Plant phenology: a critical controller of soil resource acquisition

E A Nord,J P Lynch

doi:10.1093/jxb/erp018

Abstract

Plant phenology, the timing of plant growth and development, is changing in response to global climate change. Changing temperature, soil moisture, nitrogen availability, light, and elevated CO(2) are all likely to affect plant phenology. Alteration of plant phenology by global climate change may alter the ability of plants to acquire soil resources (water and nutrients) by altering the timing and duration of the deployment of roots and leaves, which drive resource acquisition. The potential importance of phenologically-driven changes in soil resource acquisition for plant fitness and productivity have received little attention. General hypotheses are proposed for how plant acquisition of soil resources may be affected by the alteration of phenology. It is expected that the acquisition of mobile resources will be approximately proportional to total transpiration. Alteration of phenology that increases total transpiration should increase, while changes in phenology that reduce transpiration should decrease the acquisition of mobile resources. The acquisition of immobile resources will be approximately proportional to root length duration, thus changes in phenology that increase growth duration should increase the acquisition of immobile resources and vice versa. For both groups of resources, longer growing seasons would tend to increase resource acquisition, and shorter growing seasons would tend to decrease resource acquisition. In the case of resources that exhibit seasonal variability in availability, the synchrony of resource availability and acquisition capacity is important, and subject to disturbance by the alteration of phenology.

Highlights

The observation of the timing of plant emergence and flowering is a long-standing feature of human societies
Alteration of plant phenology by global climate change may alter the ability of plants to acquire soil resources by altering the timing and duration of the deployment of roots and leaves, which drive resource acquisition
There has been a resurgence of interest in plant phenology, and changes in phenology are extensively utilized as indicators of global change (Post et al, 2001; Fitter and Fitter, 2002; Parmesan and Yohe, 2003; Badeck et al, 2004; Menzel et al, 2006)

Summary

Introduction

The observation of the timing of plant emergence and flowering is a long-standing feature of human societies. One study investigating the responses of arctic tundra systems to increased snowfall reported that peak N mineralization was shifted from midsummer to winter, presumably as soil temperature was increased and increased permafrost melting in the summer led to increased N immobilization in the summer (Borner et al, 2008) Such shifts in resource availability are likely to cause changes in plant community structure. Korner suggests that changes in temperature and precipitation associated with global change are likely to have more impact on plant growth and productivity than the direct effects of elevated CO2 (Korner, 2006). The effect of water deficits on phenology and yield may depend on whether they develop during the vegetative or reproductive phases of growth (Lilley and Fukai, 1994; Nam et al, 2001). Reproductive growth are consistent with the findings that the acclimation of wheat to elevated CO2 and N stress depended on leaf age and developmental stage (Adam et al, 2000)

Summary

Findings

Conclusion