1. One proposed mechanism by which tree species coexist is through partitioning gradients of light availability. We performed a pot experiment in which seedlings of 12 pioneer species were established in 30% light, then transplanted to six light treatments designed to simulate natural gaps ranging from 25 m (≈10% full sun) to 800 m (60% full sun). Plants were harvested after 56–117 days, and co...

A method of calculating relative growth rates (RGR) and net assimilation rates is presented. The method is based on the fitting of a polynomial through the relative growth rate values calculated by the 'classical' approach rather than through the ln-transformed plant weights as in the 'functional' method. Additional ways of reducing the harvest-to-harvest variation characteristic of the classic...

Evolutionary adaptation to variation in resource supply has resulted in plant strategies that are based on trade-offs in functional traits. Here, we investigate, for the first time across multiple species, whether such trade-offs are also apparent in growth and morphology responses to past low, current ambient, and future high CO 2 concentrations. We grew freshly germinated seedlings of up to 2...

abstract confused flour beetle, tribolium confusum duval (col.: tenebrionidae) is one of the most important stored product pests of flour in iran. in this research the effects of insect growth regulators (igrs): teflubenzuron, hexaflumuron and pyriproxyfen were studied on larval and imago nutritional indices of confused flour beetle. the results showed that they were more effective on relative ...

Interstocks improve the growth and salt resistance of lemon (Citrus limon (L.) Burm. f.) trees, but their effects on orange (Citrus sinensis (L.) Osbeck) trees are unknown. We grew 'Cleopatra' mandarin (CM) seedlings, budded trees of 'Salustiano' orange (SAO) on CM, 'Valencia Late' orange (VLO) on CM (VLO/CM), and interstock trees VLO/SAO/CM in pots of sand watered with nutrient solution contai...

It has been hypothesized that slow-growing plants are more likely to maximize above-ground biomass and fitness when defoliated by herbivores than those with an already high relative growth rate (RGR). Some populations of the annual herb Datura stramonium L. can tolerate foliar damage better than others. The physiological basis of this difference is examined here in a comparative study of two ec...

Growth rates are of fundamental importance for plants, as individual size affects myriad ecological processes. We determined the factors that generate variation in RGR among 14 species of trees and shrubs that are abundant in subtropical Chinese forests. We grew seedlings for two years at four light levels in a shade-house experiment. We monitored the growth of every juvenile plant every two we...

• We tested the hypothesis that biological trait-based plant functional groups provide sufficient differentiation of species to enable generalization about a variety of plant ecophysiological traits or responses to nitrogen (N). • Seedlings of 34 North American grassland and savanna species, representing 5 functional groups, were grown in a glasshouse in an infertile soil with or without N fert...

BACKGROUND AND AIMS Nitrogen availability varies greatly over short time scales. This requires that a well-adapted plant modify its phenotype by an appropriate amount and at a certain speed in order to maximize growth and fitness. To determine how plastic ontogenetic changes in each trait interact and whether or not these changes are likely to maximize growth, ontogenetic changes in relative gr...