华石斛原生境条件下人工播种的初步探讨

Preliminary Study on artifical sowing of Dendrobium sinense in natural habitat in Bawangling Natural Reserve,Hainan Island

由于人为的采挖和原生境的破坏,华石斛野生资源受到严重威胁。因此,保护华石斛野生资源及其生境,加快野生植株的繁殖显得非常重要。该研究以华石斛种子为材料,分别于7月和9月,播种于不同的附生宿主树种(毛绵杜鹃,竹叶松,碎叶蒲桃,大叶布拉栎和大果马蹄荷),并监测其种子萌发的状况。研究结果表明:(1)华石斛种子对附生树种有一定的选择性。人工播种的毛绵杜鹃上均有原球茎萌发,萌发率达到100%,平均每株树萌发14.71个原球茎。竹叶松和碎叶蒲桃上的原球茎数增加的差异不明显,对照大叶布拉栎和大果马蹄荷则没有原球茎萌发。(2)播种时间影响华石斛种子萌发与原球茎的形成。7月份播种的毛绵杜鹃和竹叶松,原球茎萌发数较多;9月份播种的碎叶蒲桃上萌发的原球茎远远高于毛绵杜鹃和竹叶松上,达到为4.5个/株。该实验结果暗示雨季可能是华石斛播种的最佳时期。此外,人工播种树上萌发的原球茎基本集中在华石斛植株上方30cm至下方40cm的范围内,这为今后播种位置的选择提供了依据。

Aims The wild populations of Dendrobium sinense are under the threat of extinction due to over-collection and habitat destruction.Effective ex-situ propagation may help boosting the wild populations.Our aim is to find the factors which can promote seed germination and production of symbiotic seedlings whhich also guide for artificial cultivation,reintroduction and protect wild resources. Methods Seeds harvested from wild plants of D.sinense in Bawangling natural reserve,were sowed on the host trees as follows,Syzygium buxifolium,Rhododendron moulmainense,Podocarpus neriifoliu,Cyclobalanopsis blake and Exbucklandia tonkinensi at July and September respectively.The seed germination and procedure of protocorm development were observed mothly. Important findings Germination rate of D.Sinense varied from the host trees.100 percentage of seed germination in Rhododendron moulmainense is investigated while 57.14% and 33.33% in Syzygium buxifolium and Podocarpus neriifoliu,but the control host trees with Cyclobalanopsis blake and Exbucklandia tonkinensi s has no seed germination;Conract to the protocorms formation rate is 14.71 per host plant of Rhododendron moulmainense,Syzygium buxifolium and Podocarpus neriifoliu has 2.71 and 6.33 procorms in one host plant respectively.Seed germination and protocorms formation have colse relationship to the sowing period but varying from the host tree.,such as Rh.moulmainense and P.neriifoliu,has a highr protocorms formation rae in July.but on the other hand,the case happen to the S.buxifolium in Semptember with 4.5 protcorms in one host treet.The results indicated that rainy season would be the best sowing period for D.Sinense.Finally,the distance ranged from upside 30 cm to downside 40 cm away from the wild orchid individual in host trees on which protocorms is inclined to be indouced,which also show that it is suitalbe for possible site for sowing