Growth and competitiveness of wheat against C3 and C4 plant in CO2 enrichment and drought condition

Subject Areas : Journal of Plant Ecophysiology

farahnaz momtazi ¹ , hamidreza miri ²

1 - آموزش و پرورش استان فارس، شیراز، ایران
2 - گروه زراعت و اصلاح نباتات، واحد ارسنجان، دانشگاه آزاد اسلامی

Received: 2015-05-18 Accepted : 2015-05-18 Published : 2015-05-01

Keywords: growth, Weeds, competition, climatic change, photosynthetic pathway,

Abstract :

Prediction climatic models show that atmospheric CO2 concentration will be increase and this has considerable effect on plant growth and their interaction. In addition to this CO2 changes water availability will affect plant growth and development. A greenhouse experiment was conducted in Arsanjan Islamic Azad University in 2012 in order to evaluate effect of drought and CO2 elevation on growth and competitiveness of wheat against C3 and C4 crops and weeds. Wheat, sunflower, wild oat and lumbsquarters as C3 crops and weeds and corn, millet, redroot pigweed and wild johnsongrass as C4 crops and weed were subjected to two CO2 concentrations (400 and 700 ppm) and two irrigation treatments (control and drought). The results showed that by increasing CO2 concentration total dry weight, stem dry weight, leaf dry weight, root dry weight and leaf area of wheat increased significantly, but CO2 elevation had no significant effects on C4 plants. CO2 elevation increased dry weight of wheat by 30.7%. Drought stress reduced dry weight of wheat by 25.3%, but, under high CO2 condition there was no reduction in dry weight of wheat. This means that high CO2 reduced harmful effect of drought on C3 and C4 plants. The results also showed that by increasing CO2 competitive ability of wheat increasing against C4 plants. This change the competitive interaction of C3 and C4 crops and weeds at different CO2 and drought condition.