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Abstract Detail


Alsahame, Mona [1], Ryser, Peter [2].

Nitrogen remobilization from wetland monocot roots in species with contrasting root turnover strategies.

Senescence is an active, tightly regulated process towards the end of the life span of a plant organ. It allows nutrient remobilization from the dying organs and it is an essential part of a plant’s nutrient management strategy. It has been commonly studied in leaves and flowers, but not much is known about senescence in roots. There is no data on the importance of nutrient resorption from dying roots of ecologically contrasting species. Perennial herbaceous monocot species in Northern Ontario wetlands can be classified in two distinct types of root turnover strategies: species with a low fine root mortality in the fall and winter, and species which a complete fine root mortality in the fall. Leaves of all species die for the winter, and the species with senescing roots overwinter as rhizomes, bulbs, bulbils, corms or tubers. Ecological significance of the two root turnover strategies is not known. To understand the adaptive value of the two strategy types, information is needed about the effect of root mortality on plant nutrient balance. In the present project roots of three species with fall-senescing root systems (Rhynchospora alba, Sagittaria latifolia, Sparganium emersum) and three species with overwintering root systems (Carex oligosperma, Iris versicolor, Scirpus microcarpus) are investigated with respect to presence of senescence in form of nutrient resorption in the fall. Potential changes in root protein content and protease activity at the end of the growing season, from August to November, are investigated for garden-grown individual of the six species. Existing data on root nutrient remobilization is based on potential changes in root element content in dying roots, which does not differentiate between remobilization and leaching out. In the present project we assess protein content and protease activity, with the aim to confirm and quantify active remobilization processes in the roots. We hypothesize that this process is more pronounced in the fall-senescing roots. Preliminary results support the hypothesized stronger decline of root protein content in the fall for species with fall senescing roots, compared to species overwintering roots.

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1 - Laurentian University, Department of Biology, Ramsey Lake Road, Sudbury, ON, P3E 2C6, Canada
2 - Laurentian University, Department Of Biology, Ramsey Lake Rd, Sudbury, ON, P3E 2C6, Canada

Root lifespan
plant functional trait.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PEP005
Abstract ID:920
Candidate for Awards:None

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