Photosynthetica 2010, 48(4):617-622 | DOI: 10.1007/s11099-010-0079-3

Leaf development, gas exchange characteristics, and photorespiratory activity in maize seedlings

U. Kutschera^1,*, R. Pieruschka¹, J. A. Berry¹

¹ Departments of Plant Biology and Global Ecology, Carnegie Institution for Science, Stanford, USA

Five decades ago, a novel mode of CO₂ assimilation that was later described as C₄-photosynthesis was discovered on mature leaves of maize (Zea mays L.) plants. Here we show that 3- to 5-day-old developing maize leaves recapitulate the evolutionary advance from the ancient, inefficient C₃ mode of photosynthesis to the C₄ pathway, a mechanism for overcoming the wasteful process of photorespiration. Chlorophyll fluorescence measurements documented that photorespiration was high in 3-day-old juvenile primary leaves with non-specialized C₃-like leaf anatomy and low in 5-day-old organs with the typical "Kranz-anatomy" of C₄ leaves. Photosynthetic gas (CO₂)-exchange measurements on 5-day-old leaves revealed the characteristic features of C₄ photosynthesis, with a CO₂ compensation point close to zero and little inhibition of photosynthesis by the normal oxygen concentration in the air. This indicates a very low photorespiratory activity in contrast to control experiments conducted with mature C₃ sunflower (Helianthus annuus L.) leaves, which display a high rate of photorespiration.

Keywords: leaf development; maize seedlings; photorespiration; photosynthesis

Received: May 4, 2010; Accepted: October 28, 2010; Published: December 1, 2010Show citation