10个牧草品种种子生物学特性和超低温处理对发芽的影响

Biological characteristics of ten herbage species andthe effects of ultra-low temperature treatmenton germination

摘要:

【目的】 研究10 种牧草种子的生物学特性及超低温（液氮）处理后种子的发芽特性，解析超低温处理对牧草种子发芽的影响，探究牧草种子超低温处理前后热力学特征变化，为牧草种质资源的超低温保存提供技术参考。【方法】 以10 种牧草种子为材料，测定种子的千粒重、种长、种宽、宽长比、表面积及饱满率等生物学特性。采用减重法将种子含水量统一降至5%，测定超低温处理前后种子的发芽率。基于差示扫描量热技术，分析牧草种子的热力学特征。【结果】 1） 10 种牧草种子形态存在差异，由大到小为蒙燕1 号燕麦、湘中多花黑麦草、科瑞苇状羊茅、吉生1 号羊草、宁稷一号湖南稷子、腾格里蒙古韭、雅星假木豆、公农2 号紫花苜蓿、公农沙打旺、三叶草原始群体；2） 种子的饱满率和发芽率呈正相关关系；3） 10 种牧草种子经液氮超低温处理后发芽率没有下降，但生活力会降低、发芽时间更长；4）超低温处理前后差示扫描量热技术分析显示，牧草种子的水分含量和水分状态没有发生变化。【结论】 10种牧草种子的生物学特征存在差异。种子饱满率在一定程度上可作为衡量种子萌发能力的重要指标，在保存种质资源时应当注意选择饱满率高的种子。将牧草种子含水率降低到5% 时，种子发芽率不会降低，基于差示扫描量热技术可知，种子超低温处理过程中水分状态不变，因此能够实现超低温保存。

Abstract:

【Objective】 This study investigated the biological characteristics of seeds from ten herbage species and examined the effects of cryopreservation（liquid nitrogen） treatment on seed germination. The goal was to analyzehow cryopreservation treatment influences germination and to explore changes in the thermodynamic properties ofherbage seeds before and after treatment，providing a technical reference for the cryopreservation of herbage germ ‐plasm resources.【Method】 Seeds from ten herbage species were used to determine their biological characteristics，includingthousand-seed weight，seed length，seed width，width-to-length ratio，surface area，and plumpness rate.The moisture content of the seeds was reduced to 5% using a weight reduction method. Germination rates before andafter cryopreservation treatment were measured. Differential scanning calorimetry was employed to analyze the theirmodynamiccharacteristics of the seeds.【Result】 1） The seed morphology of the ten herbage species varied and includedAvena sativa、Lolium multiforum、Festuca atundinacea、Leymus chinensis、Panicum intortum、Allium mongo-licum、Dendrolobium triangulare、Medicago sativa、Astragalus adsurgens、Trifolium repens. 2） A positive correlationwas observed between seed plumpness and germination rate. 3） Germination rate of the ten herbage seeds did notdecrease after cryopreservation in liquid nitrogen； however，germination ability decreased and germination time waslonger. 4） Differential scanning calorimetry analysis revealed that the moisture content and water state of the herbageseeds did not change after cryopreservation treatment.【Conclusion】 The biological characteristics of seeds from tenherbage species varied. Seed plumpness rate can be used as an important indicator of seed germination ability. Forcryopreservation of herbage germplasm resources，selecting seeds with high plumpness rate is crucial. When the moisturecontent of seeds is reduced to 5%，germination rate remain stable. Differential scanning calorimetry indicates thatthe water state of seeds does not change during cryopreservation treatment，making cryopreservation feasible for herbageseeds.