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10:16
Design and Operation of a Continuous 13C and 15N Labeling Chamber for Uniform or Differential, Metabolic and Structural, Plant Isotope Labeling
Published on: January 16, 2014
Endogenous sink-source interactions and soil nitrogen regulate leaf life-span in an evergreen shrub
C Marty1,2, T Lamaze2, A Pornon1
1Laboratoire Evolution et Diversité Biologique, CNRS-UMR 5174, Université Paul Sabatier, 31062 Toulouse Cedex 4, France.
The New Phytologist
|June 9, 2009
Summary
Plants on nitrogen-poor soil reduce leaf life-span by using more stored nitrogen for shoot growth. This plastic response, unlike evolutionary ones, shortens evergreen leaf life.
Area of Science:
- Plant Ecology
- Plant Physiology
- Nutrient Cycling
Background:
- Understanding nitrogen dynamics in plants is crucial for predicting ecosystem responses to environmental change.
- The balance between nitrogen acquisition and use for plant growth, especially in evergreen species, is complex.
- Few studies have explored how soil nitrogen availability affects the interplay between exogenous and endogenous nitrogen sources for shoot growth and leaf longevity in field conditions.
Purpose of the Study:
- To investigate how soil nitrogen availability influences the balance of exogenous and endogenous nitrogen for shoot growth in Rhododendron ferrugineum.
- To determine the consequences of this balance on leaf life-span within a single species.
- To assess the role of nitrogen resorption and plant compartment interactions in managing nitrogen resources.
Main Methods:
- Studied two Rhododendron ferrugineum populations with differing leaf life-spans under field conditions.
- Assessed soil nitrogen availability and nitrogen resorption across various leaf age classes.
- Utilized (15)N labeling and sink organ suppression to trace nitrogen movement between plant compartments.
Main Results:
- The population on poorer soil exhibited a shorter leaf life-span (17.9 vs. 21.5 months) and relied more on leaf reserves for shoot growth (32% vs. 15%).
- Faster nitrogen resorption and shedding of young, nitrogen-rich leaves contributed to this shorter life-span.
- Wood provided over 40% of shoot nitrogen demand for both populations, and shoot development strongly influenced leaf life-span.
Conclusions:
- Plastic responses to low soil nitrogen can reduce leaf life-span in evergreen plants, contrasting with typical evolutionary adaptations.
- Leaf life-span appears more sensitive to the mismatch between shoot nitrogen demand and soil nitrogen uptake than to nitrogen demand alone.
- These findings highlight the importance of considering nitrogen dynamics and plant plasticity in understanding plant survival and ecosystem function.
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