The objective of this study was to determine effects of phosphorus on lignification and carbohydrate metabolism in Kentucky bluegrass under drought stress. Drought stress was induced by reducing of water to plants in pots. Two types of phosphorus were applied as potassium phosphate (PO4 3-; P) or potassium phosphonate (PO3 3-; PA) in drought-stressed plants. Drought had significant negative effects on plant growth, as revealed by reduced biomass of shoot. Drought-induced increase of lignin content was concomitant with the increase of phenylalanine ammonia-lyase (PAL). Soluble sugar content was highly increased but fructan content was largely decreased by drought stress. However, the application of phosphorus was efficient to ameliorate the adverse effects of drought. PA application improved reduced shoot growth and relative water content, and inhibited lignification synthesis with a reduction of PAL activity. P or PA application maintained soluble sugar and fructan content at similar levels to controls under drought stress. These results indicate that phosphorus application may mitigate the drought stress by inhibiting the lignification and promoting the fructan assimilation.

The objective of this study was to determine phosphorus effects on drought stress-induced oxidative stress in Kentucky bluegrass. Drought stress was induced by reducing of water to plants in pots. Two types of phosphorus were applied as potassium phosphate (P) or potassium phosphonate (PA). Application of phosphorus was efficient to ameliorate the adverse effects of drought. Osmotic potential, total chlorophyll and carotenoid content were significantly decreased by drought stress, but was relieved by P or PA application. Superoxide (O2 •−) concentration was significantly increased more than 14-fold under drought-stressed plants, was accompanied with increase of hydrogen peroxide (H2O2) and lipid peroxidation (MDA). However, malondialdehyde (MDA) was much less in P or PA applied plants under drought stress condition. Activities of catalase (CAT), ascorbate peroxidase (APX) and guaiacol-peroxidase (GPX) were largely increased by drought stress and its increase rate was much higher in P or PA applied plants except APX. These results indicate that drought stress-induced oxidative stress is alleviated by P or PA application due to the increase of activities of antioxidant enzymes.

The larvicidal and repellent activities of 33 plant extracts against two mosquitoes as Culex pipiens and Aedes albopictus were examined using direct contact application for larva and a patch test for adult. Chrysanthemum zawadskii var. alpinum, Cnidium officinale, Ginkgo biloba, Magnolia kobus, and Magnolia denudate at 1,000 ppm caused 100% mortality to Cx. pipiens larva within 24 hr. Ailanthus altissima, Dryopteris crassirhizoma, Houttuynia cordata, Mentha arvensis, Phyllostachys nigra, and Parthenocissus tricuspidata showed over 90% mortality to Cx. pipiens. C. zawadskii var. alpinum, C. officinale, G. biloba, M. kobus, M. denudate, and P. nigra gave 100% mortality at 1,000 ppm to Ae. albopictus. Acorus gramineus, Campanula takesimana, and D. crassirhizoma, showed 97.8%, 94.5%, and 94.4% mortality to Ae. albopictus at 24 hr, respectively. Five plant extracts (C. zawadskii var. alpinum, C. officinale, G. biloba, M. kobus, and M. denudate) showed 100% mortality both Cx. pipiens and Ae. albopictus. However, A. altissima gave 90% larvicidal activity to Cx. pipiens, whereas 7.8% mortality to Ae. albopictus. Several plant extracts which have highly larvicidal activities, were determined repellency against two mosquitoes species.

질산태 질소의 공급수준이 알팔파의 영양생장기 동안의 질소동화와 성장 및 재생기간 동안의 뿌리조직내 전분과 질소 축적에 미치는 영향을 규명하고자 0.2, 1.0 및 3.0 mM KN 하에서 10주 동안의 영양생장 후 건물 및 질소 화합물의 식물조직내의 분포를 분석하고, 24일간 1차 및 2차 재생을 각각 시킨 후 뿌리조직에 축적된 전분과 질소 함량을 분석하였다. 10간의 영양생장 후 건물과 질소화합물의 함량을 1.0 mM 처리구를 기준으로 비교한 결과,

Zoysiagrass [Zoysia marella (L.) Merr.]와 creeping bentgrass (Agrostis palustris Huds)에서 고온 스트레스에 대한 탄수화물대사 반응을 규명하기 위해 4월부터 9월까지의 식물체내의 탄수화물 대사산물의 변화를 비교 분석하였다. 각 초종의 샘플은 1998년 조성된 무안 Country Club의 green과 fairway에서 채취하였다. Creeping bentgrass의 지상부 수량은 6월부터

페레니얼 라이그라스에서 질소의 공급형태 ( or ) 및 수준 (0.2, 1.0 and 6.0mM)에 따른 질소동화와 탄수화물 대사산물에 미치는 영향을 알아보기 위해 nitrate, nitrate reductase, sugar 농도와 Fructan 농도를 조사하였다. 공급구에서 잎의 생체량은 약간 증가하다가 같은 수준으로 유지되는 반면 공급구에서는 농도가 증가함에 따라 처음수준에 비해 약 25%에서 30% 증가하였다. 공급구에서 Nitrate 농도는 Ni

To investigate the physiological responses to naturally occurring winter freezing stress in creeping bentgrass, changes in carbohydrates were monitored during winter period. Turf quality and leaf growth was nearly parallel with temperature fluctuation. Th