目的通过对决明种子硬实和萌发特性的研究,找到打破种子硬实、提高种子萌发率的适宜条件。方法观察种子外部形态,对决明种子长宽、千粒质量、净度、硬实率、含水量和吸水率进行测定,通过研磨、预先冷冻和热水处理,找到破除种子硬实的方法,考察不同温度、不同质量浓度化学物质对种子萌发率的影响。结果决明种子含水量为10.43%,未经处理的种子吸水率为45.82%,经过研磨处理和浓硫酸处理的种子吸水率分别为154.2%、159.7%。经过98%浓硫酸处理20 min后的种子发芽率为99.8%,变温下(25℃1、4 h/15℃1、0 h)种子萌发率为98.7%,200 mg/L GA3和200 mg/L PEG处理后的萌发率分别为100%和98.9%,较高质量浓度的NNA和6-BA对种子萌发具有明显的抑制效应。结论种皮硬实是限制种子萌发的主要因素,98%的浓硫酸浸泡20 min可以较好地打破决明种子硬实,200 mg/L GA3和200 mg/L PEG能在短时间内显著提高种子的萌发率,最佳萌发温度为25℃,14 h/15℃,10 h。

Objective To break the seed hardness and improve the germination rate of the Cassia obtusifolia seeds,hardness and germination characteristic of C.obtusifolia seeds were studied.MethodsSeveral physiological indexes like the weights per thousand seeds,pure rate,hard rate,content of moisture,and the rate of water absorption were measured.Methods of soaking in hot water,pre-freezing,immersing seed in H2SO4,and mechanical abrasion with coarse sand were used in the experiment.And the germination rate of C.obtusifolia seeds was determined under different temperature and different concentration of chemistry matter treatment.Results The content of moisture in C.obtusifolia seeds was 10.43%,the rate of water absorption(untreated) was 45.82%,the rate of water absorption treated by mechanical abrasion and H2SO4 were 154.2% and 159.7%,respectively.The rate of water absorption was 99.8% by the treatment of H2SO4 within 20 min.The germination rate under the alteration treatment of 25 ℃ 14 h/15 ℃ 10 h was 98.7%.The germination rate treated by 200 mg/L GA3 and 200 mg/L PEG were 100% and 98.9%,respectively.NAA and 6-BA with higher concentration have the effect of restraint to the germination of C. obtusifolia.Conclusion Seed coat is the limiting factor of germination.The seed hardness could be broken by H2SO4(98%).GA3(200 mL) and PEG(200 mg/L) could improve the germination rate of the seeds in short time(1 d) obviously.The most appropriate temperature for the seed germination of C.obtusifolia is 25 ℃ 14 h/15 ℃ 10 h.

国家自然科学基金资助项目(30070080)