黄土高原子午岭油松林的种子雨和土壤种子库动态  

Dynamics of seed rain and soil seed bank in Pinus tabulaeformis Carr. forests in eroded hilly loess regions of the Loess Plateau in China

作　　者：张希彪[1,2] 王瑞娟[1] 上官周平[2] 

机构地区：[1]陇东学院生命科学系,甘肃庆阳745000 [2]中国科学院水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室,陕西杨凌712100

出　　处：《生态学报》2009年第4期1877-1884,共8页Acta Ecologica Sinica

基　　金：国家重点基础研究发展规划资助项目(2002CB111502);甘肃省教育厅资助项目(049B-08)

摘　　要：对黄土高原区子午岭不同林龄（18a、29a、40a、54a）油松（Pinus tabulaeformis carr.）人工林及天然林（约75a）的种子雨和土壤种子库进行了研究。结果表明,该区油松种子雨一般从每年9月初开始,一直到11月底结束,种子雨降落历程与林龄大小有关,种子雨发生时间和降落高峰期有所不同。不同林龄的油松种子雨强度不同,种子雨总量大小顺序为：40a人工林（（489.9±8.64）粒.m-2）〉29a人工林（（346.8±7.45）粒·m-2）〉54a人工林（（327.1±8.13）粒.m-2）〉天然林（（146.9±5.25）粒·m-2）〉18a人工林（（78.1±2.72）粒.m-2）。种子雨总量随林龄的增加而增加,约40a时达到高峰,种子雨活力也以40a时最高。不同林龄油松林土壤种子库存在显著差异,其中18a人工林种子库最小,40a人工林种子库最大。从种子雨降落到次年4月,5种林分土壤种子库总量下降了42.34%～53.59%,空粒种子增加了26.72%～48.69%;从4月到8月份种子腐烂率由10.28%～13.62%增加到57.25%～63.28%。动物的搬运、取食和种子腐烂死亡是种子库损耗的主要因素。土壤种子库中的油松种子主要集中在枯枝落叶层,其次为0～2cm层,2～10cm层种子最少。到8月中旬,土壤中98.26%的油松种子都已丧失活性。不同林分下油松幼苗的密度差异较大,40a人工林下幼苗最多,其余依次为29a人工林、54a人工林和天然林,18a人工林下的实生苗极少,幼苗死亡率极高。在一定龄级范围内,人工林结实能力和更新潜力随林龄增加而增加,40a时更新潜力最大。虽然有大量种子下落,但由于种子大量损耗和幼苗死亡,通过环境筛作用而最终可以成熟的个体数量十分有限。The seed rain and soil seed bank were investigated using seed traps,sieving and counting seeds in the soil,conducting seed germination experiments,and measuring seedling densities in the 18,29,40,and 54 years old Pinus tabulaeformis Carr.plantations and 75 years old natural Pinus tabulaeformis Carr.forest in Ziwuling mountain area in the Loess Plateau.The results showed that seed rain lasted from late of September to the end of November.The timing of the seed rain was positively correlaed with the plantation age.The process of seed rain falling is correlated with the forest age.The appearing time of seed rain is different with the rainfall peak time.Different Pinus tabulaeformis Carr.Plantations had different seed rain density.The density of seed rains in the different ages decreased in the following order,40a plantation（（489.9±8.64）seeds·m-2）〉 29a plantation（（346.8±7.45）seeds·m-2）〉 54a plantation（（327.1±8.13）seeds·m-2）〉 natural forest（（146.9±5.25）seeds·m-2）〉 18a plantation（（78.1±2.72）seeds·m-2）.The seed rainfall peak is in 40a plantation and the seed rain activity is also the most active in it too.There was significant difference of seed bank in different plantations,with the 40a plantation is the maximum and the 18a is the minimum.From the start time of seed rain to next April,the total amount of siol seed bank was reduced by 42.34% to 53.59% in five different forest;Vacant seed had increased by 26.72% to 48.69%;from April to august,the seed rot rate had increased from 10.28%-13.62% to 57.25%-63.28%.The main reasons for the seed bank lost were animal transportation,animal feeding and seed decay.The seed of Pinus tabulaeformis Carr was mainly located at litter lever and the soil depth of 0-2 cm and 2-10 cm were less than that of the litter lever.In the middle of August,98.26% seeds of Pinus tabulaeformis Carr.was inactive.In different stands,the density of the seedling of Pinus tabulaeformis Carr.were significant different,followed as 40a plantation,29a p

关 键 词：油松人工林 种子雨 土壤种子库 黄土丘陵区 

分 类 号：S791.254[农业科学—林木遗传育种] S714[农业科学—林学]