Paper Title
Effect of Chitosan as Seed Soaking on Enzyme Activity and Germination of Rice Under High Day/Night Temperature

Abstract
Chitosan can stimulate seed germination and trigger plantimmune system under unfavorable condition. This work was aimed to study effect of chitosan on seed germination and enzyme activities during seed germination of three rice varieties under differentday/night temperatures. The experimental design was 2x3x2 Factorial in CRD withtwo types of day/night temperature (30/24, 35/30 °c) as factor A,three rice varieties (Pathum Thani 1 (PPT1), Suphan Buri1(SPB1) and RD 47 as factor B and two applications of seed soaking (seeds soaked with chitosan and seeds soaked with water) as factor C. The results indicated that high day/night temperature significantly reduced seed germination and shoot length.RD 47 variety showed the highest germination percentage and shoot length whereas PPT1 variety had less injury percentage than the others but SPB1 variety showed the highest POD (Peroxidase) and CAT (Catalase) activities during seed germination. Application of chitosan as seed soaking reducedseed injury and increased PODactivity during seed germination. Index Terms - Chitosan, rice seed germination, enzyme activity, high day/night temperature