Effects of elevated atmospheric CO₂ concentration on growth and photosynthesis in eddo at two different air temperatures

Climate Change and an Agronomic Journey from the Past to the Present for the Future: A Past Reference Investigation and Current Experiment (PRICE) Study

“…A recent meta-analysis [41] showed that rice plant height increased by 4.0% across cultivars with elevated [CO 2 ] (e.g., +200 ppm) in FACE studies. In chamber studies [18,24], however, there only a temperature effect on plant height; there was no [CO 2 ] effect and no combined effect of [CO 2 ] and temperature on plant height. Zaher et al [24] also reported a significant increase (18%) and non-significant increase (6-7%) in rice plant height under separate warming (4.0 • C) and elevated [CO 2 ] (200 ppm elevation, i.e., 615 ppm) treatments in chambers.…”

“…Elevated [CO 2 ] (+120 ppm) over the 100 years, however, could also more or less contribute to the increased plant height because increasing [CO 2 ] is predicted to increase plant temperature by decreasing latent heat loss due to the reduced stomatal conductance under elevated [CO 2 ] [63,64]. A number of factors are likely to affect the plant height of rice under elevated [CO 2 ] and/or temperature [18,24,36,38,39,41]. For example, the plant height of a high-yielding hybrid and indica rice increased by 4.5-6.1% in FACE under elevated [CO 2 ] (+200 ppm) [37,39], but not in japonica rice in both FACE [40] and chambers [18,24].…”

“…A number of factors are likely to affect the plant height of rice under elevated [CO 2 ] and/or temperature [18,24,36,38,39,41]. For example, the plant height of a high-yielding hybrid and indica rice increased by 4.5-6.1% in FACE under elevated [CO 2 ] (+200 ppm) [37,39], but not in japonica rice in both FACE [40] and chambers [18,24]. It appears that there would be a significant difference in the plant height response to elevated [CO 2 ] among cultivars [39].…”

“…Since then, there has been an incentive to develop a variety of experimental approaches for studying the effects of increasing [CO 2 ] on agricultural crops worldwide [7][8][9][10][11][12][13][14]. It has been widely reported that experimentally elevated [CO 2 ] and/or temperatures will have a wide range of effects from stimulation to suppression of rice growth processes in sunlit chambers (SC) [15][16][17][18][19], temperature gradient chambers (TGC) [20][21][22][23][24][25], open-top chambers (OTC) [26][27][28], FACE experiments [29][30][31][32][33][34][35][36][37][38][39][40][41][42], free-air temperature increase (FATI) experiments [43], and FACE in combination with elevated temperature (T-FACE) [14,[44][45][46].…”

“…With such an idea, in 2020, we commenced the world's first project, to our knowledge, to study the responses of rice crops to climate change under the current natural environmental conditions. Because the natural environment is the research facility, we did not need artificial structures in the fields for [CO 2 ] fumigation and temperature control, unlike in FACE [30][31][32][33][34][35][36][37][38][39][40][41][42][43] and chamber [15][16][17][18][19][20][21][22][23][24][25][26][27][28] studies. Instead, we only needed a past reference investigation ('reference experiment' hereafter) and current experiment (PRICE).…”