The morphological characteristics of perennial ryegrass (Lolium perenne cv. Nui), cocksfoot (Dactylis glomerata cv. Vision) and red clover (Trifolium pratense cv. Pawera) in response to four shade levels (0, 25, 50 and 75%) and two shade patterns (continuous and alternate) were assessed in three growth periods (establishment, first regrowth and second regrowth), in New Zealand, to evaluate the adaptation of different species to changes in the light environment. The experiment was conducted in a randomized complete block design, with three replications, between January and October, 2004. Most of the morphological measurements were affected by the shade levels. The specific leaf area was the morphological variable that most consistently varied in response to shade levels, presenting an average increase between 22 and 79% among the forage species. The morphological adaptations of cocksfoot were the most related to shade tolerance, whereas for perennial ryegrass they were more related to the expansion of its individual leaf area. The 25 - 50% shade range can be considered the range of highest morphological acclimation of forages to offset light constraint.
irradiance; grass; leaf morphology; legume
