Publication details
Patchy Nitrate Availability Alone Contributes to Heterogeneous Responses in Plant Functions and Chemical Composition Impacting Growth
| Authors | |
|---|---|
| Year of publication | 2004 |
| Type | Article in Proceedings |
| Conference | 89. ESA annual meeting |
| MU Faculty or unit | |
| Citation | |
| Keywords | xylem; vascular architecture; sectoriality |
| Description | Recently, it has been shown that nitrate, one of the most important mineral nutrients supporting plant growth, can stimulate plant transpiration (E) and, consequently, carbon fixation (A). The availability of nitrate, however, can be highly variable in both space and time. Previous research has shown that patchy nutrient availability will generate aboveground heterogeneity in plant growth and chemistry, especially in plants where the movement of solutes from root to shoot is restricted by their vasculature. However, it is unclear whether nitrate itself generates this response when interactions with other nutrients are minimized. Using sunflower and two broadleaf tree species, Acer rubrum and Betula papyrifera, grown in split-root hydroponics chambers, we evaluated restrictions of nitrate movement from selected roots to other parts of the plant using the short-lived radionuclide 13N (t 10 min) in combination with Positron Autoradiography. Additionally, we examined the effects of patchy nitrate availability in both short-term (rates of E and A), and long-term (leaf area, biomass distribution and leaf chlorophyll content) responses of the plants. A comparison of plant parts with and without direct access to nitrate reveals that a higher nitrate supply can lead to higher rates of E and A, larger leaf area, longer leaf lifespan and higher chlorophyll content. Our data suggest that patchy nitrate availability alone can be responsible for heterogeneity in functioning, chemical composition, and shoot development, and is especially pronounced in plants with strong vascular restrictions in the movement of xylem sap. Research supported in part by BNL LDRD and DOE/OBER. |