| 摘要: |
| 【目的】明确多花芍药生根种子对上胚轴休眠解除抑制作用最强的部位及其潜在影响原因，为阐明多花芍药种子的休眠机制提供参考。【方法】分别采用多花芍药生根种子胚乳、种皮、胚3 部分的浸提液处理白菜种子，确定抑制作用最强的部位；将该部位浸提液（1，2 g/L）添加到多花芍药离体胚培养基中，研究其对本体上胚轴休眠解除的影响；观测生根离体胚移入成苗培养基后的形态和脱落酸/赤霉素(ABA/GA3)值变化，确定上胚轴休眠解除过程中的关键时间节点。用各关键节点胚浸提液处理易萌发的白菜种子，研究其对白菜种子发芽率、过氧化氢（H2O2）含量、羟自由基（·OH）清除能力、抗氧化酶（超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、过氧化物酶（POD））活性、抗坏血酸（AsA）和谷胱甘肽（GSH）含量及NADP-苹果酸脱氢酶（NADP-MDH）、丙酮酸激酶（PK）、6-磷酸葡萄糖脱氢酶（G6PDH））活性的影响，分析白菜种子发芽率与这些指标间的相关性。【结果】①多花芍药生根种子种皮、胚乳和胚浸提液均可显著抑制白菜种子萌发及幼苗生长，抑制强度由大到小依次为胚＞胚乳＞种皮；1，2 g/L胚浸提液均可显著降低多花芍药离体胚上胚轴休眠解除率。②生根离体胚移入成苗培养基的第4，8，12，16 天，分别观测到ABA/GA3出现拐点（S2）、胚芽萌出（S3）、胚芽伸长（S4）和真叶展开（S5）关键变化。③多花芍药离体胚移入成苗培养基之前（S1）及S2～S5节点胚浸提液均可抑制白菜种子萌发，且S4节点胚浸提液的抑制强度最大，该节点胚浸提液处理白菜种子H2O2含量、·OH清除能力、SOD活性和GSH、AsA含量均显著提高，同时CAT、POD、PK、G6PDH活性均显著降低。相关性分析结果显示，各节点胚浸提液处理白菜种子的发芽率与H2O2含量、·OH清除能力、GSH含量极显著负相关，与SOD活性显著负相关，与CAT、POD、PK和G6PDH活性极显著正相关，与AsA含量和NADP-MDH活性相关性不显著。【结论】多花芍药生根种子抑制作用最强的部位是胚，胚中内源抑制物在胚芽伸长阶段抑制作用最强，其作用机制是通过影响种子活性氧及抗氧化物质含量、呼吸代谢酶活性而发挥抑制作用。 |
| 关键词: 多花芍药 上胚轴休眠 内源抑制物 抗氧化物质 呼吸代谢酶 |
| DOI：10.13207/j.cnki.jnwafu.2024.09.011 |
| 分类号: |
| 基金项目:雄安新区科技创新专项（2022XAGG0100）；国家自然科学基金项目（32071825） |
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| Effects of endogenous inhibitors on epicotyl dormancy of Paeonia emodi Wall. ex Royle seed |
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YUAN Qiuping, NI Wei, WAN Yingling, LIU Yan
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National Engineering Research Center for Floriculture,Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding,Beijing Laboratory of Urban and Rural Ecological Environment,College of Landscape Architecture,Beijing Forestry University,Beijing 100083,China
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| Abstract: |
| 【Objective】In this study,experiments were carried out to clarify the strongest inhibitory intensity of each parts of Paeonia emodi rooted seeds on epicotyl dormancy released,and the potential reasons for the influence of embryo inhibitors on epicotyl dormancy,so as to provide a reference for elucidating the dormancy mechanism of P. emodi seed.【Method】The extracts from endosperm,seed coat and embryo of P. emodi rooted seeds were used to treat Brassica pekinensis seeds,so as to clarify the location with the strongest intensity.The extracts(1,2 g/L) of this part were added to the excised embryo medium to study the effect on epicotyl dormancy of P. emodi.The changes of morphology and ABA/GA3 of rooted excised embryo were observed after they were transferred into the seedling medium,and the key time nodes to break epicotyl dormancy were determined,B. pekinensis seeds which were easy to germinate were treated with the embryo extracts from the key nodes,to investigate the the extracts effects on germination percentage,hydrogen peroxide (H2O2) content,hydroxyl radical (·OH) scavenging ability, antioxidant enzyme activities(superoxide dismutase(SOD),catalase(CAT),peroxidase(POD)),ascorbic acid(AsA) and glutathione(GSH)content,respiratory metabolic enzyme activities (NADP-malate dehydrogenase(NADP-MDH),pyruvate kinase (PK),glucose 6-phosphate dehydrogenase (G6PDH)).The correlation between the germination rate of B. pekinensis seeds and these indexes was analyzed.【Result】①The extracts of seed coat,endosperm,embryo from the rooted seeds significantly inhibited B. pekinensis seeds germination,and the inhibition intensity: embryo＞endosperm＞seed coat. Meanwhile,the embryo extracts(1,2 g/L) could significantly reduce the epicotyl dormancy release percentage of excised embryo.②On the 4th,8th,12th and 16th days after the rooted excised embryos were transferred into the seedling medium,the emergence of ABA/GA3 inflection point (S2), plumule germination(S3),plumule elongation (S4) and true leaves expansion (S5) were observed respectively.③The embryo extracts of P.emodi at S1-S5(S1 is before the transfer of excised embryos into seedling medium) inhibited the germination of B. pekinensis seeds,and the embryo extracts at S4 had the greatest inhibitory strength.S4 node embryo extracts significantly increased H2O2 content,·OH scavenging ability,SOD activity,AsA and GSH content.At the same time, the activities of CAT,POD,PK and G6PDH were significantly decreased.Correlation analysis showed that the germination percentage of B. pekinensis seeds had very significant negative correlation with H2O2 content,·OH scavenging ability and GSH content,had significant negative correlation with SOD activity,and had very signi-ficant positive correlation with CAT,POD,PK,G6PDH activity and had no significant correlation with AsA content and NADP-MDH activity.【Conclusion】The embryo was the most strongly inhibited part in P. emodi rooted seeds,and the inhibitor in embryo exerts the maximum inhibitory effect at the plumule elongation node.The inhibition in embryo may play a role by affecting ROS,antioxidant substances and respiratory metabolic enzymes. |
| Key words: Paeonia emodi epicotyl dormancy endogenous inhibitors antioxidant substances respiratory metabolic enzymes |
