The Effects of Increased Atmospheric Carbon Dioxide on Growth, Carbohydrates, and Photosynthesis in Radish, Raphanus sativus (original) (raw)
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Polish Journal of …, 2006
The objective of this study was to evaluate the effect of different CO 2 concentrations on carbohydrate, chlorophyll contents and net photosynthetic productivity in radish (Raphanus sativus L., cv. Žara) leaves. Plants were exposed to 350, 700, 1,500 and 3,000 ppm atmospheric CO 2 concentrations over ten days. Day/ night temperature was 24°C/17°C and photoperiod was 16 h. Carbohydrate (fructose, glucose, sucrose and maltose) content analysis was performed using chromatographic methods. The content of chlorophyll was evaluated spectrophotometrically. The results showed that elevated CO 2 increases total carbohydrate content and changes in hexoses/sucrose ratio. A significant increase in chlorophyll content was only in 1,500 ppm treatment. Differences in photosynthetic productivity rate were within error margins. There was no effect on carbohydrate and chlorophyll contents in radish leaves seven days after returning plants to ambient CO 2 , though higher photosynthetic productivity rate was in radish, previously grown under 700 ppm CO 2 . In summary, leaf carbohydrate contents affect the intensity of photosynthetic pigment synthesis.
The effects of CO2 on growth and transpiration of radish (Raphanus sativus) in hypobaria
Advances in Space Research, 2010
Plants grown on long-term space missions will likely be grown in low pressure environments (i.e., hypobaria). However, in hypobaria the transpiration rates of plants can increase and may result in wilting if the water is not readily replaced. It is possible to reduce transpiration by increasing the partial pressure of CO 2 (pCO 2 ), but the effects of pCO 2 at high levels (>120 Pa) on the growth and transpiration of plants in hypobaria are not known. Therefore, the effects of pCO 2 on the growth and transpiration of radish (Raphanus sativus var. Cherry Bomb II) in hypobaria were studied. The fresh weight (FW), leaf area, dry weight (DW), CO 2 assimilation rates (C A ), dark respiration rates (DR), and transpiration rates from 26 day-old radish plants that were grown for an additional seven days at different total pressures (33, 66 or 101 kPa) and pCO 2 (40 Pa, 100 Pa and 180 Pa) were measured. In general, the dry weight of plants increased with CO 2 enrichment and with lower total pressure. In limiting pCO 2 (40 Pa) conditions, the transpiration for plants grown at 33 kPa was approximately twice that of controls (101 kPa total pressure with 40 Pa pCO 2 ). Increasing the pCO 2 from 40 Pa to 180 Pa reduced the transpiration rates for plants grown in hypobaria and in standard atmospheric pressures. However, for plants grown in hypobaria and high pCO 2 (180 Pa) leaf damage was evident. Radish growth can be enhanced and transpiration reduced in hypobaria by enriching the gas phase with CO 2 although at high levels leaf damage may occur.
Physiologic and metabolic responses of wheat seedlings to elevated and super-elevated carbon dioxide
Advances in Space Research, 2008
The metabolic consequence of suboptimal (400 lmol mol À1 or ppm), near-optimal (1500 ppm) and supra-optimal (10,000 ppm) atmospheric carbon dioxide concentrations [CO 2 ] was investigated in an attempt to reveal plausible underlying mechanisms for the differential physiological and developmental responses to increasing [CO 2 ]. Both non-targeted and targeted metabolite profiling by GC-MS and LC-MS were employed to examine primary and secondary metabolites in wheat (Triticum aestivum, cv Yocoro rojo) continuously exposed to these [CO 2 ] levels for 14, 21 and 28 days. Metabolite profile was altered by both [CO 2 ] and physiological age. In general, plants grown under high [CO 2 ] exhibited a metabolite profile characteristic of older plants under ambient CO 2 . Elevated [CO 2 ] resulted in higher levels of phosphorylated sugar intermediates, though no clear trend in the content of reducing sugars was observed. Transient starch content was enhanced by increasing [CO 2 ] to a much greater extent at 10,000 ppm CO 2 than at 1500 ppm CO 2 . The percentage increase of starch content resulting from CO 2 enrichment declined as plants develope. In contrast, elevated [CO 2 ] promoted the accumulation of secondary metabolites (flavonoids) progressively to a greater extent as plants became mature. Elevated [CO 2 ] to 1500 ppm induced a higher initial growth rate, while super-elevated [CO 2 ] appeared to negate such initial growth promotion. However, after 4 weeks, there was no difference in vegetative growth between 1500 and 10,000 ppm CO 2 -grown plants, both elevated CO 2 levels resulted in an overall 25% increase in biomass over the control plants. More interestingly, elevated atmospheric [CO 2 ] reduced evapotranspiration rate (ET), but further increase to the supra-optimal level resulted in increased ET (a reversed trend), i.e. ET at 1500 ppm < ET at 10,000 ppm < ET at 400 ppm. The differential effect of elevated and super-elevated CO 2 on plants was further reflected in the nitrogen dynamics. These results provide the potential metabolic basis for the differential productivity and stomatal function of plants grown under elevated and super-elevated CO 2 levels.
