• Korean journal of applied entomology
• /
• v.19 no.4 s.45
• /
• pp.234-238
• /
• 1980

The relationships between the mean degree of hyphal growth in the leaf sheath and percent penetration in the leaf epidermis within the same predisposing temperature regime were highly significant. A positive relationship was found between degree of hyphal growth in the leaf sheath and Percent Penetration in the leaf epidermis.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.228-228
• /
• 2017

Rice production and quality could be changed by temperature condition. Extremely high temperature event have been occurred more frequently for global warming. To increase rice quality against to global warming, breeding of heat tolerance rice cultivar is needed. Ilmi which is the one of Korean leading rice cultivar shows heat stress resistant character during ripening stage. Yield and quality (brown and milled rice) of Ilmi did not show significant different under high temperature condition compared to control condition. However, the main physiological characters for heat resistance of Ilmi have been not investigated yet. Therefore we try to investigate the heat tolerance characters of Ilmi. Two rice cultivars, Ilmi and Ilpum-which is heat susceptible rice cultivar, were cultivated under natural condition in wagnor pot until heading was appeared. After checking heading date, each material was cultivated under different temperature condition, heat($32/22^{\circ}C$) and control($26/16^{\circ}C$) condition. Anti-oxidant enzyme activity was checked during ripening stage in each material. Catalase and ascorbic peroxidase activity of leaf under heat stress condition were higher in Ilmi than Ilpum especially early ripening stage. Analyzing of stress resistance using $H_2O_2$, the flag leaf of Ilmi showed more green color than Ilpum with higher chlorophyll content than those of Ilpum. We also checked the amount of $H_2O_2$ content in young leaf of each material by treating high temperature. $H_2O_2$ content in each material was increased according to treatment time. However $H_2O_2$ content of young leaf in Ilmi was less than those in Ilpum. Also catalase and ascorbic peroxidase activity in leaf increased much faster in Ilmi than Ilpum. With those data, we confirmed that heat stress resistance of Ilmi is due to the higher anti-oxidant activity against to stress condition. We will investigate the heat tolerance characters of Ilmi more in further study to enhance the breeding effect of heat stress tolerance rice.

• Korean Journal Plant Pathology
• /
• v.3 no.2
• /
• pp.93-99
• /
• 1987

Six rice cultivars showing various types of resistance or susceptibility to Pyricularia oryzae in the field were used to study the relationship between susceptibility and contents of carbohydrates, amino acids and phenolics at different plant maturities and leaf ages under controlled environmental conditions. No consistent differences between the susceptible cultivars and adult-plant-resistant cultivars were found in terms of the contents of individual carbohydrates, total amino acids and phenolics in rice leaves throughout the plant development. Only the adult-plant-resistant cultivar Dobong had lower contents of inositol throughout the plant development than the other cultivars. The amounts of sucrose, inositol, glucose, and fructose increased in all tested cultivars at eight leaf stage than those at five leaf stage, but slightly decreased at twelve leaf stage. In contrast, total amino acids and phenolics gradually decreased during plant development. With increasing age of rice leaves, the amounts of total soluble amino acids and phenolics gradually increased in healthy fifth leaf tissues, although there were no significant differences between the cultivars. In particular, a high level of phenolics existed in old fifth leaves of the cultivar Dobong. These results suggest that increased resistance to blast of matured rice plants and old leaves may be the two different phenomina derived from the physiological changes occurring during plant development and leaf senescence, probably functioning differently in P. oryzae development.

