• Journal of Korean Society of Forest Science
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• v.99 no.6
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• pp.922-928
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• 2010

There is a little information on the effect of calcium cloride ($CaCl_2$) which is used as deicing salt in Korea on the physiological responses of the street trees. Prunus sargentii is one of the most widespread tree species of street vegetation in Korea. In this study, the effect of $CaCl_2$ on photosynthetic apparatus such as chlorophyll fluorescence image and light response curve of P. sargentii in relation to their leaf and root collar growth responses were investigated. To study the effect of $CaCl_2$ treatment in the early spring, we irrigated twice in rhizosphere of P. sargentii (3-year-old) planted plastic pots with solution of 0.5%, 1.0%, 3.0% $CaCl_2$ concentration before leaf expansion. Results after treatments, total chlorophyll contents and the chlorophyll a/b, photosynthetic rate, quantum yield, dark respiration decreased with increasing $CaCl_2$ concentration. On the contrary, light compensation point increased with increasing $CaCl_2$ concentration. Through the linear regressions of correlation of photosynthetic rate with photosynthetic parameters (quantum yield, dark respiration and light compensation point), we found a significant relationship (p<0.05) between photosynthetic rate and quantum yield and light compensation point except dark respiration. Calcium cloride ($CaCl_2$) induced inhibition of photochemical efficiency ($F_v/F_M$) and non-photochemical quenching (NPQ) were found in treatments of $CaCl_2$, and these reduction rates between control and CaCl2 treatments were drastically showed at 80 days. We suggest that physiological activities are limited from treatment of $CaCl_2$. These reductions of photosynthetic apparatus ability caused eventually the reduction of leaf and diameter at root collar growth.

• Korean Journal of Environmental Biology
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• v.22 no.4
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• pp.537-542
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• 2004

To reveal the relationship between the changes in the growth and photo- synthesis induced by low dose radiation, red pepper (Capsicum annuum L.) plants were serially irradiated three times with gamma rays of 0.5, 1, 2, 3, and 4 Gy. The plant growth was monitored by the fresh weight, the stem length, and the leaf length & width. All the irradiation groups (0.5-4 Gy) were stimulated in growth at 1 day after the $1^{st}$ irradiation (DA1I), but rather inhibited at 3 days after the $3^{rd}$ irradiation (DA3I). The maximum photochemical efficiency (Fv/Fm), the photochemical quenching (qP), the non-:photochemical quenching (NPQ) and the apparent rate of the photosynthetic electron transport (ETR) were used to represent the changes in the photosynthesis by the serial irradiation. The irradiation groups except 0.5 Gy had higher Fv/Fm values at 3 DA3I than the control one. After the 3$^{rd}$ irradiation, the qP values appeared to be a little lower in the 1-4 Gy groups than in the control and 0.5 Gy ones. In contrast, the NPQ values were rather higher in the irradiation groups except 0.5 Gy. During the whole experimental period, the ETRs decreased in the control group but remained relatively constant in the 4-Gy one. In conclusion, the results obtained indicate that the stimulatory effect of ionizing radiation on the plant growth was determined by the incident dose of the single irradiation rather than by the cumulative one of the serial irradiation. They also demonstrate that the growth stimulation induced by a low dose radiation could not be positively correlated with an alteration in the photosynthesis. Additionally, we discuss in text that an ionizing radiation may partly protect the leaf senescence by delaying the development of the plants.

• Journal of agriculture & life science
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• v.53 no.6
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• pp.13-21
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• 2019

The influences of light generated by LEDs on shoot growth and photosynthesis of Tea plant(Camellia sinensis L.) were evaluated. The growth characteristics were investigated after 45 days of culture under four different light qualities: fluorescent lamp, red LED, blue LED, red+blue+white LED. Shoot growth was promoted by red light, especially root length and area were further promoted under the red+blue+white LED. Also, T/R ratio and Chlorophyll content were highest in red+blue+white. Fluor Cam was used to measure the fluorescence images of the plants, inhibition of photochemical efficiency(Fv/Fm) were not changed in all treatment. However, non-photochemical quenching(NPQ) were found rapidly increasing in blue LED, these results were that blue LED were inhibit photosynthetic efficiency and must be considered for efficiently in vitro cultivation of the tea plant. The above results suggest that light qualities could be an important factor to foster in vitro growth of the species. Also, In order to produce healthy plants, it is effective to using light qualities of red+blue+white LED on in vitro culture of the tea plant. These results could be used to mass propagating shoot and produce of healthy seedling.