Presentation on theme: "DISTANCE AND BARK PHOTOSYNTHESIS IN ASPEN TREES IN THE FRONT RANGE Lauren Kendle Winter Ecology Spring 2012."— Presentation transcript:
DISTANCE AND BARK PHOTOSYNTHESIS IN ASPEN TREES IN THE FRONT RANGE Lauren Kendle Winter Ecology Spring 2012
Background Information An analysis of 60 species indicated that there were photosynthetic processes in the bark Aspen Trees had the highest level of bark chlorophyll (Wittman and Pfanz, 2011) Photosynthesis in the bark is reduced to a quarter of summertime production during the winter ( Solhaug and Haugen, 1998) Chlorophyll is arranged in the tree to maximize photosynthesis (Pfanz et al., 2002)
Question and Hypothesis Question: Are Aspens able to adjust the amount of chlorophyll in the bark if there is a tree or an object blocking the direct sunlight? Hypothesis: The closer the object or tree is to the Aspen should result in more chlorophyll because so the tree can compensate for the decreased amount of sunlight.
Methods Paint Chip Analysis Measured at breast height on the sun- facing side Took Picture Recorded information from location
Methods continued Photoshop to standardize photos Sampled Green Pigmentation Averaged Green Pigmentation Used R for analysis of data Many limitations of in data collection
Results Hypothesis was not supported For the Categorical Data P value = 0.672 R-squared -0.04042 For data for blocked trees only P Value = 0.248 R-squared = 0.05
Discussion The Data did not support the hypothesis Maybe confounding variables Age of trees Aspect Amount of sunlight blocked Human influence in second sample site Aspens are highly competitive species and optimize the light received by increasing chlorophyll per unit of area (Aschan et al., 2001)
Further questions Is the age of the tree related to the chlorophyll content? Would changing the methods produce different results? Machine measurement of CO 2 or O 2 What other factors may influence the chlorophyll content? Soil Water Aspect
Conclusions Hypothesis was not supported in this study Not enough information collected No significant relationships based on the data collected Methods may not have adequately assessed levels of photosynthesis
Literature Cited Aschan, G., C. Wittmann, and H. Pfanz. 2001. Age-dependent bark photosynthesis of aspen twigs. Trees, 15:431-437 Foote, K.C. and M. Schaedle. 1976. Physiological characteristics of photosynthesis and respiration in stems of Populus tremuloides michx. Plant Physiology 58:91-94. Pfanz, H., G. Aschan, R.Langenfeld-Heyser, C. Wittman, and M. Loose. 2002. Ecology and ecophysiology of tree stems: corticular and wood photosynthesis. Naturwissenchaften 89:147-162 Roakowski, P., Y. Li, and P. B. Reich. 2011. Local ecotypic and speicies range-related adaptation influence photosynthetic temperature optima in deciduous broadleaved trees. Plant Ecology, 213:112-125. Solhaug, K.A. and J. Haugen. 1998. Seasonal variation of photoinhibition of photosynthesis in bark from Populus tremula l. Photosynthetica 35:411-417. Wullschleger, S.D., D. J. Weston, and J. M. Davis. 2009. Populus response to edaphic and climate cues: emerging evidence from systems biology research. Critical Reivews n Plan Science, 28:368-374.