|Eitel, Jan -|
|Vierling, Lee -|
|Litvak, M -|
|Eitel, K -|
Submitted to: Canadian Journal of Forest Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 8, 2011
Publication Date: July 11, 2011
Citation: Eitel, J.U., Vierling, L., Long, D.S., Litvak, M., Eitel, K.C. 2011. Simple assessment of needleleaf and broadleaf chlorophyll content using a flatbed color scanner. Canadian Journal of Forest Research. 41:1445-1451. Interpretive Summary: An inexpensive, off-the-shelf color scanner was evaluated for ability to measure the chlorophyll content of narrow conifer needles. Leaves of juniper and pine were scanned. The digital numbers representing the leaves in the scanned imagery were highly correlated with the chlorophyll content that had been determined in the leaves by wet chemistry. The results are sufficiently promising to suggest that a flatbed scanner can be a rapid, cost-effective alternative to more expensive optical equipment for determining the chlorophyll content in needle leaves of conifers.
Technical Abstract: Total chlorophyll a and b content of leaves is an important indicator of the photosynthetic capacity and nutritional status of plants. Chlorophyll meters, digital cameras, and optical reflectometers provide for non-destructive estimation of chlorophyll. However, their use by forest managers is limited: reflectometers are costly, chlorophyll meters are not suitable for use with narrow, needle-like leaves, and digital camera-based chlorophyll estimates may be confounded by varying illumination and viewing geometry. This study was conducted to evaluate the ability of an off-the-shelf color scanner to assess chlorophyll of needle leaves. Red and green digital numbers of the scan image were obtained from needle leaves of juniper and pine. For each leaf, the chlorophyll was extracted in 80% acetone and analyzed by colorimetry. Values of laboratory-determined chlorophyll were then predicted using the digital values from the scanner imaged leaf as a regression estimator. The digital numbers of the scanner imaged leaves were linearly related to chlorophyll with r2 ranging from 0.49 to 0.82 for red and 0.25 and 0.9 for green. Flatbed color scanning is an inexpensive, rapid technique for assessing chlorophyll of needle leaves since the resulting imagery can effectively resolve small leaf size.