Characterization and Quantification of Intrinsic Ice Nucleators in Winter Rye (Secale cereale) Leaves

摘要: Extracellular ice formation in frost-tolerant organisms is often initiated at specific sites by nucleators. In this study, we examined nucleation activity (INA) the plant winter rye (Secale cereale). Plants were grown 20[deg]C, 5[deg]C with a long day, and short day (5[deg]C-SD). The threshold temperature for INA was -5 to -12[deg]C leaves from all three growth treatments. Epiphytic nucleation-active bacteria could not account observed leaves. Therefore, must have been produced endogenously. Intrinsic nucleators quantified characterized using single mesophyll cell suspensions obtained pectolytic degradation of most active exhibited -7[deg]C occurred infrequently rate one nucleator per 105 cells. Rye cells treated chemicals enzymes characterize nucleators, which proved be complexes proteins, carbohydrates, phospholipids, both disulfide bonds free sulfhydryl groups important activity. Carbohydrates phospholipids components derived 20[deg]C leaves, whereas protein component more 5[deg]C-SD This difference composition or structure combined tendency frequent INA, suggests that are These additional may mechanism freezing tolerance rye.