Allocation, morphology, physiology, architecture: the multiple facets of plant above‐ and below‐ground responses to resource stress

Abstract

Plants respond to resource stress by changing multiple aspects of their biomass allocation, morphology, physiology and architecture. To date, we lack an integrated view of the relative importance of these plastic responses in alleviating resource stress and of the consistency/variability of these responses among species. We subjected nine species (legumes, forbs and graminoids) to nitrogen and/or light shortages and measured 11 above-ground and below-ground trait adjustments critical in the alleviation of these stresses (plus several underlying traits). Nine traits out of 11 showed adjustments that improved plants' potential capacity to acquire the limiting resource at a given time. Above ground, aspects of plasticity in allocation, morphology, physiology and architecture all appeared important in improving light capture, whereas below ground, plasticity in allocation and physiology were most critical to improving nitrogen acquisition. Six traits out of 11 showed substantial heterogeneity in species plasticity, with little structuration of these differences within trait covariation syndromes. Such comprehensive assessment of the complex nature of phenotypic responses of plants to multiple stress factors, and the comparison of plant responses across multiple species, makes a clear case for the high (but largely overlooked) diversity of potential plastic responses of plants, and for the need to explore the potential rules structuring them.

Drought affects the coordination of belowground and aboveground resource‐related traits in Solidago canadensis in China

“…In response, resource limitations would induce plant functional adjustment consistent with an improvement of the plants' capacity to acquire the limiting resource (Freschet et al, 2018;Valladares et al, 2006;Van Kleunen & Fischer, 2005). In response, resource limitations would induce plant functional adjustment consistent with an improvement of the plants' capacity to acquire the limiting resource (Freschet et al, 2018;Valladares et al, 2006;Van Kleunen & Fischer, 2005).…”

“…Recent studies have highlighted the importance of this coordination between root and leaf functional traits in response to the limitation of above-and belowground resources (such as light and nutrients; Freschet, Swart, & Cornelissen, 2015;Liu et al, 2010). This coordination improves the ability of plants to acquire limiting resources or to limit their need for a particular resource (Freschet, Violle, Bourget, Scherer-Lorenzen, & Fort, 2018).…”

Similarities between invaders and native species: Moving past Darwin's naturalization conundrum

“…Many studies focus on traits related to leaf size, leaf tissue density, plant height and seed size as representations of stress tolerance, competition for light, and dispersal ability (Carboni et al., ; Conti et al., ). While these processes are definitely important, plant responses to their environment and their neighbors are often more complicated than can be represented by these common traits (Freschet, Violle, Bourget, Scherer‐Lorenzen, & Fort, ; Kraft et al., ; Laughlin, ). Excluding traits relating to other aspects of a plant's strategy may underestimate the importance of similarities and differences in driving invasion, and bias our interpretation of which processes are important.…”

“…The role of plasticity in a species’ ecology, however, can be complex. In a recent study, plants altered the expression of nine different traits to increase resource capture when light and nutrients were deficient (Freschet et al., ). Similarly, trait plasticity may enhance competitive responses if species can shift their root traits to avoid competition belowground or their leaf traits to competitively suppress their neighbors (Bennett, Riibak, Tamme, et al., ).…”

Do plants increase resource acquisition potential in the face of resource shortfalls, and if so, how?

“…In this issue of New Phytologist (pp. 1338–1352), Freschet et al . add to our knowledge base regarding the plastic responses of individuals, evaluating the roles that different types of adjustments (allocational, physiological, morphological or architectural) play in acclimation and asking whether different species make similar or divergent adjustments.

‘This paper adds one more important and hard‐won brick to the wall …’

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