美国桂花种子低温层积过程中种子结构的变化

The changes of seed structure in Osmanthus americanus seed during cold stratification

美国桂花种子属于深休眠类型,在自然条件下,需要经过2a才能萌发。研究了美国桂花种子低温层积过程中种子结构的变化。结果表明:在低温层积过程中随着层积时间的延长,美国桂花种子种壳中的种孔呈现不断变大、增多的趋势,这说明在自然条件下美国桂花种壳不会阻碍种子的吸水、透气,从而抑制种子的萌发;胚乳中内含物透射观察发现,随着层积时间的延长,细胞膜逐渐解体,到后期淀粉、脂粒大量出现。这表明,在低温层积过程中胚乳中营养物质不断分解,为种子萌发生长提供所需的物质和能量。

Osmanthus americanus seeds usually take two years to germinate in nature.It belonged to a type of comprehensive dormancy.The changes of seed structure of O.americanus seeds during the cold stratification were studied.The results show that the pores number of O.americanus seed shell increased unceasingly and the pores diameter largen continuously during the cold stratification;It was showed that the seed shell wouldn＇t keep seed from absorbing water and breathing air instead of suppressing seed＇s germination under the nature condition.The results of transmission observation on O.americanus seed indicate that endosperm cell＇s membrane had gradually disintegrated,and at the later stage of stratification,the starch and fatty granule massively appeared largely.All of these changes show that the nutrients in the endosperm could decomposed constantly to provide the material and energy for seed germination and growth during cold stratification.