极度濒危植物贵州大花杜鹃种子的传播与萌发特性研究

Seed Dispersal and Germination Characteristics of Rhododendron magniflorum,A Critically Endangered Plant Endemic to Guizhou Province

贵州大花杜鹃属于贵州省特有的极小种群植物和IUCN评估的极度濒危植物,目前仅在龙头大山分布,且幼苗数量极少。为了探究导致贵州大花杜鹃濒危因素中是否在种子传播和萌发上存在障碍导致其居群数量微小,研究了种翅、温度、光照和凋落物4个因素对其种子传播及萌发的影响。对种子进行留翅与去翅2种处理,在不同风速及水处理条件下探究种皮膜翅对种子传播的影响;设置不同温度及光照条件下,贵州大花杜鹃种子萌发的影响;模拟生境条件下凋落物的情况,测定不同基质对种子萌发及幼苗形态建成的影响。结果表明:种翅有助于贵州大花杜鹃种子的风传播与水传播;但在实际生境中,由于其处于丛林密林处,这2种方式实际传播效率并不高。温度适当提高会促进贵州大花杜鹃种子萌发,光照对贵州大花杜鹃的种子萌发没有明显影响,但对幼苗建成影响较大;过厚的凋落物会阻碍贵州大花杜鹃种子的萌发,造成幼苗数量少,种群更新困难。

Rhododendron magniflorum is an extremely endangered plant evaluated by IUCN,and its wild population is very small.At present,it is only founded in Longtou mountain in Guizhou,and seedlings in the wild are very rare.In order to verify whether there are obstacles in seed dispersal and germination which might cause its extremely small populations,we studied the effects of seed wing,temperature,light and litter on seed dispersal and germination of R.magniflorum.The effect of seed coat membrane wing on seed dispesal was investigated under different wind speed and water treatments while the effects of temperature on seed germination were examined under different temperatures and light conditions.The effects of different substrate conditions on seed germination and seedling morphogenesis were measured.The results showed that the seed wings were beneficial to both wind and water dispersal of seeds.However,in its native habitat,because it is in the dense forests,the transmission efficiency of seed dispersal could be limited;the increasing temperature will promote the seed germination of R.magniflorum.The light has no obvious effect on its seed germination,but has a great effect on the seedling establishment;thicker litter would hinder successful germination of R.magniflorum seeds,resulting in a small number of seedlings and difficulty of population regeneration.