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.Additional key words: Brassica Campestris L., climate change, nutrient uptake rate, phytotron, Raphanus sativus L.
The cultural practice of removal of the secondary-lateral branch of watermelon during the production in greenhouse requires intensive input of human labor. Secondary-lateral branch removal practices were examined in horizontally trained two watermelon cultivars (Citrullus lanatus), 'Sambock-gul' and 'Speed-honey' to determine the comparative differences in labor input as well as to understand their impact on plant and fruit growth and fruit sugar accumulation. Two experiments were conducted. Experiment 1 consisted of two treatments for plants trained with one main stem and two lateral branches: removal of the entire secondary-lateral branch or removal of the secondary-lateral branch below the fruit set node (partial removal). Experiment 2 consisted of three treatments for plants trained with either two or three lateral branches after topping the main stem: removal of the entire secondary-lateral branch, removal of the secondary-lateral branch below fruit set node, or removal of the secondary-lateral branch below the 5th node above fruit set node. Results showed that removal of the secondary-lateral branch below the fruit set node lowered human labor input by 50% compared with removal of the entire secondary-lateral branch. Additionally, some physiological benefits were also found for the plant treated by partial removal of the secondary-lateral branch. While fruit growth rate and fruit sucrose accumulation were much slower than those under other treatments until 3 weeks after pollination, 4 weeks after pollination sucrose accumulation started to increase steeply, and reached the highest concentration observed, 18.2 mg mL -1 . A greater increase in the length of fine roots, 0.2 mm in diameter, was observed under the partial removal treatment than for the entire removal treatment. During the fruit ripening period, the younger and developing leaves on secondary-lateral branches had a higher growth rate and higher photosynthetic activity than those of leaves on lateral branches. The integrated data indicate that active leaves on the secondary-lateral branch are likely to compete with the fruit as a sink during the fruit growing period, leading to slow fruit growth. However, during fruit ripening, the leaves on the secondary-lateral branch are likely to become a supportive source of carbon, leading to enhancement of sucrose accumulation in fruit.
Employing statistical design of experiments, we have performed studies on the characterization of electrodes using TiO 2 and process variables in the fabrication process of nanocrystalline dye sensitized solar cell. Systematic experiment to identify the effects of process variables on cell's efficiency has based on broad-band absorption of light by tailor made organometallic dye molecules dispersed on a high surface of TiO 2 . Employing statistical design of experiment on TiO 2 photoelectrode forming process, structural characterization of electrodes and process variable have been investigated. Through the statistical analysis we have found that the particle size of TiO 2 and the amount of PEG/PEO are significantly affecting on the cell efficiency. In addition, a significant amount of interaction exists between the particle size and the amount of PEG/PEO.
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