Why do species of woody seedlings change rank in relative growth rate between low and high irradiance

摘要: It is often assumed that if a plant species has higher relative growth rate (RGR) than another in deep shade, it will have lower RGR at high irradiance (Spurr & Barnes 1980; Thomas Bazzaz 1999; Walter 1973). In other words, change rank (crossover) between low and irradiance. This idea was suggested chiefly by the finding shade massbased net photosynthetic rates of leaves plants exceed those sun plants, while reverse true (Bjdrkman Holmgren 1963; Boardman 1977; Givnish 1988). been to scale up level whole-plant (Shugart 1984). past decade, however, contrary view concerning RGRs emerged, grows faster also do so (Kitajima 1994; Poorter 1999). According this later view, light plays role maintaining mixture forest only through well established trade-off survival bright 1994, 1996). Similar experimental studies responses for woody seedlings report surprisingly different results. Here we indicate why such disparate results produced. We provide simple analytical approach understanding crossovers should occur among particular stages ontogeny. useful maintenance richness, as interpreting specialization physiology morphology contrasting regimes.