介质阻挡放电低温等离子体处理对小麦种子活力及幼苗生理的影响

    Wheat seed vigor and seedling physiology using dielectric barrier discharge plasmas

    • 摘要: 为揭示低温等离子体处理对小麦种子活力及幼苗生理特性的影响,该研究以济麦22、百农307为处理对象,对其进行不同时长(0、6、9、12、15 s)的介质阻挡放电(dielectric barrier discharge,DBD)低温等离子体处理,分析其对小麦种子萌发、幼苗生长、种皮形态结构、幼苗代谢生理及抗氧化性指标的影响。结果表明:以氩气为气源的DBD低温等离子体处理明显提高了小麦种子发芽率及其幼苗根苗长、鲜干重、活力指数;各处理时长条件下小麦种子吸水率均有所增加,当处理时间为9 s时,两种小麦种子的吸水率增幅最大,分别显著增加了6.4%(济麦22)、5.9%(百农307)(P<0.05);小麦种子接触角随处理时间的延长而逐渐减小,表明其润湿性能逐渐提高;处理9 s时小麦的种皮结构组织轮廓模糊,呈现明显裂纹;处理后小麦种子的新生幼苗中光合色素含量、可溶性蛋白含量均得到不同程度的增加;处理后小麦种子的新生幼苗抗氧化能力有所提高,当处理时间为9 s时,两种小麦幼苗中的丙二醛含量降幅最大,分别显著降低了15.6%(济麦22)、18.0%(百农307)(P<0.05)。因此,DBD低温等离子体有效改善了小麦种子活力及其幼苗生理特性,可作为潜在的种子强化方法用于提高作物生产中的种子质量及促进后续小麦生长。

       

      Abstract: Wheat production cannot fully meet the ever-increasing growth rate of the demand in recent years. It is of great practical significance to improve the seed quality and crop growth for high wheat yield. Currently, the commonly-used methods include the seed soaking with chemical reagent, field application of fertilizer and pesticide after seeding, and genetic improvement of crops. But all of them have some limitations. Therefore, a green and safe physical technology is required to improve the seed vigor and crop growth in production. Fortunately, dielectric barrier discharge (DBD) low-temperature plasma has been used to promote the germination and growth of vegetable seeds, particularly in the degradation of mycotoxins in agricultural products. However, little has been reported on the role in the quality of wheat seeds. This study aims to reveal the direct effects of low-temperature plasma treatment on the wheat seed vigor and seedling physiology. Jimai 22 and Bainong 307 were treated by DBD low-temperature plasma with argon as gas source. A systematic investigation was made to explore the effects of different treatment times (0, 6, 9, 12, and 15 s) on seed germination and seedling growth, morphological structure of seed coat, metabolic physiology and antioxidant activity of seedlings. The results showed that the DBD low-temperature plasma treatment significantly increased the germination rate of wheat seeds, seedling root length, fresh dry weight and vigor index. The water absorption rate of wheat seeds increased under all treatment time conditions. The water absorption of wheat seeds increased by 6.4% (Jimai 22) and 5.9% (Bainong 307), respectively (P<0.05), when the treatment time was 9 s. The contact angles of wheat seeds decreased gradually with the increase of treatment time, indicating the increasing wettability of wheat seed. Once treated for 9 s, the structure of seed coat was blurred with the outstanding cracks. There was the increase in the content of photosynthetic pigments and soluble proteins in the newborn seedlings of wheat seeds after treatment. The total chlorophyll contents in the seedlings significantly increased by 7.1% (Jimai 22) and 11.4% (Bainong 307) at the treatment time of 9 s, respectively, while the contents of soluble protein in the seedlings increased the most, when the treatment time was 12 s. There was the higher antioxidant capacity of the newborn seedlings of wheat seeds after treatment. The contents of malondialdehyde in the wheat seedlings decreased by 15.6% (Jimai 22) and 18% (Bainong 307), respectively (P<0.05), when the treatment time was 9 s. Therefore, DBD low-temperature plasma was effectively improved the wheat seed vigor and the seedling physiological properties. A potential seed enhancement can be achieved in the seed quality and subsequent wheat growth in crop production.

       

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