三种兜兰属植物种子发育过程及其与无菌萌发的关系

某些兰科植物的种子成熟前，在无菌萌发过程中有较高的萌发率，而成熟后萌发率急剧下降。本研究针对这一现象，对三种兜兰属植物种子的发育过程进行了解剖学观察，并对授粉后不同时期的种子进行无菌播种，80d后统计其萌发率，以探究种子发育过程中的解剖学特征与萌发率之间的关系。研究结果表明种胚刚发育到椭球形胚的时候，胚柄尚存，种皮细胞尚未皱缩，此时三种兜兰的萌发率都能达到较高水平，表明这是适合兜兰属植物萌发的最佳时期；此后，种皮开始皱缩，木质素类物质积累导致种皮透水性下降，推测这可能是导致其后期萌发率下降的主要因素之一。

The Seed Development of Three Paphiopedilum Species in Relation to Asymbiotic Germination

There is an optimum time for the asymbiotic germination of some species in Orchidaceae. A better understanding of the seed development would provide information for the germination events. The relationship between asymbiotic germination rate and the anatomical features in seed development of three Paphiopedilum species was studied. The highest frequency of seed germination was obtained when the embryo began to take an ellipsoidal shape, yet the seed coat had not dehydrated, and the suspensor cells were still present. After that, the parenchyma cell of the seed coat began to dehydrate and lignin substances accumulated, therefore lead to the down shift of the permeability of the seed coat, which maybe the main obstacles for the germination of the mature seeds of the Paphiopedilum species.