ; P. Antunes ; F. Guinel 1
2
1 Wilfrid Laurier University; Algoma University
With growing concerns about agricultural sustainability and food security, the use of rock fertilizers and
agrominerals is receiving renewed interest. A wide variety of geological resources have been proposed as
crop nutrient sources, with silicate rocks the predominant focus. Carbonatite rocks are known to weather
more readily than silicate rocks; yet, they have received relatively little attention as it is thought their high
Ca and Mg contents hinder effective nutrient release. However, there is strong evidence that the nutrients
within carbonatite rocks are easily accessible to plants, and that these rocks have appreciable effects on
crop plant growth. Here we propose a framework to understand the mode of action of carbonatites on soil
fertility and plant nutrition by integrating research at multiple scales, i.e., from individual plants to the
ecosystem, including soil microorganisms. The model stems from greenhouse experiments on two crops,
pea and wheat, and an extensive survey of the carbonatite deposit. It is emphasized that a systems-
approach must be taken when examining carbonatites as their effects are strongly context-dependant, and
there is evidence that a three-way interaction between plant-carbonatite-microorganisms is responsible for
some of the observed effects on plants. The framework presented is intended not only to synthesize the
currently knowledge on carbonatites as rock fertilizers but also to guide future research on this and other
similar geological resources.

James Jones (jone3630@mylaurier.ca)

TOPIC 24: Post-Harvest Physiology and Management
(Posters P212-P213)

P212. Effect of pre-harvest hexanal spray on the quality of ‘Honeycrisp’ apples during post-harvest
storage
*
Sriskantharajah, K. ; A. Sullivan; G. Paliyath; J. Subramanian
University of Guelph

‘Honeycrisp’ is most popular apple variety among consumers due to its desirable flavor and texture
characteristics. However, its quality can decline over time in storage, that challenges the growers to fetch
the price in market. Hexanal is a natural product which has proven to enhance the post-harvest shelf life
of many fruits by inhibiting phospholipase-D enzyme (PLD), the key enzyme that triggers the membrane
breakdown. Ethylene is one of the prime stimuli that triggers the PLD enzyme to initiate the membrane
deterioration cascade. Eventually, this process accelerates softening and reduces the quality
characteristics. ‘Honeycrisp’ apples from trees that were sprayed with hexanal (as a formulation) were
harvested and compared against control during post-harvest storage. Internal Ethylene Concentration
(IEC), PLD enzyme and quality parameters such as color, firmness, total soluble solids and physiological
loss of weight were assessed throughout the storage. IEC was significantly lower on the 60 day of
th
storage on treated fruits and subsequently progressed at lower level (45 % - 15 %) throughout remaining
storage compared to other treatments. PLD enzyme activity was increased throughout the storage,
however hexanal treated fruits showed 5 - 7 % reduction. No significant differences were observed in
quality characteristics among the treatments. By assessing these parameters, we show that hexanal could
enhance the storability and marketability of ‘honeycrisp’ apples.
Karthika Sriskantharajah (sriskank@uoguelph.ca)

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