Biologia Plantarum, 2007
The effect of elevated carbon dioxide concentration on the changes in the biomass, photosynthesis and nutrient composition was investigated in two leafy vegetables. Spinach (Spinacia oleracea L.) and fenugreek (Trigonella foenum-graecum L.) plants were grown in open top chambers under either ambient (ACO 2 , 350 ± 50 µmol mol -1 ) or elevated (ECO 2 , 600 ± 50 µmol mol -1 ) CO 2 concentration and analyzed 40, 60 and 80 days after exposure. The plants grown in ECO 2 had higher net photosynthetic rate and lower stomatal conductance when compared with the plants grown in ACO 2 . ECO 2 also changed the nutrient composition: a lower N, Mg and Fe contents and higher C and Ca contents were observed in the leaves of plants exposed to ECO 2 than in those grown at ACO 2 .
Horticulture, Environment, and Biotechnology, 2011
Future forecasts for climate change predict the global mean surface air temperature rise by 1 -4 and double current atmospheric CO2 level before the end of 21 century. Increased atmospheric temperature and CO2 concentration are particularly important concerns for agricultural, horticultural and native plant production. In this study, effects of long-term exposure to elevated temperature and carbon dioxide (CO2) on the growth and physiological responses of 3 cultivars of Chinese radish (Raphanus sativus L.) and 3 cultivars of Chinese cabbage (Brassica campestris L.) were examined. In result, the radishes exposed to elevated CO2 for 90 days after sowing (DAS) resulted in little or no change in the root dry weights and the rate of photosynthesis compared with those grown in ambient levels of CO2. In contrast, long-term exposure to elevated CO2 in cabbage had variable effects on the leaf dry weight. As a result of acclimating to the elevated temperature, the radish 'Chunha' had a higher rate of photosynthesis, stomatal conductance and internal CO2 concentration than in the control condition. Furthermore, the long-term exposure to a combination condition of elevated temperature and CO2 increased root dry weights of the radishes 'Cheongdae' and 'Chunha' more than elevated temperature alone. The combination of elevated CO2 and temperature stimulated the growth of roots more than that of shoots in the radish 'Chunha', and thus may have led a higher rate of nutrient uptake than other radish cultivars. In contrast, when the cabbage 'Chun-gwang' was exposed to a combination of elevated temperature and CO2 for 90 DAS, the leaf dry weight decreased about 3-fold more than that only exposed to elevated CO2 with drastic decreases in stomatal conductance, internal CO2 and photosynthesis rate. When the cabbage 'Samjin' was exposed to either elevated temperature alone or both elevated temperature and CO2 for 80 DAS, the decrease in the leaf dry weight was less than that of the other cabbage cultivars. Results indicated that the radish 'Chunha' and the cabbage 'Samjin' tolerated either elevated temperature alone or combination condition of elevated temperature and CO2 more than other cultivars.
