Leaf Area Renewal, Root Retention and Carbohydrate Reserves in a Clonal Tree Species Following Above-Ground Disturbance

• Published in: The Journal of ecology 2002-08, Vol.90 (4), p.658-665
• Main Authors: Landhäusser, Simon M., Lieffers, Victor J.
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Aspen; Autoecology; Biological and medical sciences; clonal woody species; Fundamental and applied biological sciences. Psychology; Human ecology; Leaf area; Metabolism; non‐structural carbohydrate; Plant ecology; Plant physiology and development; Plant roots; Plants and fungi; Populus tremuloides; Root systems; Saplings; Sprouting; Starches; Stems; Storage and secretion, pigments, phytochrome; sucker regeneration; Trees
• ISSN: 0022-0477; 1365-2745
• DOI: 10.1046/j.1365-2745.2002.00699.x

1 Removal of the above-ground portion of clonally regenerating trees results in a massive imbalance in the ratio of root to leaf area. We investigated the resilience of clones following above-ground disturbance in terms of root carbohydrates, leaf area renewal and root retention. 2 In a 2 x 2 factorial experiment, 40 Populus tremuloides saplings were cut at times of high (late fall) or low (spring after leaf flush) root carbohydrate reserves. Leaf area renewal was manipulated by allowing either only one or all root suckers to re-grow. 3 Root starch concentrations were 10 times higher at the time of cutting in the fall compared with the spring, whereas sugar concentrations were only 10% higher. When saplings were cut in fall and all suckers were allowed to develop (FA treatment), suckers were taller, and had more biomass and leaf area and higher leaf area ratio than all other treatments. In particular, leaf area and leaf area ratio recovered within a year to near pre-treatment levels compared with at least a 50% reduction in the other treatments. 4 At the end of the first season after cutting FA saplings also had the greatest root mass and lowest amount of dead root mass, and root starch concentrations of these saplings had returned to pre-treatment values, compared with a 20% recovery for spring-cut saplings with a single sucker. Root mass and root starch concentrations were correlated with leaf mass in all treatments. 5 Adequate carbohydrate reserves at the time of disturbance and rapid redevelopment of leaf area by extensive sprouting seem critical for resilience of the clone and allow for the retention of the clonal root system and a rapid rebuilding of carbohydrate reserves. Clones with poor sucker and leaf area development showed extensive root mortality and reduced carbohydrate reserves and their prospects for growth in the following year were comparatively poor.