Abstract
Elevated CO2 concentration may promote plant growth while high temperature is inhibitory for C3 plant species. The interactive effects of elevated CO2 and high temperatures on C3 perennial grass growth and carbon metabolism are not well documented. Kentucky bluegrass (Poa pratensis) plants were exposed to two CO2 levels (400 and 800 μmol mol−1) and five temperatures (15/12, 20/17, 25/22, 30/27, 35/32°C, day/night) in growth chambers. Increasing temperatures to 25°C and above inhibited leaf photosynthetic rate (Pn) and shoot and root growth, but increased leaf respiration rate (R), leading to a negative carbon balance and a decline in soluble sugar content under ambient CO2. Elevated CO2 did not cause shift of optimal temperatures in Kentucky bluegrass, but promoted Pn, shoot and root growth under all levels of temperature (15, 20, 25, 30, and 35°C) and mitigated the adverse effects of severe high temperatures (30 and 35°C). Elevated CO2-mitigation of adverse effects of high temperatures on Kentucky bluegrass growth could be associated with the maintenance of a positive carbon balance and the accumulation of soluble sugars and total nonstructural carbohydrates through stimulation of Pn and suppression of R and respiratory organic acid metabolism.
Highlights
High temperatures during summer months is a primary factor limiting the growth of C3 cool-season plant species as temperatures often exceed the optimal range of 10 to 24 uC for shoot and root growth during these months in many areas [1]
Turf visual quality (TQ) of plants exposed to ambient CO2 decreased below the minimum acceptable value (6.0) at 14 d of 35uC and at 21 and 28 d of in both 30 and 35uC, whereas that of plants exposed to elevated CO2 did not drop below 6.0 at any temperatures at any day of treatment
Temperatures above 25uC resulted in declines in all these parameters under both ambient and elevated CO2 conditions. These results demonstrated that temperatures above 25uC were detrimental for Kentucky bluegrass growth and photosynthetic activities
Summary
High temperatures during summer months is a primary factor limiting the growth of C3 cool-season plant species as temperatures often exceed the optimal range of 10 to 24 uC for shoot and root growth during these months in many areas [1]. Extensive effort has been taken to examine effects of elevated CO2 on plant growth under optimal or non-stressful temperature conditions and most studied reported positive effects on plant growth in various plant species [3,4,5,6,7,8,9,10,11]. Limited studies reported the combined effects of elevated CO2 and elevated temperatures on plant growth [12,13]. Few studies reported elevated CO2 may increase the optimum temperature for plant growth [18]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
