Impacts of climate changes on crop physiology and food quality (original) (raw)
Related papers
2008
ABSTRACT A rising global population and demand for protein-rich diets are increasing pressure to maximize agricultural productivity. Rising atmospheric [CO 2] is altering global temperature and precipitation patterns, which challenges agricultural productivity. While rising [CO 2] provides a unique opportunity to increase the productivity of C 3 crops, average yield stimulation observed to date is well below potential gains. Thus, there is room for improving productivity.
Crop Responses to Elevated Carbon Dioxide and Interaction with Temperature
Journal of Crop Improvement, 2005
Atmospheric carbon dioxide concentration ([CO 2 ]) and other greenhouse gases have risen over the past few decades. If this continues, it could indirectly lead to increases in global temperature. Responses of grain legume crops (soybean, dry bean, peanut and cowpea) to elevated [CO 2 ] and interactions with temperature are summarized. Our research shows that, in the absence of biotic (pests, diseases and
Crop response to elevated CO2 and world food supply:: A comment on
2007
Recent conclusions that new free-air carbon dioxide enrichment (FACE) data show a much lower crop yield response to elevated CO 2 than thought previously -casting serious doubts on estimates of world food supply in the 21st century -are found to be incorrect, being based in part on technical inconsistencies and lacking statistical significance. First, we show that the magnitude of crop response to elevated CO 2 is rather similar across FACE and non-FACE data-sets, as already indicated by several previous comprehensive experimental and modeling analyses, with some differences related to which "ambient" CO 2 concentration is used for comparisons. Second, we find that results from most crop model simulations are consistent with the values from FACE experiments. Third, we argue that lower crop responses to elevated CO 2 of the magnitudes in question would not significantly alter projections of world food supply. We conclude by highlighting the importance of a better understanding of crop response to elevated CO 2 under a variety of experimental and modeling settings, and suggest steps necessary to avoid confusion in future meta-analyses and comparisons of experimental and model data.
Semi-arid Crop Responses to Atmospheric Elevated CO2
Semi-arid tropics host most of the poor and small-holding farmers of the developing world. Global warming is seen largely as a consequence of continuous increase in the emission of carbon dioxide and other greenhouse gases into the atmosphere leading to unusual changes in global temperatures and rainfall patterns. This in turn is expected to increase the water scarcity in the environment, affecting plant growth and metabolism. In this context, we reviewed semi-arid crop responses to elevated CO 2 levels in terms of growth, yield components, physiological, biochemical and molecular changes. Predicted rise of carbon-dioxide in the atmosphere may benefit the plants by increasing the crop water use efficiency and net photosynthesis leading to greater biomass, yield and harvest index. C 3 and C 4 crop plants vary in their degree of response to elevated CO 2 , which will likely affect the proportion of land area occupied by these crops in future. Stomatal conductance will probably be reduced at higher CO 2 concentrations reducing transpiration per unit leaf area and consequently increasing the leaf temperature. The high CO 2 is an ameliorative of the adverse effects of drought and acts by altering the plant, biochemical and molecular systems. Understanding of the direct effects of elevated CO 2 and its interactions with the other climate variables is needed in order to predict the impact of climate change scenarios on crop growth and food security in future.
Response of different agricultural plants to elevated CO2 and air temperature
The aim of this study was to estimate the response of different agricultural plants to elevated CO 2 and temperature and to check a hypothesis that current ambient CO 2 concentration is a limiting factor for growth of most agricultural species. Experiments were conducted in the chambers with a controlled climate. Seven most common agricultural crops and one weed species fat hen (Chenopodium album L.) were selected for the investigation. Dry over-ground biomass, concentration of chlorophylls and carotenoids were evaluated at the end of the experiments. The over-ground biomass of all investigated species significantly increased along with an increase in CO 2 concentrations and for most species the greatest biomass accumulation was observed at 700-1500 ppm. Response of fat hen biomass accumulation to elevated CO 2 concentration was comparatively small and statistically insignificant, indicating that for this species current CO 2 concentration is not a limiting factor. Analysis of the results on integrated impact of elevated CO 2 (700 ppm) and temperature (+4ºC) on the growth of investigated plants showed that the plant response is highly species specific. Tomato and soybean, which are considered the greatest warmth-loving plants under local climate conditions, produced the highest amount of biomass at elevated both CO 2 and temperature. For other investigated species, no positive interaction between CO 2 and temperature was detected and differences in biomass formation under elevated CO 2 alone and elevated both CO 2 and temperature ere not statistically significant.
Functional Plant Biology, 1994
A possible scenario for the end of the 21st century is that the atmospheric CO2 concentration will be in the range of 510-760 μL L-1 and that the mean global temperature will be 1.5-4.5�C higher. Further, there may be greater incidences of extreme climatic events, which together with the CO2 and temperature changes will influence development, growth and grain yield of cereals such as rice and wheat. For these C3 plants, the driving force for the growth response to elevated CO2 is higher leaf CO2 assimilation rates (A). However, the response of A to CO2 depends on temperature with maximum absolute increases occuring at temperatures which do not cause flower abortion, while negligible increases are observed at low temperatures. At high temperatures, where A is reduced because of partial inactivation of photosynthetic enzymes, the increase in A due to CO2 enrichment is still observed. Other factors, such as changes in shoot water relations or hormone concentrations, may influence growt...
Global Change Biology, 1999
The microclimate in facilities for studying effects of elevated CO 2 on crops differs from ambient conditions. Open-top chambers (OTCs) increase temperature by 1-3°C. If temperature and CO 2 interact in their effect on crops, this would limit the value of OTC experiments. Furthermore, interaction of CO 2 and temperature deserves study because increases in atmospheric CO 2 concentration are expected to cause global warming. This paper describes two experiments in which a recently developed cooling system for OTCs was used to analyse the effects of temperature on photosynthesis, growth and yield of spring wheat (Triticum aestivum L., cv. Minaret). Two levels of CO 2 were used (350 and 700 ppm), and two levels of temperature, with cooled OTCs being 1.6-2.4°C colder than noncooled OTCs. Photosynthetic rates were increased by elevated CO 2 , but no effect of temperature was found. Cross-switching CO 2 concentrations as well as determination of A-C i curves showed that plant photosynthetic capacity after anthesis acclimated to elevated CO 2 . The acclimation may be related to the effects of CO 2 on tissue composition: elevated CO 2 decreased leaf nitrogen concentrations and increased sugar content. Calculations of the seasonal mean crop light-use efficiency (LUE) were consistent with the photosynthesis data in that CO 2 increased LUE by 20% on average whereas temperature had no effect. Both elevating CO 2 and cooling increased grain yield, by an average of 11% and 23%, respectively. CO 2 and temperature stimulated yield via different mechanisms: CO 2 increased photosynthetic rate, but decreased crop light interception capacity (LAI), whereas cooling increased grain yield by increasing LAI and extending the growing season with 10 days. The effects of CO 2 and temperature were not additive: the CO 2 effect was about doubled in the noncooled open-top chambers. In most cases, effects on yield were mediated through increased grain density rather than increased individual grain weights.