差示扫描量热法在稗草种子灭活中的应用

Study on Inactivation of Barnyard-grass Seed by DSC

[目的]为了减少热除草设备的能耗、提高工作效率,研究稗草种子灭活的升温速率和最高温度。[方法]采用差示扫描量热法(DSC),研究了升温速率和最高温度对稗草种子玻璃化转变的影响。同时,对加热后的种子进行发芽率试验。[结果]升温速率是影响稗草种子玻璃化转变的重要因素。升温速率为5 K/min时,玻璃化转变不明显;升温速率为20 K/min时,玻璃化转变明显,玻璃化温度为75.9℃;升温速率增加到25 K/min时,玻璃化转变滞后,玻璃化转变温度为80.2℃。对加热后的种子进行发芽率试验,发现玻璃化转变是种子退化的重要原因。升温速率为5 K/min、最高温度为91℃时,稗草种子的发芽率为57%。而当升温速率达到20 K/min、最高温度为91℃时,种子全部丧失活性。[结论]影响杂草种子灭活的升温速率和最高温度,对于热除草设备的设计和田间作业参数设置具有重要的参考意义。

[ Objective] The heating rate and the highest temperature on inactivation of Barnyard-grass seed were studied in order to decrease energy consumption of thermal weed control equipment and improve the work efficiency. [ Method ] lhe effect of heating rate and the highest temperature on inactivation of Barnyard-grass seed was studied by differential scanning calorimetry （DSC）. Germination experinaent of Barnyard-grass seed heat treated was carried out. [ Result ] Heating rate was the main factor resulted in glass transition of Barnyard-grass seed. Glass transition was not distinct at 5 K/min heating rate. At 20 K/min heating rate, glass transition was obvious and glass transition temperature （Tg） was 75.9 ℃. However, when heating rate reached to 25 K/min, glass transition lagged and Tg was delayed to 80.2 ℃. And the glass transition plays an important role in viability loss of Barnyard-grass seed. At 5 K/min heating rate and 91 ℃ highest teroperature, germination of Barnyard-grass seed was still 57%. But when heating rate increased to 20 K/min, all of the seed lost viability at the same highest temperature. [Conclusion] The factors of weed seeds inactivation heating rate and the highest temperature have important reference value for designing thermal weeding equipment and settings operating parameters in the field.