Effects of light intensity and nitrogen nutrition on growth and photoinhibition of container-grown illicium L. taxa

Abstract

There are conflicting reports as to the ability of Illiciums, a genus of broad-leaf evergreens popular in the United States, to grow and survive in high light intensities, during production and in the landscape. We used photosynthetic light response curves to investigate taxon differences in photosynthetic gas-exchange of plants produced in high and low light. In general, all taxa had highest rates of photosynthesis when produced in low light. A second study investigated the influence of light intensity and rate of nitrogen application on the growth of Illicium taxa. In general, increasing nitrogen application rate did not promote growth, or ameliorate growth reductions of either taxa grown in high light. Optimal growth and nutrient uptake occurred in the lowest light treatment. We concluded that Illicium taxa studied benefited from production at low light intensities, and suggest all taxa be grown in low light to optimize growth and fertilizer efficiency.