狭叶坡垒种子雨的空间格局及种子萌发特性

Spatial distribution pattern of seed rain and seed germination characteristics of endangered plant Hopea chinensis

在广西十万大山自然保护区的狭叶坡垒集中分布区选择5株成熟狭叶坡垒母树,通过地表取样,分析狭叶坡垒种子雨的空间分布格局特征及其种子的萌发特性,结果表明,(1)狭叶坡垒种子雨散布在母株附近,集中在离母株主干1-7 m区段内,占种子总数的97%;单株平均掉落种子数为27.14个.m-2(5.8-70个.m-2),其中,东向比西向多,南向比北向多,但无显著性差异;沟谷面多,背沟谷面少,其差异也不显著。(2)种子雨中有活力的种子占总数的51.3%,因各种原因坏死的占35.65%,昆虫幼虫蛀食的占9.91%,未成熟的占3.13%。(3)种子无休眠期,正常种子的萌发率为(93.60±4.77)%;火烧土较适宜狭叶坡垒的种子萌发,酸性土的萌发率最低,不同播种基质对早期幼苗生长影响不显著。(4)种子被水淹后,其萌发力和成苗率均降低了40%左右,且幼苗生活力下降;种子大小对种子的萌发有影响,千粒重大的种子萌发率比小的高约20%。(5)林窗幼苗成苗率为(52±5.66)%,比林下高约30%。

Five mature plants of Hopea chinensis population were randomly chosen to study the spatial distribution pattern of its seed rain and seed germination characteristics in Shiwandashan, Gangxi Province. （ 1 ） The seeds on the ground mainly distributed under the parent tree crown within 1 -7 m from the trunk, 97% of seeds total. The average seed rain density estimated from the traps deployed under the crown was 27.14 seeds · m^-2, ranging from 5.8 to 70 seeds · m^-2. （2）Of the total H. chinensis collected by seed traps ,the viable accounted for 51.3%, the rotten fruit 35.65%, the infected by larvae 9.91%, and the immature 3.13%. （3） The natural fresh seeds expressed no dormancy stage, and its germination rate was up to （93.60 ±4.77）%. Ash soil was more favorable for the seed germination, while in acid soil, the germination rate of seeds was the lowest than the others. The soil medium had no significant impact on the seedling viability. （4） After water soaking, the seed germination rate and its seedling rate percentage both decreased 40%, furthermore, its seedling viability was declined. The germination rate of large seeds was 20% higher than that of small seeds. （5） The seedling rate in the forest gap and edge was （52 ±5.66）%, and it was 30% higher than that in understory.