Shading effects on growth and leaf gas exchange of some container-grown shrubs

The growing environment infl uences quality, size, and scheduling of nursery crops, thereby establishing production costs and profi tability. Improper light levels in the production environment may negatively affect plant growth and physiology. However, adjustments to the light regime of the production environment must be made carefully, because changes may not always be cost-effective. As shown in previous research projects conducted on woody ornamentals (1,2,5), sun- and shade-acclimation responses can vary according to the species and information regarding sun/shade tolerance of the most widely grown species may be benefi cial for nursery and landscape industries. Therefore the objective of this study was to determine the effects of different light levels on containerized shrubs, by assessing leaf gas exchanges and plant growth characteristics under three levels of irradiance (100% full sun, 70% and 40% of full sun)