2002
We evaluated the effects of an elevated [CO 2 ] on photosynthesis and growth of cassava plants grown in open-top chambers with an adequate supply of water and N and a sufficient rooting volume. Cassava plants (Manihot esculenta Crantz. cv. Motilona) showed higher photosynthetic rates (P n ) when grown and measured at elevated [CO 2 ] (680 µmol mol -1 ) than when grown and measured at ambient [CO 2 ] (480 µmol mol -1 ). No downregulation of photosynthesis due to elevated [CO 2 ] was found, since carboxylation efficiency increased after 220 d in spite of a decrease in leaf soluble protein, Rubisco, and leaf N content. Soluble sugar and starch contents decreased with time under elevated [CO 2 ], the decrease in starch content coinciding with the beginning of the increase in root mass. Canopy P n by leaf area decreased with time under elevated [CO 2 ] but, when canopy P n was expressed by ground area, higher and constant rates were observed, suggesting a higher productivity in plants grown at elevated [CO 2 ]. The absence of differences between growth [CO 2 ] in root:shoot ratio observed suggests that elevated [CO 2 ], while causing increases in the shoot as well as the root, did not affect the pattern of biomass allocation. Acclimation responses of gas exchange parameters changed during the experiment. The absence of downregulation of photosynthesis was associated with a decrease in leaf sugar and starch contents of plants grown at elevated [CO 2 ], which suggests a favourable source/sink relationship.
Australian Journal of Botany, 1992
An analysis of elevated CO 2 effects (2-4 times ambient) on dark respiration rate and carbon content was undertaken for a wide range of plant species, using both published reports and new data. On average, leaf respiration per unit leaf area was slightly higher for plants grown at high CO 2 (16%), whereas a small decrease was found when respiration was expressed on a leaf weight basis (14%). For the few data on root respiration, no significant change due to high CO 2 could be detected. Carbon content of leaves and stem showed a small increase (1.2 and 1.7% respectively), whereas C-content of roots was not significantly affected. In both data sets direction of responses was variable. A sensitivity analysis of carbon budgets under elevated CO 2 identified changes in respiration rate, and to a lesser extent carbon content, as important factors affecting the growth response to elevated CO 2 in quite a number of cases. Any comprehensive analysis of growth responses to increased CO 2 should therefore include measurements of these two variables.
Responses of plants to the rising concentration of atmospheric carbon dioxide : An analysis
2006
The impact of rising concentration of atmospheric CO2 on the productivity of crop plants was studied using Open Top Chamber (OTC) and Free Air CO2 Enrichment (FACE) technologies, established under National Fellow Project at Indian Agricultural Research Institute, New Delhi. These investigations led to the establishment of South Asian CO2 research network of Bangladesh, Nepal, Sri Lanka, Pakistan and India to study the effect of elevated level of CO2 on the productivity of cereals, pulses and oil seeds. Indian studies revealed that elevated CO2 significantly ameliorated the effect of adverse drought stress in Brassica species. It also demonstrated the possibility of transferring CO2 responsive characters in Brassica hybrids. The data generated from these investigations may possibly help in developing plant type and identifying a suitable crop management system for future high CO2 environment. !IIfflicHI cnfi':rr ct't ww:rr Cf)f \iFf q IdIq {O I if '!fH ~ f)-ffi ct't% ...
Journal of Plant Physiology, 1985
When grown for six weeks in a CO 2 enriched atmosphere (1150 microlitres per litre) dwarf cucumber plants (Cucumis sativus L. cv. Spacemaster) showed enhanced rates of development in the form of longer internodes, more male flowers, more leaves and more dry matter than plants grown under ambient (330 microlitres per litre) CO2 levels. Under CO2 enrichment there was an increase in leaf area and dry weight per unit leaf area, the latter being attributable to increased starch levels in the leaves. The pool sizes of key transport sugars (i.e., stachyose, verbascose, raffinose, and sucrose) were similar in leaves of plants grown under the different levels of CO 2. However, in leaves of CO 2 enriched plants the amino acid pool sizes, particularly those of glycine and serine were lower. Following 14C02 pulse-labelling of source leaves of similar morphological age proportionally less 14C was recovered in starch under high CO 2 while more of the currently labelled photosynthate appeared to be exported. The endogenous level of starch was higher in leaves of plants grown under CO2 enrichment, and although the pool sizes of the key transport sugars remained constant during the chase period, a greater proportion of the recently-fixed 14C was channeled into the transport sugars under high CO 2. The distribution of 14C in petiole extracts and phloem exudates of the feed leaves showed a similar increase of label in transport sugars, such as stachyose, and a decline in the amino acids, particularly glycine and serine. Taken together the data indicate that CO2 enrichment not only altered photoassimilate partitioning in the leaves, but also altered the nature of the metabolites exported. I) This research was supported by grants from the Natural Sciences and Engineering Research Council of Canada and the Ontario Ministry of Agriculture and Food (B.G.) and was carried out during tenure of an Ontario Graduate Scholarship (M.M.). 2