Title

Estimating Nitrogen Uptake of Individual Roots in Container- and Field-Grown Plants Using a 15N-Depletion Approach

Document Type

Article

Publication Date

2009

Publication Title

Functional Plant Biology

Volume Number

36

Issue Number

7

DOI

10.1071/FP08330

Abstract

We only have a limited understanding of the nutrient uptake physiology of individual roots as they age. Despite this shortcoming, the importance of nutrient uptake processes to our understanding of plant nutrition and nutrient cycling cannot be underestimated. In this study, we used a 15N depletion method that allowed for the measurement of nitrate-N uptake rates on intact, individual, fine roots of known age. We expected that N uptake would decline rapidly as fine roots aged, regardless of the environmental conditions and species used. We compared age dependent uptake patterns of young grape cuttings with those of mature vines and with those of tomato. Although patterns of declining uptake with increasing root age were similar for all species and conditions tested, large differences in maximum N uptake rates existed between young cuttings and mature vines, and between woody and herbaceous species. Maximum rates were 10-fold higher for tomato and 3-fold higher for the grape cuttings, when compared with uptake rates of fine roots of mature vines. Coefficients of variation ranged from 43 to 122% within root age groups. The large variability in physiological characteristics of fine roots of the same age, diameter and order suggests that there is a functional diversity within fine roots that is still poorly understood.

ISSN

1445-4408

First Page

621

Last Page

628

Link Out URL

https://doi.org/10.1071/FP08330

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