栀子种子萌发条件优化及萌发抑制物的初步研究
Optimization of seed germination and detection of germination inhibitors in gardenia fruits
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摘要: 【目的】探讨栀子种子萌发受抑制的原因及抑制物存在的部位,寻求提高发芽率的最佳方法,为其人工栽培提供参考。【方法】以江西樟树和安徽亳州两个栀子主产地的栀子果实为材料,探讨浓硫酸浸泡2~24 h对栀子种子吸水率的影响;研究栀子种子、果肉和果皮甲醇提取液(0.005~0.050 g/mL)对白菜种子发芽率和幼苗生长的抑制作用;测定浓硫酸、赤霉素(0~1.5 g/mL)和生长素(0.1~5.0 g/mL)、不同温度(15.0~30.0℃)和发芽床(蛭石、纱布、滤纸、湿沙)等处理的栀子种子发芽率。【结果】浓硫酸处理后不同产地栀子种子的吸水率普遍提高,达到饱和时其种子平均吸水率高于未酸蚀种子34.31%。果肉甲醇浸提液对白菜种子发芽的抑制作用更高。随着栀子果皮或种子的甲醇浸提液浓度的增加,白菜种子萌发势和发芽率呈缓慢下降趋势;经0.005~0.015 g/mL果肉甲醇浸提液处理的白菜种子萌发势和发芽率缓慢下降,但当大于0.015 g/mL时,白菜种子萌发势和发芽率急剧降低;随着果实甲醇提取液浓度的提高,白菜发芽种子根明显变短,芽缩短,长势变弱,以果肉的甲醇提取液抑制物作用最强,其次为果皮、种子;此外,提取液对根的抑制作用强于对芽的抑制作用。浓硫酸处理的栀子种子发芽率为零,且种子极易霉变。随着生长素浓度的增加,栀子种子发芽率明显降低,种子出现发黑现象。在0.3~1.2 g/mL赤霉素范围内时,随着赤霉素浓度的提高,栀子发芽率逐渐升高,其中以1.2 g/mL赤霉素的发芽率最高。在20~30℃范围内,栀子种子有较高的发芽率,而在20℃以下,发芽率极低。在30℃最适温度条件下,以滤纸的种子发芽率和发芽势最高,其次为湿沙、纱布、蛭石。【结论】栀子果肉和果皮中均存在抑制种子萌发的物质,是抑制种子萌发的首要因素。栀子果皮、种子和果肉中抑制白菜种子萌发的化学物质种类或数量可能不同。浓硫酸、生长素对栀子种子发芽具有抑制作用,赤霉素则具有促进作用。栀子种子的最适发芽条件为:用1.2 mg/mL赤霉素避光浸泡48 h后,在滤纸培养床上30℃恒温避光培养。Abstract: ObjectiveGardenia seeds were processed by different treatments to investigate the causes of inhibiting seed germination and its inhibitor positions in order to seek out the best method for improving germination rate, which provided ref-erences for artificial cultivation. MethodGardenia fruits collected from two main producing areas of Zhangshu in Jiangxi and Bozhou in Anhui were used to investigate the effects of concentrated sulfuric acid soaking for 2-24 hours on water absorp-tion of gardenia seeds. The effects of methyl alcohol extracting solution(0.005-0.050 g/mL) of gardenia seeds, and pulp and peel on germination rate of cabbage seeds and seedling growth were studied. The germination rate of gardenia seeds was measured in different treatments of concentrated sulfuric acid, gibberellin(0-1.5 g/mL), auxin(0.1-5.0 g/mL), temperature(15.0-30.0℃) and germination substratum (vermiculite, gauze, filter paper, and wet sand). ResultAfter the treatment of concentrated sulfuric acid, water absorption of gardenia seeds from different producing areas was generally improved. Mean water absorption of the saturated seeds was 34.31%higher than seeds without acid etching. Inhibiting effects of pulp methyl alcohol extracting solution on cabbage seeds were greater. With the increase of peel or seeds methyl alcohol extracting solution concentration, the germination vigor and rate of cabbage seeds showed slowly declining trend, and the same results was also observed in treat-ments of 0.005-0.015 g/mL pulp methyl alcohol extracting solution. When the pulp methyl alcohol extracting solution was over 0.015 g/mL, the germination vigor and rate of cabbage seeds sharply decreased. Higher methyl alcohol extracting solution con-centration of gardenia fruits made root and seedling shorter and growth weaker of cabbage. The pulp had the strongest inhibiting effects, followed by peel and seed. Moreover, the inhibiting effects of extracting solution on root was greater than seedling. Gardenia seeds treated by concentrated sulfuric acid could not germinate and were easy to mould. Higher auxin concentration could obviously reduce gardenia germination rate and seeds became black. In the range of 0.3-1.2 g/mL gibberellins, more gib-berellins meant higher gardenia germination rate, and the highest rate occurred in treatment of 1.2 g/mL gibberellins. In the range of 20-30℃, gardenia germination rate was relatively high, while it was exceedingly low under 20℃. At the optimum temperature of 30℃, the order of germination rate and vigor was filter paper, wet sand, gauze and vermiculite.ConclusionThe substances inhibiting germination of seeds did exist in pulp and peel of gardenia fruits and they were primary inhibiting germination elements. Kind and number of chemical substances inhibiting seed germination in gardenia peel, seed and pulp may be different. Concentrated sulfuric acid and auxin inhibited gardenia germination, while gibberellins promoted gardenia germination. The optimum conditions for gardenia seed germination was as follows:seed soaked in 1.2 mg/mL gibberellins solu-tion for 48 h under dark condition, and then culturing on filter paper at 30°C in the dark.