Effect of CO2 enrichment in under drought stress condition on growth and weed competetiveness against corn

Subject Areas : Journal of Plant Ecophysiology

H.R. Miri ¹ (استادیار دانشگاه آزاد اسلامی واحد ارسنجان)

Received: 2014-05-28 Accepted : 2014-05-28 Published : 2013-11-01

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Abstract :

In order to study the effects of CO2 enrichment with changed water availability on growth and competetivness  of corn against C3 and C4 crop and weeds, a greenhouse experiment was conducted at Arsanjan Islamic Azad University in 2012. The experiment was evaluation the effect of two CO2 concentrations (400 ppm and 700 ppm) and two irrigation treatments (control irrigation and drought) on corn, wheat, sunflower, millet and the weeds pigweed, lambsquarter, wild oat and johnson grass in monoculture and mixed culture with corn. Measured traits were leaf area, stem dry weight, leaf dry weight, shoot dry weight and plan relative yield. The results showed that CO2 enrichment increased shoot growth, leaf area and root growth of wheat, sunflower, lambsquarter and wild oat while there was no significant changes in corn, millet, pigweed and Johnson grass. Drought stress reduced wheat, sunflower, corn and millet by 25.2, 30.3, 30 and 32% respectively but, in elevated CO2 concentration these values were 0, 10.3, 0 and 19.7%. In fact CO2 enrichment reduced detrimental effects of drought on C3 and C4 plants. The results also showed that with increasing CO2 concentration competitiveness of C3 weeds increased against corn. This means that the competition interaction of C4 crop can be change against weeds in drought and increased CO2 concentration which it can increasing C3 weeds damages on crop plants.