| 摘要: |
| 【目的】探讨影响冬瓜种子休眠的原因，确定种子休眠特性，为探明冬瓜种子休眠机理及破除方法提供理论指导。【方法】以冬瓜种子为材料，对其进行外观观察及形态指标和质量测定，分析数量性状分布规律及其相关性；采用恒温烘干法和2,3,5 氯化三苯基四氮唑染色（TTC）法检测种子含水量和生活力；采用去皮法和吸水法处理种子，计算其发芽率和吸水率；以蒸馏水为对照（CK），分析0.02，0.04，0.06，0.08，0.10 g/mL冬瓜种子种皮、种胚水和甲醇浸提液对白菜种子萌发、幼苗生长的影响；此外还分析了0.02，0.04，0.06，0.08，0.10 g/mL种皮、种胚甲醇浸提液对白菜幼苗超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、过氧化物酶（POD）活性的影响，探讨冬瓜种子的休眠机理。【结果】冬瓜种子的种皮坚硬且厚，种子长、宽、厚平均值分别为1.155,0.694和0.226 cm，千粒质量平均值为52.820 g，含水量为75.800%。种子长、宽、厚在4~5级分布频率均较高，种子胚根长在9级分布频率最高，种皮质量和种胚质量均在6级分布频率最高，种子千粒质量和含水量主要分布在4~6级。种子厚与种子长、宽，胚根长与种子长，种皮质量与种子长、种子厚、胚根长均呈极显著正相关。在同等条件下培养5 d后，完整冬瓜种子无萌发，而去皮冬瓜种子发芽率达到54.67％。冬瓜种子的种皮透水性良好，吸水处理21 h后，冬瓜完整种子和破壳种子的吸水率仅相差5.80%。冬瓜种子种皮、种胚水和甲醇浸提液对白菜种子萌发和幼苗生长均有不同程度的抑制作用，其中种子种皮、种胚水和甲醇浸提液对白菜幼苗根长的抑制效应大于苗高；随着浸提液质量浓度的增大，种皮、种胚水和甲醇浸提液抑制效应总体增强；种皮和种胚甲醇浸提液的抑制效应大于水浸提液，种胚浸提液的抑制效应大于种皮浸提液。冬瓜种子种皮和种胚甲醇浸提液总体能抑制白菜幼苗的SOD、CAT、POD活性。【结论】种子中的内源抑制物和种皮机械束缚可能是冬瓜种子休眠的重要原因，而种子各部位浸提物可能通过抑制保护酶活性而影响幼苗生长。 |
| 关键词: 冬瓜 种子萌发 休眠特性 抑制作用 |
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| 基金项目:福建省属公益类科研院所基本科研专项（2022R1031003）；特色蔬菜育种攻关与产业化开发项目（zycxny2021009）；国家大宗蔬菜产业体系福州综合试验站项目(CARS-23-G-53);福建省农业科学院蔬菜科技创新团队项目(CXTD2021038) |
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| Seed dormancy characteristics of Benincasa hispida Cogn. |
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YE Xinru,LIU Jianting,QIU Boyin,et al
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| Abstract: |
| 【Objective】The dormancy reasons and characteristics of Benincasa hispida seeds were explored to improve the understanding of dormancy mechanism and development of dormancy breaking method.【Method】The appearance of seeds was observed and related indexes were measured.The water content and viability of seeds were detected using thermostatic drying method and TTC method,respectively.The seed coat permeability and seed germination were measured by water absorption method and peeling method.The effects of water and methanolic extracts of see coat and embryo at concentrations of 0.02,0.04,0.06,0.08,and 0.10 g/mL on seed germination and seedling growth of Brassica pekinensis were analyzed using distilled water as control (CK).The effects on activities of superoxide dismutase (SOD),catalase (CAT),and peroxidase (POD) of Brassica pekinensis seedlings were also analyzed to explore the causes of seed dormancy.【Result】The seed coat of Benincasa hispida seeds was hard and thick,and seed length,width,and thickness were 1.115,0.694, and 0.226 cm,respectively,with thousand seed mass of 52.820 g and water content of 75.800%.Seed length,width,and thickness were distributed more frequently at levels 4-5,seed radicle length was distributed most frequently at level 9,seed coat quality and seed embryo quality were distributed most frequently at level 6,and seed thousand seed mass and moisture content were mainly distributed at levels 4-6.There were highly significant positive correlations between seed thickness and seed length and width,between radicle length and seed length,seed coat quality and seed length,and between seed thickness and radicle length.There was no germination of intact Benincasa hispida seeds,while the germination rate of peeled seeds reached 54.67% after 5 d of incubation under same conditions.The seeds absorbed water well,with a difference of 5.80% between intact and shelled seeds after 21 h of water absorption treatment.The water and methanol extracts of Benincasa hispida seed coat and seed embryo had different inhibition on seed germination and seedling growth, and the inhibition effect on seedling root length was greater than that on seedling height.The inhibition effect increased with the increase of extracts concentration.The inhibition effect of methanol extracts was greater than that of water extracts,and the inhibition effect of seed embryo extracts was greater than that of seed coat extracts.The methanolic extracts of seed coat and seed embryo inhibited SOD,CAT,and POD activities of seedlings in general.【Conclusion】The presence of inhibitory substances and seed coat obstacle was an important cause of seed dormancy in Benincasa hispida seeds,and extracts of various seed parts may affect seedling growth by inhibiting protective enzyme activities. |
| Key words: Benincasa hispida Cogn. seed germination dormancy characteristics inhibiting effect |
