RELATIONSHIP BETWEEN CHLOROPHYLL CONTENT AND NEEDLE COLOR OF Abies religiosa KUNTH, SCHLTDL. et CHAM

Evaluation of the physiological performance of plants as an environmental response is crucial to understand the ecological succession in plant communities and to implement strategies that increase plant survival and growth for restoration efforts and commercial plantations; however, evaluating plant physiology often requires complex and expensive technical equipment not normally accessible to all researchers and non-specialized people. In the present study, we explored the relationship of the visual condition of the needles with an indicator of their photosynthetic capacity related to chlorophyll content in Abies religiosa. A visual stress index was developed to evaluate the response to environmental stress in seedlings of A. religiosa during a reforestation effort, and the correlation between leaf chlorophyll content and different categories of the stress index. The replicability of the index was also tested to determine its applicability by non-specialized people. A high correlation was detected between the index and chlorophyll concentration (r(2) = 0.76; P < 0.0001). Additionally, there was a significant agreement on the index among several observers (W = 0.95; P < 0.0001). Overall, the stress index is related the physiological condition of the plants and can be adopted by people, after training, to make evaluations of the physiological status of A. religiosa seedlings.