the effect of light quality and quantity on morphological and physiological traits of maize (zea maize l.) cultivars in greenhouse conditions

in order to study the effect of light quality and quantity on morphological and physiological characteristics of two late and early maize (zea maize l.) s.c., an experiment was conducted in greenhouse conditions, ferdowsi university of mashhad, iran, during 2008. the experiment was carried out factorial based on randomized complete block design with six treatments and three replications. different light conditions (including natural light, additional two hours lighting after sunset, and reduction of the quality and quantity of light conditions during plants growth, were investigated. the results indicated that leaf area in both maize hybrids increased by light measured until 28 days, and then decreased compared to the natural lighting conditions. in comparison with natural light conditions the dry mater of leaf and stem was increased by adding light until flowering stage. leaf area and dry weight was reduced in both hybrids with decreasing lighting conditions. leaf length to width ratio increased by adding the lighting measure till the seventh leaf appearance and later on reduced. this ratio increased with reduction of light duration. chlorophyll content increased by adding light duration till the sixth leaf appearance. the chlorophyll content of two hybrids in screen conditions decreased compared to other conditions. in general, leaf area, stem and leaf dry weights, height and lodging index of short season hybrid was lower than long season hybrids. the present study showed that extending light duration resulted in increasing of the dry weight and development stage of maize.