PEG和GA_3引发处理对老化毛竹种子理化特性的影响

Effects of PEG and GA_3 priming on the physiological and biochemical characteristics of aged moso bamboo ( Phyllostachys edulis) seeds

【目的】研究聚乙二醇(PEG)和赤霉素(GA_3)引发处理对不同老化程度毛竹种子生理生化的影响,探寻提高毛竹种子活力的最佳处理方法。【方法】采用高温高湿法(温度40℃、相对湿度95%)模拟种子自然老化过程,筛选出不同活力水平的毛竹种子;然后采用PEG和GA_3进行引发处理,测定其生理生化指标。【结果】随着毛竹种子老化程度加深,种子浸出液相对电导率、可溶性糖和MDA含量增加,可溶性蛋白质含量降低,超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)等保护酶活性降低,种子内源GA_3和吲哚乙酸(IAA)含量降低,脱落酸(ABA)含量升高,GA_3/ABA比值降低。而且,种子老化程度越深,种子活力提高越显著。与未引发处理相比,PEG和GA_3处理均显著降低毛竹种子浸出液相对电导率和MDA含量,降低膜脂过氧化水平,保护细胞膜的完整性,提高可溶性蛋白质含量,保护酶活性及GA_3和IAA含量,降低ABA含量,从而提高GA_3/ABA比值。【结论】适宜的PEG(质量分数为20%、20℃浸种24 h)和GA_3(质量浓度为500 mg/L、25℃浸种12 h)引发处理均能提高老化毛竹种子的活力水平,促进种子萌发,可为毛竹实生苗繁育提供参考和技术指导。

【Objective】The viability of moso bamboo（ Phyllostachys edulis） seeds often decreases quickly during the natural storage process,resulting in a short life of seeds,so it is important to enhance the vigor and germination rate of moso bamboo seeds for storage,production,and utilization. The objective of the present study was to investigate the effects of polyethylene glycol（ PEG） and gibbereilin（ GA3） priming on the physiological and biochemical characteristics of aged moso bamboo seeds,and explore optional methods for improving the vigor of aged seeds.【Method】High temperature（ 40 ℃） and high humidity（ 95% ） were used to simulate the natural aging process of the seeds,and different vigor levels of moso bamboo seeds were selected. Then,the selected seeds were primed by polyethylene glycol（ PEG） and gibberellic acid（ GA3）,and the physiological and biochemical characteristics of aged moso bamboo seeds were tested.【Result】With an increased degree of aging,the relative conductivity and soluble sugar,MDA and abscisic acid（ ABA）contents increased,and protective enzyme（ SOD,POD,and CAT） activities and soluble protein,GA3,indole acetic acid（ IAA） and GA3/ABA contents decreased. Furthermore,the higher the degree of seed aging,the more obvious the improvement of seed vigor was. Compared to the control,PEG and GA3 treatments could significantly decrease the relative conductivity and MDA content to reduce the level of membrane lipid peroxidation and protect the integrity of themembrane. The two treatments could also increase the protective enzyme activities and soluble protein,GA3,IAA and GA3/ABA contents,as well as decrease the ABA content. 【Conclusion】The proper PEG（ soaking for 24 hours with a concentration of 20% at 20 ℃） and GA3（ soaking for 12 hours with a concentration of 500 mg/L at 25 ℃） priming treatments could significantly enhance the seed vigor of aged moso bamboo seeds,and promote seed germination. These results could provide reference and technical guidance for moso bamboo seedling breeding.