• Journal of Crop Science and Biotechnology
• /
• v.10 no.1
• /
• pp.39-44
• /
• 2007

The effect of inabenfide was investigated in rice seedlings subjected to salt stress in relation to changes in chlorophyll fluorescence(${\Delta}F/Fm'$), lipid peroxidation, salicylic acid(SA) content, and catalase(CAT) activity. A reduction in shoot growth of rice seedlings by 120 mM NaCl treatment was significantly alleviated by pretreatment with 30 ${\mu}M$ inabenfide. Sodium ion content was not affected by pretreatment with inabenfide, suggesting that alleviation was not due to a reduction in sodium ion uptake by the rice seedlings. At three days after NaCl treatment, the rice seedlings pretreated with inabenfide showed a higher ${\Delta}F/Fm'$(30%) and lower lipid peroxidation(28%) compared with the rice seedlings treated with NaCl alone. After NaCl treatment, CAT activity in the third leaf of rice seedlings decreased significantly but alleviated by pretreatment with inabenfide. Furthermore, pretreatment with inabenfide also reduced the level of SA which accumulated drastically in the third leaf of rice seedlings within a day after exposure to salt stress. These results suggest that inabenfide prevents SA accumulation in rice seedlings under salt stress which eventually induces the alleviation of salt stress damage.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.24 no.4
• /
• pp.19-25
• /
• 1979

Lowland and upland rice were grown under the both of lowland and upland conditions. Ecological variations in plant characteristics such as plant height, leaf emergence, length of leaf blade, leaf angle, leaf width, heading date, culm length, panicle length and straw weight were observed. Plant height, leaf emergence and heading were accelerated under the lowland condition for both lowland and upland varieties, while leaf length, leaf angle, leaf breadth, number of leaves were increased in upland condition for both lowland and upland varieties.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.47 no.4
• /
• pp.301-304
• /
• 2002

The variation of alternative and cytochrome respiration during ripening in rice leaves (Oryza sativa L. cv. Takanari) was examined. The capacity of both respiration pathway was measured by inhibitor titration method using gas-phase oxygen electrodes. The alternative respiration rate decreased from 31.3% of the total respiration rate at around heading to 11.7% at 34 days after heading in the first fully expanded leaf from the top, and further to 6.4 % at 34 days after heading in the fourth leaf from the top. In contrast, the proportion of cytochrome respiration to total respiration increased with leaf senescence. The possible cause of alternative respiration as either an increase in inefficient respiration or a decrease in growth efficiency during ripening was discussed.

• Journal of the East Asian Society of Dietary Life
• /
• v.14 no.4
• /
• pp.379-386
• /
• 2004

Jeung-Pyun is a traditional Korean fermented rice cake leavened by yeast. To develop a functional Jeung-Pyun, mulberry leaf(ML) were added to the rice at the levels of 0, 2, 4, 6, 8%, respectively. Physicochemical, sensory, texture and surface characteristics of Jeung-Pyun were examined. The specific volumes of all the Jeung-Pyun's with ML were significantly lower than that of control(0% ML) and 4% ML sample showed the highest volume among them. The pH of ML Jeung-Pyun batters decreased with fermentation time. Overall quality of Jeung-Pyun with ML obtained lower value than the control. Among the texture properties measured with rheometer, hardness, cohesiveness, gumminess and brittleness of ML Jeung-Pyun decreased according to the amount ML added and springiness was not significantly different. The surface structure by SEM showed that Jeung-Pyun added with 4% ML had the largest and the most uniform air cells. In conclusion, the most acceptable concentrations of ML on the basis of overall quality in sensory evaluation and physicochemical characteristics were 2% or 4%.

• Bulletin of the Korean Chemical Society
• /
• v.6 no.4
• /
• pp.228-230
• /
• 1985

(Z)-13-Octadecen-1-yl acetate, the pheromone mimic of the Rice Leaf Folder Moth, Cnaphalocrosis medinalis, was synthesized from 1,13-tridecanediol in three steps. Monoacetylation of 1,13-tridecanediol followed by PCC oxidation gave 13-acetoxytridecan-1-al. Wittig olefination of the 13-acetoxytridecan-1-al with pentylidenetriphenylphosphonium ylide afforded (Z)-13-octadecen-1-yl acetate, the pheromone mimic of the Rice Leaf Folder.

