Plant Growth Responses to Environmental Change

Plant growth patterns and rates adaptively respond to changes in the environment. Such adaptive changes confer competitive advantages and allow the plant to survive adverse conditions. Here, I will focus on adaptation to changes in nutrient availability.

Altered nutrient availability can impact plant growth at the cellular, organ, and whole plant level: Local (in the order of 50-100 ^m) differences in soil phosphate availability suffice to alter root hair growth, which in low phosphate, is stimulated in a cell-autonomous manner (Bates and Lynch 1996). Likewise, cell expansion in leaves subjected to low water activity is reduced, but can recover when water is available again (Granier and Tardieu 1999). When mature leaves are exposed to high light or CO2, leaf growth is stimulated and stomatal density increases. Developing leaf primordia exposed to low light or low CO2 will develop with the characteristics of the mature leaves, indicating that at least some aspects of leaf growth are controlled by systemic signals (Lake et al. 2001; Yano and Terashima 2001; Ferjani et al., this volume). Unfortunately, the precise mechanisms by which any nutritional cue elicits one or more signals controlling cell growth, division, or expansion are not yet known.

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