| 摘要: |
| 【目的】探索沙藏层积对滇牡丹种子萌发的影响，为滇牡丹种苗繁殖和栽培奠定基础。【方法】以人工栽培的滇牡丹种子为试验材料，采取室温沙藏层积至上胚轴露出时，每隔15 d取60粒，对滇牡丹种子在沙藏层积过程中的萌发指标进行测定，根据层积过程中种子外部形态特征的变化，将种子划分为6个不同萌发阶段（S1~S6），并利用体视显微镜观察沙藏层积前（S0）和不同萌发阶段种子结构及种胚的变化特征，分析胚乳中贮藏物质（蛋白质、淀粉、油脂）的组织化学染色情况，同时测定各萌发阶段胚乳和种胚中营养物质（可溶性糖、可溶性蛋白）及酶（过氧化物酶（POD）、超氧化物歧化酶（SOD））活性的动态变化。【结果】室温沙藏层积过程中，滇牡丹种子的瞬时发芽率和活力指数均呈现增大趋势，瞬时发芽率在沙藏90 d时增加到85.00%，活力指数增加到20.82。在S0阶段，种胚较小；S1阶段（层积30 d），种子吸水膨胀；S2阶段，胚根突破种皮，少量种子开始萌发；S3阶段，下胚轴明显伸长和增粗；S4阶段，子叶进一步增大，胚根明显伸长和增粗；S5阶段，随着胚根的不断伸长，子叶继续变大；S6阶段，能够观察到少许种子的上胚轴明显伸长。从S2到S6阶段，滇牡丹种子的横纵径、厚度、质量、去皮质量均未显著增加，但种子纵径、胚乳长、胚乳宽、胚长、胚宽分别从S1阶段的(12.19±1.71)，(10.75±1.83)，(9.22±1.59)，(3.20±0.69)，(1.56±0.43) mm到S6阶段显著增加至(14.07±0.42)，(13.46±0.28)，(11.14±1.57)，(70.53±14.43)，(8.85±0.31) mm，胚率从S1阶段的(30.21±4.31)%显著增大到(525.02±116.10)%。种子萌发过程中，胚乳和种胚中可溶性蛋白和可溶性糖含量总体呈下降的趋势；组织化学染色结果显示，胚乳中贮藏物质含量最多的是油体和蛋白质，淀粉含量较少。胚乳和种胚中POD活性总体均呈先升高后下降的趋势，分别在S3和S1阶段达到最高值23.20和58.07 U/g，胚乳和种胚中SOD活性总体呈增加趋势，均在S5阶段达到最高值320.42和2 604.39 U/g。【结论】沙藏层积50~70 d的滇牡丹种子发芽率较高，酶活性较强，有助于种子的进一步萌发，取此时段的种子播种，辅以适宜的栽培管理措施，能有效提高种子的出苗率。 |
| 关键词: 滇牡丹 沙藏层积 种子萌发 贮藏物质 |
| DOI： |
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| 基金项目:国家自然科学基金项目(32060089)；云南省万人计划“云岭产业技术领军人才”专项(云发改［2018］212号)；云南省重大基础专项生物资源数字化开发应用项目（202002AA10007）；云南省千人计划专项(2019) |
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| Seed germination characteristics of Paeonia delavayi during sand storage stratification |
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ZHANG Pingfang,PU Tian,YU Xiao,et al
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| Abstract: |
| 【Objective】This study explored the effect of sand storage stratification on the germination of Paeonia delavayi seeds to lay a foundation for the propagation and cultivation of Paeonia delavayi seedlings.【Method】The seeds from artificial cultivation were collected and 60 seeds were taken every 15 days to measure the germination index during sand stratification process at room temperature since the epicotyl was exposed.According to the changes in external morphological characteristics,the seeds were divided into 6 different germination stages (S1-S6).The structure of seeds before stratification (S0) and at different germination stages as well as the change characteristics of seed embryos during germination were observed using a stereomicroscope.The histochemical staining of stored substances (protein,starch and oil) in endosperm was analyzed and changes of nutrients (soluble sugar and soluble protein),enzyme activities (peroxidase (POD) and superoxide dismutase (SOD)) in endosperm and seed embryo at each germination stage were measured.【Result】During the stratification process of sand storage at room temperature,the instantaneous germination rate and vigor index of Paeonia delavayi seeds showed an increasing trend,with instantaneous germination rate increased to 85.00% and vigor index increased to 20.82 after 90 days.At S0 stage,the seed embryos of Paeonia delavayi seeds were smaller,and the seeds swelled by water absorption after stratification for 30 days (S1 stage).At S2 stage,the radicle broke through seed coat,and a small number of seeds began to germinate.At S3 stage,the hypocotyl elongated and thickened significantly.At S4 stage,the cotyledons further enlarged and the radicle significantly elongated and thickened.At S5 stage,the cotyledons continued to grow with the continuous elongation of radicle.At S6 stage,the epicotyl of a few seeds was obviously elongated.From S2 to S6,the transverse and longitudinal,thickness,mass and peeling mass of seeds changed insignificantly,while the longitudinal diameter,endosperm length,endosperm width,embryo length and embryo width of seeds significantly increased from (12.19±1.71), (10.75±1.83),(9.22±1.59),(3.20±0.69) and (1.56±0.43) mm at S1 stage to (14.07±0.42),(13.46±0.28),(11.14±1.57),(70.53±14.43) and (8.85±0.31) mm at S6 stage.The embryo rate also significantly increased from (30.21±4.31)% to (525.02±116.10)%.During seed germination,the soluble protein and soluble sugar contents in endosperm and seed embryo generally showed a downward trend.The histochemical staining showed that oil body and protein were the most abundant storage substances in endosperm,while starch content was less.POD activity in endosperm and embryo increased first and then decreased,reaching the highest values of 23.20 and 58.07 U/g at S3 and S1 stages,respectively.SOD activity in endosperm and embryo generally increased,reaching the highest values of 320.42 and 2 604.39 U/g at S5 stage.【Conclusion】The seeds of Paeonia delavayi after 50-70 days of sand storage stratification had high germination rate and strong enzyme activities,which was conducive to further germination of seeds.Supplemented with appropriate cultivation and management measures,seeding at this time can effectively improve the emergence rate. |
| Key words: Paeonia delavayi sand stratification seed germination storage substance |