• Korean Journal of Soil Science and Fertilizer
• /
• v.48 no.5
• /
• pp.397-403
• /
• 2015

Heavy metals reduce the photosynthetic efficiency and disrupt metabolic reactions in a concentration-dependent manner. Moreover, by replacing the metal ions in metalloproteins that use essential metal ions, such as Cu, Zn, Mn, and Fe, as co-factors, heavy metals ultimately lead to the formation of reactive oxygen species (ROS). These, in turn, cause destruction of the cell membrane through lipid peroxidation, and eventually cause the plant to necrosis. Given the aforementioned factors, this study was aimed to understand the physiological responses of rice to cadmium (Cd) and arsenic (As) toxicity and the effect of essential metal ions on homeostasis. In order to confirm the level of physiological inhibition caused by heavy metal toxicity, hydroponically grown rice (Oryza sativa L. cv. Dongjin) plants were exposed with $0-50{\mu}M$ cadmium (Cd, $CdCl_2$) and arsenic (As, $NaAsO_2$) at 3-leaf stage, and then investigated malondialdehyde (MDA) contents after 7 days of the treatment. With increasing concentrations of Cd and As, the MDA content in leaf blade and root increased with a consistent trend. At 14 days after treatment with $30{\mu}M$ Cd and As, plant height showed no significant difference between Cd and As, with an identical reduction. However, As caused a greater decline than Cd for shoot fresh weight, dry weight, and water content. The largest amounts of Cd and As were found in the roots and also observed a large amount of transport to the leaf sheath. Interestingly, in terms of Cd transfer to the shoot parts of the plant, it was only transported to upper leaf blades, and we did not detect any Cd in lower leaf blades. However, As was transferred to a greater level in lower leaf blades than in upper leaf blades. In the roots, Cd inhibited Zn absorption, while As inhibited Cu uptake. Furthermore, in the leaf sheath, while Cd and As treatments caused no change in Cu homeostasis, they had an antagonist effect on the absorption of Zn. Finally, in both upper and lower leaf blades, Cd and As toxicity was found to inhibit absorption of both Cu and Zn. Based on these results, it would be considered that heavy metal toxicity causes an increase in lipid peroxidation. This, in turn, leads to damage to the conductive tissue connecting the roots, leaf sheath, and leaf blades, which results in a reduction in water content and causes several physiological alterations. Furthermore, by disrupting homeostasis of the essential metal ions, Cu and Zn, this causes complete heavy metal toxicity.

• Korean Journal of Organic Agriculture
• /
• v.18 no.2
• /
• pp.199-208
• /
• 2010

To investigate a comparison of rice yield and quality between organic and conventional cultivation, study for occurrence of rice diseases carried out in rice (Oryza sativa L.) field of Noahn and Bannam region. The results obtained as following: 1) Bactericide and insecticide were applied twice and four times at Noahn and Bannam region in conventional cultivation (C.C) of rice field, respectively, it was applied twice at two region in organic cultivation (O.C). Rice strip virus, leaf blast, neck blast, sheath blight, bacterial leaf blight, rice water weevil, rice leaf folder, and plant hoppers were occurred mainly in rice field. Leaf blast, neck blast, and rice leaf folder were occurred highly at O.C compared with C.C. 2) Growth level of rice in clum and panicle length was lower at O.C than C.C. Number of panicles per hill was by 0.6 higher at O.C than C.C. Number of panicles per hill was by 0.6 higher at O.C than C.C in Noahn region. Number of spikelets per panicle, grain filling ratio, brown/rough rice ratio, and weight of 1,000 grains was lower at O.C than C.C. Number of panicles per hill was by 0.8 lower at O.C than C.C in Bannam region. Number of spikelets per panicle and grain filling ratio was higher at O.C than C.C while brown/rough rice ratio was lower at O.C. Total yield percentage of rice in O.C was level of 84% at Noahn region and 94% at Bannam region compared with C.C. 3) Head rice percentage was lower at in O.C than C.C at two region. Protein and palatability (Toyo value) were lower at O.C than C.C in Bannam region causing occurrence of neck blast and rice leaf folder by oversupply of nitrogen fertilizer. Protein, whiteness, and palatability (Toyo value) were adequate level at O.C in Noahn region by lower nitrogen fertilizer.