Land plants have evolved various mechanisms for responding to unfavourable environmental signals, which allows them to tolerate or avoid environmental stresses such as water deficit. To date, physiological and molecular mechanisms that contribute to drought tolerance have been intensely studied, however the mechanisms that confer drought avoidance have been less understood. To avoid drought conditions roots must sense environmental stimuli and respond by regulating growth away from water scarce areas or toward wet areas. Indeed, roots respond to numerous environmental stimuli, such as gravity, light and moisture gradient, and exhibit gravitropism, phototropism and hydrotropism, respectively. Of these root tropisms, hydrotropism can be considered to contribute directly to drought avoidance. As soil water status is affected by gravity or intense light, positive gravitropism and negative phototropism are assumed to contribute to drought avoidance. In this chapter, we describe what happens to cells faced with a water deficit and then outline the molecular mechanisms underlying different tropisms, with particular emphasis on the molecular mechanism contributing to root hydrotropism.
|ジャーナル||Advances in Botanical Research|
|出版ステータス||Published - 2011 4 29|
ASJC Scopus subject areas
- Plant Science