Data Collection & Experimental Design
Figure 5: the experimental procedure for this experiment. White spruce seeds of different 6 different populations are collected across Canada and planted randomly in the experimental site. After that, needles of the trees are collected for terpenoid concentration analyses and eastern spruce budworm response test. |
Sample collection
Dataset 1
We have collected white spruce seeds from six specific locations spanning five different provinces across Canada. The map displayed in Map 1 provides an overview of the geographical distribution of these sites. Table 1 offers comprehensive data, including the province, location, latitude, longitude, and elevation, which was compiled by the Alberta Forest Service.
Table 1: information of the seed source: six specific locations spanning five different provinces across Canada.
Dataset 1
We have collected white spruce seeds from six specific locations spanning five different provinces across Canada. The map displayed in Map 1 provides an overview of the geographical distribution of these sites. Table 1 offers comprehensive data, including the province, location, latitude, longitude, and elevation, which was compiled by the Alberta Forest Service.
Table 1: information of the seed source: six specific locations spanning five different provinces across Canada.
Map 1: Location of the 6 sites, (From left to right: Alberta-Slave lake forest, Saskatchewan-Old channel river, Ontario-Twist lake, Quebec-Dasserat, Quebec-Cimon, New Brunswick- Upper green river)
White spruce seeds from different sites were completely randomly planted at experimental sites at Calling Lake (55°16'18.8 "N, 113°09'54.6 "W; elevation 639 m) in Alberta. All seeds are grown on clay-loam soil, and they have a distance of 2.5 m between each other.
Five 20-30-year-old mature white spruce trees with a diameter at breast height (DBH) larger than 20 cm are selected as samples to collect foliar tissue for the later chemical analysis. Foliar tissue was collected from the current branches of each spruce tree via a pole pruner in July 2020. And each genotype origin had 5 replications. The collected foliar samples are stored at -40℃ with dry ice until chemical analysis. Each sample was ground into a fine powder with liquid nitrogen in a grinding bowl and stored in a 15 ml falcon tube at -20℃ until chemical analysis. |
Figure 6: Collection of white spruce needles (Ullah et al., 2021)
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Measuring terpene compounds
Ullah et al. established leaf needle extraction protocols (2021). We collected a 100 mg leave sample from each spruce tree and extracted it with 0.5 ml hexane two times. The concentration of terpenes was measured by sending extracted phloem samples to a Gas Chromatograph/Mass Spectrometer (GC/MS, Agilent 7890A/5062C, Agilent Tech., Santa Clara, CA).
Measuring eastern spruce budworm response
We modified the 100 ml McMorran diet by individually incorporating 25 g of dried needle powder from 29 samples collected from six specific locations. We dispensed 10 ml of the prepared diet from the stock into 60 ml Dixie cups, introducing a pre-weighed 4th instar larva into each cup. Additionally, a red McMorran diet without adding any morphotype served as the control group. In total, we established ten replicates for each sample, totaling 290 cups for the experiment. The diet was weighed before being dispensed into the cups. Subsequently, we re-measured the larval weight during the 6th instar and at the pupal stage. Ultimately, we gathered data on larval mortality and final larval weight in milligrams.
The experimental procedure in this section was established by Ullah et al. in 2021. It's important to note that the data used for this particular aspect of the project is simulated data.