Plant response to irrigation with water enriched with carbon dioxide

Abstract

SUMMARY The influence of irrigation with CO2‐enriched water on plant development and yield is reviewed. The reason for irrigation with CO2‐enriched water was – in most cases – to increase yield. The present evaluation considers results from over a hundred studies performed since the first experiment in 1866. Special emphasis is given to the comparison of 85 experiments made by Mitscherlich in 1910 with 358 irrigation experiments made in the last 80 years. In a statistical analysis of these experiments, the measured plant parameter (often growth and/or gas exchange rates) showed a highly significant mean increase of 2.9 % in plants irrigated with CO2‐enriched water as compared with control. Evidence of five mechanisms was found. The subterranean carbon dioxide concentration influences: (a) the rate of nitrification and hence of nitrogen availability; (b) the rate of weathering and pH, and hence the availability of other plant nutrients; (c) the CO2 uptake via roots into the transpiration stream, contributing to the rate of leaf photosynthesis; (d) the hormone levels in the plant; and (e) the rate of pesticide decomposition in soils. After examining the available evidence we found that (a) and (b) in some experiments are important to plant growth, since they change the physiochemical environment of the roots. On the other hand, while (c) could theoretically contribute up to 5% of plant carbon assimilation, it usually contributes less than 1 %, while (d) contributes most of the observed effects of CO2‐enriched water on plants. In addition, pesticide decomposition in soils can be delayed by supra‐ or sub‐optimal CO2 concentrations.

The influence of enriched rhizosphere CO2 on N uptake and metabolism in wild‐type and NR‐deficient barley plants

“…Aeration of the nutrient solution with elevated levels of CO2 was achieved by mixing CO2-free air with pure CO2, The CO2 concentration was continuously monitored with an APPA-3 infrared gas analyzer (Anarad Inc, Santa Barbara, CA, USA), C02-free air was generated by passing air through a 1 x 0,05 m column of soda lime tested for efficacy at the beginning and the end of the experiment with the infrared gas analyser. To prevent release of CO2 from the rhizosphere and its assimilation by photosynthesis (Enoch and Olesen 1993), a fan was used to maintain a gentle air movement over the plant shoots. The air composition was routinely sampled above the lids of the containers with an ADC LCA2 infrared gas analyser (Analytical Development Corporation, Hoddesdoti, UK) and did not differ from ambient CO, concentrations.…”

Are the Fractionation Corrections Correct: Are the Isotopic Shifts for 14C/12C Ratios in Physical Processes and Chemical Reactions Really Twice Those for 13C/12C?

“…Additionally, 13 C and 14 C tracer experiments (Amiro and Ewing 1992;Ford et al 2007 and references therein) have confirmed that DIC uptake does occur in some plants, including Phaseolus vulgaris. However, as summarized by Enoch and Olesen (1993) and Ford et al (2007), different experiments have produced sharply different estimates of the extent to which the process occurs, including cases where the effect is so small as to be unmeasurable. The only common ground in the literature seems to be a widespread agreement that the carbon contribution to fixed biomass from root uptake is at most a few percent of the input from photosynthesis, and probably much less.…”

Influence of electric conductivity management on greenhouse tomato yield and fruit quality

“…The influence of irrigation with CO 2 -enriched water on plant development and yield has been reviewed [59]. Recently, studies [38,39] showed that elevated rhizosphere dissolved inorganic carbon (DIC) under salinity stress stimulated tomato growth and was related to the site of NO 3 -reduction (root for salt-stressed plants) and higher NO 3 -uptake [41].…”