具有较强抗旱能力的树一般具有哪些特征

For long-lived organisms like trees,classic ecological theory suggests that growth–stress tolerance trade-offs areexpected to underlie intraspecific variation in functional traits (Grime, 1977;Adler et al., 2014; Reich, 2014). A growth–stress tolerance trade-off suggeststhat under harsh environment conditions, tree species/populations will exhibita trade-off by constraining growth for improved stress tolerance. There are avariety of functional traits (drought resistance traits) that allow individualsto tolerate periods of low water availability. Trees with improved droughtresistance may have xylem more resistant to drought-induced cavitation (Tyree& Sperry, 1989; Maherali et al., 2004), denser leaves with less waterdemand and more tolerance of increased xylem pressure during drought (Wright etal., 2004), lower leaf area-to-sapwood area ratios which reduce evaporativedemand and the xylem pressure required to move water to the foliage(Martínez-Vilalta et al., 2009), increased production of root tissue and deeperroots for more efficient uptake of water from soil (Jackson et al., 2000), andleaves with lower turgor loss points (Bartlett et al., 2014) and higher heattolerance (Knight & Ackerly, 2002). Given the carbon costs associated withthese traits, trees with tolerance to drought might be expected to grow slowerunder wetter conditions in order to be able to survive drier climateconditions. A more thorough understanding of which functional traits mediategrowth–stress tolerance trade-offs will improve our predictions of species'drought response.