Overcoming dormancy of Senna multijuga seeds with an ultrasonic probe the comparison with ultrasound and sulfuric acid baths

ABSTRACT: Understanding germination is extremely important for the production of seedlings that are used in revegetation of degraded areas. Some species enter dormancy as a survival strategy to overcome adverse environmental conditions. Their seeds germinate only when this process is interrupted, which can occur naturally when the conditions become more favorable for the survival of the species or by induction. Studies showed that ultrasound can increase the germination rate of seeds. The objective of this research was to evaluate the effect of an ultrasound probe and compare it with other methodologies implemented for seed germination of Senna multijuga (Rich.) H. S. Irwin & Barneby, a species used in revegetation of degraded areas. The experiment evaluated the effect of the ultrasonic probe at different powers on seeds that were placed to germinate in a gerbox on paper moistened with distilled water. Ninety-five percent of seeds treated with ultrasound and only 14% of non-treated seeds (control) germinated. There was no significant difference in the germination among the treatments with different powers. The speed of germination index (SGI) reached 4.7 in seeds that underwent the treatment, and 0.6 in the control group. From the results it is possible to conclude that the ultrasound probe is an efficient treatment to accelerate seed germination in this species; and consequently, contributed to production of a greater number of seedlings to be used in revegetation of degraded areas in a short period of time.

摘要：了解种子萌发过程，对于退化地区植被恢复所用苗木的生产至关重要。部分物种会以休眠作为生存策略以抵御不良环境条件；其种子仅在休眠过程被打破后方可萌发，该过程既可在环境条件转为更利于物种生存时自然发生，亦可通过人工诱导实现。已有研究表明，超声波处理可提升种子萌发率。本研究旨在评估超声波探头的处理效果，并将其与其他用于退化地区植被恢复物种——多叶决明（Senna multijuga (Rich.) H. S. Irwin & Barneby）种子萌发的方法进行对比。本实验将种子置于铺有经蒸馏水湿润滤纸的发芽盒（gerbox）中萌发，评估不同功率超声波探头对种子萌发的影响。经超声波处理的种子萌发率达95%，未处理的对照组种子萌发率仅为14%。不同功率的超声波处理组间，种子萌发率无显著差异。处理组种子的发芽速率指数（Speed of Germination Index, SGI）达4.7，对照组则仅为0.6。基于上述实验结果可得出结论：超声波探头处理可有效加速该物种的种子萌发，进而在短时间内产出更多苗木，用于退化地区的植被恢复工作。