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.

ABSTRACT
Ⅰ. INTRODUCTION
Ⅱ. MATERIALS AND METHODS
    1. Plant culture and treatments
    2. Determination of lignin content
    3. Lignification-related enzyme activity
    4. Carbohydrate analysis
    5. Statistical analysis
Ⅲ. RESULTS
    1. Relative water content (RWC) and biomass
    2. Lignin concentration and activities of lignificationrelatedenzymes
    3. Soluble sugar and fructan concentration
Ⅳ. DISCUSSION
Ⅴ. ACKNOWLEGEMENT
Ⅵ. REFERENCES

• Dae-Hyun Kim(Department of Animal Science, College of Agriculture & Life Sciences, Chonnam National University, Gwangju 61186, Republic of Korea)
• Bok-Rye Lee(Department of Animal Science, College of Agriculture & Life Sciences, Chonnam National University, Gwangju 61186, Republic of Korea)
• Sang-Hyun Park(Department of Animal Science, College of Agriculture & Life Sciences, Chonnam National University, Gwangju 61186, Republic of Korea)
• Tae-Hwan Kim(Department of Animal Science, College of Agriculture & Life Sciences, Chonnam National University, Gwangju 61186, Republic of Korea) Corresponding author