The response of the perennial teosinte Zea diploperennis (Poaceae) to nitrate availability

Zen diploperennis is a perennial Mexican teosinte with favourable clonal propagation characteristics. Being a species of che genus Zen it is used in maize breeding programs as a source of virus' resistance and other genetic traits, including regeneration capacity. Determination of optimal growth conditions of this species is important from the perspective of its potential as a forage crop as well as its potential use in breeding programs and genetic engineering. The responses of 2-month old Z. diploperennis plants to nitrate availability were investigated. Significant differences have been found in the growth, CO2 exchange (photosynthesis, respiration), chlorophyll and nitrogen concentration between plants grown at high (HN) and low (LN) nitrate supply. At HN, the plants grew faster than those cultivated at LN. Rates of photosynthesis, leaf respiration, root respiration (including the nonphosphorylating alternative pathway), quantum yield, photosynthetic nitrogen-use efficiency, concentration of chlorophylls and some growth parameters (total biomass, specific leaf area, leaf mass ratio and shoot mass ratio) were higher for the plants at HN. At both HN and LN, we found relatively high values of PNUE.